Why did Civil War bullets have grooves?

[@hickok45]

Very interesting! Thanks for researching this and sharing.

[@TheAbleBodiedSoldier]

Woah I didn’t you watched paper cartridges!

[@MMA10mm]

@Paper Cartridges - I’ve been a shooter, caster, commercial loader, civil war reenactor, WWII historian, handloader, and gun/ammunition researcher for 45 years, and you just taught me something new. My hat tips to you, sir!

[@papercartridges6705]

Thank you for the kind words of encouragement! Glad you enjoyed my niche subjects.

[@warskye5686]

Always learning something new. Great job

[@Maverick966]

​@@papercartridges6705 I have a question, why was the Pritchett bullet slightly more accurate than the Miniè bullet even without the grooves?

[@taofledermaus]

I also heard, or maybe just surmised, that the grooves also scraped out some of the black powder fouling as it travelled down the barrel. We saw some surprising things shooting .69 cal Minie' balls from a 12ga using a sabot. They had great stability through rifling with a spin but also were stabile shot through a smooth bore with no spin at all. The 725 grain Minies are quite unpleasant shooting from a 7.5 lb. shotgun.

[@lucarinaldichini324]

That's taofledermaus in the flesh and bones, guys!

[@papercartridges6705]

There may be an ancillary benefit to having multiple grooves to reduce fouling, but I have never encountered this reason in any of the period documentation, in English or French. Fouling is chiefly controlled by the grease softening the fouling of the precious shot, and then when the bullet expands upon firing, it drives out the fouling ahead of it. The sooner the bullet expands before it moves far down the barrel, the much better job it does scraping fouling. Properly sized bullets (2 thou under bore size) can be fired almost indefinitely.

[@astridingmarsdottir2400]

@@papercartridges6705 I think another aspect of the cannelures or grooves around the cylindrical section of the bullet is it slightly weakens the structural rigidity of the bullet. Initial gas pressure as the powder charge ignites, expands the base ring sufficiently to fill the rifling grooves and prevent blow-by; initial acceleration causes the bullet to slightly foreshorten, or upset into the rifling, thus establishing proper alignment of the bullet to the axis of the barrel.

[@normanbraslow7902]

No.

[@sinisterthoughts2896]

​@@lucarinaldichini324and?

[@treysmith8917]

you mean they aren't blood grooves?

[@neonjoe6180]

😂😂😂😂😂😂

[@mickeyholding7970]

You're probably aware but it's for engaging the rifling.

[@mathewgoebel4078]

You hit your target they may well be.

[@ungabunga6961]

@@mickeyholding7970 see the thing is, the whole point of rifling is to ensure the optimal alignment of the blood grooves.

[@genekrafft948]

No

[@natecofga4679]

Learned something new today. I thought for the longest time that those grooves were for the bullet to "catch" the rifling in the barrel. I figured that when the power was ignited, the grooves would expand to catch unto the rifling starting the bullets turning. I didn't even think about putting lube on the grooves for easy of loading either. Thanks for the info.

[@ranman7688]

Ok, seriously, I had to pause the video for a moment so I could collect myself after his "groovy" joke.

[@boingkster]

For providing a platform against which the air may stabilise the round in flight and also to reduce the friction present while driving the round down the barrel. The grooves were also thought to aid in clearing fouling by utilising their multiple bands to clear fouling more effectively than a plain based bullet.

[@skepticalbadger]

It's not a quiz.

[@rollotomasislawyer3405]

How about to grip the rifling and improve accuracy professor?

[@PhilipFear]

​@@rollotomasislawyer3405 The bullet could be a smaller diameter than the bore to make it easier to ram them down the barrel and expand out into the rifling when powder explodes behind the bullet's hollow base to force the back out into the rifling for the trip out of the barrel....

[@Ugly_German_Truths]

@@rollotomasislawyer3405 it would be counterproductive for that as it increases the way the material of the bullet "walls" has tob e moved to get that contact. A Minié ball is undercaliber until fired, then the expanding gasses widen the hollow at the end until the bullet gets pressed into the grooves. Early models had a "hat" at the end that was supposed to speed up that spreading motion, but it was later found out that just slightly enlarging the hollow worked even better.

[@ralphh.2200]

The grooves also thinned the sidewall of the bullet at the Ogave, allowing that area to more efficiently expand & better take the rifling at the moment of expansion... as well as providing a more complete seal, post ignition..Enjoyed your video very much.

[@normanbraslow7902]

Ballisticslly, you are right, all other theories to the contrary.

[@jameshoward8609]

You are exactly correct! Besides holding the lube the only reason the grooves are there are to allow the bullet to expand enough to contact the rifling on the inside of the barrel so that it will spin more accurately. Also there are alot of bullets still made with grooves on them. Almost every cast bullet still has them for lube and the same rifle engagement reasons. only plated bullets are not grooved.

[@ralphh.2200]

@@jameshoward8609 Back in the late 70s I bought full packages of originals at the bigger gun shows.They includes a Williams cleaner round and a paper pouch of about a dozen percussion caps. We have the same last name and I enjoyed your Kern River video.

[@yt.602]

Thanks for this definitive explanation for the grooves, I've seen many examples of the projectiles and never known the truth. Properly researched by the ammunition designer and by you for this video. Great explanation, very interesting, not at all boring.

[@RidgeRunner86]

In a nutshell, it places the aerodynamic center of pressure behind (aft) the center of gravity relative to the direction of flight. Think fletching on an arrow or fins on a rocket or a tuft of fibers on a blow-dart.

[@rollotomasislawyer3405]

Or... to impart spin to the projectile, improving the accuracy of the rifled musket.

[@PhilipFear]

It places DRAG to the rear of the bullet and thus stabilize flight....

[@MrKentaroMotoPI]

The instability is caused by the Mach-helix effect that occurs at low supersonic Mach numbers (described in 1950's missile aerodynamic textbooks). The Mach-helix effect moves the center-of-pressure forward. The circumferential grooves are oriented in the wrong direction to suppress the Mach-helix effect. The grooves, and the concave base, do move the center-of-gravity forward. The grooves also weaken the bullet aft structure and promote super-plastic material deformation. Rifling efficiency is thereby increased. Modern rifle bullets have shapes optimized to reduce wave drag above Mach 2 (e.g. .223). These shapes are too long to effect a center-of-gravity shift on, but the spin stabilization from higher rifling rotational speed (as pointed out in the video) counters the Mach-helix effect, as does the generally higher flight Mach numbers.

[@blankeny]

When I was a child living in Glenn Arm Maryland, we as kids dug lead balls circa 1860's out of trees and the balls had small dimples in them much like miniature golf balls...

[@stacybrown3714]

You found "chewed balls" believed to stabilize better in flight than their smooth counterparts. Methods of making them varied but the name came from biting them with the back teeth.

[@blankeny]

@@stacybrown3714 ok, but I truly feel bad for the individuals assigned this feat... I know that is why golf balls are dimpled!!!

[@pepealasquid6005]

​@@stacybrown3714best way to lead poisoning

[@MarkTurner-vs7uc]

I have one I found at Gettysburg as a child in the early seventies. Right out of the dirt. Still have it.

[@novagiantmedia1154]

Thanks for the video... good to know, I did always wonder about that. Now I know the whole history.

[@blackpowderburner7296]

Personally I fill them with peanut butter. The peanut oil it contains softens fouling and my shooting buddy is deathly allergic to peanuts so he never asks to try my rifle.

[@mahbriggs]

I am not very well versed in black powder weaponry. I had assumed that the groves were to help the mini ball skirt to expand and prevent gas blow by. Learned something new! Good subject, and a really interresting presentation!

[@rchydrozz751]

I also believe this. The back of the bullet is hollow. Gas pressure from the back, expands pushing outward into the rifling. Same as my pellet guns. The pellets are hollow in the back with a thin skirt, and expand from the co2 into the rifling. To help seal and spin for better accuracy.

[@leneanderthalien]

Minié ball, not "mini'"

[@mahbriggs]

@@leneanderthalien Commonly referred to as "mini" in official publications. Now you have learned something new!

[@owenlaprath4135]

I was never interested in the Civil War, but this is a fascinating morsel of engineering history!

[@Pappysan]

Americans are the only people in history that fought a war to end slavery! That war was the "Civil War!"

[@jamessandlin-hx9jp]

To improve acuracy and distance this war was revolutionary as far as battle went

[@okaro6595]

The original Minnié bullet had an iron plug in the base to cause the expansion. The bullet used in the Civil War that just had the hollow base was invented by James Burton. It made the manufacture much simpler.

[@Eduardo_Espinoza]

James Burton from donut media is more popular than i thot!!!

[@samcolt1079]

WRONG

[@asherdog9248]

An episode on the Gardner bullet would be interesting.

[@johnmckenna8989]

Very interesting, for sure.....It's akin to folks saying 'rifling' was invented to spin/stabilize bullets for accuracy, when in actual fact rifling was invented to 'capture' the fouling from black powder, working so well the grooves were lengthened by 'spiraling' them in the bore....spin/stabilization was just a surprise benefit.....Had many arguments over this one....lol John(west coast, Can.)

[@hnangell]

Thank you! Im convinced and seldom have such an impressive revelations, thank you again!

[@daveh9521]

The grooves were for expansion. I had a .58 Enfield for years (very fun to fire). The skirt grooves allowed compression and made an excellent seal in the barrel. This improved accuracy and spin with a better grip on the rifling. This compression can easily be observed on rounds that have been fired.

[@papercartridges6705]

Can you provide the source for your claim that the grooves are for expansion? I cited numerous 19th century period sources as evidence for my argument in my video. You may be confusing the Tamisier grooves on a Burton-Minie with the grooves on the Wilkinson/Lorenz compression bullet, which were indeed for expansion, but these bullets were never used by the U.S. at any time, and don’t have a “skirt” as you reference.

[@daveh9521]

@@papercartridges6705 Hi, I wrote back earlier today, but for some reason KZbin will not allow me to include links (this has happened to me before). This is what I wrote without links: I had an Enfield for many years and shot countless rounds through it. I also cast my own .58's. The "skirt" system of outside grooves (also lubrication) and hollow or "conical" base allowed the round to be more easily loaded w/o a patch. This system would then expand upon firing, sealing the barrel to grip the lands and grooves, increasing speed and accuracy. Compare a new Minne ball to a vintage fired one, and you will see the skirt difference. Note: near "intact" bullets found on the battlefields were "dropped rounds", those hastily lost by soldiers (can't blame them...).

[@dsan94]

​@daveh9521 and yet you didn't provide a single extant source whereas paper cartridges provided a number including the designer of the grooved bullet adopted throughout the period.

[@patwelsh5561]

Great stuff, Brett. Glad to see you’ve increased the frequency of your uploads recently!

[@nealkrueger6097]

The grooves serve the purpose of are one tie point for the paper cartridge. Two allowing the fired buelllet to expand into the groves of the rifle barrel upon firing. Since bullets were slightly under sized to allow easier loading in a fouled bore. However, a small side effect is that the groves will hold a lubricant, allowing slightly easier cleaning

[@henryofskalitz2228]

Very very interesting I always thought they were for lubricant only

[@BoggWeasel]

I shoot BPCR, all the bullets are grooved, reason being they are squeezed thru a press where a beeswax based grease is squeezed into the grooves. This grease helps to keep the black powder fouling soft and stops it choking the barrel. and makes the bore easier to clean. Black powder fouling can set hard as a rock and be a real pain to clean up.

[@malcolmgary1086]

YES!!! I greatly appreciated your presentation style AND the knowledge imparted.

[@papercartridges6705]

I appreciate that!

[@karinbeyaert9950]

First time in years somebody tells me something I did not yet know in this field!

[@paladinxx9106]

The grooves are designed to hold lubricant to soften fouling and to help scrape away fouling from the previous shot. If a sufficient powder charge is used to expand the base of the bullet into the rifling, it will do its job. The ideal powder charge for a particular minie would expand he skirt into the rifling, provide sufficient velocity to stabilize the bullet, but not too much to deform the the skirt when the minie leaves the muzzle.

[@papercartridges6705]

I have to ask… did you watch the video? Before the US adopted the grooved bullet in 1855, the French had adopted grooves on their bullets a decade earlier, and never added any lubricant into the grooves.

[@18661873]

I never stayed awake nights thinking about this but I was always curious. Good video.

[@WesProphecy2032]

I found a few of these grooved bullets along with musket balls all over the place in central Texas. Not sure if there was a war here or if it was from hunters.

[@WesProphecy2032]

Turned out it was fighting between Comanche and settlers. Given all the arrowheads found in the same area they had a heavy fight in that area. The arrowheads were mainly found on the higher ground while the bullets were found near the cliff that follows the dry creek

[@tonywilkey4369]

Current lead projectiles still have these grooves which are used when crimping the metallic case, this can be beneficial in tube magazines so the recoil doesn't push the projectile further into the case.

[@lumaduecharles32]

Always more to the story. I was sure I knew why. Its not a hat rack. THANKS

[@Mrbuggsnot]

The Prittchett and Boxer bullets have smooth sides, so why don't they have trouble with tumbling?

[@papercartridges6705]

That’s an excellent question. The Pritchett/Boxer bullets relied solely on the spin from the rifling to stabilize them. Grooves cause drag and the British made the deliberate decision to use a smooth bullet, to get a higher velocity. Also, British bullets were made by pressure instead of being cast, and they believed this made them inherently more balanced. That said, as a Pritchett shooter, I’ve seen a ton of keyholes. They are much less forgiving to shoot accurately than a Minié with grooves!

[@tacfoley4443]

@@papercartridges6705 You really ought to try shooting your Pritchett bullets in my Pritchett rifle. That ought to be interesting.

[@normanbowstead3616]

Brilliant explanation. I’m always intrigued and extremely interested in these technical details. Getting to love black powder shooting even more.👍

[@r2d141]

I never gave it any thought. Thank you for the detailed break down.

[@neiljohnson6815]

Those are grease groves to lubricate the round to get higher muzzle velocities.

[@emmettreed272]

Actually this is the same reason that most common air gun pellets have waists. Although not formed with a sharp edge waist, the hollow base moves the center of mass forward in such a way to minimize needed aerodynamic corrective forces (applied to the skirt) to stabilize bullet flight.

[@astridingmarsdottir2400]

This phenomenon seen in air gun pellets was noted by the Romans who employed a wasp-waisted ballista bolt without any form of fletching, relying instead on increased base drag to stabilize the bolt in flight. It would seem the idea was discovered, forgotten, and then rediscovered multiple times in the last 2000 years.

[@BennettEberle]

I have shot .177 pellets out of a smoothbore Daisy BB gun by muzzle loading the pellets into the bore and ramming them down the barrel with an improvised ramrod. They always hit the target point first regardless of the distance to the target. Pellet guns have a very slow twist, meant more to average out the imperfections than to impart stability, so the gun isn't shooting "knuckleballs".

[@Chiller01]

Learned something new today.

[@G53X0Y0Z0]

Arrows fly best (straighter with less wobble) with some weight forward of center. You are correct, helical fletching on arrows does not make them spin with much rpm like some people believe, but it does provide increased drag on the rear of the arrow which stabilizes the arrow well and can be helpful when arrowheads are not perfectly inline with the shaft. While modern bullets seem to do well, I suspect the older bullets with weight removed from the rear of the bullet benefit in at least ways. The configuration of the grooves on these Civil War style bullets would tend to flare out as they were pushed down the barrel, providing a more consistent seal. A hollow base would enhance the effect of expanding outward due to pressure, just like a hollow point causes bullets to mushroom easier.

[@Civilwar.relics]

Making it simple the mini ball would sometimes roll when loaded if you didn't hold the heavy gun perfectly, the groves made it so that doesn't happen and shots were more efficient.

[@jasonashley4579]

You can find them things everywhere here, all along the little blue river.

[@joewoodchuck3824]

We still have multiple grooves in modern cast lead bullets. I can't speak with authority on the history, but the top groove is a crimp point for the cartridge case mouth to hold the projectile in place. The rest of them are grease grooves.

[@michaelsmith2733]

Those 58 cal mini's were bad news. If the bullet didn't kill you the surgeon would.

[@jimf1964]

They may help stop wobble, but I find them a pain in the butt for reloading in brass cartridges. Gotta get the crimp just right, or seat deep enough to go past them.

[@papercartridges6705]

They give me the same trouble especially loading .45-70 or .577 Snider. If they aren’t lined up just perfectly straight…

[@jimf1964]

@@papercartridges6705 I’m doing 45 colt. Pain in the butt. But it’s my first foray into old school. Maybe I just got a lot to learn, but with difficulty in finding ammo nowadays, I’ll have to reset my dies every time I get new bullets

[@tarnishedknight730]

Are you checking the length of your brass and trimming as needed? Brass does not always stretch the same all around. You can easily have one side higher (longer) than the opposing side. Just a thought.

[@jimf1964]

@@tarnishedknight730 what I meant was the crimp is so easy to end up in one of the grooves and be useless

[@leadshark9461]

Excellent video. Very informative as always. Hope we see more of the Lorenz soon.

[@rockosgaminglogic]

The base obturates to create a gas seal and the grooves make it easier for that to happen.

[@TexasEngineer]

I heard from a Civil War battle museum that the North and South used a different number of grooves to tell if it was freiendly fire. They had their bullets sorted into North and South by the number of grooves. I have not heard this anywhere else. Is this just an anomaly of a particular battle?

[@papercartridges6705]

Another myth about the grooves is that Union bullets had three grooves and Confederate bullets had two. It probably started with the Confederate Gardner bullet, which did have two grooves, but only amounted for perhaps 10% or less of all CS produced rifle musket bullets. Both sides generally produced bullets with three grooves, with considerable variations in shape and weight, from arsenal to arsenal.

[@son-of-a-gun]

I guess the grooves around the bullet are meant to create a labyrint seal. The pressure doesn't vent off around the lead bullet. Bullets/slugs with several grooves leave the barrel with a higher muzzle energy. Of course the groove " lips" dig into the barrel spiral far more effective.

[@robertpresley6414]

I thought it also aided in scraping out the fouling since the grooves face forward.

[@papercartridges6705]

I suppose it couldn’t hurt!

[@richardsolberg4047]

Have heard that also , the 3 reasons for the grooves are not exclusive .

[@OleJoe]

A few years ago during a visit to.Vicksburg, Mississippi I remember taking a tour of a Civil War era home at the military park. The lady said that the house still had damage from the war. I walked around to the back and the back wall was shot full of little holes here and there. You could still see the slugs lodged into some the holes. I can tell you one thing, God help you if you were shot. The thousands of names on the monuments and the hundreds and hundreds of graves (on both sides) were absolutely frightening.

[@job38four10]

I was one that thought groves was for lube, air stabilization does make more sense, good info..........

[@krwada]

The boat-tail actually adds a little more drag to the bullet. This allows the bullet to better "buck the wind", thus increasing accuracy at range.

[@robertfoster7807]

boat tails reduce drag by reducing partial vacum created at the back of the bullet

[@robstirling3173]

Hmm, I would agree with Taofledermouse, the Minie was designed to expand on firing and so obturated and scraped the fouling from the barrel, hence the forward rake of the grooves.

[@papercartridges6705]

You certainly don’t have to agree with me, but consider, I am simply repeating what they wrote and said in the 1840-1860s period. It’s not like I woke up one morning and decided to make up a story about why bullets have grooves. This is why I took pains to put up numerous screenshots of the original period documents. None of them (emphasis: none!) ever said the grooves were for scraping fouling. You are of course free to disagree, though you would be running against the grain of the abundant period documentation.

[@pfarnsworth84]

Another reason that the grooves would not be beneficial on "modern" bullets is that because most of them are supersonic, wind wouldn't even engage them until after they dropped below the sound barrier, and the result would likely be terrible. Fortunately, since then, we've gotten much better at figuring out ballistics and aero/fluid-dynamics.

[@caseyhowell7341]

I would like to see a bullet with dimples like on the surface of all golf balls, this is what gave birth to the game we see today and it's necessity for accuracy that was nowhere to be found until the dimples were added thus reducing surface air drag to a minimum creating the ability to control it with ridiculous accuracy, just wonder would dimples on a copper jacket have the same benefits of pinpoint accuracy even with a rifled barrel that spins it into a stable flight could only be better with less drag maybe even slightly increase the muzzle velocity and overall energy can also increase just from speed.

[@papercartridges6705]

Some people will knurl round balls for that exact reason. They shoot much better than ordinary round musket balls. The concept only seems to work for spherical balls though, but I’m not an expert by any means.

[@nonokodog622]

I'm a little suspicious about the the graph of straight vectors ( 4:16 ) of the "slip stream", AKA laminar flow being incident normal to the groove. The flow wouldn't see a flat surface since the bullet is rotating. The air will stick to the bullet creating vorticity which is drag inducing. A buoyancy force will be created opposite to where the air stacks up in greater density. I may be full shit....but that's what i think based on some background knowledge. EDIT: I'm not sure that the physics of vorticity was understood very well in 1833. Also, it's a really hard topic that scares the crap out of me. en.wikipedia.org/wiki/Navier%E2%80%93Stokes_equations

[@papercartridges6705]

The grooves do create drag which is why the English decided the benefit of the grooves in maintaining stability was not worth the considerably loss of velocity, and the British rifle musket bullets were completely smooth. But I am definitely not an expert on the scientific side and I tried to keep the explanation as basic and as layman as possible for a short video.

[@nonokodog622]

@@papercartridges6705 Love your content, I hope I didn't sound critical. Just thinking out load in the comments...

[@rambysophistry1220]

@@nonokodog622 So, I am really late to this comment, and physics isn't my strongest suit, but forgive me for thinking out loud as I parse through this. It seems to me there are going to be several force vectors acting on the spinning, grooved bullet as it plows through the air. There will be the drag force normal to the reverse face of the bullet, the lift force normal to the reverse of the gravity face of the bullet. There is the velocity vector normal to the forward path of the bullet and a gravity force normal to the gravity face. Because the bullet is rotating there is also a conservation of rotational momentum and its vectors. Several of those forces will be irrespective of whether the bullet is grooved or not. The velocity vector's initial condition is irrespective, the gravity force will be irrespective, as will the rotational momentum. However, the drag force, and lift force, importantly will not be irrespective. When the ungrooved bullet starts to process around its rotation, that is wobble, it will become more and more unstable as the procession worsens with each rotation, until it has become perpendicular to the velocity vector. At which point the bullet will start to rotate around its abnormal axis of rotation and "key hole". Since the lifting force is shoved along the path of rotation like a gyro, and the procession emphasizes instabilities. When the bullet is grooved, however, the drag force increases opposite the velocity vector, the lifting force increases opposite the wobble, and there is a restorative force vector that pushes the bullet back into its rotation along its shorter rotational symmetry plane. It essentially turns procession from a runaway force, to a self-defeating force.

[@nonokodog622]

@@rambysophistry1220 I think we're saying the same thing. Perhaps we can consider an arrow with flights. We know that if the arrow point rotates slightly the opposite side flights will have a force on them pushing the point back. The rotation of course acts like a fly wheel to store energy and creates a torque along the axis which helps the bullet stay stable. The bullet's rotation might also acts like flights as it grabs the air and forms a "boundary layer" very close to the bullet. That air is denser than the air in the laminar flow. The grooves exaggerate the depth of the boundary layer, making it more effective as a sort of arrow flight.

[@rambysophistry1220]

@@nonokodog622 I think the math works out the same, I am just clarifying what I think is happening with the bullet. I could also point to a golf ball, where the dimples increase the accuracy of the ball drastically compared to if it were smooth. Probably with roughly the same force vectors. Either way, I wasn't trying to say you were wrong, just trying to work out what I was thinking, sorry for not being clear.

[@RidgeRunner86]

Groovy video!

[@ZacLowing]

Dozens and dozens of experts didn't watch the video and instead just ran down here to post the wrong answer to the title.

[@tsafa]

Excellent information. Great video

[@FoulOwl2112]

Works along the same principle as the dimples on a golf ball.

[@Dominic.Minischetti]

Man I learned something new today! Thanks!

[@phil20_20]

Barnes copper bullets have the grooves. The hard solid copper doesn't engage with the rifling as well as jacketed lead bullets. 😉 Indeed, the bullets would have to be smaller diameter than the barrel grooves if not for the relief provided.

[@LisaMeador-h5n]

When did they quit making bullets with the grooves. I have two that seem newer than the minie balls I have. I can't tell how many grooves there are because the ends are melted/splintered out but they do have at least one ring. Thank you.

[@robertwalley6692]

I was or it was my first thought that it built more pressure in the barrel and allowed the bullet to catch the groves in the barrel also.

[@rwseemore1]

Outstanding explanation

[@russellkeeling4387]

This could possibly be where the expression "groovy" came from.

[@knoll9812]

Lots of comments snd different explanations. My tuppence Is that more than one explanation can apply Also they gave grooves becuse they worked.the french test and kept the bbest.thry didn't have to explain. Imperical versus theory

[@gjalabaster6726]

The grooves were there to help cut down on blowby, allowing for the pressure to push the round more efficiently. Today’s rifles have closer tolerances so the grooves are not necessary. As the gases work their way around the first ridge, the gas expands into the area provided by the first groove slowing its flow and the energy lost is exchanged into the bullet. And then so on the process continues into the next grooves thus slowing down the speed of gas flow relative to the acceleration of the bullet. You can find this phenomenon used today in jet engine compressors where a seal is desired, but with no contact with the compressor housing.

[@papercartridges6705]

With all sincere respect, could you please provide one historic source (just one) that states the reason you gave for grooves in the bullets?

[@gjalabaster6726]

@@papercartridges6705 truly I will say, I have no references. This is because they fully didn’t understand onto which they had stumbled. Remember, the Industrial Revolution was still very young. The theories at the time were the wind vain and the expansion theories. But at close examination of expended rounds, the expansion theory is inconclusive. Correlating what I know in steam and aviation, to me, what I said in my previous post is the most likely physics.

[@edwinokeefe2345]

" Taking control of their minds ' is 1984

[@PhilipFear]

They are gas check groves that allows the back of the bullet to expand out to engage the rifling groves in the barrel on the way out of the barrel.... This way you didn't have to force it in to the rifling while you ram them down during loading....

[@Dougarrowhead]

Very good explanation

[@davidnewland2461]

I imagine the grooves assisted in engaging the rifling of the barrel

[@papercartridges6705]

About 50 people have said this so far in the comments, but none of them have done me the great courtesy of explaining how or why the grooves around the cylindrical portion of the bullet interface with the grooves in the rifle barrel, which are perpendicular.

[@schmiddy8433]

Would enough lubricant stay in the grooves after leaving the barrel to reduce the flight stabilizing characteristics? I wonder if unlubed bullets would be any less prone to tumbling

[@clintwilde1048]

One of the more interesting Myth Busters involved the testing of bullets fired into water, the question being posed concerned shooting a submerged combatent. All supersonic bullets shattered on impact and the pieces rained down into the pool being used as a test bed, with underwater cameras to show what was happening. A .223 or a .50 cal, all came apart on impact into harmless chunks. But, sub sonic bullets, such as pistol rounds from a 9mm, and older firearms like Peacemakers using .45LC, or the 1911 with .45ACP, and specifically black powder rounds such as the Minie ball, contained a tremendous amount of lethality if fired into the water at several feet. I think the conclusion was that if you had to take on a submerged combatant, an old black powder firearm was the only way to go. Had to add that in reference to this video info about the 1in7 inch twist for the AR, and 1 in 6ft twist for the older rifle and his comment about the bullets spin speed, another Myth Buster tested spin rate by firing a 9mm straight down into ice, the bullet was screaming it was spinning so fast, the RPM being in the 100,000+ range.

[@bruceinoz8002]

Arrows? They "wobble" a LOT from the moment of launch because the flexibilty of teh shaft allowds the force from the dtring to BEND the shaft during launch. Bullet spin? in flight, the rotational speed" of a bullet is basically unaltered from launch to impact. As opposed to "linear" speed" which is serious;ly affected by air resistance. The original Minie Ball had a "plug" in its base to aid "expansion", the Brits worked out that if the "grooved "tail" of the bullet were thin enough, gas pressure alone would expand it to engage the rifling. Remember , the entire point of these bullets was that expansion. The "raw' bullet was barely the diameter of the lands and thus easy to ram down even a fouled barrel. In earlier times, rifled barrels required that the bullet be "started" at the muzzle with significant force, then rammed down the barrel. "Expanding" skirts on bullets took the hard work out of reloading.. That Greenhill chap did a LOT of work on bullets, velocity and twist rates WAY back in the mid 19th Century. Definitely worth a read!

[@papercartridges6705]

I’d encourage you to watch my other videos and possibly even read my book “The English Cartridge” if you do want to learn more about the expanding ball and ammunition of the mid 19th century. You’re very very close, but there are some deep gaps in your knowledge.

[@sirjhonson8218]

I know some guys that use those bullets to load as a shotgun slug because they are so straight shooting.

[@Eduardo_Espinoza]

My first thought was they were like little pistons from an engine, with the grooves where the rings would be. Then, I thought they were like pre golf ball dimples for reducing drag, by closing the wake, like vortex generators at the end of the Mitsubishi Evo's roof.

[@johnslugger]

*Real men don't need lubricant to get the job done!*

[@warwolf416]

Huh leave it to the French to develop another advancement in firearms tech for the time. I should stop picking on them 😂. Was great to learn that! I always just thought it was for the grease. Knowing that now, does the grease actually interfere with the grooves stabilizing the ball since your filling them in?

[@richardsolberg4047]

Would think the grease is gone as soon as the bullet clears the muzzle , spin and muzzle blast , look at the crown of a gun shooting even modern lubed bullet , there will be a deposit of grease or wax on it .

[@scottharris6423]

Boring, no. Interesting! But your explanation does it also apply for the lead bullets that my Dad & I would grease the 2 or 3 grooves for our cast lead bullets for .32 cal, 45 cal. Long Colt, & 45 cal ACP Bullets that we reloaded ourselves?

[@papercartridges6705]

I don’t think the grooves in modern bullets are designed for that effect, they are probably more for holding modern lead bullet lube which is necessary to prevent leading. But as a secondary effect, they may help some way with stabilization. Modern bullets also rotate so fast that they remain much more stable than the very absurdly slow twist of muzzleloaders.

[@mikebeddingfield2144]

Groves were for wax to hollow in the base was to alow expansion of the base so it would engage the barrel rifiling to stabilize it during flight. All this was slowly released mostly by accident because of having to fire damaged round balls

[@mickeyholding7970]

Thanks Brett, excellent

[@danielcurtis1434]

So basically you want all the weight that in the center. So removing material from the front back of sides will improve stabilization??? I know you want the weight centered front. However the “open tip” hollow points also improve accuracy as seen in “open tip match” ammo like sierra matchking. This seems inconsistent to me???

[@michaelredman5750]

If a bullet is tipped nose down so that the grooves on top of the bullet are exposed to drag, any tipping action the grooves accomplished would result in the nose of the bullet moving to the left or right depending on the direction of the rotation. This would actually result in the wobble increasing. This is known as precession. Any helicopter pilot and tell you about it.

[@papercartridges6705]

The grooves aren’t a magic solution for everything, and their function is rather crude… I mean, deliberately causing drag on something supposed to be aerodynamic, is less than ideal. But like the feathers on a badminton cock, the drag keeps the nose (more or less) oriented and prevents the long bullet from doing what it really wants to do, which is rotate around its shortest axis, and tumble like a buzz saw.

[@ianturpin9180]

Diablo pellets rely on the same to aid accuracy.

[@danielcurtis1434]

I always read that civil war rifled muskets had a twist rate of 1:40-48”? That’s considerably more than 1:72”? I’m just curious why the twist rate increased abc how it all happened? Anyways first time watching this channel. Great content fir such a small channel!!! Keep up this niche content and I think the sky is the limit!!! You got one more subscriber!!!

[@papercartridges6705]

Some of the short rifles had a faster twist but the US Springfield rifle musket as well as the P/53 Enfield had one turn in 6 feet twist. Because shorter rifles had slower velocity they needed a quicker twist to stabilize the bullets. It also made them noticeably more accurate. Thanks for the subscribe! Hope you enjoy my nerdy ramblings.

[@johngraesser4911]

Not sure about BP arms, but with precision rifles, twist rate is dependant on the length of the bullet.

[@danielcurtis1434]

@@johngraesser4911 I know it’s complicated!!! My understanding is that for stabilization you also need an amount of barrel length. So you want a tighter twist for a shorter barrel for projectiles of the same length. I think the issue is the minie ball was designed to be inherently stable for use in smoothbores. However where the rifling is advertising is probably another story. I really wish someone with physics experience would do a deep dive!!!

[@Bhartrampf]

Interesting, i wonder why blck powder cartridge bullets of today have square groves in them, like the 44-40? It isnt particularly fast either, is it because they are loaded into a brass case and their for needed to be more robust? Or is it because we increased the barrel twist, even though the bullet is still going slow? I love the study of interior ballistics, but have always wondered about this.

[@ludditeneaderthal]

Those are actually grease (lube) grooves. They also give lead somewhere to displace to when you run the bullet through a sizing die, besides the base of the bullet, which would have very adverse effect on accuracy. You'll notice swaged lead bullets (sized in actual manufacture) tend to be ungrooved (or knurled), cast bullets of "traditional" type have such square grooves, and cast Lee "tumble lube" type bullets have narrower, shallower, more numerous semi-circular profile grooves. The minieball was used in barrels rifled at "round ball" rate of twist (quite slow, 100-150 caliber twist rate), while a .44-40 has a more appropriate to typical bullet length (35 to 50 caliber twist rate), thus is far better stabilized. The more elongated a bullet, the faster twist rate is needed for "ideal" stability. If such truly piques your curiosity, get a copy of "hatcher's notebook", he has an entire section on ballistics, interior and exterior, as well as a few decades of info on such diverse topics as the "golden age" of machine guns, the perfection of the '03 Springfield rifle, development of the semi-auto battle rifle, and many more quite interesting musings from his career as an army ordnance officer from the turn of the last century until ww2

[@jameshoward8609]

So, at the beginning of your explanation you stated the groove made it easy to Tye the string to hold the paper wrapping on. Wasn't the paper wrapper used to make the bullet slide down the barrel and engage the grooves better? Hence "LUBE GROOVE" It was just by accident that the French discovered that it also made the bullet fly straighter even though they got the reason incorrect.

[@papercartridges6705]

The original groove was just a notch for tying the cartridge paper to the bullet, this was pretty common in 1840s era early rifles. The groove had nothing to do with lube on these early bullets. The string prevented the paper patch from sliding off the bullet during loading.

[@jameshoward8609]

Correct the paper patch was used to allow a tight fit for the bullet as it goes down the barrel and to keep it from fowling the barrel with led as the bullets were softer. So even if they didn't know what they were doing it worked. Hence the guy from France thinking the grooves helped the wind keep the bullet straight acting like fins. When they finally figured out that more grooves and a bit of lube is all they needed the paper patch went away.

[@chrislee176]

Answer: grooved add aerodynamic drag for stability, and to carry lubricant.

[@papercartridges6705]

Correct! About 90% of the other comments are wrong.

[@crystalclearwindowcleaning3458]

Very interesting. Always more to the story.

[@hidgik]

Why don't they make the bullets spherical? Would it not eliminate the tumbling issue?

[@brorjordas1979]

So, the grooves kinda just gave the projectile a slight shape of a diabolo, as like airgun pellets. Drag n all that even mentioned here.. Kinda neat of a video. Was interesting.

[@settlesmachiningtools8671]

Very insightful thanks for the lesson 🙂

[@gerardmiele4197]

So it’s kind of like the riffling in a barrel but on the bullet.

[@lightbox617]

Is it like an arrow or like a gyroscope?

[@keithmoore5306]

actually it depends on the model of M16!! it varies from 1 in 14 down to 1 in 7 depending on which round in use at the time of production! the current model is 1 in 7!

[@papercartridges6705]

Interesting. I’m not a “modern gun” guy but the M4 carbines my Reserve unit has have that 1/7 stamped on the barrels. I assumed they all were 1 in 7. Thanks for the comment, I learned something!

[@keithmoore5306]

@@papercartridges6705 not a problem it seems all centerfire cartridges under .243 are that way! and 223/556 is also bullet sensitive too, if you don't match the slug to the target it can really suck on terminal effectiveness where ball ammo in 6.5 and larger will do the job pretty good! i know a ranger who served in somalia who tells a story from the shoot out where they were issued penetrator ammo from the gulf because some of the iraqi's had body armor, (i've heard more than one vet say quartermaster always supplies for the last fight!!) he said that ammo went straight through the somali's and they just stood there looking at them! 20 some years later he's still pissed to core over that!

[@gemmeliusgrammaticus2509]

Fascinating!

[@coololdluke3905]

It was the 1860s, everything was groovy in the 60s

[@CS-xo4kh]

Makes a lot of sense. Thank you!