Grendel not loading second round

[Chazroh]

I have a 18" jp barrel kit with a rifle length gas system and rifle stock. With the Adj gas block open all the way the gun won't load a second round into the chamber. Or with just one round in the mag it, the carrier locks back on the bolt catch but not far enough to lock the bolt back. The gas port hole is .091, short question is, is that too small? Am I undergassed?

[A5BLASTER]

Do you have the gas block tight against the shoulder on the barrel?

[Chazroh]

I do, I have put loc tite on it and seated it several different times

[A5BLASTER]

Double check you didn't get locktite in the gas port of the gas block and causing a restriction in your gas tube.

[A5BLASTER]

What gas block are you useing?

Did you install the gas tube in the gas block yourself?, If so double check the hole in the gas tube is lined up with the port hole in the gas block itself could be off a lil and causing a restriction.

I'm not sure what size the port in the barrel is suppose to be.

[A5BLASTER]

When you have taken the gas block off the barrel did you clean around the shoulder on the barrel with a good brass brush to remove as much of the old locktite as possible. I found the red locktite breaks down the barrel coating in that area and if you don't clean it off before your reapply more locktite and the gas block it can build up and cause it not to seat just right.

Might want to check this as well.

Give JP a call about the port size and see what they say, if it is small I'm sure they will fix the problem asap.

[Chazroh]

I only put loc tite on it this last time, the gas block/tube came assembled from jp, it's a jp adjustable block.

[A5BLASTER]

Maybe a dump question but do you have the right buffer and buffer spring in the rifle?

Anouther dump question did you try the block at any setting other then wide open?

What ammo are your useing factory or handloads?

Do you have anouther lower you can try the upper on?
What mags are you useing? New or old mags?

Who's parts do you have in the lower and the upper?

[Chazroh]

I am using a standard rifle buffer and spring. I have shot handloads and factory ammo through it with the same results, I have tried a different lower, different bcg, different mags. I have asc mags, but a fella at the range let me use another brand with the same result.
It's an Anderson lower and lpk, with a magpul Prs stock, shoots just fine with my other Grendel upper, and 223 upper,
It's an aero upper with jp gas block/tube,barrel,and bolt.

[ricsmall]

Sounds over gassed. Have you tried with the gas block closed down some? Try that. In the meantime maybe LR 52 can verify the correct gas port diameter for that length pipe with rifle gas. I'm thinking around .091"-.094". Also, is your carrier an m16 carrier or a neutered semi auto carrier?

Richard

[Chazroh]

I have closed the gas block down and when I do it won't eject the spent casing, it's a m16 bcg

[ricsmall]

Well in that case your either under gassed or there's something else going on. If it were mine, I would plug chamber and blow air through muzzle, making sure there was good air flow while moving gas block around. Does bolt move freely in carrier? Next step is to verify correct port size. Also inspect gas block to ensure there is not something causing restricted flow. Keep
us posted on progress.

Richard

[Lastrites]

When you pull back on the charging handle is the resistance the same all the way back or does seem to get harder to pull the last couple of inches?

When manually pull all the way back does the bolt face stop about 1/8" to 1/4" in front of the back edge of the ejection port?

[just_john]

Some gas blocks don't sit tight against the shoulder on the barrel. The original design left space for the sheet metal forward handguard plate. Did you remove the rear set screw ( which lines up with the gas port ) and slide the block back on the barrel with the set screw over the gas port to see how far it should go? Then, if there is a gap, measure so that the gap can be duplicated when the block is formally installed?

[A5BLASTER]

Just-john, he has a JP barrel and JP spec's their gas block placement to be tight against the shoulder, that's why they strongly sujest to use their gas blocks because most other company's gas blocks won't line up due to that spec.