ar 10 6.5 creedmor

[labradoodle]

I had a bad gun smith build me an ar 10 in 6.5 creedmor.

it will not strip the first round off the mag and go into battery. if you drop the mag pull bolt half way back a let go it with lock up. stays lock back with the last round and cycles though the mag fine.

so far with factory ammo 120 grain ammo ( I know not the best) it was holding a 10in plus group at 100 yards. With my bolt gun I can get .25in groups. I know the gas gun won't do that but it should be better.( I handled for the bolt gun)

the bolt carry is just a cheep no name I can steel bare steel. would it be worth it to upstage to a jp system for the bolt carrier and buffer spring.

it has an 18in Krieger barrel

what else should be look at to fix this gun. I want to try to shoot it a mile.

 

[WhiskeyBiscuits]

Where do it hang up when the magazine isn't inserted? Are you seeing any marks on the barrel extension from the bolt hitting the lugs?

 

[labradoodle]

it takes the round half way off the mag. thought it wasn't oil enough so took the bolt carrier apart will put back together same problem

 

[Murdy88]

Could be a burr on the feed ramp cut of the barrel lugs. Doesn’t take much to have issues. Not sure if an AR 10 has two feed ramps like an AR 15 style, if it does, could just be the right or left ramp has a burr that’s catching the bullet or case.

If it’s just the first round in the magazine that could make sense.

 

[West.mass.hunter]

I had feeding issues with both of my ar10's. I built both m top to bottom with aero precision parts minus the triggers. 308 and 6.5cm. With pmags they wouldn't feed or cycle at all. I bought a D&H tactical steel mag and ran boxes and boxes through both arms without any issue. Bought 7 more D&H mags after that.

 

[labradoodle]

I have put 1200 rounds though it I was at a class and had to use the gun it did it every time only on the first round

what would make the accuracy that bad

 

[Murdy88]

If there is a burr catching the bullet, it could scrape bits off it or even shove the bullet deeper into the case causing loose headspace.
I’m not familiar with AR-10s but some ar-15 barrel will have the ramp issue and I know an AR 10 buffer spring is powerfull enough to shove a 9mm bullet further back into the case if it catches on the feed ramp.

 

[labradoodle]

I use lancer mags don like p mag

when I pull the round out no damage or marks

 

[Murdy88]

Something is definitely wrong with that accuracy. Even on cheap ammo in a cheap barrel that’s real bad. Might be best to take it by a gunsmith to check it out. Sorry but my knowledge is limited on this. You have a pic of the round jammed up?

 

[LeftyWilbury]

AR10s are finicky beasts. gas issue can make cycling problematic. i had to open up gas ports on both my AR10 ballistic advantage barrels to get enough gas to reliably cycle. then adjust accordingly with adj gas block for suppressor use. 10" groups sound like something is loose. scope mount. bad scope. good luck

 

[jimh406]

I'd visit an AR forum. They'll probably tell you how to fix it. Probably needs a new trigger or adjustment. Otherwise, sell the gun and buy a Ruger SFAR.

 

[WhiskeyBiscuits]

Could be a burr on the feed ramp cut of the barrel lugs. Doesn’t take much to have issues. Not sure if an AR 10 has two feed ramps like an AR 15 style, if it does, could just be the right or left ramp has a burr that’s catching the bullet or case.

If it’s just the first round in the magazine that could make sense.

That's what I'm thinking too. Over torqued barrel nuts are common with AR style rifles. There'd be evidence of the bolt striking the barrel extension.And yes, anything that accepts a double stacked magazine will generally have 2 feed ramps.

 

[Murdy88]

OP watch this video and see if it looks like what you have going on. This guy is a great source for AR related issues.

 

[WhiskeyBiscuits]

it takes the round half way off the mag. thought it wasn't oil enough so took the bolt carrier apart will put back together same problem.

Does it do this with different mags? You said it hangs up when the magazine isn't inserted too. When the mag isn't inserted, where does the bolt hang up? Is the bolt catching on the locking lugs? Also, are you seeing brass shavings?

It sounds like your barrel extension is clocked and the bolt is striking the locking lugs. That could also be why it won't chamber the first round bc the feed ramps aren't aligned properly. And if it's chewing up the bullet going into the chamber that would explain the poor accuracy. Try loosening the barrel nut and re-tighten to proper torque spec. See if that helps.

 

[RockAndSage]

OP, start with the simplest things first. You've cleaned and lubricated the gun.

You know the gun doesn't want to cycle that first round on a full mag when manually charged.

Two things:

1) Are you pulling the charging handle back hard, and letting it fly on its own? Often, this problem you're describing can be replicated by "riding the bolt" on a full mag, which is essentially pulling the charging handle back, and holding the handle as the BCG goes back forward, making the system cycle far more slowly and less violently than when you actually fire. Never do this. Be sure to yank back all the way and let go, in one smooth motion.

2) If it's not an issue of riding the bolt, it may simply be the spring tension inside the magazine. Download the magazine by 1 round, and see if the problem still happens. If it's a 20 rd mag, load 19.

Let us know if this changes anything.

 

[SloppyJ]

Sounds like your mags suck. As far as the accuracy, it could be anything. However, there are some really cheap fixes that you can try.

First, I would disassemble the entire rifle and clean it. Check out the fit between where the barrel extension hits the front of the receiver. If you can see any light peaking through, that's going to be one of your biggest issues. Even if you can't, I'd lap the face of the receiver. Wheeler makes a kit that's very reasonable.

Next, I'd bed the barrel in the reciever. If it's a loose fit then that could be part of your problem too. I use loktite retaining compound around the barrel extension and twist it a bit to get it to spread out while inserting before locking it into place.

It could just be a shit barrel and you might be better off to get another one. I'd try those two steps first and go from there. Good luck. Also, don't pay anyone else to assemble an AR for you. It's ridiculously easy to do yourself with minimal tooling.