.308 Win - 175gr Sierra Match King with IMR 4064 (part 2)

[@haroldcook2146]

I really enjoy re-watching these older videos of yours. Both of our reloading styles have matured since back then, but I always pick up on something that makes me think, “Oh, yeah, I forgot about that.”

[@BobJoe64862]

Any chance we are gonna get a part 3?

[@arl0xen551]

You are my first and #1 resource for reloading, sir. Your shooting is, getting better, and it sometimes skews your results I think. Your process in the lab is fabulous.

[@brutusgallicus3568]

I load 42.5gr IMR4064 or 43gr Varget in Winchester brass with CCI primers. My rifle is a CZ Varmint Synthetic with a 26 inch barrel.

[@thomashamilton8451]

What Velocity ?

[@billprice6248]

i like the presentation good job.

[@nomamartini1310]

The stagnant velocity indicates that you found an accuracy node. Check out 6.5 Guys who have toyed with the velocity nodes load development. Basically, it’s a point when added powder yields the same velocity. It’s also explained that it’s the point where the Bullet is working with the barrel harmonics, opposed to against it.

[@Aereaux]

I have an Aero Precision M5. I originally had a fixed gas block and with just a muzzle break I had no problems with operation or chewing up brass. I put on a suppressor and of course it was over gassed. Operation was messed up. There is so much pressure that the bolt moves back and springs forward faster than rounds can come up out of the magazine. Ejection moves from 3 o:clock to about 1 and I had some cartridges that just kind of fell out of the receiver. An adjustable gas block needs to be turned way down. Maybe open only 2 turns or so. Bottom line is that weapon operation (cycling of cartridges) with too much gas can look similar to too little gas except for the marks on the brass.

[@TheChampionp]

I've been using the Lee neck sizer alongside the Redding Body Sizing Die. I have .003 headspace (in the semi-auto, tighter in the bolt actions) and neck sizing helps prolong trimming intervals. I'm about to buy the Redding precision shellholder set so the headspace will be set exact when using cam over. Longrangeonly has a video describing the same method except with bushing neck dies.

[@Gunner-73]

John, try measuring the bullet below the ojive to see if they are consistent. I stopped using sierra bullets a long time ago because some would be 308, some 309 some 311 and some 312 caliber. That might be what is cause your FPS inconsistencies. Try weighing the bullets, measuring the lengths, that is why I switched to Nosler ballistic tips.

[@cogunlover5550]

Very good video. I'm glad to see someone else is having issues getting accurate loads with IMR 4064. I have tried and a handful of different breast with my 175 grain match Kings and have not had very good luck. I have however had great luck with Varget and reloading 15. More testing coming soon. I've been stuck on my 6.5 Creedmoor for the past couple weeks and loving the accuracy.

[@mrmidnight32]

What happened? Did you just give up on this series? Lol Went to look for part 3 with Varget or IMR 4895 and saw nothing.

[@1RobHunter1]

It does not chew up the brass at 41gr of 4064 or Varget from AR308's. However, it will not give you the most velocity either. This is why I like running my bolt guns for 308 Win at higher pressure - no brass damage. I can run lower pressure in AR308 but around 2450 - 2500fps. Now we are getting into 30-30 Win 2400 FPS with 160gr Flex Tip and LeveRevolution in a much lighter easy to carry lever carbine / rifle with a 1-3x20mm Weaver optic. Those Marlin 336 or Glenfield 30 half magazine = 1.5" groups at 100yds no brass damage in a lighter hunting system.

[@billbee235]

Johnny, I basically did the same exact test for my AeroPrecision M5E1 which has a criterion 24 inch barrel from Fulton Armory. I ended up going back and doing a 10 round Satterlee test to determine the velocity flat spot and just went with that as my load and have had much better success when taking the rifle to distance. My biggest problem was running into pressure and Popping primers when I got over 42.6 brains of imr 4064. Currently my lower node is 41.7 IMR 4064 with a 175 SMK. I ha surprisingly excellent results with W760 and 165gr Gamekings

[@usa5865]

I've been working on cloning this too with lapua brass and 4064. I'm using cci br-2 primers and 42.3gr. I was using wlr primers and the br-2's made a huge difference. I'm not suppressed

[@IU_RK84]

I have several boxes of Federal gold metal match 168gr. This video made me investigate. I have pulled several bullets and measured the powder to be 41.5 gr. Very consistent. Per the box 2650fps. Sierra shows load data for only 1 powder and it’s exact. IMR3031. Looking into the powder and comparing. It sure looks exactly like 3031.

[@sylviacandler5541]

In my Krieger 10T, IMR XBR 8208 with a Fed 210 shoots a single bullet hole, same bullet as you are shooting 175g MK

[@jimvandemoter6961]

Your comparison of brass is interesting. I load 9mm for my pistol. Winchester brass jams almost every round. I get best and consistent results with Federal, Blazer and Starline brass. I'm using 124gr FMJ bullets with Hodgdon CFE. I do sort my brass. It makes a difference.

[@Thorsaxe777]

Johnny, My accuracy was best with IMR-4895, Now that was with a whole different gun "M1A super match w/Kriger barrel" and that was 20 years ago. Some people shot IMR-4064, however, then again, different barrels, bullets, and brass. The Velocity we held at was 2580 fps as the sights are calibrated at the velocity. anyway, keep at it and you will find the sweet spot. Oooh and by the way, we were shooting 168 Gr HPBT, Mine preferred Hornady bullets. Dave.

[@Toolness1]

Johnny, not sure if you'll see this but I had a little tip for using the Lee trimmer like I've seen you do in other vids. If you take the cutter end that the gauge screws into and clamp it in a mini vice grip from Harbor Freight, it'll give you a 90 degree angle there and you barely have to hold on. When you use the drill and try to hold on to that short knurled knob, it sometimes takes a lot of force to keep it from spinning and it'll wear out your hand if you're doing a large batch. They make a tiny vice grip that is only about 4 inches long, perfect for the job. Also, I've had the brass catch and the knurled piece spin in my hand and the cutter chewed me up pretty good. Give it a try next time, I've had mine clamped in a little mini vice grip for like 2 years now. I just leave it that way, but that's my primary method of trimming......

[@roarytenorio3969]

Johnny, I would suggest you also try the 8208 and AR-Comp powders, both suppressed and un-suppressed. My experiences with AR-Comp indicate less pressure with equal or better velocities in both calibers (16" ARP 223Wylde and 16" BA Hanson).

[@ashleypalmer7983]

Some comments: IMR 4895 would be my choice, however it isn’t significantly different in burn rate than 4064 to affect the functioning issue. 4831 is a much slower powder than 4064 and the port pressure will be significantly higher. So I voted for Benchmark. In the old days when M1s and M14s ruled Camp Perry, the civilians loading for their gas guns generally did not load powders slower than 4064. The M14 guys would batter their rifles and occasionally get breakage, the M1 guys bent operating rods and then the guns would instantly throw shots all over due to rods beating on the barrel or binding erratically in the gas system. Try BR-2 primers or Winchesters, you might like the results better. Gas guns need longer headspace than bolt actions. For functioning. When I barreled M1A rifles, I set mine up with headspace 1.632 which is “GO” +.002. This allowed functioning and increased safety. If you set it up tighter you could get into “slamfire” territory. You should consider IMR 8208XBR powder to follow your next selection. It’s faster than 4064 and slower than Benchmark and may be the best compromise. Ditch the suppressor until you find a load. Suppressors are sized for the amount of gas volume. In a 308 you have nearly double the charge and nearly double the gas produced. Which is why your gas settings are so touchy suppressed. Shoot over the magnetospeed.

[@mr.gunwrites2491]

I vote for IMR4895. Because that's the #1 powder I've chosen for my .308s, my second powder IMR4064. So please the IMR4895, also because I've got an 8lb. keg of it, heaps SMKs and and TMKs. Thanks for your through work and matter-of-fact diagnostic explanations.

[@14truelies]

Can you or have you tried the nobler 175 RDF

[@greybone777]

4064 is a great powder. It's very accurate in 3006.Blc2 and varget are outstanding in both cartridges. I can tell you that federal match ammo is hard to duplicate.

[@clinthenker6505]

Without having read all the posts for this VB... What about switching to a heavier buffer and/or stiffer buffer spring to slow the bolt movement allowing the brass to be more in sequence to limit or prevent ejector marks? You are already using and adjustable gas block wouldn't hurt to make adjustment on the other end as well. Can't remember if you're using a standard MILSPEC buffer (3.84 oz). There are options of a heavier buffers and spring combinations or JP makes a heavy buffer (JPSCS2-10H2) with assorted tuned buffer springs. I'm not partial to any. Just getting the thought juices flowing. Thx.

[@wizardny]

From what I could find on the interwebs FGMM 168gr was IMR 4064 with 42.8 grains and 175gr was 41.7 grains of 4064. I took apart a 155gr Hornady American Gunner round and it had 39.7 grains of what looks exactly like CFE223. This stuff shoots great in my 1-10 Ruger American Predator. What I did find odd was it's way below starting load for that bullet and powder.

[@THutch556]

Good video JRB, I hate to see this expensive Barrel not print 1/2” groups for you using quality components like 175 SMK’s in Lapua brass. 1.5” groups with that set up is tough. In the poll and comment section in the video for what barrel to choose I stated JP was just to much of a chance when choosing a match barrel, and it would be worth picking a proven match barrel company like Krieger or Criterion for a savings. JP is a good company known for making match rifles, but to many unknowns for there barrels. Anyone know who makes there barrels? or what blanks they are or if they are finished lapped? How did the inside look with a bore scope? Might be a reason they were in the clearance section. That’s not to say you won’t come up with some better accuracy or find a good load with the JP, but hate for it to be you are always chasing a good load as the load you are testing has worked for me in all .308’s. It will be interesting to see across the board what it does with other known quality bullets for consistent accuracy. I know you can shoot JRB and your hand loads are solid from watching all your previous reloading videos. So at this point the JP IMO is falling short, although still early to fully tell. Hope this one turns around for you JRB and you get into some great accuracy. As far as powders for your next video, of the three you have listed I would choose 4895. For what it’s worth RE-15, Varget and IMR 4064 all play really well with the 175 SMK’s for me, would like to see you test RE15 or Varget as they are proven accuracy powders in 308. In my experience adjustable gas blocks are definitely necessary with the AR-10 and it can be a finicky beast compared to the AR-15 in terms of gas and function. Keep up the great work.

[@donalddickins8493]

I agree. I dont know what crazy people said jp but if you gave me 400 dollars and said pick a barrel jp would not even be in the top 10.

[@allenclayton7]

Try a different bullet or powder. Clearly the barrel does not like 175s and 4064.

[@thomasburch1260]

I remoced the lirrle oring around the ejector spring and it seems to help save my brass

[@billbee235]

This video is fantastic because now I know I’m not alone lol. I have an M5E1 with a 20” ballistic advantage bull barrel and was struggling to build a good load. I was able to get some sub MOA groups but it’s just not consistent. My best loads were almost identical to yours.. I used 175 grain SMK / 43gr of 4064 / Hornady brass and CCI 200 primers which got good results. I also got good results with 175gr Nosler rdf bullets and 42.6gr of varget but it’s more or less an MOA shooter with an occasional sub MOA group

[@twg2118]

Excited to see if you can come up with a powder that will work nicely with the gas system on your 308. I will be following this series for sure.

[@ryanparrish5361]

I've had very inconsistent results with IMR-4064 in the 308. It seems to be sensitive to temperature and position in the case. I've had very good luck with RL15 and especially Varget.

[@1RobHunter1]

ARMY AMMUNITION DATA SHEETS, SMALL CALIBER AMMUNITION, TM TM 43-0001-27 , Page - 208, M852 National Match 308 Win, It lists IMR- 4895, but Federal Match Grade uses IMR 4064 and or Sierra Accuracy load is Viht N540 39.5 @ 2400, 175gr HPBT, Federal Case - thick, Sierra manual pdf online.

[@taylorjames1013]

I had this super weird test series, I tried to use M80 pulls for 300 Blackout Subsonic with Trail Boss. My loads got slower and less consistent the higher the charge. It was for a bolt gun, so cycling wasn't an issue. I went from a charge that barely got up to 700fps to a compressed load that almost filled the case to the rim at about 930fps. The data sorta made a sine wave. It was weird.

[@glenc4173]

Second thought of the day. I am assuming by the size of your suppressor that it has a small expansion chamber. I really think you are not going to be able to dial in a good gas setting to be used suppressed/unsuppressed. The exception might be with the faster powders since the pressure at the muzzle will be significantly reduced. That is why I have a very large expansion chamber on my can. Forgive me if you already mentioned that in this video since I have had little sleep the last few days.

[@paullanglois5562]

I'd be interested to see you work up that load with the IMR4895 you have on the bench. I currently using it for a load in my bolt gun. I was seeing ejector pressure signs before reaching even 2500fps, I want something that's about 2600. Debating on repeating it with alpha brass to see results. Or switch powders. Accuracy was good though.

[@mr.gunwrites2491]

I'm very much interested in your analysis using IMR4895 for your next testing because I use it in all my 5.56s w/55 gr FMJs & 69gr SMKs. Plus I'm sitting on 8 lbs. of it, a whole lot of 175gr TMKs, and a heap of once fired IMI & LC brass. Everyone loves the Talking Hand's through explanations. [HANDSHAKE]

[@burnsm2012]

Fast burning powders with heavy bullets are a recipe for failure. Start slow and work up. Been there down that. Not to mention the pressure curve will be far greater with the faster powder trying to push a large projectile. Go with the short cut. I've had good results granted it was a Savage bolt gun.

[@glenc4173]

The ejector swipes aren’t necessarily a bad thing. Think of them as a counter for firings. I just don’t like when extractor starts tearing up the brass.

[@albertlemont5471]

Late comment. I just started loading the 308 again. With a 150 interlock. Hornady says 44.9 max load. Same weight bullet in the Nosler manual says 48.0 max. Both with 4064. 48 gr of 4064 is right to the too of the case. With massive compression. I have loaded up to 46.1 so far with no pressure signs. Still very compressed. Never seen such a compressed load as this.

[@thebaddest2562]

More buffer weight and a flatwire spring will slow down the bolt opening enough to stop brass ejector swipe and allow for a gas setting thatll run surpressed and unsurpressed without adjustment while only being slightly overgassed surpressed. Use a H3, by h3 i mean 3 tungsten weights, + flatwire spring. Ull be amazed just swap spring and buffer then adjust gas unsurpressed ur ready to rock. The surpressor increases dwell time, the weight and spring combo counters that by allowing the action to stay closed a fraction of a second more thus eliminating brass issues caused by action timing/gas presure curve. Accuracy/precision generally will improve. The accuracy gains are achieved because the action isn't moving b4 bullet leaves/preasure drop. Also the tubbs flat spring has more force against the bolt carrier group closed and has lighter weight at full stroke than milspec type spring. Not sure why but this helped my gun tremendously, I can even shoot my cast pc load without a gas adjustment then full power surpressedloads with gas issues and no abnormal brass wear or marks . They also make weights for the bolt carrier that are adjustable and slide into carrier from the buffer side. I tell ya what ill buy the spring and buffer combo for ya if u let me know where to send it. Ur buffer tube is a regular rifle length buffer tube I assume. Or I could donate the cash and u order it either way. Prob bout 50-60 bux i think for a buffer and spring both i think. For what it's worth I also like the 1 piece gas ring for the ar10 setup, seems to work spoother and lasts alot longer, like bout never wears out, has less friction and that works out well with the big frame guns

[@frankw7266]

My pet load is the 168 SMK on top of 42.5gr 4064. So long as I'm having a good day, I can pretty consistently put out 3/4 MOA.

[@Spartan536]

+Johnny's Reloading Bench What is likely causing your velocity variation is the drastic shift in dew-point, humidity and barometric pressure. This will not only affect down range ballistics but also powder burn due to the variance. Some powders do worse with changes, but IMR 4064 is pretty good at handling it which is one reason why the US Military is likely going to replace M118LR with MK 316 Mod 0, due to lessons learned in Afghanistan where the temperatures and pressures change rapidly based on location and time.

[@jakermeister]

I find Lapua Brass is usually very tough. Can you try another bolt to see if the marks go away? Just maybe it (the bolt) has some machining issues?

[@julianbownes9468]

Would have loved to see the bolt gun work this load. 44 is around max given the components you’re using and the fact that this is a boat tail bullet. I have found .4-.6 MOA at 42.5-43.3 with 4064 with 180 SGK, 178 ELDX and ELDMs.

[@14truelies]

How does hornady and winchester brass compare to the federal? I hear hornady has a good volume. I'm trying to decide which of the 3 to go with. Doing 178 hornady ELD match bullets with IMR 4064 and varget to see what I can get good velocity and accuracy from. Out of a savage 11 in 308 of course 1:10 twist. 22" barrel. Factory still. Got a MDT LSS XL gen 2 chassis coming and a 24" Kreiger 5R barrel in 1:10 twist coming as well. May cut barrel down to 20". Not sure yet. Thank you

[@reloadeverything8695]

Yes to hell with athority more reloading vids woohoo! Lol been dying for some reloading man. I have 500 cases I cleaned ready to go but I'm waiting till my birthday to load so I can shred the loading experience with my dad.

[@julianbownes8752]

Would love to see this as a series. Would like a happy ending. You’re running a new barrel and such.

[@stefanschug5490]

Just wondering if you noticed the variation in muzzle flash without the supressor ? According to Quickload ballistics you burn about 98.15 % of your IMR 4064 powder with that load in the 20 inch barrel of your gun. The variation in the muzzle flash suggests to me an uneven ignition or burning rate of the powder. I would try a slightly faster powder to have utilized all the powder withing the given barrel length.

[@chrisp2096]

my quickload says: .308 SAAMI (max pressure 62000 psi) 175gr Sierra Matchking - bullet length 1.266" brass length: 2.014" seating depth: 0.480" OAL: 2.800" powder IMR 4064 42.00gr barrel length 20" 1) brass with 56.0gr capacity: 100.9% capacity - 52994 psi - 2484fps 2) brass with 55.4gr capacity: 102.2% capacity - 54377 psi - 2497fps 3) brass with 54.4gr capacity: 104.4% capacity - 56866 psi - 2520 fps 4) brass with 53.4gr capacity: 106.7% capacity - 59620 psi - 2544 fps

[@stillenacht8518]

A heavier buffer and stiffer spring will increase dwell time in the action, allowing the case to shrink just a little more as pressure drops, so it doesn’t tear your brass up. On the opposite side of that, it may mean that your rifle will be choosy with ammo when you switch from suppressed to unsuppressed, but you can always adjust your gas block to a load.

[@stillenacht8518]

@stephen jerome It could go either way, really. Try one and then the other or mix them up to solve the problem.

[@theelwhastrummer7166]

I'm beginning to think that AR10 just tears up .308 brass no matter what. I've been testing loads in 125gr and 150gr FMJ'S, several different powders, charge weights, and brass types. For me, most anything beyond minimum loads are flattening and or blowing primers, and leaving some gnarly ejector swipes. I'm not using a supressor, and have had to continuously work on my gas block setting to get bolt hold open. It makes me wonder if I should build a better upper.

[@carlgressel574]

I'm dying to know if you have done more testing on this setup. I'm shocked at the lack of accuracy when companies like Ballistic Advantage are making guarantees of MOA for very cheap barrels. I hope you find a load that likes this barrel better!

[@DenverLoveless]

Go up in charge weight. Edit: I think you'll find somewhere around 43.4 (ish) IMR4064 to be an interesting improvement.

[@chrisjones4128]

I think the gap in the hornady causes measurement inconsistencies when compared to one piece headspace gauges. I'm seeing 0.010" difference in mine on the piece of brass.

[@steveo6453]

go with the bench mark but I am curious to see if the 4831 puts the Lapua brass in the can. Great channel Johnny , I can't wait...

[@jdh9_]

I agree with the chronograph diagnosis. In my experience those optical chronographs can read quite differently depending on the amount of light reaching the sensors. Definitely try your magnetospeed instead.

[@everythingphil9376]

Please publish the ambient temperature when you shoot. Drastic changes in velocity with the same charges was my frustration before I realized it was the temperature changes. Lol.

[@davidpeterson6147]

H4350 will be prefect for 175 gr and above. One of the things about being a reloader is trying other powders for which there is no load data. H4350 is just a couple steps faster than H4831SC so it will work.

[@MichaelBrown-um8qc]

4 curiously thinking . I like to watch how well the 4831sc repeats & operates the gass rifle .😊 I love 4064 in my wild cat . I can see your neck tension / seat depth is showing in the group prints. Do you have any small primer 308 cartridges ? To test & print a target or two ?

[@44hawk28]

First of all, you're wasting a lot of velocity by using a mere 20in Barrel on 175 grain match King. However I have noticed that whenever you're using very slow powders anything higher than Max is still safe because it's a slow-burning powder. As long as you aren't compressing the load by a great percentage. The best shot group I ever produced was the very first 20 round shot group of my 7 millimeter mag with 140 grain Speer Spire point, with a load that was three grains over Max of h4350 but that was a 26-inch Barrel if I remember correctly. Because you have to give time for all of that powder to burn. Then you should be using a minimum of a 24-inch barrel for 175 grain 308. And a 22-inch barrel for the 168 grain Sierra matchking. Slow powder is very forgiving, but push that shoulder back as little as you need to for whatever chamber you're going to put that load in. On my 7 mm mag I only neck sized the brass because I only had the one rifle the Ruger Model 77. My 20-round group was .049 in spread. That's for all twenty rounds, I can cover the entire hole with a dime. In 1979 I thought that that's how guns are supposed to shoot, but the guy sitting next to me shoting a 22 250 benchrest rifle I'd never seen a group like that in his life out of four rounds much less 20. But it was a benchrest champion they gave me the load that was three grains over Max. Surprisingly it would also shoot Hornady bullets which are completely different in their shape just as accurate. Remember that the most recent accurizing activity buy firearms manufacturers, especially with these benchrest rifles read things like the Ruger precision rifle, is a tighter chamber. So try and keep all those Dimensions within .002 or less for any expansion of the brass within the chamber. Because your functionally decreasing chamber size if you increase the brass size. You've got brass Dimensions there function to a semi-auto chamber. When you're using them in bolt-action rifles. And once again, slow powder is very forgiving. And I did notice that you have some cases there that will hold a full three grains more powder than other cases. That's why there's a difference between military brass and 308 brass. 308 brass is civilian brass and it does not nearly as thick and durable as military specification brass. Your problems with the stress on the brass, or indicative of using direct impingement without a good gas adjustment. I have never liked direct impingement systems that's why I never bought an AR until Ruger came out with theirs. And I bought an sr25. To go with my M1A my Sako Finn wolf oh, and my Ruger heavy barrel 1972 Model 77

[@rider547]

Try AA 2495. I’ve had good groups with it in my RRA LAR8. Worked well with both 168 and 175 gr Match bullets. Thanks for the great videos!

[@44hawk28]

Not too long ago somebody was working on a 155 grain bullet that supposedly had better BC the 175 grain match Kings, I don't know whether or not they ever got it out. But if that bullet is available try that in that 20 inch barrel. You may like it and the gun may like it a lot better. Why don't you deburr that ejector just a little bit. Still another reason why I don't like direct impingement. I'm not understanding these numbers either. I still say your biggest issue is that short barrel. The rifle is still trying to get the bullet completely stabilized when it's out the end of the barrel. Direct impingement does not lend itself well to anything other than I am our powder. I am our powder was designed specifically for AR style direct impingement systems. Anything that approaches the behavior of ball powder gums up the works when used on a direct impingement AR. Another reason why I bought a piston-driven AR

[@tylerreeves5163]

I have the same set up, but with the Heavy Fluted Faxon Match series barrel, 20” 1:10 twist also, but i have yet to shoot it. Ill let you know how it goes with some Federal gold

[@ewathoughts8476]

First let me thank you for almost following my suggestion. I assumed you would not have Fed primers available. What I take away is that the new Fed ammo was more accurate than the reloads of the same cases. In my experience this is normal since the resized cases have larger internal volume and metal hardness than when they were new thus adding in variables. Resized cases will not expand in the exact way as they did when new. Different primer also adds another variable. Even using small base dies will not return the cases to new spec. If you inspect fired cases you will find that the case bulges unevenly towards the head, and even small base dies will not remove the bulge evenly. This bulge (stretching) will knock the base of the cartridge off perpendicular to the cartridge axis. The resized case base no longer lies flat against the bolt face, and if the headspace is zero, the projectile is cocked out of alignment with the bore slightly. It is hard to orientate the bulge into the chamber in an auto-loader consistently. Therefore each projectile leaves the cartridge canted to a different point of the clock. The result is less accuracy than we are hoping for. I my experience none of the concentricity gauges on the market are any good. The Hornady one measures between the bullet tip and cartridge base (rim) and does not take into account the bulge, and the others measure between the bullet tip and case sides (bulge) but do not take the rim into account. Therefore the axis measured is not the actual axis of the cartridge as it sits in the chamber. If you still have one unfired case of the Fed Match , measure the internal volume and compare to the once fired and twice fired Fed cases. How much % difference is there? This data might be interesting.

[@1RobHunter1]

My vote - Varget or Hodgdon 4895 at 41gr to 41.5gr in AR308. It mirrors the M14 National Match fps and soft recoil, more accuracy. The 42gr is a max in Semi-Auto's. I found Winchester Brass - very easy for case prep, more volume. Also in a 308 Win, you really need a 20" barrel at minimum for powder burn, velocity.

[@dolanhall1872]

Sure wish youd test with the Federal primers Johnny. You know what they are, not like its a guess like when you did the Black Hills 5.56 clone testing. Then the only variable is the few tenths of a grain difference in powder. The fewer variables you change, the better off you are and can validate what that 1 change did in comparison. Have you ever used a DOE (design of experiment)?

[@gordonv2456]

I would try H4895 if I had it. 42.5 and 44 are nodes for Varget(I use 42.5). I've had all the brass damage you are getting without a suppressor. I bought a carrier weight and it got me about another grain of powder. I have the adjustable gas. Move on to long range and try small targets with MOA loads with SD's in the teens. You might be surprised how well a Matchking flies after it settles down. I have 4064 to try but I also want to try it in my garands.

[@WestDesertShooter]

I’ve had great luck with 4831 I would be very interested to see such a slow powder in 308. I would suspect excellent SDs but slow velocity. Perhaps not the next video but I would definitely like to see it at some point!

[@stuckcase7775]

Velocity will falter significantly-can’t get enough in the case. I toyed with Imr 4350 at 50 gr-yep 50-neck sized brass with a lot of crunch-175 s barely fit in Magpul mags-depth ended when powder could not be crunched anymore-shot ok-velocity was 75’ less than max charge of Varget

[@danielgreene7987]

Power pro 2000mr works great in my ar-10 and ar-15. Most consistent groups in ar-10. I have tried cfe 223 but it's not as accurate in my rifle. I also get virtually no ejector marks with either powder at top velocities with slr sentry gas block adjusted right. The extruded powders almost always give me ejector marks in the upper loading range with ar-10.

[@DenverLoveless]

From Hodgdon: 175 GR. SIE HPBT .308 Winchester IMR 4064 41.5 45,200 PSI / 45.6C 2,728 59,500 PSI

[@jacquesbeliveau2716]

You should conduct a test on the constancy of primers by manufactures. If you use cci bench rest 2 has a start point for other comparison and consistency by manufacturer.

[@tedweldon8442]

I’ve been using the Caldwell G2 chronograph, it has its own lights so never any change for ambient light. Pretty cool with the chronograph on the top with the sensors pointing down at the led lights. All Bluetooth same app. Powder wise id says benchmark will be to fast might split the difference with something you know ramshot tac vvn530

[@rich1958]

I saw 3 unicorns, boogie man, and big foot over the last year but still can’t find primers.

[@av8rgrip]

I have been able to clone GM308m 168g smk with IMR 4064, but I have been unable to do the same with the 175 smk. I am using a REM 700 1/10 twist with suppressor that shoots .5 or less MOA with the GM308m2. I have been getting inconsistent velocities with the 175g bullet.

[@AWZ1287]

Part 3?

[@richardtibbetts5020]

IMR 4895..I use it in cailbers similar to the .308..and .308

[@stuckcase7775]

A man of reason. Awesome

[@gmcassell1]

got 1/2 inch groups using imr 3031 39gr with 175 smk. howa heavy barrel 10 twist

[@vinceacuna4060]

Have you looked into the Wiser precision Chrono mount for the magneto speed? The 6.5 Guys just did a review on it. It shouldn't have any affect on groups with nothing hanging on the barrel.

[@dross1492]

Possibly try Nosler in the same weights. My rifles like Nosler much better than Sierra?

[@skeezixzx9r]

Just spit-balling. Could a heavier buffer keep it locked up longer and eliminate the case damage? Great vids, keep plugging away!

[@burnsm2012]

Harold Lewis. The bolt will only unlock once the gas has traveled down the gas tube and unlocked the bolt. The buffer only slows the recipricstimg mass of the bolt. The dsmge is done inside the chamber with to high of pressure and or rough cuts on extractor.

[@AgileK9TopDog]

I added a KAK 5.3oz carbine buffer. It appeared to make a difference.

[@chrishoesel]

I'll be trying to add some more tungsten to my JPSCS in my LMT MWS which is over-gassed (and non-adjustable) for just this same reason. I'm experiencing all the same symptoms that Johnny is. I'm also using LC and IMI match brass. I lost 600 pcs of new IMI match brass that I fired suppressed and blew out all the primer pockets, plus I could not get to resize at the base. I concur on the IMI match brass H2O capacity being 54.3-54.4

[@Ghostrider-71]

Just getting started with reloading for rifle.....great video, very helpful.

[@meanman6992]

Sounds more like a timing issue than amount of gas. No easy way to mess with timing.... but for suppressed use it sounds like there needs to be a bit more delay before the bolt starts trying to unlock and extract. I seem to recall Armalite held a patent on the (real) AR-10 BCG that had a slight change in the cam grove which slightly slows down and delays the unlocking and extraction. Anyone care to comment or correct be my guest.

[@rjm_338lm7]

Can you please do a M118LR and MK316 equvilant evaluation/development similar to your MK262 series? The powder in the M118LR has been documented as R15 and IMR 4064 (41.75gr) for MK316. I also have tried the GM308M2 as well as the GM762M2. When I acessed the GM308M2, the powder carge was in the mid 40's for 10rds. The GM762M2 averaged 43.3gr for what looked like IMR4064. I was getting rougly 2775fps from a 25" M40A5 clone with the 762M2. Also pierced primers with M110 clone 20" build with krieger barrel 1/10 twist. Went back to the 308M2 and was hovering around 2700 +/-. Let me know wat you think...we can share data. I have recently settled on 41.8gr IMR4064/CCI 200 Primer/Federal brass/175gr SMK/COAL @ 2.820". This has shown to be very reliable across multiple platforms.

[@stuckcase7775]

IMR 4895, 4064, 3031, 4320 all work well. REL 17,15, 12 also work well. Varget, win 748 throw them in also with about half a dozen newer mixes. This is why the 308 makes great sense in the time of designer cartridges

[@The_Cyber_Nomad]

Moist air is less dense than dry air. The humidity from the rain could be having an effect on the velocities.

[@roadrunner1960]

IMR 4895, Good video Johnny

[@ElTerrible666]

The brass might be soft. Try some 7.62x51 brass. The ejector marks are from chamber pressures. You’ll get extractor marks from over gassing.

[@snakeyes7711]

That "mysterious" velocity plateau is a velocity node.

[@volanteaggie]

So I spoke with my socom buddy who texted one of the guys involved in the mfg of the m118lr. He confirmed that it is imr 4064 and currently loaded with 42.5 gr. It used to be rl15 but they switched (didn’t know exactly when) because of the better temp stability. This is second hand so take it for what it’s worth.

[@chuckfinley3152]

John C i can confirm this, pulled a couple of bullets from gmm and they were 42.5gr, it “looks” like 4064

[@firearmsfuelfabrication]

I run an oss helix 7.62. It has no effect on the gas system.

[@f22cap2s2k]

Im running 43.5gr 4064 with a 178gr Hornady BTHP. Avg 2625 fps. A bit high pressure...ejector marks and deposited a few bits of primer on 3 rounds into the suppressor. Guess I need to come down to 42.5?

[@jerrysnyder9388]

Couple of questions = how does the 2.800 fit into the Pmags? and did yoy crimp the loads from today? Thanks

[@deist3r]

Your attempt to replicate the military round/Federal factory is actually close to the spec they asked for from manufacturers making their 175gr round. Maximum average of 1.3 MOA = approx. 1.3611 inches. It's possible IMR 4064s consistency meets that standard but limits you to get smaller groups. I vote a different type of powder if you're gonna chase sub-1inch/1moa group

[@saulcardenas1268]

Johnny, if you haven’t done so already, can you put together a vid of what equipment you have and use. I want to get into reloading, but I am not completely sold on kits. I don’t want to buy a kit just to upgrade later. I want to get it close to right as possible the first time. I shoot 5.56, 224 Valkyrie, 6.8 and 308, 9mm and .45. I also shoot the actual Mk 262 Mod 1 with my issued match rifle. I watch your videos closely to see if in the future I can find a solution to out perform my issued ammo.

[@paulharveu526]

Saul Cardenas check out his beginning to reloading series. It's probably the single best, how to start source I've ever seen.

[@saulcardenas1268]

Paul Harveu, I have seen the episodes that you mentioned. I see him using the Redding T7 more than he does the presses in the above mentioned episodes. I would like to know what he uses now and the most. I also agree with you, he is my go to guy to learn the art.

[@garysnyder527]

I started out with a Dillon Progressive and wish I had done otherwise. Live and learn. Today I would go with a Mac press and Redding dies . Buy a match die set and watch several reloader's videos.

[@Kurogane_666]

I have to ask, what bullets would you suggest, closest match and hunting bullets, I want to use as close to the same weight as I can

[@tjarmand]

is the gempro250 worth it jrb?? im thinking of getting one to add to my rcbs charge master lite.. get it to under one gn of what I want the trickle up with the gempro.. what do u think?? starting f class finally this yr so trying to get the sd and es down just a lil more.. I usually get around 5 to 8 sd so im not sure if it will help much but if it might I am willing to try..

[@BlackdogADV]

I have an identical barrel and receiver. Looks like out barrels favor 168 gr.

[@dalefrahm9060]

He should do a part on Varget it shoots really well in my LR308 DPMS 24" barrel. I've got way below sub moa

[@thepoorfarmer8829]

4064 and varget shot almost identical in my.308

[@stroudads]

I run IMR 4064 at 43 grains with a 168 and it’s a tack driving machine in my savage model 12

[@tooks1509]

I use 4064 because I also loaded 223 and 3006 with it…. I’ve been using the same 7 pound jug for about two years now.