Empty case necks dented?

[Chance-dg]

Klem...….several months ago you reiterated to me very good advise on my build,,,,,Barrel, trigger, glass and trigger time. all the rest is just icing on the cake. (My weak point is the trigger tripper).

I am running a Geissele 2 stage enhanced match trigger and a Leupold VX6 2x12 in an Aero Precision Lt Wt one piece mount. The Leupold will be off to their factory for a reticule change as the duplex is too thick for precision work. This is a hunting carbine for Montana prong horn and deer mostly and I am having the LR Varmint put in it. The upper is all BCM on an AP Gen 2 lower and LPG with BAD enhancements and a BCM SOPMOD Mod O stock.

I fired a cold barrel 6 shot group yesterday of .893 in. with a Nikon P223 scope and mounts and the 90g TNT factory load on my red neck shooting bench. Vertical stringing caused this group to be this large and was shooter induced. This GB barrel is a one hole shooter when I do my part.

[Chance-dg]

How did you choke the gas down???

[Chance-dg]

I can always open the SA gas block a bit on this hunting carbine last shot bolt open doesn't really matter

[Bigs28]

How did you choke the gas down???

When the set screw is all the way open it is max bleed off with maximum gas coming through the block. After you completely shut off the bleed off by closing the set screw then it starts to shut off the the incoming gas all together. It's no longer bleeding off and just choking off the incoming gas. If you take the block off and look inside the hole you will see it opening and closing depending on which way you turn the set screw.

[Chance-dg]

I have AP 10.5, Sig 556 14.5 and Ruger 16in. fast twist .556 pistols and SBRs for ranch guns and my trusty 1911's. The very best personal defence weapon is the one you have in your hand when SHTF......lol

[Chance-dg]

I need just enough gas coming thru the block to run the BCG..correct? with the rest exiting the block in a forward direction hence mitigating recoil??

[Chance-dg]

just wrapping my mind around this

[Bigs28]

Ok so their are two ways to use the gas block. If the set screw is set in the middle then 100% of the gas comes into the block, through the gas tube, to the receiver. You have a choice now. Open the set screw which now diverts some of the gas out the front of the block "bleed off". OR close the set screw and reduce the amount of gas coming into the block, through the gas tube, to the receiver. You can't reduce the gas and bleed off together. It's one or the other. The bleed off wasn't enough for me wide open so i had to switch to closing gas off.

[Chance-dg]

Thanks for this explanation...….so is the SA worth the money?? or just go with a standard adjustable GB Seekins etc. for my next build in Grendel?? YES I have the bug.

[Bigs28]

The sa works. It will stay on that upper. My next adjustable gb will be jp. They are the lowest profile ive found.

[Chance-dg]

Thanks for the explanation and help.....I have turned to gas block to max pressure and have a couple of H1 and H2 buffers I am now playing with to get the rifle dialed in. I am still going to shorten the plunger spring a coil or 2 to eliminate the slight case mouth denting issue completely. I am beginning to really like this SA gas block for its adjustment range.