300 WSM AR10

[Gregg C]

Did you do the test with one round only in the mag, fire it and see if the bolt locks back? That is the first test, and will show if you have a low gas problem to fix, which is what it looks like to me.

It does lock back reliably.

I still think the bolt is skipping over the cartridge base on the chambering forward stroke. One simple approach to try first is slightly lifting the magazine lips of the steel magazine a little to make the top cartridge sit higher so the bolt will catch it coming forward. For this the work the bolt assembly has to come all the way back under gas pressure so it can strip the round out of the magazine coming forward.
cohunts post is accurate. It is either under gassed for the reasons I listed before or the buffer spring is too strong.

That thing about the mag lips...that was my initial thought. Not the lips adjustment, but was thinking the cases weren't high enough. That's what I'm going to do next. Try for another .030 or .040 protrusion into the bolt path.

 

[Earnhardt]

Question: what could possibly cause a jam on the side of the cartridge? Actually bends the neck, and horribly collapses the body below the shoulder. Hope some one here can help steer me in the rite direction. DPMS 308

Ok, so all this has nothing to do with a WSM or SAUM AR?…

 

[Earnhardt]

Not a dummy round, no. But these two dimples are on most every case.View attachment 360625

What cartridge is this?

 

[Citified]

The original poster stated .30&. The Mag adjustment might be the next easiest item to address.

 

[bamban]

The original poster stated .30&. The Mag adjustment might be the next easiest item to address.

Sorry, I am the OP, title says "300 WSM AR10"

"I have an itch to scratch. I have all the components to build a lightweight AR10 (yes Armalite) in 300WSM. I have a 10T barrel, reamer, GG, barrel extension, superlative adjustable gas block, KAK magnum BCG, and Armalite build kit. Even have 100 pieces of 300 WSM virgin brass."

 

[Citified]

I apologize. This thread has taken on a life of its own. I am trying to help the guy with his AR

 

[bamban]

I apologize. This thread has taken on a life of its own. I am trying to help the guy with his AR

No problem, help away. Others will learn from it.

 

[Earnhardt]

Yes, I know the original poster was talking about a WSM AR

So this awesome WSM AR thread, got turned into a hijacked "help me fix my AR" thread, by someone else?

Bummer

 

[cohunt]

80% lower built by a friend----- hmmm.

I've had lots of inconsistencies with large frame 80% lowers....first thing I would check is how high the magazine sits in the lower. Also check the height of your bolt catch with an empty mag inserted. I've seen inconsistencies with bolt catches too.

Take the pins out and put a mag in just the lower and take a side view pic of it and post it.

It could be that your mag catch sits lower than others-- I can't remember if you said what magazines you are using...metal mags can be "tweaked" poly mags cant-- hybrid mags like Lancer can also be tweaked some.

As far as feed ramps-- they can be reshaped with chainsaw sharpening round files then polished with a dremel/wool pad and polishing compound.

Did you say how long the gas system/tube is? On large frame ar's I recommend running an adjustable gas block- especially if you plan on reloading.

Do you know what size the gas port is?

 

[cohunt]

Doesn't have an adjustable gas block, so a lighter spring may be on order here. Would starting with a spring, or buffer, make more sense?

What spring and buffer do you have in it now? ( probably buffer but need to know more details)

See above post too-- since it's an 80% home built it might have multiple problems and take more troubleshooting.

As far as ammo-- I'd start with some healthy big bame hunting ammo-- I have found some of the so-called "nato ammo" to be loaded weak and create cycling issues

I see you are using 7.62x51-- for some reason I thought this was a 300wsm-- where did I get confused?

Edit--- I see now--- you are not the original poster of this thread-- you need to start your own thread troubleshooting your AR so things don't get confused and the OP can keep this thread cleaned up.

 

[budlight]

Sorry about the confusion. It is a home built, started as an 80%. I didn't build it, a friend of mine did. The ammo says it's NATO ,7.62 x 51 PPU 20 head stamped.

Those are lower pressure rounds. You can build an AR for low pressure like service rifles or you build for 308 bolt rifles.

I was going to suggest finding someone with a fully functional AR and swap another upper to your lower.

 

[Earnhardt]

Gregg C, please start another thread in regards to fixing your AR's problems....

Let's get this back on track as a WSM/SAUM AR thread

 

[bamban]

Gregg C, please start another thread in regards to fixing your AR's problems....

Let's get this back on track as a WSM/SAUM AR thread

Thank you.

 

[budlight]

Sorry, I am the OP, title says "300 WSM AR10"

"I have an itch to scratch. I have all the components to build a lightweight AR10 (yes Armalite) in 300WSM. I have a 10T barrel, reamer, GG, barrel extension, superlative adjustable gas block, KAK magnum BCG, and Armalite build kit. Even have 100 pieces of 300 WSM virgin brass."

I was looking at your KAK magnum BCG. Did they have a recommended buffer spring and weight to use? 300WSM has about the same foot pounds as a 450 marlin