308 build issues

[M1911a1g17]

@mac1911 it is 5.4 oz.

@paul73 mine has not had that issue thank god haha.

I did figure out that the gas port is undersized. It is .089 and should be .093-.096. Also the bcg is going to far back. So gonna use a spacer.

 

[M1911a1g17]

update:
I opened up the gas port to .096 with a reamer bit. As it was undersized at .089.
Added 2 quarters as a spacer in buffer tube.

I got it running pretty well. The only issue I had was it picked up a round and just clicked instead of a bang. Chambered the round and everything. Not light strike though. But other than that if cycled 16 of 20 rounds, that previously wouldn’t cycle at all. So getting there! Any suggestions on what that could be?

 

[SKumar]

What clicked? Was it the hammer falling? If it's not a light strike, I suspect the bolt is not fully in battery. If you're happy with the buffer springs and gas system, it might be as simple as trying out a new bolt.

 

[KH56010]

I had a bunch of issues with my AR10 build. Actually had bought a complete upper that was just slapped together hand tight by Aero (never buy their crap). The gas port was undersized which you fixed. I didn’t enlarge mine, but mixing buffer springs and a wide open adjustable gas block got it running 90 percent. Then under the extractor at least with Aero bolt carriers, there are two rubber Orings. They make the extractor so tight that it can cause cycling issues and was doing the same as your hammer strike. It no boom. Removed one Oring (per their instructions to another user on Reddit having an issue that reached out to them) and it has been flawless ever since.

 

[M1911a1g17]

@SKumar the bolt seems decent but that could be an option. Do you have any suggestions of a good one?

@KH56010 hmmm that’s very interesting. I will have to check that out. There is definitely no lack of force on the extractor currently. I will give that a try and reach back out with the results. Just curious, what ammo do you run?

 

[KH56010]

@SKumar the bolt seems decent but that could be an option. Do you have any suggestions of a good one?

@KH56010 hmmm that’s very interesting. I will have to check that out. There is definitely no lack of force on the extractor currently. I will give that a try and reach back out with the results. Just curious, what ammo do you run?

It runs absolutely everything now, no name, bulk, about 1000 rounds of PMC and a ton of different match rounds by federal and hornady in all different weights. The extractor was so tight that it was deforming the rim of the casings that were ejected. After removing one of the Orings that stopped happening as well.

 

[M1911a1g17]

@KH56010 that is exactly what is happening with mine. The rims are pretty messed up. Have you tried Hornady black? I was getting some primer flow with them.

 

[KH56010]

I’ve shot:

Hornady Ammo 308 Win 168 Gr ELD Match

Creedmoor .308 167 Gr Scenar Ammunition In Lapua Brass

Creedmoor .308 175 Gr Ammunition In Lapua Brass

308 Win - Federal Gold Medal Match 168 Grain BTHP

Federal Non-Typical .308 Winchester 180 Grain SP

308 Win - PMC Bronze 147 Grain FMJ-BT

And a couple other Federals that I must’ve picked up on NES and some bulk stuff.

Your cases look exactly like mine did before making the changes. Now that I think about it, I ordered a couple different buffer springs but I may have actually got it all running with the stock spring. I also ordered another bolt carrier that ended up back ordered so I never needed it. I think I did try it and everything worked with that BCG as well.

 

[M1911a1g17]

@KH56010 that is very good to know. I am gonna try that tonight and hopefully hit the range tomorrow.

 

[KH56010]

@KH56010 that is very good to know. I am gonna try that tonight and hopefully hit the range tomorrow.

Cool, give us a range report when you try it out.

 

[M1911a1g17]

@KH56010 will do for sure

 

[M1911a1g17]

Update: got her running very well now. Not a single hiccup. Ran through 60 rounds of m80 ball no issues and a box of Hornady black no issues. Learned a lot during this process! Thank you guys!

 

[M1911a1g17]

Had to ream the gas port to .093-.096.

Had to add a quarter to the buffer tube as a spacer, as the bcg was going to far back and contacting the buffer tube.

Changed the gas tube to an armalite ar10 rifle length tube.

But after all that she’s running well now.