FireShooter Posted July 22, 2014 Share Posted July 22, 2014 I just built my first 308 gas gun. It's based off a DPMS platform. 18" JP enterprise bbl, 1:10. Sun devil receiver set, and all jp internals. I'm wanting some long range loads for this thing, so I loaded up 168gr BTHP over 46gr Varget to 2.800". It chrono at 2750 avg. but the groups are absolutely horrible. Am I pushing this round too fast or should this load be holding descent groups. I'm talking 4" groups at 100yds, and most of it is not me. Any ideas? I'm new to reloading so any help is awesome. Link to comment Share on other sites More sharing options...
andrewst359 Posted July 22, 2014 Share Posted July 22, 2014 I'd do a ladder test and find out what your rifle likes. Link to comment Share on other sites More sharing options...
sschultz Posted July 22, 2014 Share Posted July 22, 2014 Or try a differant brand of bullet. Link to comment Share on other sites More sharing options...
striped1 Posted July 22, 2014 Share Posted July 22, 2014 start with Federal Gold Medal Match in 168 and 175 and see if that groups any better. You then at least have a consistent place to start to begin to eliminate variables. Link to comment Share on other sites More sharing options...
RiggerJJ Posted July 22, 2014 Share Posted July 22, 2014 Why would you start with the max load for that bullet? All loading mfgs suggest starting at 10% below minimum, which is 41gn for that bullet...so you should be starting at about 36-37gn, not 46. I agree with striped1, get some match ammo and shoot some groups first, then start low and work up with your Varget/168 load, cronoing and shooting groups. That way you will find the optimum load easier and safer. jj Link to comment Share on other sites More sharing options...
Nugget Posted July 22, 2014 Share Posted July 22, 2014 That load seems pretty hot for a gas gun. Any pressure signs. Fastest load is not always the most accurate load. Link to comment Share on other sites More sharing options...
ToddKS Posted July 23, 2014 Share Posted July 23, 2014 Back that charge off to 41.0gr and work up from there in .5gr increments. Fastest load is rarely the most accurate. That said I just spent some time working up 308 loads for a friends M1A. Varget is my powder of choice but it did not perform well out of that semi auto. Ramshot TAC performed best followed by IMR 4064. Link to comment Share on other sites More sharing options...
FireShooter Posted July 24, 2014 Author Share Posted July 24, 2014 (edited) Thanks for the help. I tried some ladder testing, as well as some FGMM 168 and here's the results. Apparently I was loading the 308 way to hot for a gas gun. I slowed down the bullets and went up to a hornady 178gr hpbt match. The FGMM held at .6 moa and the 178 gr with 40.6 of varget held .45 moa with 1 flier. These are both 5 shot groups. Edited July 24, 2014 by FireShooter Link to comment Share on other sites More sharing options...
FireShooter Posted July 24, 2014 Author Share Posted July 24, 2014 This is the 178 with varget Sent from my iPad using Tapatalk Link to comment Share on other sites More sharing options...
FireShooter Posted July 24, 2014 Author Share Posted July 24, 2014 And here's FGMM 168 Sent from my iPad using Tapatalk Link to comment Share on other sites More sharing options...
FireShooter Posted July 24, 2014 Author Share Posted July 24, 2014 These are at 100 yards at 3600' elevation at 95 degrees. Not bad for a gas gun in my opinion. Of course the nightforce 5.5-22x56 helped me out quite a bit. Sent from my iPad using Tapatalk Link to comment Share on other sites More sharing options...
Doc Hunter Posted July 26, 2014 Share Posted July 26, 2014 (edited) What brand bullet. If they are Priv-Part you are wasting your time and money. Mixed brass will also be a fail. Edited July 26, 2014 by Doc Hunter Link to comment Share on other sites More sharing options...
dauntedfuture Posted July 29, 2014 Share Posted July 29, 2014 FGGM is darn good ammo and it will be hard to beat that. DO NOT RELOAD the new federal brass, it is very very soft. Stay away from the Privi bullets, they don't shoot well. The 168 BTHP is an overall good bullet but its old technology. The new "better bullet" replacement would be the 175 BTHP, you can load it almost as fast and the ballistics are better, out of a 22" barrel you can keep them supersonic at 1000 yds, not so with the 168. With that said I would try some Sierra 150 BTHP match bullets if your shooting 500 or less, the profile is the same as 168's with a shorter shank; they will likely shoot as well with less recoil. This aside, I would error on the side of accuracy and function over attempting to hot-rod the .308 like in a .308 30" barrel palma gun. Your real velocities will be slightly less than what's in the books with your shorter barrel but you will likely not see a difference until you get past 500 yds. Link to comment Share on other sites More sharing options...
Howa4au Posted July 30, 2014 Share Posted July 30, 2014 The 175's-178's are much better for long range but my gas gun didn't like them as well as the 168's- especially 168 Amax. You are definitely running them too hot with 46 Gr of Varget. I would stay under 45 grains. I am getting my best groups at anywhere from 43.5- 44.0 grains. About 2,650 fps Link to comment Share on other sites More sharing options...
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