Jump to content
MT Bill

First round of test loads

Recommended Posts

So I finally got the time to load up some ammo for my RPG 6x6.8. It has a 20" barrel, a new frontier lower with a BTE trigger, and a cheap Burris 3-9x40 that I had laying around.

 

I started off by sizing, trimming and reaming the primer pockets on 100 once fired Federal cases. My first bullet to try was the 58gr V-max. I started with 29gr of IMR 8208 and worked all the way up to 32gr loading 5 each in 0.5gr increments.

 

I decided to break the barrel in at this time, so the first ten shots were getting on paper as well as shoot one clean etc.

 

Accuracy was up to my expectations, especially considering the 20-30mph gusting winds. All loads shot sub moa with a few three shot clusters of .2-.3 moa. With some more concentration I have no doubts that I should see 5 shot groups under 1/2 inch.

 

My question is regarding velocity. I saw no signs of pressure even with the 32gr loading, but velocity barely got above 3,300fps. I loaded these using the .268 bushing, and after measuring loaded cases I figure I only had .002"-.003" of neck tension. My assumption is that I need a little more neck tension to help with velocity. From what I've seen posted here, I was hoping to see 3,400 fps+ with this load. Am I on the right track here?

 

Thanks for any input,

 

Bill

Share this post


Link to post
Share on other sites

I use a .267 bushing for my SSA brass. IIRC Federal brass is thinner. I would try using a .267 and 31.5 grains of 8208 You can also use a CCI 450 primer if your not already.

Share this post


Link to post
Share on other sites

Thanks for the reply.

 

I'll load my next batch using the .267 bushing, and I had my local gun store order in some CCI 450 primers. Hopefully sometime in the next couple of weeks I can get out and give it another try.

Share this post


Link to post
Share on other sites

I loaded up another batch of test loads using the .267" bushing and CCI 450 primers. Velocity was up compared to the last batch. Cases are Federal once fired. Bullets used were 58gr v-max and 70gr ballistic tips. I didn't see any signs of pressure across the board. So I'm wondering if I should push them just a tad more, or just work on the ones shown below.

 

You'll notice a few flyers in these groups, I'll have to work on that!

 

abe0b457116a82363538196e8d6bab40.jpg

73d8a5f128c462408c8576f1686c3da8.jpg

b630f8cc86ab5c4c47e16dfc4d3c834f.jpg

4a29ba1385ded2a55b3cbd2d18b3448b.jpg

 

One thing I noticed was a little bit of leakage around the gas block.

21f6da45883ca924a40fece76d86e80c.jpg

Being fairly new to AR's I'm not sure if this is something to worry about, or leave alone.

 

And here's a shot of the rifle.

 

053dd6858d4544537ed9ab492197fd1d.jpg

Edited by MT Bill

Share this post


Link to post
Share on other sites

Nothing to worry about. That is High Temp RTV silicon. I use it to hold the set screw from backing out. The black is burnt powder residue. All gas blocks leak to some degree.

 

It looks like your getting zeroed in on a load. Keep us updated on your progress

Share this post


Link to post
Share on other sites

I loaded up some more test loads and made it out to the range this morning. Conditions weren't exactly ideal with the wind blowing between 15-30mph, but I'm happy with the results despite the wind.

 

I bumped up my loads a little from the last run and overall I'd say it payed off. IMR8208 ended up with the win for both the 58gr v-max and the 70gr ballistic tip.

 

These loads are safe in my rifle, but may not be in yours. As always, start low and work up slowly.

 

I loaded ten rounds each for the 58 grainers going from 31.5 to 32.5 grains of 8208. The winner here. . . 32.5 grains.

 

c2bee076fd6ab8bd205b25f8f5e79391.jpg

 

That's five shots in just over a half an inch with four of them in 0.149"! With an average velocity of 3,445fps this load should be the ticket for coyotes.

 

The 70gr ballistic tips did well with 8208 as well. 31.5 grains gave me an average velocity of 3,278fps going into a 0.634" group.

 

30a6a4484585d15c2c66784ed0cb17ae.jpg

 

Overall, I'm pretty pleased with today's results. This rifle and the BHW barrel are a great pair!

 

Bill

Share this post


Link to post
Share on other sites

Very nice, sir !

Share this post


Link to post
Share on other sites

Nice groups.

Other powders that work super in the 6x6.8 w/55-95 g bullets.

h335, w748, h4198, blc2, varmint pro, benchmark, they all give good speed/accuracy.

I tested over 100 loads with the above looking for that "best" powder for all weights & it turned out to be h335 & x8208 w/h335 giving me more fps & accuracy vs x8208.

Benchmark & h4198 gave the fasted speeds, but opened groups up.

My best 55g loads ran shy of 3600 fps in my 22" bbl. This was my coyote hammer load.

Share this post


Link to post
Share on other sites

Thanks retcop.

 

Thank you for the information 5spd. I was thinking about trying Exterminator, Benchmark, H335, and TAC. Sounds like I might have to move H335 to next in line.

 

Did you try different primers? So far I've only used CCI and Winchester, but was thinking about tinkering with Remington primers.

Edited by MT Bill

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

  • Recently Browsing   0 members

    No registered users viewing this page.

×