6.5 CM AR-10 Difficult to extract manually

[Stephen Chandler]

Hi,

Fresh build of an AR-10 in 6.5 CM.

Stag-10 upper and lower receiver set
BA 24" Stainless barrel
Tool Craft High Pressure dual ejector bolt

I've put 90 rounds through it, and it has ran and shot great it is pretty accurate as well.

When manually manipulating the bolt, it is difficult to extract a round out of the chamber by hand. It can be done, but its definitely not smooth or 'easy'.

I have tried both a factory round, as well as a reloaded 'dummy' round that was fired in the rifle, then the shoulder bumped .005". They both behave the same way upon extraction.

The weapon functions as expected with no issues when being fired this is only an issue when manually operating it.

Any ideas? Is this normal? Maybe because of the double ejectors or something?

 

[JR1200W3]

Do the loaded rounds drop in without force? What does the web of your fired brass measure compared to virgin brass or factory loaded? Are there any gouges or cuts on the brass when you do extract the rounds? Those answers might help you eliminate friction in the chamber as a cause.

 

[47chevycoe]

Take a permanent marker and cover the entire case and bullet. See if it’s contacting anywhere when chambered. I just had the same issue with a 260 barrel. The neck shoulder junction was too big causing tough extraction.

 

[Stephen Chandler]

Do the loaded rounds drop in without force? What does the web of your fired brass measure compared to virgin brass or factory loaded? Are there any gouges or cuts on the brass when you do extract the rounds? Those answers might help you eliminate friction in the chamber as a cause.

The brass looks decent when its extracted, no cuts or scrapes. I pulled the barrel last night, and just looking at it and dropping cases in, the factory rounds drop in very nicely and come out easily, my reloaded ones do as well.

I know the barrel nut was over-torqued (long story) i am wondering if this has something to do with the issue. I will re-torque it correctly when it goes back together later today and re-test.

Take a permanent marker and cover the entire case and bullet. See if it’s contacting anywhere when chambered. I just had the same issue with a 260 barrel. The neck shoulder junction was too big causing tough extraction.

great idea, i will check this out as well.

 

[camocorvette]

The back side of the bolt head that locks into the barrel extension is new. The edges are rough. Clear it, clean it and oil up the bolt well. Then cycle the action 100 times or so. That's my guess.

 

[bfoosh006]

Can the OP post pics of the cases ? Both fired and un fired ?

 

[Stephen Chandler]

Can the OP post pics of the cases ? Both fired and un fired ?

Yes, I will get it out this weekend. All of the brass that's been fired in this has already been tumbled.

 

[bfoosh006]

Yes, I will get it out this weekend. All of the brass that's been fired in this has already been tumbled.

Thank You.
When you get your next fired brass, we would like to see it, after firing , for any odd scuffing from feeding or the chamber.

 

[Stephen Chandler]

i think i figured the problem out. Apparently i forgot to grease the barrel nut threads when i torqued it, while that probably would have been okay, i did decide to crank it a bit (okay a lot) past torque to line up the nut for the gas tube.

When my shims came in, i went to take it apart and it was so tight i broke 2 of the cheap armorers wrenches and 1 aluminum reaction rod. I ended up having to freeze it overnight to get it apart.

After putting it back together, shimming the barrel nut (lubing it this time) and torquing it down. I noticed a significant difference in extracting both factory ammo as well as reloaded.

Also, got it out to the range and it definitely appears to be shooting better. Much closer to what I expected it to shoot vs what it was shooting last time.