Robb (and anyone else): Can the dissimilar metals problem cause gas leaks other than causing the gas block to slip? Robb dimpled the barrel and red loc tited the set screws. Can the different expansion rates cause leakage as the rifle heats up?
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Robb (and anyone else): Can the dissimilar metals problem cause gas leaks other than causing the gas block to slip? Robb dimpled the barrel and red loc tited the set screws. Can the different expansion rates cause leakage as the rifle heats up?
It can if using an aluminum gas block and a obviously steel or stainless barrel. Usually you'll only see this when running the rifle really hard or on full auto. I too prefer steel or stainless gas blocks for this reason (especially on CAR length systems). This is also why I prefer pinned gas blocks whenever possible and why I always recommend 'shaving' a FSB into a lo-pro gas block to fit under long rails (9-12" rails w/CAR or midlength gas systems) instead of just a dimpled lo-pro non-OEM gas block. But if you do decide to go with a lo-pro gas block I recommend sending it to ADCO, AR15barrels.com or John Noveske for taper pinning.
Chief Armorer for Elite Shooting Sports in Manassas VA
Chief Armorer for Corp Arms (FFL 07-08/SOT 02)
If this were an issue for me, as I do not personally own a S&W carbine it's not, but if I did, I would go directly to the source and call or write to S&W's customer service department... I am not sure I would rely solely on postings on the disinformation net...
Just my .02
Buck
MossieTactics.com ~ KMA 367
Regarding pinned versus bolted gas block:
I think the whole set screw concept is a bad idea. The problem is that tightening the set screw draws the block away from the barrel on the set screw side, possibly creating a small gap. So you end up with uneven contact.
However, the cross-bolt clamp style gas blocks made by GG&G, YHM, VLTOR, and DD should be fine. Military Morons did a test of the VLTOR clamp-on folding front sight gas block. They clamped the upper in vice blocks and torqued the front sight to see when it would slip. They ended up slipping the barrel in the upper and ruined the timing pin in the barrel before the gas block slipped.
I like the fact that a clamp on gas block sight can be adjusted to get the rear sight centered as well.
This applies to civilian and LEO semi-auto carbines, though. For hard full auto use in combat, I think a regular pinned FSB should be mandatory for the most part.
KintlaLake
KintlaLake Blog
"Blasphemy is an epithet bestowed by superstition upon common sense." (Robert Green Ingersoll)
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