AR10 Question

[gpr]

So finally got my Stag AR10 in 6.5cm. Gun shoots amazingly well, like I didn't think a factory AR10 would ever shoot that well.

The thing seems to be hard on brass. Any spent brass has a big scratch down the side of it. Also if i eject the shell with out firing it, the scratch goes down the brass and on the bullet as well. Then the rim where the ejector grabs it is very rough. My AR-15's have never done this.

The other odd thing is when I rack a shell into the chamber, the first 1" pulling on the charging handle is extremely difficult. Almost feels like the shell is stuck in the chamber. Once i get the bolt moved it cycles smooth. But i'm shooting brand new factory ammo and it will cycle just fine when fired.

I called stag about it and they sent me an RMA to send it back to them to get check out. I was just wondering if there would be an easy fix, and if others have seen this on AR10 before? I will probably send it back to them to get checked out, but would rather try and fix it myself so i don't have to ship it off.

 

[Mmfujita]

So finally got my Stag AR10 in 6.5cm. Gun shoots amazingly well, like I didn't think a factory AR10 would ever shoot that well.

The thing seems to be hard on brass. Any spent brass has a big scratch down the side of it. Also if i eject the shell with out firing it, the scratch goes down the brass and on the bullet as well. Then the rim where the ejector grabs it is very rough. My AR-15's have never done this.

The other odd thing is when I rack a shell into the chamber, the first 1" pulling on the charging handle is extremely difficult. Almost feels like the shell is stuck in the chamber. Once i get the bolt moved it cycles smooth. But i'm shooting brand new factory ammo and it will cycle just fine when fired.

I called stag about it and they sent me an RMA to send it back to them to get check out. I was just wondering if there would be an easy fix, and if others have seen this on AR10 before? I will probably send it back to them to get checked out, but would rather try and fix it myself so i don't have to ship it off.

A adjustable gas block and a heavy buffer helped my brass a lot. I also taped some Velcro on the shell deflector. You will get a million answers. This helped my brass.

 

[bigjake83]

A adjustable gas block and a heavy buffer helped my brass a lot. I also taped some Velcro on the shell deflector. You will get a million answers. This helped my brass.

Yes definitely get the AGB (must have), and a quality Buffer (ie. JP SCS) but I don't feel you need the heavy version unless you're shooting with a Can. Also very important, take the time to polish your Feed Ramps / Barrel Extension, and look for and burrs, also the Velcro trick is awesome keeps the dents out, I use RTV black Silicone, works great and never falls off. Lastly if using Metallic Mags take some 600 Grit and smooth out any burrs or imperfections.

 

[gpr]

When polishing the feed ramps, do you take a small flap wheel on a dremel and smooth out the machining marks while also knocking off the edges? Then take some polishing compound and polish them up like a mirror? I can see this helping as it is amazing how much polishing a trigger surface lightens/smooths the pull.

I am shooting suppress, and on all my other AR-15's i have adjustable gas blocks and they really helped. With this gun and a suppressor it really didn't seem over gassed. I didn't get the typical tons of gas blowing back in my face with excessive force slamming open the bolt. Plus with my AR-15's the spring sound was terribly lound and annoying in my ear, but this AR-10's spring isnt loud like that, and honestly the SCS didn't seem any quieter to me.

The very very odd thing is i installed a JP silent capture spring with heavy buffer, the gun would not function or cycle properly. It would not close the bolt all the way. and i was getting light primer strikes 75% of the time and the ejector was not grabbing the brass. When i would try to rack a round and it would never grab hold of the old round and eject it, so as it went forward it would grab another round trying to force it into the already full chamber. Put the stock spring and buffer back in and the issue went away. I'm starting to wonder if the JP SCS didn't work because of the binding issue with the barrel/bolt face...Thus why it is very hard to pull the charging handle when a round is chambered???

And when i say the charging handle is difficult to pull, i mean that sometimes it is so hard to pull back that it takes everything i have to pull the charging handle. I even installed a larger charging handle latch to get a better grip and still struggle pulling it.

For this velcro trick I am assuming you are simply gluing the soft fuzzy velcro to the face of the shell deflector? That is a really good idea, and Im gonna do this on all my ARs.

thank you for all the help and suggestions!

 

[bigjake83]

When polishing the feed ramps, do you take a small flap wheel on a dremel and smooth out the machining marks while also knocking off the edges? Then take some polishing compound and polish them up like a mirror? I can see this helping as it is amazing how much polishing a trigger surface lightens/smooths the pull.

Yep that's about right, I use a dremel with a 600 grit lapping compound, and then hit it with Flitz. Just be careful and take your time, you can go to town on the feed ramps but don't take to much off of the inside edges of the barrel extension.

I am shooting suppress, and on all my other AR-15's i have adjustable gas blocks and they really helped. With this gun and a suppressor it really didn't seem over gassed. I didn't get the typical tons of gas blowing back in my face with excessive force slamming open the bolt. Plus with my AR-15's the spring sound was terribly lound and annoying in my ear, but this AR-10's spring isnt loud like that, and honestly the SCS didn't seem any quieter to me.


The very very odd thing is i installed a JP silent capture spring with heavy buffer, the gun would not function or cycle properly. It would not close the bolt all the way. and i was getting light primer strikes 75% of the time and the ejector was not grabbing the brass. When i would try to rack a round and it would never grab hold of the old round and eject it, so as it went forward it would grab another round trying to force it into the already full chamber. Put the stock spring and buffer back in and the issue went away. I'm starting to wonder if the JP SCS didn't work because of the binding issue with the barrel/bolt face...Thus why it is very hard to pull the charging handle when a round is chambered???

That is odd... I would just stick with a quality heavy buffer , from Heavy Buffers.com And whatever spring they recommend/tubbs flat wire. http://heavybuffers.com/antitilt308.html

And when i say the charging handle is difficult to pull, i mean that sometimes it is so hard to pull back that it takes everything i have to pull the charging handle. I even installed a larger charging handle latch to get a better grip and still struggle pulling it.

For this velcro trick I am assuming you are simply gluing the soft fuzzy velcro to the face of the shell deflector? That is a really good idea, and Im gonna do this on all my ARs.

Yes Sir..

thank you for all the help and suggestions!

 

[bfoosh006]

First... be sure your chamber is clean.

As for the polishing of the feed ramps, I used a felt dremel cone... much safer at polishing. Allow it to bevel itself to a proper size. And be SURE to clean out all the fuzz from its use... I the fuzz will lock up your tight bolt.

Also , I polished the extractor "angle" surface as well.

As for the tight "extraction" issue... your bolt and receiver probably just needs to break in to each other.

I also suggest an Adjustable GB... it will help your brass from being abused. The .308 AR platform has ample gas.

I use a 9.3oz .308 Rifle length buffer in mine... that also allows the round to be chambered slightly ( milliseconds ) longer and allows extraction at a lower chamber PSI...

The Adjust GB and heavy buffer allows me to stay on target FAR easier....

 

[gpr]

I plan on getting an adjustable gas block, and polish the feed ramps. Since stag is sending me a label to have the gun inspected I'm gonna send it off and see what they say.

How do you know what buffer weigh and spring to go with?

 

[bfoosh006]

Trial and error... is how I learned.

https://www.ar15.com/forums/industr...terion-barrel-results-10-Sept-17-/301-284190/

https://www.ar15.com/forums/industr...-again-UPDATED-with-Tn-G-results-/301-285762/

 

[mtgale00]

Sounds like your barrel extension wasn't deburred properly (if at all). Inspecting the scratch carefully will tell you what side of the barrel extension its on. A burr on the muzzle side of the barrel extension (most likely location) will be difficult to remedy. If there is a burr, flitz, paste and felt bobs won't solve this issue in any way shape or form, period. An abrasive mounted point is the right tool to make a repair.

 

[padom]

Those scratches on the case and bullet upon extraction are from a sharp/unpolished barrel extension. This is the reason I only use JP melonited barrel extensions. They are deburred and polished then melonited. Leaves your brass scratch free.

You can fix this by getting your Dremel and this attachment and hitting the inside of the barrel extension teeth from 12 oclock to 4 oclock. this is the area where the bullet and case are being pulled against upon extraction. Remove the entire upper, flip it upside down and go to work. You can even stick your finger in there and feel the backside of the barrel extension teeth, I guarantee they are sharp. You want to slightly polish them till they feel smooth and not sharp/pointing anymore. Easier to do with the barrel removed but can also be done with the barrel in the upper. Ive done it both ways. Its just tight. MAKE SURE you blow the chamber and barrel extension area out with break free or carb cleaner and clean thoroughly as well as the barrel. You are removing a small amount of metal and need to get all that out before putting everything back together and shooting it.

Dremel 520-02 SIC Impregnated Wheels 1/2"
https://www.amazon.com/gp/product/B015PK3DKI/ref=oh_aui_search_detailpage?ie=UTF8&psc=1

 

[Maelstrom]

What adjustable gas block do you recommend?

 

[gpr]

I have used several different brands of adjustable gas blocks, and honestly they all work basically the same. Some have a screw with a detent, and i really like those. However, any gas block i have setup i set it and leave it at that setting, thus the detent is useless after that.

I ordered a wojtek adjustable gas block. They are $38 shipped and are clamp on low profile blocks that have a set screw like most of them out there.

 

[gpr]

Alright an update on this. Sent the gun back to stag which was a giant waste of 3 weeks. All they did was say that it wasn't covered under warranty because I changed the butt stock and grip.... the tech must not have seen where i bought it as a bones kit and needed to add these to even shoot the gun.

Anyway, I took the barrel off and polished up and smooth out the feeding ramps along with smoothed up all the lugs. I tested it and the brass is coming out much nicer and isn't being scratched.

However, I still have the issue of once a round is in the chamber it is hard to pull the charging handle to remove it. I'm wondering if the chamber is a bit small, and the friction between the chamber and the brass is the cause?

My question is can or should I go to town trying to polish the chamber? Or do i simply need to take the barrel to a gun smith and have it finished reamed?

 

[bfoosh006]

I polished my chamber with "0000" / quad ought steel wool wrapped on a 30/06 chamber brush... 0000 steel wool won't scratch glass.

So you would have to Shreck the heck out of it to snafu it.... just go slow, and be sure to remove the loose threads of steel wool that come off.

typically ... the sharp edges will burnish in with the bolt lugs after a few dozen rounds.

IMHO... try polishing the chamber lightly, clean said chamber thoroughly.. and try again.

 

[bfoosh006]

I use the SLR adjustable.