Cleaned an old eagle arms upper I had, took it to the range Friday. Ran fine for two mags, then started jamming up horribly and had to be retired for the day. When it jammed it was obvious that it was short stroking (based on the mangled empties I was pulling out of the receiver to clear it).
Disassembling the weapon revealed the action wasn't fouled. Gas port / tube was clear of obstructions.
But there was a LOT (and I mean THICK) amounts of fouling residue on the inside of the hand grips (it's an M4 carbine length gas system). It looks like a LOT of the gas is getting around the gas tube where it is pinned in the front sight post. Which could explain the short cycling (no other cause is evident - also, magazines and ammo were each conclusively proven good in another rifle).
I'm thinking it's time to fit and pin a new gas tube in?
Any other thoughts on what to check? Everything else in the upper seemed fine. Ejector, extractor, recoil spring, etc are all fine, chamber was clean, bolt travels freely, etc. The enormous amounts of gas residue in the handguard was the only oddity I found.
Disassembling the weapon revealed the action wasn't fouled. Gas port / tube was clear of obstructions.
But there was a LOT (and I mean THICK) amounts of fouling residue on the inside of the hand grips (it's an M4 carbine length gas system). It looks like a LOT of the gas is getting around the gas tube where it is pinned in the front sight post. Which could explain the short cycling (no other cause is evident - also, magazines and ammo were each conclusively proven good in another rifle).
I'm thinking it's time to fit and pin a new gas tube in?
Any other thoughts on what to check? Everything else in the upper seemed fine. Ejector, extractor, recoil spring, etc are all fine, chamber was clean, bolt travels freely, etc. The enormous amounts of gas residue in the handguard was the only oddity I found.