had a Shaw 16" M4 barrel with standard FSB, I added a 12" YHM rail over a Low prile gas block and wolf ammo started short stroking causing Failures to feed. Before the wolf was running like a singer. I seal around the gas block with lock-tite when I installed it like I did when I installed the FSB. Anybody have any idesa on a fix? I know somebidy will say "just don't shoot wolf ammo" but that is the point I want to shoot wolf ammo in this AR.

Thanks for your help guys,

Silicon

Si,

Since Wolf was shooting fine before the switch from standard FSB to low gas block, I doubt that the ammo is at fault, because pressure will be the same at the barrel's gas port.

I have two thoughts on this.

First:
By changing to another gas block, you may not have lined up the barrel's gas port with the block's gas port, thereby, not allowing enough gas to enter into the system.

Second:
Let's say that both gas ports (barrel and gas block) are lined up perfectly.  Then, I would suspect that the block's gas port is too small to allow enough gas into the system.  The only way to fix is to enlarge the block's gas port next to the barrel.

Either way, I see your problem as one of not enough gas entering into the system.

I do not know how to line up the barrel's and block's gas port.  A possible idea: loosen block, take off gas tube, and insert pipe cleaner into gas block.  Maybe you could snake it around to feel for proper alignment; then tighten in place.  A borescope sure would be handy.

Posting photos of the new gas block on the barrel may give ideas on how best to align the ports.

Maybe other folks will post ideas.  You can also post this tread in the "Troubleshooting" section.

+1  Nothing wrong with the ammo, you either misaligned the gas block or it is internally restricting gas flow somehow.  Take the gas block off, inspect it for obstructions.  Re-check and remeasure for gas port alignment.  

found the problem, after taking the gas block on and off twice. I found that the gas block was fine, and alinged correctlty. After the second time it still didn't cycle right so I took the BCG out and noticed the Gas key on the Bolt carrier was lose as hell, the front screw had backed out. I took the key off and clean it and the carrier so it would fit tight and then reinstall with the screws. then i sweged the screws in four places and put it all back together. now it runs like a champ.

Thank for all the input, thought I'd post what the fix was.

Silicon