Gas Gun Loads .308

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castingdonkey

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I was browsing the web looking for a thread where multiple re-loaders agree'd on a good Varget load for 168 smk in .308. The Hodgdon data showed 42-46 grains. Shooters that had been out with their AR-10's were saying that 41.0 was primo. That 43 was higher than they would push it. I know we hear all the time to start low and work up in .5 increments. I went ahead and loaded 3 of each load starting at 41 and walking it up to 43. Is anyone on here loading hotter than that in their gas gun? Should I bother loading any hotter than that? I really don't enjoy removing projectiles to salvage components.

FYI I've read 50 threads about how IMR makes a better powder for 308's. I finally found some Varget and want to load something with it.
 
I tested Varget in my M1a's and my lots were too slow and caused case head separations. Pressures at unlock were too high.

Varget is an outstanding bolt gun powder, I believe a number of F Class records have been set, and National Championships won, with Varget and 185 Bergers, but this is in bolt rifles.
 
Bigbore it looks like you were loading 155's have you loaded any 168's? I've been loading sierra 2125's with H335 and getting great groups. Swapped my scope out for a long range scope and started tagging steel at 600 with the 2125's. Wanted to go for 800 figured 168's would get it done. Hope I don't get case head separation, that would not be cool.
 
I tried a few 168s but I didn't like the low velocity. I wanted to run the same weight hunting bullet's as my target bullet's. So went with the 155 spmk and 150 sgk. The velocity out of the 18" auto was to slow with the heavier hunting bullet's for reliable expansion past 300 yards IMO.
 
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Scroll down the page to the .308 Winchester loads. You will see loads for 168 grain bullets like the Sierra Match Kings or similar including Varget load data. Varget starts at 35.5 gr and works up to 42.7 gr. Max Load. That Maximum is service rifle loads and can be taken to 44.0 grains at your own risk depending on the rifle used. The 42.7 grain load in an M1A should get you up around 2600 FPS, your mileage may vary.

You do not mention the gas gun but for M1A Varget is about the slowest powder I would want to use. Actually in my own M1A I tried it but never went back to it. I like the tried and true H4895, IMR4895, IMR4064 and a powder I have done well with in bolt and gas guns (M1A and AR-10) has been AA2495.

Ron
 
In my own admittedly short reloading experience, H4895 has been the magic fairy dust for my most accurate .308 loads.
 
Thanks guys, I went to the range this morning and shot the loads mentioned earlier. Went home and loaded up 40 more at 41gr. Had a blast beating up the 500 yard steel targets. The rifle is mid length PA-10 16". I have a 6-24 Viper PST FFP EBR2. Built it on a budget, Palmetto sales and Black Friday deals. Figured with all of the internet hype that I'd have my work cut out for me making some repairs but the rifle seems to function flawlessly. It's the only AR-10 I've ever shot though. ReloadRon I'll scroll down and check that out, thank you. Next load will be the 175 SMK's.
 
.308 ammo used in M1 and M14 match rifles won and set records with IMR4064 moreso that with 4895. So did the .30-06 before the .308 kicked it off the firing line.

In the .308, 44 grains under 168's, 43 under 180's and 44 grains of IMR4064 with a 169. Military teams loaded thousands of rounds of the same lot of ammo to be shot across a dozen or so rifles. All shot that stuff in new cases about 2/3 MOA tested at 600 yards.

With the shorter barreled AR platforms, to keep the heavier bullets leaving fast enough to stay supersonic at long range needed powder charges that were over SAAMI spec. The Army Team did great with Berger 185's in their AR10s with 20 inch barrels winning and setting records.
 
Thanks again guys, I went shopping today and managed to stumble across some 175 smk's and a couple pounds of IMR 4895 and 4064. Brass is tumbling....
 
Have you figured out how to get them to the door for less than 40 cents a piece? I'm heading to the poor house with my reloading bench!
 
When I shot a lot out of the AR10 gasser I used 42.5g varget and a 175 smk. It shot very well and I never saw a need to find a higher node or push it harder.
 
Thanks Red B, I'll be working that load up from the 41 here soon. 41 grains of Varget under a 168 smk shot really well out to 800 yesterday. We decided to walk out to 1,000 but only had one 168gr cartridge left. It landed at bottom center missing the 1k yard steel plate by about 1'. Put the 175 smk's in and smacked the 1,000 plate repeatedly. 48 & 48.5 grains of 4895 showed no signs of higher pressure. We will be working that load up higher too. I screwed up yesterday and dumped the remaining imr 4895 back into the can of 4064 that I hadn't even used yet. Not happy about that, I guess I have some more cannon propellant.
 
The 168gr SMKs are not popular for ranges past 800 yards, most people that like to shoot long range use bullets that weigh 175gr or more. To get the 168gr SMK up to supersonic speeds at 1000yds you need a longer barrel and different powder (a good 32" barreled bolt gun would help too). But even then the greater mass of the 175gr bullet will hold it's velocity better and it will resist the wind better. Varget is used by quite a few people but it's not my favorite for the .308. I've gotten very good results using IMR 3031 under a 175gr SMK out to 1100 yards with my M1A Loaded model rifle with 22" barrel. I also use IMR 3031 with my SOCOM model rifle that has a 16.25" barrel. The short barrel is just as accurate but it doesn't reach out as far because you can't push the bullet to the higher muzzle velocities. IMR 3031 is a very useful powder for gas guns.
 
I definitely noticed a 1/2 mil less hold over on the 175 vs 168. Thanks for the advice, when I get back from work in a week I'll be back at it.
 
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