The Iconic American WW2 Thompson: the M1A1

[@terry7907]

“The government said the drum mag is fine for the civilian market”… My, how times have changed.

[@Chaddlee]

Al Capone was technically a civilian, so you can see their point.

[@robertwilson8184]

Same general timeframe they argued short barreled rifles, short barreled shotguns, and suppressors were justified to be heavily regulated because they "have no military application, and thus no place in the militia."

[@johnnytyler5685]

@@robertwilson8184 If that is truly the argument that was used to make SBRs, SBSs and suppressors part of the NFA, then it shocks me a little bit that none of these modern pro-gun groups who litigate against all of our modern, unconstitutional "gun control" have filed lawsuits to get those items removed from the NFA list IMMEDIATELY. Because if the argument that GOT those items onto the NFA list was that they "had no military application and thus no place in the militia", then getting them OFF of the NFA list should be as simple as saying "every single one of those items has EXTENSIVE military applications today and therefore they should be removed immediately as 'the militia' should have easy access to them". Short barreled shotguns may not be used extensively by the military, but short barreled rifles and suppressors are BOTH used EXTENSIVELY by our modern military.

[@robertwilson8184]

@@johnnytyler5685 I absolutely concur with your sentiments. Unfortunately we have allowed nearly 100 years of precedence to be established by this point. It’s an uphill battle. In my opinion, all we need is one phrase: *Shall not be infringed.*

[@pzyqux6641]

@@johnnytyler5685 Now they have changed their reasoning to why they want those guns gone. The philosophy of gun-controllers is that a militia should not exist, as they want to rely on the government for safety (like people did before the american evolution). You can argue that it is a stupid philosophy as much as you want and i would probably agree with you, but that is what they think. They are scared that short barreled rifles might be concealed easily, that full-auto weapons have too much destructive power for "a civilian" or that suppressors could let someone attack you without making noise (these people, with few exceptions usually base their gun knowledge from movies). I am afraid that talking about a militia is just going to make the gun-controllers put their fingers in the ears and scream. They do not want to listen.

[@zendell37]

"I'm sorry I don't have the rarest version of these guns on hand to show you something very slightly different than a previous version". That's alright Ian. We forgive you. Just don't let it happen again.

[@abhishekjrp13]

😂😂😂

[@LostShipMate]

Which is weird since he has at least 3 more behind him, and probably a few hundred more on hand. bad luck I guess.

[@ethanjohnson2548]

@@LostShipMate The three behind him are almost certainly the ones used in the previous Thompson videos. He films several at a whack, not just one and go home. If you look at the last Thompson video, the middle Thompson is replaced by the one in this video, identifiable by the Kerr sling.

[@Lowlandlord]

As I was watching I was like, "It's okay Ian, I believe you that this is almost exactly the same on the other one, you don't need to show me for me to believe you".

[@billmccrackin8825]

Cue the “never used” fireplace collection.

[@beast0339]

When I was a kid, my grandad was a woodcarver. and one day, when we'd visited my grandparents in France, he and my dad put together a wooden M1A1 Thomson for me to play with after we had all gone as a family to see the beaches at Normandie, I spent many hours of my time in the countryside running around with it, eventually my grandad gave it away to a young French farmboy who lived across the way from them. Never saw it again after that, so I hope he got as much enjoyment out of it as I once did.

[@LilPistachiofr]

Thats so wholesome I cant🥺

[@sulla175]

At first I thought Ian said "drum magazines were fine for the Sicilian market." It turns out they agreed.

[@Buljbasaur]

Ah, the days when the perfect gun for the civilian market is a 50 round sub machine gun originally called the Annihilator.

[@anthonyhayes1267]

@chris younts Australian farmers dealing with alternating waves of emus and rabbits would appreciate that kind of firepower

[@JumboSherman]

Gun control but epic

[@hfarthingt]

The freedom the second amendment guarantees

[@ryanjackson1999]

those were simpler times

[@clownworld4655]

As it should be. Damn atf

[@thisnicklldo]

I'm no gun guy, but I do like engineering, and history. Your channel is outstanding for both content and production. Thank you, very interesting series.

[@Darelumga]

This is why am here, too.

[@kam_iko]

same here. don‘t own (or plan to) a gun & never fired one, but i watch (almost) every video that comes out. (for the engineering & history)

[@MD-zf5yy]

I enjoy guns but don't own any. I'm with you and am here mostly for the fascinating history and engineering on a lot of the ones Ian showcases.

[@DgtlOutcst]

I too watch for these reasons. Though I would love to own a gun my country's laws and lack of "gun culture" basically means that won't happen.

[@cliftonjames785]

I love guns, but I only own a pistol. If I could, I'd own like a dozen firearms lol however, it wasn't video games or movies or my countries gun culture that got me interested in guns, it's the history and engineering that fascinates me. I especially love ww2 era semi auto rifles and bolt guns. If you ever get the chance to fire a gun, take it! Even if you're against owning guns

[@DiezALOT3128]

1940s tank: M4A1 gun: M1A1 2000s tank: M1A1 gun: M4A1 i love it when things work out like that.

[@wd4030]

Diez ALOT Illuminati confirmed

[@SuperFunkmachine]

M1 was as a ton of things, guns, tanks, planes, mortars, helmets.

[@sargesacker2599]

Cold War Tank: M60 Gun: M60

[@kaziklubey966]

I wonder how many gluttonous Muricans died because they put an m60 mg at some point instead of an m60 tank hahahahah

[@kaziklubey966]

Americans may have banged my mom on call of duty but they couldn't invade any small sized country in the world.

[@unbearifiedbear1885]

Every American service weapon ever: "Nice. What shall we call it?" *"M1."*

[@JR7noir]

Mk1

[@Thebuzzki11er]

More like every piece of gear and land vehicle.

[@ramal5708]

In supply depot: Soldier: Sarge I need ammo for M1s Supply Sergeant: Which M1? Soldier: All of it

[@Caseytify]

"If you hit it, you can name it." CRAAAACK!!! {home run} "I call it the masturbater."

[@garrisonnichols7372]

M1 for Americans because the Germans took all the cool names already

[@scottishtargetshooter6664]

Hi Ian. I'd just like to say that I really enjoyed the series about the Thompson sub guns. Many years ago an old ex-soldier regaled a bunch of us with tales of the Thompson that he carried in to action while he served with the Royal Tank Corp. Johnny alway said that he loved the Thompson for its accuracy on single shot, its hard hitting bullet and its relibability. He told us once that the only reason he didn't end up either dead or a POW was because he was issued with a Thompson so that when the tank was hit and the crew bailed out and took cover he was able, along with his mates, to keep the enemy at bay until they were relieved. Thanks again for the interesting series.

[@darthtruk7206]

The M1A1 Thompson has always been my dream gun. There is just something about it, just absolutely beautiful....

[@FishHeadly1]

Same here, been in love with the Thompson since I was a kid.

[@Tarik360]

The minimalism of it really does it eh?

[@Zoddom]

Weapons in and of themselves are not meant to look good. Which is why my favourite aircraft is the A-10C and my favourite tank is the M4A3E8. Theyre ugly but they fucking excel at what they were designed for.

[@darthtruk7206]

@@Zoddom couldn't agree more. I agree with you on the M4A3E8 being the most beautiful battle tank, but my favorite aircraft is the Hawker Typhoon. Not the most beautiful but it sure as hell was an awesome ground attack aircraft.

[@orangelion03]

My brother still has the "replica" Thompson he bought with lawn-mowing money in the 70s.

[@keithsimpson2685]

The grip on a Thompson is so weirdly good. Perfect palm swell and angle for such an expedient version.

[@B2091]

Nice video, very in-depth. Such a good looking gun I managed to pick up a M1A1 a few years ago. It has the A1 hand stamp and low serial number. What sold me on it was the British broad arrow stamp on the receiver. Also has re-mounted British sling swivels for British/Commonwealth use.

[@ultrablue2]

Ian, you did a fantastic job of detailing the differences between the different Thompsons and telling it’s evolution. It will be wonderful to see all of them shot back to back and get your impressions of the experience.

[@NiloWafer19]

The three most wonderful days in my future I look most forward to: - My wedding day - The birth of my first child - The day I purchase an M1A1 Thompson for myself (Not necessarily in that order)

[@MrJhonnyJackson]

You're assuming you will have a child. Which means you're assuming you will get laid....... optimistic i say

[@jigsaws02]

same

[@DK-nv9zu]

Move M1A1 up to the front of that list. Once a wife and kid(s) enters the equation, toys fall a few notches on the list of priorities

[@teaser6089]

@@MrJhonnyJackson Technically you don't need to get laid to get a kid, just saying :P

[@NiloWafer19]

@@MrJhonnyJackson Well, since I'm getting married in 20 days now, I'd assume so.

[@USSEnterpriseA1701]

For anyone that is curious, the current production semi-auto guns are internally more or less based off of the M1 type bolt with a really long separate firing pin/striker added. It and it's spring do take the place of the single central recoil spring, so two more recoil springs are added AR-18 style to what would be the buffer plate in the gun shown here. It's not a great system for accurate shooting, with a lock time similar to a flintlock rifle (well, at least a flintlock on a good day when the pan lights right away), but that's not really the point of them anyway. Another interesting note about them is that the bolt is the same for either the M1A1-lookalike variant or the 1928-lookalike variant. The bolt has two perpendicular holes in it to accept either a side or top mounted bolt handle, of course which one it uses is determined by the receiver type, but it's kind of a neat simplification that results in interchangeability.

[@SgtStinger]

The felt buffer pad delete would also increase the ROF since the felt absorbs some of the energy in the bolt while the rubber buffer is more springy and makes the bolt retain more of the energy when it bounces against the back of the receiver.

[@jballew2239]

The felt oiler pads were of dubious value overall. With the Blish lock they may have had some function, but post 28A1, they were useless. The loss of the closure actuated firing pin though..The move to a fixed firing pin surely saved time and cost, but it was definitely a step down in safety.

[@SgtStinger]

They are not oiler pads. They are recoil absorption pads.

[@jballew2239]

On either side of the bolt on the 28A1 and earlier? You'd better check a manual. Those are oiler pads.

[@sarodimin]

I'm curious if that hammer assembly worked as an accelerator. You've got a lever multiplying the force from the bolt slamming forward, whereas the fixed pin has no multiplier and is scrubbing more energy from the bolt as it hits the primer. We can apply more kinetic energy with a lever in the action. Say the hammer only multiplies the force by 1.3 times, which is doable in that kind of space, that'd make a good bit of sense all things considered. Base fire rate without the hammer: ~700 rpm With hammer: ~900 rpm 700*1.3=910 rpm It might be slightly higher on the multiplier but the frictional losses from the mechanism itself are probably decently high I'd think.

[@jballew2239]

Unlikely, as the triangular "hammer" had to both pivot, and work against a spring loaded firing pin. You could not expect any primer kick either, as U.S. .45 ACP of the day was securely crimped.

[@gonephishing]

ahah, some engineer sure got his/her ego checked when they removed the lock and it functioned just fine.

[@Tunkkis]

That would be mister Blish, though he might have had his ego already whacked by the failure of the Thompson Autorifle, which also utilized the "Blish principal" in its "locking system". In reality it functioned as a glorified delayed blowback in a full power rifle round. Issues followed, quite unsurprisingly.

[@chuckaddison5134]

Mr. Blish originally developed the lock for naval artillery. I seem to have read somewhere that it actually worked there. Being an early application of static friction or stiction. However, the pressures and dwell times are substantially higher in guns with cailbers in inches rather than fractions of an inch.

[@teaser6089]

@@chuckaddison5134 The problem is that the Blish prinsiple isn't a thing. There is friction alright, but it's not created in the way the Blish Prinsiple discribes it :)

[@johnkelinske1449]

Problem is, you can't just remove the lock, the gun as orginally designed and made won't function without it.

[@erikbukovac5944]

@@johnkelinske1449 pretty sure it would work, but it would have a higher ROF just like the m1 model. the blish "lock" was just delaying the action, it wasnt doing anything critical to the operation of the gun

[@engineer_cat]

the only downside to watching future videos today is that I won't have new Forgotten Weapons content tomorrow :'(

[@alexanderm3504]

Time travel!?!

[@_Nyx_]

@@alexanderm3504 Patreon supporters get early access to videos

[@ianmacfarlane1241]

You could watch 'Remembered Weapons' 😉

[@engineer_cat]

Ninjava true, but that’s not how I found it. When the first in the series went live, there was a link to the second at the end of it, and from there to the third, and so on.

[@gregormiller4037]

Jessi...just use the transport in the Enterprise.

[@LeFeuauxpoudres]

I'm always surprised with each episode on how Ian can memorize all this history on every single gun.. Awesome work!

[@GatCat]

Testing for Thompson: “yep, alright, looks good.” Testing for modern infantry weapons: “Washington, we need another 10 years and $10billion…”

[@brentfarvors192]

Soldiers in deployment: Brings their own M4...

[@garypiont6114]

Thankyou Ian. Great vid.😅

[@troy9477]

I always thought the rate of fire went down a bit when they went to blowback. Guess not. Fantastic series. Excellent job explaining the differences and changes. I have long been a Thompson fan. Great to see them all together for more thorough explanation. Great video as always. Thank you

[@johnc2438]

I was assigned to the Seabees in Vietnam (1970 - 1971) and was pleasantly surprised to find that some teams still had Thompsons at the team sites in the Mekong Delta. They'd typically unscrew the rear stocks so they could easily stow them -- and grab them quickly if needed -- in jeeps, trucks, and heavy equipment they used while on the road or on the job. I learned to take it apart, clean it, and reassemble and fire it when I visited the team in Ben Tre City in late 1970. I have a couple of old pics of me firing one (sans rear stock) and an M2 carbine (a full-auto-capable version of the M1 carbine). Easy to shoot and clean! And it used the same ammo as our sidearms, too. 😎

[@jeyendeoso]

Ian i really love these series of videos on a model development, such as the berthiers, the winchester lever action development and now the thompsons. I have always tried reading about the difference in each model, but its always so confusing and not simple and straight forward like you show us. Thank you, thank you so much.

[@TuShan18]

In my humble opinion, the thompson is the most beautiful smg ever made.

[@kitemanmusic]

Savage ruined the beautiful design. They had to, of course.

[@anthonyhayes1267]

My choice would be the mp-34

[@rbgerald2469]

PPSH-41?

[@MasterTaters]

@@kitemanmusic I think that it looks neater.

[@LilPistachiofr]

Alongside with the suomi m31 imo

[@lasers4less]

This was my dad's WW2 issue weapon. He used to carry a German MP40- MP42 in n Africa Italy as was shorter with stock folded. He used to clamber in & out of Canadian desert rats Sherman's grants often as was REME regiment. Officers were ok as long as you carried something effective he said plus he was Staff sergeant in no time.

[@richardjohnson4238]

Good video Ian. I've wanted a Thompson since I watched "Chip Saunders" use one in "Combat" the long running TV series in the 60's. I was finally able to achieve that dream when I purchased one a few weeks ago...sort of. This one is made my Uramex, and shoots BB's, but I figure it's about as close as I'll ever come to the real thing.

[@ericmitchell985]

The only thing I can think of with the hammer increasing the rate of fire is that, when the bolt slams closed and actuates the hammer, the action of the firing pin being shoved forward is applying an equivalent force backwards on the bolt, making it open just a little bit earlier. That is, it's kind of acting like an accelerator lever, simulating a sort-of intentional bolt bounce.

[@stephenmartin8331]

The hammer and firing pin in the M1 allowed for the round to be fully seated in the chamber when the round was fired. The fixed firing pin in the M1A1 would set off the round a fraction before fully seating the round, causing the bolt to decelerate on the final part of movement forward. This meant that some energy was expended slowing the bolt when moving forward, instead of all the energy being used to cycle the bolt rearward, That's why the rate of fire went down when the fixed firing pin was adopted.

[@Elong_Musket]

The precursor to the M41A pulse rifle in all its glory.

[@cliftonjames785]

@@exploderish nah... it's like a weird slavic version of the mp40. I'm not saying it's a bad smg, it's just ugly as hell lol function over looks though I guess

[@XanderTuron]

@@cliftonjames785 I think he may have been referring to the the USCM M56 Smartgun from Aliens.

[@waynehindes3396]

10mm explosive tip, standard light armor piercing ammo. Might have the movie a few times and I love the m41a Semper Fi

[@Feiora]

@Sarge Thebandit01 Lotsa people love the M41A! Its my fav scifi gun and I tend to use mods that bring it with accurate sound files and everything into the games I dabble in... All cause I watched the Alien franchise as a kid and fell in love with that sound... (I like the Smartgun too, M56?)

[@Feiora]

@@XanderTuron That was so much fun to use on Colonial Marines! Yes ya lil inky skinned freaks go ahead and crawl all over the place cause my rounds are still gonna find ya!

[@fab006]

Wow. I am actually very impressed by the amount of simplification that went into this one!

[@akjeff64]

Went to an older guys house to do some cable work, we started talking about the military, turns out he was a WWII vet, and pulled a box from under his bed and inside was a Tommy Gun, beautiful weapon!

[@geneladner8123]

Apparently I'm going to have to get used to the fact that EVERY one of this guy's videos are AWESOME! Yet another excellent presentation by an excellent PRESENTER!

[@Shapecharge08]

By still having the bolt hold-open on the M1A1, it invalidates all of its corresponding reloading animations in video games.

[@prd6617]

well the dev need to make some(many) change so the game would be balance... most common that i found on older fps game, fn p90 have same damage as 9mm smg, slow reloading speed and slow rate of fire compare to other 9mm smg like hk mp5a series. in reality p90 have more rate of fire and more power on the bullet than 9mm

[@GuillePtZ]

Day of Infamy took that into account :)

[@Halinspark]

@William Halter What if you're in a vehicle all day? It wasn't meant for people who could just carry a rifle.

[@donwyoming1936]

When FN brought out the P90s for us to play with back in 1990, they pitched them as a replacement for the M9s gate guards were packing. Submachineguns were already being phased out. If vehicle crews absolutely had to have a compact weapon, M231s were readily available.

[@Bagheera2]

@William Halter I had no idea the armor they used could stop 7.62 NATO. I thought it was mostly for shrapnel and lower power rounds.

[@finaloption...]

I would have to call that a successful series bud. You have fulfilled my quest for knowledge on these wonderful machines! Keep up the great work.

[@Phil-ey6yh]

Even 3 years later, i still love this series. Very, VERY informative!

[@dongilleo9743]

I always wanted to have a Thompson SMG, having grown as a kid in the 1960s up watching the Sargeant on the TV show Combat carrying one. That was an unfulfilled dream. I also had a yearning for an M-1 Carbine, after watching Gregory Peck carry one in the movie Pork Chop Hill. I eventually bought two, and a Ruger Blackhawk in .30 Carbine to go with them. All are long gone now from when I had to downsize. I imagine a lot of firearm owners have similar stories of TV shows or movies that peaked their interest in some certain gun.

[@vladimirmarecek6971]

"The stock is permanently screwed." Same...

[@paulswickard7488]

I bought a 1927 K for Christmas last year. Best gift ever. Keep us informed Ian .

[@michaels5210]

Was so pumped when you said there was going to be a whole series of vids dedicated to the Thompson.

[@dalecomer5951]

Nice job. My company in Vietnam had a mint condition M1A1 in its original wood case with all the accessories. Before my time there the CO and some of the other officers and senior NCO took it to the local "range" (wide spot in the river). The fact that no rank and file were invited didn't help the popularity of the CO. Many felt a few E-5 and below could have been included if only as a form of recognition for those who had been doing their jobs well. There was some lingering resentment and the story became part of the unit lore. There were no range outings for Mr. Thompson in my time there. We were allowed to look at it in the case but only the armorer was allowed to touch it. He cleaned it once a month anyway. Iconic isn't the word for it.

[@no1DdC]

Anyone else noticed that the safety selector switch has visible wear, whereas the full auto / single shot selector looks almost unused? It's unsurprising, but still interesting.

[@Ironman1o1]

Not shocking. Any time a situation called for accurate single shot fire, it was likely better handled by someone with a M1 Carbine, or Garand

[@RyTrapp0]

@@Ironman1o1 Yup, don't want the full boogy guys wasting their valuable ammunition

[@WalterBurton]

Unsurprising, but still interesting. I hear you. Yes. You are not alone. Or should that be, "No, you are not alone?" lol

[@stevewilson4514]

With the lower rate of fire and the fact it’s a close range weapon I’m sure the soldiers and Marines were able to develop trigger control that allows them to get off either a single round or two shot burst.

[@nuancolar7304]

Another recognizable change in the military version was the discontinuation of the Cutts compensator that was so prominent on the 1928A1 models. The compensator made for an attractive addition to the gun, but I’m sure those took a lot of time to mill and likely added greatly to the cost.

[@LoneRanger869]

Hey Ian, for your next Forgotten Weapons t-shirt perhaps consider the Blish Principle/Lock patent. 😄👍🏻

[@StanislavG.]

That's a cool idea actualy

[@willsmith1170]

Lone Ranger I agree! ☝️ “forgotten nonsense “ 😂

[@GREENPUKE99]

As to the reduced firing rate in the fixed firing pin M1A1, look up "Advance Primer Ignition". Basically the hammer fired M1 fired after the bolt had reached full forward travel leaving only the weight of the bolt and spring tension to be overcome to move the bolt backward, while the fixed firing pin of the M1A1 fires the primer while the bolt is still moving forward adding forward momentum to the bolt weight and spring tension as forces to be overcome to move the bolt rearward.

[@Robespierres_Ghost]

This Thomson series is so interesting. Would love more like this but few guns can justify a 4 part series.

[@WarMachine550]

Excellent series. All of your videos are excellent. The history and mechanical explanations are top notch. You should have a show on the history or discovery channel.

[@jagx234]

The evolution of series are my favorites.

[@ForgedHistory]

You are literally keeping the flame alive for all us gun nerds! Long may your channel bring us goosebumps on a daily basis!!!

[@mikegrandbois7204]

I've personally looked at the rarest Thompson. Savage Aluminum receiver prototype Thompson. Ian needs to do that video! Only 3 in existence I'm told.

[@samuelclayton4405]

Thanks Ian. Interesting series. When I was young I qualified with an M-3a1. In 1976. Always wanted to fire a Thompson.

[@joshboy1st]

I have a deactivated M1 Thompson here in the UK Ian, my one is a true M1 not an a1, 173949, was told mine was on a Russian lend lease contract, mint unused condition lol, but all welded up heavy paper weight sadly ):

[@PERK-30]

Leave Britain now if you enjoy having rights.

[@DerLoladin]

A neat piece of history regardless. You ever considered using the serial number to look more into the history of the batch that it came out of?

[@DerLoladin]

Squid Master reactivating guns in the UK is almost impossible when done to the UK standard and also highly illegal.

[@joshboy1st]

@@DerLoladin thats correct inposs to bring it back plus very much against the law. Mines 1942 dated all i no.

[@joshboy1st]

@@PERK-30 if i could leave now i would. Dream would be working for colt or somthing buiding firearms.

[@sthenzel]

The Blish lock and its principle may not have worked as intended or thought, but in the configuration it provided a delayed blowback. the first 1/4" or so of bolt travel compresses the main spring much more, maybe 1/2", this reduced the ROF substantially. With the actuated firing pin, the pin hits the primer at about double the speed of the bolt, by that the primer most likely got off a tiny bit earlier than with the fixed firing pin. To develop this thought a little further it would be necessary to know if the moving firing pin has a little overtravel and by that can protrude a little further out of the bolt face when accelerated by the "hammer", this would explain the earlier primer ignition even more.

[@HellbirdIV]

It's interesting how much changed in the "iconic" Thompson gun over the ~30 years it was in the limelight. The only thing that really remained intact was the external shape of the receiver and its caliber, with everything else being changed: the Annihilator had no stock, the later models did, the finned barrels were removed on the M1928A1 and the front grip, the sights and controls changed, then finally with the M1 and M1A1 you completely change out the internals and the magazine well to no longer take drums. By the end of it all, the WW2 Thompson is farther from the 1919 model than the MP40 and Sten guns are to one-another. Besides the overall form factor, it's actually a completely different gun, sort of the way that the Czech vz. 58 looks somewhat like an AK but isn't at all.

[@recoilrob324]

Using a fixed firing pin can take advantage of 'advanced primer ignition' where the cartridge is actually being fired while the bolt is still moving forward a bit. The hammer version of bolt fires once the bolt is fully forward so does not use the advanced ignition to delay opening. API can also use a lighter action spring taking advantage of the bolt forward inertia to keep it closed long enough. Comparing the action springs of a full auto Thompson to one of the semi clones shows this very dramatically....the semi's are quite stiff to rack where the full autos are very easy.

[@wasdwazd]

The Army really loved their M1 designation.

[@justinfletcher7630]

Those 21s and 28s with the sights and bluing were such a sharp looking gun

[@WillN2Go1]

This is a very interesting series, thank you. re: The increased rate of fire of the earlier hammer models. It appears that there's about a 1:2 lever with the hammer mechanism, meaning the distance from the pivot to the firing pin is twice the distance of the pivot to where the bump hits. This would move the firing pin forward at twice the speed of the receiver block (it would also reduce the amount of force by half....but this and other factors probably don't matter). This would of course only affect the timing of the last bit of travel of the receiver. The Blish Patent. Dissimilar metals. I've never heard it expressed as reducing the coefficient of friction. I think you said that this was not correct. Where I learned about this is when I put a motor on a steel Acme threaded rod (to use it as a lead screw) to drive a steel nut to move an easel up and down. It would randomly seize up. No amount or type of lubricant made any difference. Peter Carlson (he guy who made all those big balloon dogs for Jeff Koons) suggested I replace the steel nut with a bronze nut. There's something about the atomic structure of the elements that causes this. But if you simply used a different metal the atomic structure could never line up and so it would never seize. Lubrication at this point didn't matter. Did you mention gangsters use of the Thompson? I think there were two notable uses, that of course appear in dozens of movies (so I could have my reading of history completely distorted by the movies I've seen). The St Valentine's Day Massacre and a notorious very public drive-by, or drive-up (or series of these) when Al Capone's gang was consolidating bootleg territories also in Chicago. I can see why the movies loved the Thompson, it made a lot of noise, you could use live ammo to shoot up a store front, prop car and the results would show up well on film. Also the face of the movie star everybody came to see wasn't tucked down cheek against a rifle stock.

[@Tonetwisters]

Not forgotten by this old man ... Incredible machines. I'd love to own one ...

[@starfleethastanks]

I'm coming off binging The Man in the High Castle by binging Ian's Thompson series. This is great.

[@RTC_Sam]

I'm about midway through season three, myself. And heavily lookin' forward to finishing it later! Without spoiling anything, how is the rest of the season?

[@taccovert4]

Possible reason for the RoF slowing down: The Fixed Firing Pin is only impacting the cartridge with enough force to detonate the primer once the bolt has completed its travel into battery. The mobile firing pin with that hammer-ish thing driving it could have been striking the primer ever so slightly out of battery.....the weight of the bolt still slamming it home before pressure buildup got great enough to make it problematic, but that would in a way appreciably accelerate the firing cycle if it's starting early.

[@Owlpunk]

Ahh, imagine how in the future, on October 10th or so, we will reminisce about this video.

[@spankmedaddytrump5612]

Its been nearly 2 years and its my first time watching this haha. Weird seeing comments like this coz you will reminisce bit I will be awed

[@Wehrmacht3GD]

Thanks for making this mini series Ian.

[@nerfensaege11]

Uploaded on the 17th of September hehe somebody has been uploading videos to yt while keeping them private

[@ender25ish]

Fascinating series, really enlightening about the Thompson, certainly a lot of things that i didn't know. Great job Ian.

[@ralphh4131]

The wood is so beautiful. I love the dark stain. I'd hate to be on the other end of that gun.

[@ewathoughts8476]

The M1 hammer/firing pin linkage absorbs some of the bolt forward energy as the hammer lever strikes the receiver. Therefore the bolt forward speed (inertia) is reduced as the chamber pressure comes up. This means the bolt provides less holding force at firing, and thus is propelled to the rear faster. The M1A1 firing pin contacts the primer about 50 thousands before the bolt is fully home at full speed (inertia) and thus the cartridge pressure has somewhat more energy to overcome to start the bolt backward. Simple physics. M1 bolt is slightly lighter than the M1A1 bolt as well as the A1 is not hollowed out for a firing pin and spring.

[@Dirt_McGurt]

Double time travel today!

[@cre8ivecat23]

Dirt McGurt hell yeah my man

[@fatehkhan9269]

How

[@alexanderm3504]

So the Philadelphia Experiment was real!?

[@Jamie-dw2jj]

All hail the gun JESUS 🤗 let us embrace his teaching 🤗

[@EmpPeng2k7]

Fascinating series, love it when you do these the L85/86 was another series I enjoyed

[@jimmydesouza4375]

I wonder why they didn't reduce the thickness of the walls of the upper receiver in the M1 to reduce weight. Since it doesnt need the grooves cut in to it any more it didnt need to be thick enough to still have enough metal to stay intact with the grooves...

[@Vorse_Raider]

Reducing the thickness of the receiver would require pretty extensive testing to it everything attached to it. The receiver is the frame of the gun, and compatibility of parts may be affected. The whole gun may require new tooling to be built. All that could require production of new Thompsons to be stopped as they switch over and the military certainly wouldn't want that. Regardless of how much they reduce the weight, it would always weigh more and be more expensive than the M3's stamped design.

[@buddafingaz9403]

Got both the M1A1, & also the M1928 Chicago Typewriter, as well for Airsoft AEG. They're both all metal bodies, & real wood where needed. I absolutely love them. And their both Semi/Fully Automatic, & are both licensed, & numbered from Thompson, & Auto Ordinance, out of Worcester, Massachusetts. Awesomeness, great video my friend, would absolutely love to own a real one someday 👍💪🙏

[@sean7456]

7:35 "George E. Goll, I believe he was a .... SAVAGE inspector." *cue airhorn*

[@thecorbies]

Hi Ian. I've really enjoyed this Thompson series - thank you. I am also extremely impressed at the way you deliver ALL your videos, in that you really seem to 'know your stuff'. Meaning, that you don't have to check with cue cards or similar, it's all knowledge that is 'in there' - presumably because of your deep rooted interest in firearms. Regards Mark in the UK

[@sirtornado2938]

“Pass me the m1a1” “Which one the bazooka the rifle or smg?”

[@bonedoctor1]

Don't forget the M1A1 paratrooper carbine.

[@shootymcshootfacekoff7972]

@@bonedoctor1 or the Abrams mbt

[@garypiont6114]

Combat the TV show is on it

[@drobb4207]

Ian, my dad carried one along with his 1911. He was an Air Commando glider pilot in Burma, China and India. He kept 1000 rounds and a half case of grenades under his seat. He never spoke of his service until his 70's. He spoke highly of those weapons. Dad would have liked you.

[@matthayward7889]

Normally I’m a guy that like the original version of anything, but this is definitely my favourite Thompson 👍

[@DonMeaker]

I suggest the M1A1 bolt sets off the primer slightly before the bolt has stopped, so some of the recoil/direct gas pressure is used to stop the bolt, with the remaining gas cycling the bolt. 'Advanced Primer Ignition' is what it was called by Oerlikon, or in the L2A3 Sterling. In an API blowback, they first have to do the work of overcoming forward momentum to arrest the forward motion of the bolt. Because the forward and rearward speeds of the bolt tend to be approximately the same, the true API blowback allows the weight of the bolt to be halved, or if completely API, calculations for the rate of fire could be made with 2x the weight of the bolt, which would lower the rate of fire by square root of 2, from 900rpm to 636 rpm. compared to the M1 bolt that had come to a complete stop, and set the primer off by a hammer and firing pin. Since the primer ignition in the M1A1 occurred late, some of the bolt motion was not stopped by the cartridge recoil, that is, it wasn't completely API, so the rate of fire would be slightly higher than that.

[@JohnCenaRektU]

Ian, would you like to get 3 more people with you and do some gangster-like shooting of an old rusty car, for example, firing all 4 Thompsons at the same time?

[@unbearifiedbear1885]

With hats, coats and cigars White walled tyres optional

[@neutronalchemist3241]

There are three possible reasons why the ROF slowed down when they adopted the fixed firing pin. 1) Rebound. In the previous model, when the cartridge was fired, and started pushing rearward, the bolt already rebounded vs the receiver and was slightly retreating, so the recoil found less resistance. 2) Advanced primer ignition. The fixed firing pin fired the primer when the cartridge was still seating, and so the bolt was still pushing forward due to inertia. So part of the recoil energy was used to stop the bolt. 3) The hammer spring. It was compressed when the bolt was pushed forward, so it aided the rearward movement.

[@brucebaxter6923]

Wonder if the primer ignition rates were different with the fixed vs floating firing pin? Depth of dent or something?

[@GeneralChangFromDanang]

I'm wondering if maybe it took a little time for the casing to unstick itself from the fixed firing pin on ejection. Seems kinda far fetched though.

[@Winterydee]

If you're wondering as why the M1 version had a higher cyclical rate of fire then M1A1 version, the following is most likely the reason why. The difference in rate is due to the hammer style firing pin(M1 version) activating before the round is fully seated in the barrel of the weapon and starting the whole cycling process sooner. In the pure blowback bolt with fixed firing pin(M1A1 version) the cycling does not start till after the whole bolt has finished moving all the way forward and the round is fully seated. Because of this it is adding a small amount of extra distance before the cycling process begins again, along with an additional amount of extra friction from the round being fully seated to overcome.

[@DaemonPrimarch]

How deep does this rabbit hole go?!

[@shadowcaster1159]

Probably my favorite smg with the stick mag preferably without the front hand grip looks very nice

[@Mongo63a]

Interesting that the M1 and A1 ROF change between them. I can't think of a reason there should be that much of a difference between them.

[@dividedbyzero96]

Possibly the force of firing acting on the firing pin, pushing back on the hammer causing it to act as a sort of bolt accelerator. Obviously just a wild guess.

[@Mongo63a]

Actually you might have some thing there.

[@G0ldbl4e]

I think the Blish lock is acting as a lever delayed blowback, it's forcing that heavy block on the actuator to move to the rear of the bolt faster in the same way a lever-delayed blowback gun works. 13:07, compare to this picture of a lever delayed gun 1.bp.blogspot.com/-Kwi5ArzCa8k/UbLPzbu3EnI/AAAAAAAABpw/NkMOcLqTsMU/s400/lever-delayed-action-animation.gif

[@ABCKorpi]

My guess would be that with the floating firing pin, as soon as the lever is tripped, the round is fired. Whereas with the fixed firing pin the casing has to get further into the chamber gradually increasing friction and bleeding velocity from the bolt. When the force exerted on the primer is finally big enough to fire the round, the bolt will have notably slowed down and travelled a bit longer. Just speculation here too but that to me sounds most plausible.

[@joekahno]

Actually, many guns using a fixed firing pin crush the primer enough to fire the cartridge before it's fully chambered. Having to overcome the last of the forward inertia before rearward travel can begin gives an effect similar to having a heavier bolt.

[@SR-tn6gv]

As a emergency preparation engineer Ian I would say you called it correct. The minute resistance of the firing pin seating on impact is more than enough to alter the cyclic rate.

[@weeg91]

"I believe he was a SAVAGE inspector" 7:30

[@johnsears6077]

Connecticut pride, many Bosch were felled by the hand of Bridgeport CT

[@richardbell7678]

Does the hammer on the M1 bolt act as an accelerator driving the firing pin forward at a faster velocity than the bolt? That might explain the faster rate of fire of the M1 over the M1A1.

[@Treblaine]

It would just continue with its inertia. The overall effect would be to delay the fire rate a tiny amount as the bolt closes but there is a delay for the firing pin to continue forward with the same inertia. But there is a possibility the bolt is bouncing open at the exact moment the cartridge fires which may result in the fire rate increasing. This all depends on how good the ammunition is, whether there will be even the tiniest amount of delay between the primer strike and the powder fully igniting.

[@NoEdits704]

This series was fantastic. Thanks for doing this.

[@jonathanpresson777]

Ian, is the neck on the bolt more solid than with the fixed firing pin? Could that increase the weight enough to help in lowering the cyclic rate? Just a thought.

[@therealityspectrum-epictvp4988]

I just ran into your M1A1 Thompson review and break down. This was an absolutely outstanding presentation on this weapon -- the best I have ever seen. Great Job! I think I rather go into combat with a Thompson than an M3. At least if I run out of Ammo, it is strong and heavy enough to slug someone with.

[@michaelmckinnon1591]

M1A1 Commando actually 711 rpm from 1970

[@leanderjohnsen8339]

M1A1 vs M1 rate of fire pretty much comes down to the Advanced Primer Ignition Blowback principle vs pure blowback. When the primer is set off whilst the bolt is still moving forward, it will take longer time for the bolt to stop its forward motion and begin cycling rearwards due to the extra momentum and inertia from the bolt moving. This effectively increases dwell time and also gives more time for the chamber pressure to drop, this reduces the bolt velocity quite a bit compared to closed bolt pure blowback.

[@Winterydee]

The M1 version had a higher cyclical rate of 900 rounds per minute. The M1A1 had a lower cyclical rate of about 650 - 700 rounds per minute. This different in rate is due to the hammer style firing pin(M1 version) activating before the round is fully seated in the barrel of the weapon and starting the whole cycling process sooner. In the pure blowback bolt with fixed firing pin(M1A1 version) the cycling does not start till after the whole bolt has finished moving all the way forward and the round is fully seated. Because of this it is adding a small amount of extra distance before the cycling process begins again, along with an additional amount of extra friction from the round being fully seated to overcome.

[@KATAKOTO69]

That simplified disassembly makes me appreciate the pps 43 a lot more!

[@FixedWing82]

My guess is the rate of fire dropped slightly for the M1A1 vs M1 because the fixed A1 firing pin was pre-detonating the cartridge just slightly before the bolt had fully bottomed out, so the detonating round was offsetting some of the residual forward momentum of the bolt, which knocked rate of fire down just a hair. Whereas with the M1 and earlier guns, the firing pin doesn't fire a round until the bolt is fully bottomed out on the receiver. If I recall there are some machine gun designs that operate on this advanced detonation principle where the round is intentionally detonated while the bolt is still moving forward, as it offsets recoil somewhat... or maybe I just need to drink more coffee this morning

[@FrostyShock349]

the Oerlikon 20mm when not tuned up properly can have an out of battery detonation, bless the soul of the operator with a quick recovery

[@spoeny]

Advanced Primer Ignition. I think it was mostly on german WW2 aircraft cannons, if I remember correctly MG 151 and MK 108.

[@Insanerobert44]

I think you're right, the bolt on M1 series could enclose the bullet better after which the pin triggered the detonation of the bullet, which actually made the bullet and the bolt retraction slightly faster (would be nice to test it nowadays with high-speed sensors), compensating for the delay of the firing pin activation system. In comparison, the fixed pin on M1A1 would detonate the bullet just before it's movement course ended, doing exactly what you said. The micro-cavity made between the bullet and the bolt would actually delay the recoil enough to make the fire rate difference of 200 rounds/minute less than M1 series. In the same time, there should be a slight difference between accuracy patterns as well and I wonder if that was observed on the guns.

[@stephenkolasa9838]

When I was growing up in the late 1960's a friend of mine would bring his reproduction MP40 along when we would stage war games in the acreage behind our house. I remember thinking that this was the coolest subgun ever ! After firing both a Thompson and a MP40 ,the Thompson wins hands down because" coolness" doesn't count in a firefight ! My only other Thompson story takes place in 2011 in India.I was walking along the Lake road in Srinagar I came across a small Command post. Outside the post was a Sergeant with a Thompson slung across his back. The Thompson was minus its stock and burnished to a bright silver from having all its blueing worn off ! Still loved and in service after all those decades !

[@jimbob9714]

Patty Hearst will hear the burst ….. tomorrow

[@geegaw14]

Roland would be proud.

[@jacobzindel987]

I love that Warren Zevon songs are turning into memes now.

[@jacobzindel987]

@@geegaw14 van Owen will take care of that.

[@merylpelosi8485]

My father, a WWII vet told me many stories which dovetail with your excellent rendition. I was told a person could order one of these from Western Auto for around $225.00.

[@Name-ps9fx]

The M1 Thompson was “too expensive” at $43 each? I’m curious...how much did the Garand cost?

[@garrisonnichols7372]

$85 dollars per unit from Springfield Armory and $83 from Winchester. That's what the price given to US military in 1940. In 1945 the price dropped to $31 because the time and labor needed was cut in half.

[@garrisonnichols7372]

The problem with the Thompson was that it took more time to machine the receiver and it wasn't seen as such a necessary weapon compared to rifles and machine guns. Once the M3 Grease gun started being made in large numbers the production of Thompsons stopped altogether.

[@immikeurnot]

Not only was it expensive, it weighed as much as the M1 Garand. The Thompson was seriously outdated by the time WWII came around, even the "updated" versions. Shoot all the WWII SMGs in the same day and the Thompson will be the one that disappoints.

[@thomasfamilycomesfirst8389]

I have two deactivated WW2 Thompson SMG´s, one 1928A1 with Cutts compensator and one M1A1. The strange thing on the M1A1 is that there are the same "FIRE/SAFE" and "SINGLE/FULL AUTO" selector switches installed like on the 1928A1 model. There is also a serial number and manufacturer mis-match on the 1928A1. The serial number of the upper receiver is engraved on the trigger group by hand and the original serial number is crossed out, the upper receiver is from Auto-Ordonance and the trigger group is from Savage Arms, it could be a 1928A1 from Lend/Lease program with the Russians. They disassembled the Thompson, stored the parts and assembled it without looking for matching serial numbers. There are also no military inspector stamps on the M1A1. It would be interesting where the two Thompsons came from. I also would like to know why they changed the term "Calibre" on the 1928A1 to "Caliber" on the M1A1.

[@ljc7738]

For those who dont know how to see the todays video yesterday just support him on patreon and Marty Mcfly and the Doc will help you

[@benjaminabrams5000]

Great Scott!!!

[@bearhaslanded637]

I wonder if the floating firing pin acted like an accelerator on the M1, when the gun fires it pushes the firing pin back which pushes the hammer against the receiver giving the gun a faster initial kick and a higher rate of fire?