Reloading for the AR10

Discussion in 'Reloading' started by jlamb, Jul 26, 2010.

  1. jlamb

    jlamb Well-Known Member

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    Does anybody reload for the AR10 in 308? I'm going to just use standard data for 150grn BTSPs and RL15. Has anybody backed off their loads because the AR10 is a semi-auto action?

    Thanks!
     

  2. Longshot38

    Longshot38 Well-Known Member

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    I load for a DPMS 308 and use standard load data. If the gas system on a AR is configured correctly then there is no reason standard data can't be use. This is where an adjustable gas system comes in. It is not something that is a must but is sure is nice when getting thing tuned correctly (especially when suppressing a gas gun).
     

  3. jlamb

    jlamb Well-Known Member

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    Thanks, I'll give it a try. :D
     
  4. RockZ

    RockZ Well-Known Member

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    I called Sierra and the ballistic tech said back off
    1.5 gr. From max
     
  5. Kevin Thomas

    Kevin Thomas Well-Known Member

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    Jlamb,

    Same data should apply, just make sure you're using powders suitable for the gas operation of the action; basically mid-range burning speeds such as 4895, Varget, and yes, RL-15. You should heed the advice to back down if you're using military 7.62mm brass, as it is a bit thicker than the commercial stuff. It's also good to use in autoloaders, since it's made with gas operation in mind.

    If you haven't loaded for autos before, they're different and need to be treated as such. Small base dies, possibly, but full length resizing ALWAYS. Use chamber gages on the completed ammo, and use them or a bump gage to set your dies for resizing. Not the same thing as loading for a bolt gun, but not really difficult, either.

    Kevin Thomas
    Lapua USA
     
  6. Nomad

    Nomad Banned

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    Have loaded for auto-loaders learned that the small base do a good job and
    usually get about 4 or 5 reloads on your brass, military spec holds up the best.
    Powders from H332 to H414 will work, varget and reloader 15 seen to be the
    standard but h4895, blc2, W748,h335, tac, 4064, Imr 8208 all do very well.
    Imr 8208 tested recently showed great results..
    Varget at 44.5 win brass cci 200 showed good results in a couple of semi-autos.
     
  7. jasonprox700

    jasonprox700 Well-Known Member

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    Loading for your AR10 isn't much different than any other gun. I have 3 AR15's and 1 LR308 (DPMS' version of the AR10). I use the standard load data. I do the same with my gas guns as I do with my bolt guns, start low. I will usually back off a couple grains at least and then work my way up. Pressure signs will be about the same, so nothing new there.

    As for small base dies, I think that all depends on the gun. What I found with my .308 is that I need to keep my brass somewhat clean. If it has some sizing lube or grime, it may give me problems with continued shooting.
     
  8. lynxpilot

    lynxpilot Well-Known Member

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    I would always start at the recommended lowest load and work my way up just like any other load. I've heard, but have no scientific data to back it up, that loading between autoloaders and bolts is no different. I have an adjustable block on mine and tune it to just-cycling and no more. On my loads lately on a DPMS LR-308, I'm using IMR-4064 below Hodgdon's maximum, but above most others' maximum for that powder and that bullet (175 gr Sierra MK HPBT). Seems like IMR-4064 gives the best MV's at acceptable pressures and I like it. I full-length resize every round because it is an autoloader and I use CCI-34 primers because they are designed for free-floating firing pins. I guess the bottom line is, that no, I wouldn't back off on anything so long as you use the standard procedure of starting at minimum recommended load and working your way up, constantly looking for pressure signs. Then again, that's just academic and you know it already.
     
  9. jlamb

    jlamb Well-Known Member

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    Thanks guys. I reloaded some 168 SMKs and found that 43.0 grn of Varget gave my under 1", 3-shot groups through my 16" barreled DPMS AP4. I think a new trigger will make those groups even smaller.

    Any advice on AR-15 triggers? The DPMS LR308 takes the standard AR-15 trigger assembly.

    j
     
  10. lynxpilot

    lynxpilot Well-Known Member

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    I just ordered a Jewell for the DPMS. The DPMS trigger is pitiful, to say the least. I could let you know in about a week on the Jewell. Web searches indicate Jard is inconsistent and Giselle is very expensive but good, but you'd have to find out on your own about those. There are also folks who do aftermarket mods like polishing and such, on the stock trigger, and they are apparently very well done. I've heard those are very inexpensive compared to replacing the trigger.
     
  11. jlamb

    jlamb Well-Known Member

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    Thanks. I'll look for your post.

    J
     
  12. jasonprox700

    jasonprox700 Well-Known Member

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    I had my trigger done by Bill Springfield. Although not nearly as crisp as say a Jewell, it is very good for only $35 and the turn around time is fast. I use mine for close in woods hunting, so benchrest accuracy isn't a concern. Even with this trigger, I can still group most loads at or below 1 moa.

    I am planning on doing a .260 build in the next couple of years for long range plinking and varmint hunting. I will spend the money and get a good trigger for that.
     
  13. jlamb

    jlamb Well-Known Member

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    Most gunsmiths around Salt Lake have just suggested a new trigger. I figure that I can put it in no problem.
     
  14. edward hogan

    edward hogan Well-Known Member

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    Can't use slow burn rate powders with gas operated semi rifles...

    IMR 4064 & 4895 are about the standards; Varget and Reloader 15 also are excellent.

    The Sierra manual has a section on match ammunition, check out the loads for Service Rifle and use them as your guide.


    The RRA 2 stage NM trigger is pretty decent for $130. Might want to use an RCBS Precision Mic or Wilson Case Gauge on your DPMS to evaluate your chamber dimensions. Can spend a lot of money on a match trigger, but if your chamber is crowding the far end of a No-Go dimension, which is to say it is very long OAL; you won't get the performance you expect, if shooting commercial or even match loads. Then there is the barrel itself. Not like DPMS puts match grade barrels on its production rifles.

    Glen Zelliger's books Competitive AR one and two are both good reads and can give you many insights about getting all possible accuracy from your DPMS.