adjustable gas block suggestion for canned AR pistol

I chose the SLR Sentry 7 for my 10.5" .300 BLK pistol build as I plan to put a can on it. After lots of research it seemed to be the best blend of quality, price, ease of adjustment, customer service, etc. I have not gotten to test fire it yet but installation was a perfect fit and this thing is Solid!

DoubleMag said:

The whole exercise was to find a possible fix to cut down on gas. Is an adjustable gas block part of that fix? His thinking is yes

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His thinking is wrong. Virtually all of the blowback comes through the chamber.

If it cycles fine suppressed and unsuppressed, tell him to leave the gas system alone and buy a gas buster type charging handle. Personally, I don't find the blowback from an AR particularly bothersome, even with standard charging handles. Most other rifles are worse (and louder).

As I handload 300Blackout some powders like 1680 I get more blowback than say, H110 (if memory serves) and some of the tricks with the charging handle do work like using a sylicon gasket maker or the gas buster types. Some have holes drilled in the sides to vent. The forward assist type of vent can help and can be drilled out, too, to do so. But for me it's been powder choice that helped more than anything.

I think every gas operated rifle should have an adjustable gas block, and that goes double for one that can take a suppressor. With that said, I don't know that it's really going to make the gun noticeably more pleasant to shoot. You're still going to have gas blowing back in your face. The way to deal with that is taking some form a gasket and making a seal between the charging handle and upper receiver. You need some form a gasket and a can of neutral kiwi shoe polish, which is the best release agent for most things like that. You put the shoe polish on the receiver, liberally, and then build up some gasket on the charging handle. Push the charging handle closed, wipe off the excess gasket maker, and then wait for it to dry. Voila!

Here's a writeup:

http://www.03designgroup.com/technotes/do-it-yourself-gas-buster-charging-handle

(that may or may not be the best page describing the process, it was just the first hit on searching for 'DIY gasbuster'. It's not a complex process)

The other easy DIY mod is to drill a gas relief hole in the charging handle:

http://www.rockstomper.com/firearms/ar15/ar15chmod03.jpg

DoubleMag said:

Several votes for charging handle fix will pass it on.
gpjack , so I do not misunderstand your great description. After the custom work, the gasket material remains on the charging handle vs receiver. Correct? The entire length of handle or just the back portion closest to face. Should the handle be ruffed up a bit for better adheasion 1st i.e. scotchbrite pad.
Please remember I am passing this on. Sounds like a great idea and he likes to tinker

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My suggestions for the sealant route would be

1) Use Permatex Right Stuff, not silicon. It's stronger, bonds better, and is already a dark grey color

2) clean & dry the charging handle well with alcohol or brake cleaner for good adhesion

3) put a bit of wax or grease on the upper so the sealant won't stick to it

4) I would apply it with the charging handle just a few thou back from where it's held with the bolt fully closed. That way your "gasket" will be squished a little bit when in battery

All that said, I've never found it necessary to "seal up" an AR, just don't get that much gas. And I've run quite a few different cans on AR uppers from 7.5" to 22", calibers 5.56, .300 BLK, .308, 9mm and 10mm Magnum. One .308 was so over-gassed with a suppressor that it reliably stovepiped empties, and I still didn't have much coming up into my face

By its very nature the volume of a can acts as a booster. You will get a lot of gas from the bore after extraction has started. I have a piston operated side charger that I can't shoot with a can without getting powder burns on my lips-- I have to wear a bandana or mask. I keep one with the can.

Mike