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Posted: 5/5/2017 11:21:39 AM EDT
| I have a PSA 308AR on the way. Up to this point all my 308 reloading was for bolt guns. Is there anything I need to know about loading for a gas gun? I will be loading on a Dillon so ball powder is preferred. I would also like to use 150gr bullets but not totally set on that. |
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You are in for a steeper learning curve than most other calibers. .308 brass varies widely making it impossible to safely mix and match case brands, even for blasting ammo.
I use Lake City or IMI brass when reloading for .308 semi-autos and I resize them to SAAMI go-gage specs, the minimum allowed headspace for a new rifle leaving the factory. I use 168 grain bullets 90% of the time because they shoot so well. I suggest you buy a 1000 bullet box of Nosler .308" 168 grain Custom Competition bullets. They are the best deal available for true match grade ammo. Nosler also sell a 155 grain .308" match bullet in 1000 bulk boxes if you're dead set on lighter weights. When loading 168 grain match bullets seated at 2.2800" oal I've used: 43.0 grains of WW-748 40.5 grains of AA-2460 40.0 grains of IMR-4895 41.0 grains of IMR-4064 40 grains of H4895 41.5 grains of VihtaVouri N150 40.5 grains of VihtaVuori N140 41.5 grains of Varget 41.5 grains of RE-15 ...................................all near or at maximum charge weights when loading Lake City or IMI military surplus brass. Military surplus usually weighs close to 180 grains empty and unprimed. Winchester commercial brass can weigh as little as 155 grains. The difference is the thickness of the case heads and cartridge walls. DO NOT MIX THEM UP. The VihtaVuori powders are relatively fine grain and should work fine through your Dillon. The H4895 is finer grained than the IMR variety and should work OK too. Varget and especially IMR-4064 will give you fits through a Dillon. Semi-auto .308 can not handle loads anywhere near what bolt actions can. Starting loads in many manuals are close to maximum when using military brass in semi-auto rifles. If you can find a copy of the NRA book, now out-of-print, titled "Semi-Auto Rifles - Data & Comment" buy it. It's still widely available from online used book stores. It has several articles using pressure testing equipment and over 1000 rounds tested developing match grade .308 ammo for semi-auto rifles. The author (William C. Davis Jr.) served as the US representative to NATO for ammunition compatibility and development. He's one of the most highly respected ballisticians of the 20th Century. |
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I have an ar308 and got .75 MOA using Nosler 168gr custom competition bullets. Rem 9-1/2 primers, PPU brass and 44.5gr of varget. 2.801" COL
My gun is picky. I measure every powder charge. I don't shoot enough to use a powder dispenser. I'll load 20 rounds a week for a caliber for a month then shoot them. |
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sorry man, that old "not for semiautos" is for the M1/M14 type, and does not apply to AR10's. They can handle commercial loads and heavy bullets as well as any bolt gun that would break parts on an M14. Its not that its a semi auto, its the op rods that suffer on the older ones and is the limiting factor. In the AR10 you can use the reloading maunuals like any bolt gun and work up to find the accuracy you want and check for pressure indicators, most notably on the AR10 are ejector marks.
I know you used to be associated with the AMU, and I respect your experience, however its just not the same when using an AR10. Matter of fact the AMU load for their AR10 with 185's has been 45.0 Varget and was recently swithched to 44.5 of varget, same load they use for the mag length 175 load in those rifles. Old lots of M118LR that were breaking M14's in Iraq with the old load (44.3 RE15) function fine in the M110 (and any other AR10) even in the heat. I know you will disagree and fight it, and that's ok. They are two different systems and the AR10 does not have the limitation of the op-rod which was the cause for the restrictions to "semi autos" in the past. |
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That is the best way to do it, just one brass type. I chose and ordered a bunch of LC OFB, and that is all I feed my AR 10.
Using 150gr FMJ's for now, but have a decent supply of 168gr mil spec from Widener's to use someday. So far I have just used RE-15 and the 150's. The book mentioned above is a good source. |
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For AR10 types, I've found the 150FMJ to be quite accurate (right around 1MOA - pretty good for a non-match bullet).
I have a Dillon press and have had excellent results with W748, TAC, W844, and W846 ball powders, especially with reduced loads that are not at max pressure. I use the OBT and QL method described on this site and elsewhere, and have found that node 7 (around .958ms, around 45kpsi, 2450fps+/-, in a 16" barrel) to be pleasant to shoot, accurate, and easy on the brass. |
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Win is good 308 brass, and significantly lighter than most mil surplus or Fed. Lots of good powders, am liking 748 with mag primer (CCI 34). Of the 2 ar-10 styled rifles owned, neither is accurate with less than 165 grainers. Both have 1::10 twist. Like always, a lot depends on individual rifle, rifling twist gas port size.
Would also not use the heaviest loads in ar-10, even though they may be able to take more than an op rod type. Case head swipe is something to look out for, and not necessarily indicating higher pressure. Related to powder speed, port size and recoil spring/buffer weight (timing). |
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Quoted:
sorry man, that old "not for semiautos" is for the M1/M14 type, and does not apply to AR10's. They can handle commercial loads and heavy bullets as well as any bolt gun that would break parts on an M14. Its not that its a semi auto, its the op rods that suffer on the older ones and is the limiting factor. In the AR10 you can use the reloading maunuals like any bolt gun and work up to find the accuracy you want and check for pressure indicators, most notably on the AR10 are ejector marks. I know you used to be associated with the AMU, and I respect your experience, however its just not the same when using an AR10. Matter of fact the AMU load for their AR10 with 185's has been 45.0 Varget and was recently swithched to 44.5 of varget, same load they use for the mag length 175 load in those rifles. Old lots of M118LR that were breaking M14's in Iraq with the old load (44.3 RE15) function fine in the M110 (and any other AR10) even in the heat. I know you will disagree and fight it, and that's ok. They are two different systems and the AR10 does not have the limitation of the op-rod which was the cause for the restrictions to "semi autos" in the past. Caveat: USAMU Armalites use rifle-length gas systems, and the firing pins are very tight in the firing pin hole in the bolt face. Anything with shorter than a rifle-length gas tube and some other bolt face may give you blanked primer cups. USAMU's record-setting loads pushed Berger 185 Juggernauts. |
| Prob already know this.. but semi's require a bit more neck tension due to the cycling forces.. 3-4 thousandths seems to be the going average. If 4 thousandths doesn't cut it then a light crimp may help. The BCG on mine is pretty heavy and causes bullets that aren't held tight to slip longer (COAL grows) when the bullet comes to a stop in the chamber (same principle as an impact bullet puller).. so I need a light crimp, and with my shooting it hasn't made a difference on accuracy. |
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Quoted:
Caveat: USAMU Armalites use rifle-length gas systems, and the firing pins are very tight in the firing pin hole in the bolt face. Anything with shorter than a rifle-length gas tube and some other bolt face may give you blanked primer cups. USAMU's record-setting loads pushed Berger 185 Juggernauts. |
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I'm about to start loading for my GII. So no experience loading for it.
But I've loaded for the M1A for years. Lots of "stuff" out there about loading for semi-autos that my M1A doesn't seem to be affected by. I do not mix GI and civilian brass but I do mix civilian brass, always have. No issues. Military brass does have less case volume so you do need to load less powder. I've used standard .308 dies (Pacific/Hornady, Lee and RCBS) and never seen an issue with any of them. I've never been able to get IMR 4895 to meter consistently. Not in the Lyman 55's, nor the RCBS Uniflow, nor the Lee plastic powder measure. I still use IMR 4895, but I use a Hornady electronic measure/scale unit to do that. I've not yet experimented with TAC for the .308. In the past I tried W748, H335, IMR4064, W760, and a few others but got best groups with IMR 4895. Sierra bullets gave me better groups than Hornady or Speer bullets. Never tried any other brands. 180 grain Sierra Matchkings gave me the best groups at longer ranges (600 yds.) so I used them for 300 and 100 yds. as well. None of that may apply at all to the AR10. What will apply is consistent brass preparation. Consistent powder charges. Consistent bullet seating. And working up the most accurate load for your rifle. In my experience, with most every rifle I've got, the most accurate loads usually are a couple hundred feet per second below the maximum loads. Good luck with it. Keep us informed on the powders/bullets you try and what you find that works (reliability and accuracy). You might find some things that will help me when I start loading for my GII. |
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1 st thing I learned when loading for AR 308 rifles is the sizing of cases. I have reloaded 308's for bolt guns ,garand 308's (so called Navy Model )
My original reloads would not chamber and had many feeding and other problems. Use your 308 case guage and make up some dummy loads (no primer,powder) and see if a couple of your dummy loads will feed and chamber ok. 2 nd thing- These rifles will shoot just about any reasonable powder/primer/bullet you could make , but start low and stay below max charges. Enjoy John |
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