Quote:
Originally Posted by Dosssch
Greetings from Sweden
Like everyone else, I have had problems firing low power 7.62 ammunition in my M&P10 Sport.
I recently drilled up the gas port with a 2mm drill (0.078 ").
I have also changed my gas block to an Odin adjustable gas block.
My question is if I will destroy the barrel or gas block if I tune my gas block to shoot low power 7.62 ammunition and then fire high power 308 180 grain Sierra GameKing ammunition?
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I just saw this post again after seeing your input in the Radian Raptor charging handle thread..
So back to undergassed 7.62 ammo, drilling up is the right decision, a gas rifle will not function without sufficient gas..
I bought a Wilson Combat, and it also proved problematic with 7.62 X 51 with very poor ejection, the rifle ran fine, and the empties leave the rifle, but just kind of "bounced out"..
your concern is being over gassed, its very simple, you need an adjustable gas block, open it up for 7.62 X 51, turn it in a couple of turns to decrease the diameter of the metering valve with full power heavy bullet .308 ammo..
I ended up with a KAK 5.4 oz 2.5" carbine buffer and heavy orange Sprinco spring in mine, and replaced the ejector and spring with a KAK ejector and spring to addres the lethargic ejection.. the heavy buffer and spring, slow down the unlocking, and slow the recoil cycle,, a heavy buffer does indeed increase reliability, and that heavy spring and buffer assure more positive chambering of the next round off the top of the magazine..
I ended up at .995 with the heavy buffer and spring requiring more gas, I am running my gas block wide open, with the new KAK ejector, it does indeed get them out of rifle with a bit more energy... 7.62 is still not what I would like, but it is a lot more energetic. No signs of being over gassed, in fact I wish I had opened up the gas port a little more, as my gas block is wide open, as evidenced by the adjustment bolt being about 1/2 way out of the gas block..
to be clear, my rifle functioned reliably at .082, but the ejection was very poor...
what issues were you having prior to drilling your port??
and to answer your question about hurting your rifle??? it probably is just fine as is, but if you notice signs of it being overgassed, for example slamming of the BCG into the buffer stop, (yes you will feel it), that can be addressed with a heavy buffer, (Eugene Stoner designed the AR-10 to run with a 5.4 oz buffer), or a heavier spring..
what were your specific issues with the 7.62 X 51 ammo??