Diagnose my 7.5" pistol feeding issues, please

[JRHorne]

All,
I assembled a 7.5" pistol build that is having some problems. I am going to list out all of the components and factors as well as the results from several tests at the range last night. I'd greatly appreciate if you all would help me diagnose the problem it has feeding.

Build:
Odinworks 7.5" .223 Wylde Barrel with Low profile gas block (Note 1 below)
KAK flask can (larger one)
Black pistol length gas tube from Rainier
Anderson Upper and Lower (Note 2 Below)
PSA Lower Parts Kit
KNS Antiwalk pins
PSA BCG
KAK shockwave tube and brace as well as buffer tube, buffer, and spring
Aero 9" keymod handguard

Note 1: I had this barrel professionally coated. The guys have coated tons of gun stuff before and their reviews were great. My wife was nice enough to grab the barrel for me when it was ready since their shop is on her drive home. However, these dumb@$$es coated the barrel extension AND the inside mouth of the extension including the feedramps! Needless to say I was pissed. So I got the dremel out with the light buffer pad and removed all I could. When doing this, I *think* I removed a little bit of the metal on one of the feed ramps. I am not sure, and the polisher I was using SHOULDN'T have removed it, but it may have.

Note 2: So after the aforementioned barrel issue, I go to assemble the upper and the feedramps on the barrel don't line up well with the feedramps on the Anderson upper. I bang and pound in an attempt to make sure the barrel is seated as far as it'll go in the upper, and it still isn't great (not surprising). However, the barrel feedramps don't extend over the ramp edge on the upper, so the rounds shouldn't have had anything to catch on.

Now onto the range results.

First test: 1 round of 5.56 green tip in a Lancer Warfighter mag. Insert mag, chamber, gun goes boom (and is pretty accurate as well) and the bolt locks back on empty mag. Repeat this with 2 more rounds of 5.56 green tip, then do the same with .223 PMC and Wolf Gold. All fire, extract, and lock bolt back perfectly.

Next test: load 3 rounds into Lancer mag and fire semi rapidly. All 3 rounds are of same ammo type. For all 3 ammo types, each round is easily fired in a somewhat rapid pace, and all go bang and extract perfectly. On the last round, the bolt does NOT hold open for any of the ammo types.

Final text: Full mag of several types of ammo. By this time, whether the weapon being dirty is a problem or something else, I have no idea. But what happens is, fire one round, it extracts fine, but does not chamber next round. The next round doesn't get hung up, nothing. Recharge, fire and extracts just fine, and same thing, next round doesn't chamber.

Unfortunately, I ran out of time and didn't get to start at the beginning and see if things getting dirty impacted the first two tests. Any thoughts? I can get some pictures sometime this week or weekend. Thanks M4C!

[HeruMew]

If the bolt is cycling, but not going far enough back to chamber the next round, it could be few things:

When pulling on the charging handle, does it get gritty, tough, right before the bolt face crosses the mag lips?

How much lube have you used since assembling, they may want a bit of lube to keep going during the break in if things are tight.

Check your gas system. Gas block is lined up properly, you didn't mention the weight of the buffer, but I can't imagine that isn't slightly overgassed as a pistol.

So, with that. I would start with the gas block. Check that out. Make sure all is still well and solid.

Oh yes, and please provide pictures and such with your next reply for visual aids.

[Iraqgunz]

Sounds like a gas problem.

[JRHorne]

Sounds like a gas problem.

Story of my life....
I'll get some pictures. I was concerned with the coating that it may have undersized the gas hole of the barrel, but I didn't want to start tinkering until I knew I had a problem. I also am need to verify alignment of the gas block. I'll get some pictures soon.

[HeruMew]

Story of my life....
I'll get some pictures. I was concerned with the coating that it may have undersized the gas hole of the barrel, but I didn't want to start tinkering until I knew I had a problem. I also am need to verify alignment of the gas block. I'll get some pictures soon.

Oh....

I didn't even think about that. If they coated the barrel, they easily could have coated the gas port. But, hopefully, they would run at least a reamer or something to clean that up.

Granted, this is the same company that painted your extension. Haha.

ETA: I want to include, I don't know how "tuned" that barrels gas port was, and I don't know how thick the coating is. Even a few mils can set things off based on the info the more experienced guys provide.

[Clint]

Story of my life....
I'll get some pictures. I was concerned with the coating that it may have undersized the gas hole of the barrel, but I didn't want to start tinkering until I knew I had a problem. I also am need to verify alignment of the gas block. I'll get some pictures soon.

7.5" Pistol gas barrels should have very small ports and would be more sensitive to getting restricted by coating.

The port should probably be cleaned out to make sure and gas system alignment double checked.

[JRHorne]

Thanks everyone. Obviously I checked the port and it wasn't completely closed, but that is going to be the first thing I do. Once I clean it out and ensure alignment of the gas block, I'll do the same test and report back. I'll get those pictures too.

[TED]

Thanks everyone. Obviously I checked the port and it wasn't completely closed, but that is going to be the first thing I do. Once I clean it out and ensure alignment of the gas block, I'll do the same test and report back. I'll get those pictures too.

It's missing 4 inches of barrel. try adding that and see if it clears up. ;-)

HUMOR!!

[hotrodder636]

I find it sort of odd that the bolt would lock back on a single round but not at the end of 3.

[JRHorne]

I find it sort of odd that the bolt would lock back on a single round but not at the end of 3.

This is what was messing with me as well. Only thing I can think of is the combination of gas problems over the course of the 3 rounds got the cycle off enough to not lock it back. I also wonder if the coating into the gas hole makes it more likely to clog up so when I was firing the first rounds (when the gun was clean) the issue wasn't as bad.