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Posted: 12/18/2012 2:17:29 PM EDT
| Working up a load for LAR-8. Using CCI large primers, H4895 powder, LC brass, and 175 grain FMJBT. The "sniper bullets" from wideners. Loaded up some with 38 grains of powder with mixed results all fired, but not real consistent groups. Anybody have any experience or powder/grain recommendations here? Thanks |
| It is a 1:10 twist, primers look fine at 38, so I am going to work up in .5 to 40 grains. Once I get the best group work in .1 up and down from there to get the best powder ratio. Is that twist compatable with that bullet weight? I am also going to buy some higher end bullets it the best weight for that twist. Thanks |
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I lean a bit toward old school approaches but if you are shooting 600 yards or less a 168 gr MK will do the job just fine as will a 165 gr BTSP for use on game.
The 175 gr MK really comes into it's own at 800-1000 yards where the round stays supersonic longer and transitions better. Weight wise it's a bit past the sweet spot for the .308/7.62x51 if you're looking at a hunting load. I shot thousands and thousands of 173 gr FMJBT bullets in both M118 Ball rounds and as components received through DCM for match shooting. As FMJs went they were not bad bullets, but they were never up to the same accuracy standard as the 168 gr MK. The 175 gr bullets from Wideners are longer than a 175 gr MK, so barrel twist may be an issue with them and they are 1) FMJ and 2) not match grade, so you'll probably get better results if you sort them by weight and then inspect the bases for consistency. I tend to take that as a given with any bulk bullet, if I expect to get anything resembling decent accuracy. The major accuracy challenge with FMJs is that it's much harder to get a consistent base shape. Most companies use a very small hollow point in match bullets as it's a low drag point and it allows for far more control and consistency in the base when making the bullet. Another low(ish) cost option for you might be the Nosler Custom Comp FMJBT. They seem to be more accurate and are less expensive then a MK. Load wise I am a fan of IMR 4064 but that's a hold over from loading rounds that functioned well pressure curve and consistency wise in match grade M1As and M14s. I load for a specific velocity but it tends to be around 43 grains of 4064 with both 165 gr BTSPs and with 168 gr Mks. |
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Load wise I am a fan of IMR 4064 but that's a hold over from loading rounds that functioned well pressure curve and consistency wise in match grade M1As and M14s. I load for a specific velocity but it tends to be around 43 grains of 4064 with both 165 gr BTSPs and with 168 gr Mks.
43.0 of 4064 or Varget should be a good load for anything from 125 to 180. Agree that 168s are the best all-around compromise for anyone getting started. Most will never shoot past 200-300, let alone to 600 or farther. |
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Quoted:
Load wise I am a fan of IMR 4064 but that's a hold over from loading rounds that functioned well pressure curve and consistency wise in match grade M1As and M14s. I load for a specific velocity but it tends to be around 43 grains of 4064 with both 165 gr BTSPs and with 168 gr Mks.
43.0 of 4064 or Varget should be a good load for anything from 125 to 180. Agree that 168s are the best all-around compromise for anyone getting started. Most will never shoot past 200-300, let alone to 600 or farther. I'll add this comment out of concern for safety. 43 gr of 4064 under a 180 gr bullet is not safe in my rifle. I use 42 gr and it is as far as I feel safe pushing it. It's probably okay under the lighter bullets (below 160 gr) but I would say it is not safe above that. The moral here is simple - start low and work your way up. |
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Be careful not to slide bolt gun data into gas gun use.
Dakota Fal mentioned 168s. He mentioned IMR-4064 as well. ReLoder 15 is another. My advice, buy a Sierra load manual. I'm not saying that in the context of you need a manual either. I'm saying Sierra manual for your application is a performance tool. Read, study, reflect what's being used in rifles like yours and good things will happen. 168s are outperforming the 175s in LaRue and DPMS. Build a good cartridge and for the cost vs groups debate. DPMS is the better value. What am I saying ? It's more about how you load for the gas gun than what brand of gas gun. |
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43 or so grains of IMR 4064 is not a max load in my rifles with a 165 gr or 168 gr Sierra, but be sure to work up your own loads as YMMV.
Something else to consider... While there is basically no difference between US commercial .223 brass and 5.56mm NATO brass, that is not the case for .308 and 7.62 NATO brass - the wall thickness of 7.62 NATO brass is much thicker and the case volume is consequently smaller, so pressures will be higher. For example, a max load for a 165 gr BTSP in a bolt action may be 46 grains of IMR 4064 with a commercial case, but with a military match case you may get similar velocity and pressure at 43-44 grains, and a 46 gr load would be dangerously unsafe. |
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Hodgdon shows 40 - 42.7 grains of H-4895 for 175 grain bullets. I realize you said LC brass but I believe you should increase your powder charge.
I also agree that you need a better bullet for accuracy work - try the Sierra MK or Hornady AMAX or Match or Nosler Custom Comp. |
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