Hexagon Production (HP) L96 hop chamber, too tight?

[kojak]

I installed one last night, and the nozzle from my Army Force kit wouldn't even fit in the chamber. After I sanded and polished the nozzle down a hair, it fit just fine.

 

Unfortunately, loading a BB into the chamber now requires too much effort to close the bolt, enough that the nozzle is leaving dents on softer ammo. Is it OK to bore out the BB loading area of the HP chamber? Is there an internal O-ring or something to worry about?

[Maekl]

There is an oring in there indeed that causes your issue.

[kojak]

It's been working fine with a stock nozzle ever since I fished out the o-ring with tweezers. I also enlarged the window to make room for a flat hop, and filed the sides slightly so the "pot metal ring" could fit properly.

 

Even though it took some work, it's a nice simple unit that does the job well. I'm wondering if the grub screw could be replaced with a longer bolt, to make hopup adjustment easier in the field?

[kojak]

I'm thinking of taking a Dremel to this thing yet again, this time adding a slight bevel where the BB first enters the chamber. I'm getting an occasional feeding jam with the BB stuck between the nozzle and the edge of the "hole" where it's supposed to go.

[kojak]

Beveling the left and right sides of the inner opening, where the BBs load from the double-stacked mag, solved my feeding issues completely.

 

I also switched the hop adjustment grub screw for a socket cap screw, that installs from outside the barrel, with a drop of Loctite blue to keep it steady. It's much easier to set the hopup in the field now that I don't have to fish around in the dark magwell for the screw.