Ar-10 6.5 SAUM

[375ultramag]

Finally got my Ar-10 6.5 saum dialed in and running great. It was definitely a challenge to say the least but I learned a lot and it was a fun project. I'm currently running 130 gr. Berger vld hunting at 2850 out of a 22 inch barrel without any pressure signs. It's running right around 1/2 moa at 100 and 3/4 moa out to 400 and that could've been me. I'm sure I can go more but for now I'm going to run it there for more testing. Brass is about as perfect as a bolt gun and no problems reloading. Just thought I'd do a little post about it and let people know it's definitely possible but it's a bit of pain to get the kinks worked out.

Build specs:
Kak magnum modified upper
Kak magnum bolt carrier group
Aero precision lower
Magpul STR stock
Lancer Systems carbon fiber handguard
Rise Armament Blitz trigger
Jp Enterprises adjustable gas block
BSF carbon fiber 22 inch +2 6.5 creedmoor barrel that was reamed out to the SAUM
Geissele Super 42 spring with H3 buffer

Load:
Adg Brass
H1000 powder
Federal 215m Match
130 gr. Berger Vld hunting

Any questions ask way. I'd be glad to help if someone is trying to go to same route. Thanks.

 

[cohunt]

How do those speeds compare to a bolt gun in same cartridge, seems pretty slow for a saum but Ive never loaded for 6.5saum before

 

[Earnhardt]

What is your buffer weight? 9-15 oz?
Gas block is how many clicks open?
Gas port size?
How many grains of H1000? (56-58?)
Quickloads says you are at ~ 48,800 psi right now, with that bullet weight and velocity.

 

[Lefty38-55]

This thread is useless without pictures ...

I like pictures ...

Nice build!

 

[backwoodsshooter]

This thread is useless without pictures ...

I like pictures ...

Nice build!

 

[waveslayer]

Tagging. Love the SAUM, in a gas gun, how interesting!!!

Pics and some more details on the build. How's the brass life out of a gasser?

 

[cohunt]

I've seen a 300wsm gas gun before-- it had quite a few issues with cycling/feeding

 

[waveslayer]

I've seen a 300wsm gas gun before-- it had quite a few issues with cycling/feeding

Thanks, no disrespect but must not have been built right. OP said he hasn't had issues. Nemo built some amazing big AR 10's no issues with the ones I played with nor AA with their gasser in .338 Lapua.

Now back to this amazing build

 

[375ultramag]

Sorry guys on the road for the rest of the day. I'll get some pics up tomorrow. And answer your questions.

 

[cohunt]

Thanks, no disrespect but must not have been built right. OP said he hasn't had issues. Nemo built some amazing big AR 10's no issues with the ones I played with nor AA with their gasser in .338 Lapua.

Now back to this amazing build

Actually this is what the op said :
"Finally got my Ar-10 6.5 saum dialed in and running great. It was definitely a challenge to say the least but I learned a lot and it was a fun project. "

I took that as he had problems getting it running correctly

 

[naja302]

Tag…I have one but have neglected it

 

[375ultramag]

Sorry for the delay. Out of state hunting. But to answer some of the questions.

Speed: Right now I'm running it about 300 fps slower than my bolt 6.5 saum with 140's but that's also 4 more inches of barrel.

Gas port: I'm not sure of the gas port size it's the stock gas port the BSF uses for their creedmoor barrel.

Load: I'm running Adg brass 60 hrs. H1000 130 vld at 2.140 cbto which is about 2.80 coal to fit a pmag

Gas block: The gas block is around half way out. I never counted the clicks actually. I started 4 from closed and backed out 1 at time during testing until it was cycling right.

Buffer: The buffer is an H3 so 5-5.4 ounces.

Brass life: I'm not sure yet. Brass comes out in great shape.

So the issues: Had to cut 3 full curls of the ejector springs (dual ejectors) so it wouldn't gouge the brass on ejection and polished the barrel extension with a dremel and polishing tips.
Put adhesive felt on the brass deflector so it would stop denting the brass.
Upgrade to the heavier H3 buffer and Super 42 spring
Seat the bullets to fit into a mag
And switch from Hornady brass (too soft) to ADG.
I'll add the 2 pics I have from when I started the build and take more when I get back to camp later today. Thanks

 

[375ultramag]

I'll also add. I shot a doe at 275 yards with it on Monday and dropped her. Behind the shoulder entrance and broke the offside shoulder. I clean all of the tips on my bergers with a .035 torch tip drill bit set.

 

[ripzip]

Wonder if you could build one off of the 6.5 PRC? I guess anything could be possible.