Shotgun gas ports

[Guess_Who80]

I have a mossberg sa-28 turkey and it's over gassed. The load is tested and it's safe but the slow burning powder is overloading the gas system. I need the gas ports smaller. Would like to have them tapped for set screws with centers drilled out at ~. 050 then fine tune from there. Gun will prob never see more than 200 rounds in my lifetime and it'll be a dedicated turkey gun with only that load. It's that good . The 2 ports roughly measure .113 each. Anyone interested?

 

[akajun]

why do you think its overgassed? Might be better/easier to make a smaller set of pistons to let more gas escape

 

[Guess_Who80]

The extractor is ripping the rim, throwing the hull a mile, been shot maybe 10 times and already see where the bolt is slamming the receiver, not loading the next round from the tube, etc. I shoot the same powder in a 20ga gas gun and it does the same. Pumps, singles/doubles, inertia or recoil operated guns cycle them fine. I know of guys that had the ports welded shooting the same powder for the same symptoms and that fixed it. The loads have been pressure tested by precision reloading and are under saami max.

 

[MilGunsmith]

You might try changing powder. By changing the powder burn rate you can still have the same chamber pressures with a lower port pressure. It also affects the port dwell time, which is how long the port pressure is at the peek pressure. We went thru this with M855A1 ammo, they where originally only looking at the chamber pressure and velocity and ended up having problems with the port pressures.

 

[Guess_Who80]

I looked into the powder change but lose to much velocity and have to reduce the payload. Right now I can get almost 20 gauge performance in a lighter, slimmer, shorter gun that fits me to a tee. Pattern is only slightly less and about 150 fps slower than the 20

 

[GGaskill]

How about welding one port? Could always drill it if you need more gas.