Trying out 150's in the 308 AR10

TexMex247

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So I had previously churned out several batches of 175gr bullets hoping to find the perfect middle ground that would run through a bolt rifle and a gas gun equally well. I hit a ceiling of about 43.5gr IMR 4064 in the gas gun before it's starting to show light pressure signs. The bolt rifles groups that load sub moa(5 shots)with maybe an outlier pushing it to an inch and a quarter every once and a while.

The gas gun would still hover from 1.25-1.5" which is still good enough. On my last outing I put a couple 150gr Sierra FMJs through it and although POI was way off I saw a lil cloverleaf happening. So I thought might as well roll with it. That load at 45gr IMR 4064 also had extremely light ejection marks.

That being said, I think it's time to commit to a different bullet weight and see how it goes. I have no intention of ever shooting the gas gun over 300 yards so the lighter bullets should suit. I decided to duplicate the 45 gr loading and bump them a half grain down to load some Hornady SSTs.

The SST takes up a lot more space in the brass so I'm hoping 45gr(C) isn't going to be too rowdy on the gun. I also have BLC2, W748, XBR8208 and Tac rifle powder all in my back pocket. It would be great to find a load with TAC or BLC2 since a have several pounds of those. If any of y'all have been down this road before it would be great to hear about where you wound up.

I'm looking for an accurate but affordable target load so I'd like to keep the projectile costs under 30 cents each. If the SSTs work out I'll be a happy camper as I'm confident it could be a one size fits all round for hogs, deer, coyotes, punching paper and ringing steel.
 

Dawico

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I worked up a load with 165gr SSTs for a bolt gun in 308 using H4895. Shot about 1/2 moa.

Tried them in my AR10 and it did even better.

SSTs have always shot well for me and are a great hunting bullet.
 

Dawico

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There are many powders that do well in 308.

Keep in mind the supposed Gold Standard of ammo, Federal GMM. Rifle manufacturers try to get their rifles to shoot it well. If you chase that round you should have good luck with a load that works well across multiple platforms.
 

TXAZ

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I have a ~ new .DD Hunter in .308, 18” barrel and don’t reload.
But I bought about 20 different types of .308 ammo from 145 - 208 gr.
175 Federal OTM & 185 Berger Juggernauts were best overall, .6-.8 MOA.
The Berger 208’s were excellent but too long and had to be manually loaded.

Interest differences in about six 150 grain rounds from different manufacturers: The UMC were ~1MOA, the Wolf were ~ 5 MOA.
Good luck!
 

TexMex247

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Well it definitely wasn't the best day for testing but I ran some rounds I made anyhow. It was spittin rain intermittently but I squeezed off 40 rounds or so. Overall the SSTs just didn't perform any better than the Sierra FMJ. Best group was just over 1.5". Most were closer to 2". I might go ahead and move to another powder and repeat these loads.

Next time I get a good chunk of time I'll take the chronograph and see how mine are stacking up against the 168gr GMM. I know from previous testing the 175gr GMM was a bit of a let down in this rifle, also grouping around 2". I have 165sst, 168gr gold dots, 168gr Speer bthp as well as some soft point 150gr bullets. So definitely have a few options to work with.

Right now with powder prices high and availability scarce I'll probably cook up a light bullet load with W748 and save the 4064 for my heavier bullets. If I can get BLC2 to shoot the 165-168s well that would be great. For now it's back to the drawing board, a reloaders work never ends.
 

popper

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XBR8208 Works good with 168 Amax in mine. Better than 335 or 4895. ARComp worked best for me but unavailable now. LC mixed date MG fired brass.
 
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