
Originally Posted by
patrick0525
Thanks for the link. I wanted to know the outside diameter of the barrel at the gas port. On your barrel, the drawing says it's 0.750" which is pretty standard.
If your barrel was a thick heavy match style barrel (thicker than 0.750" at the gas port), it would make sense (to me) to have a relatively large gas port.
If my math is right, your port size (the area which is the radius squared times pi) is about 62% bigger than the Colt port. Keep in mind that a lot of smart people think even the Colt port size is too large for a 16" bbl with carbine gas system (but right for a 14.5" bbl with carbine gas system). But also keep in mind that there are a lot of overgased ARs out there that run fine.
The bottom line is that your bolt/carrier velocity is probably too fast for the PMAG spring.
Joe Mamma
"Reliability above all else"
NRA Certified Pistol and Rifle Instructor, Life Member
Glock Certified Armorer
Beretta & Sig Sauer Certified Pistol Armorer
Colt Certified 1911 & AR-15/M16/M4 Law Enforcement Armorer
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