What size gas port?

[silvery37]

I have an 300 whisper AR with a 16'' noveske barrel. I made some loads using accr no 9 and 220 grain matchkings. The action would not fully cycle. I loaded up to a little beyond supersonic with the 220s and the action would still not cycle. The best measurement I could get on the gas port was right around .07. Is this too small or was the powder too fast?

[Ron458]

Is the gas port in the pistol or carbine position? Model 1 in carbine position uses .125 gas port. I am new to the whisper also. Ron

[redtazdog]

I have an 300 whisper AR with a 16'' noveske barrel. I made some loads using accr no 9 and 220 grain matchkings. The action would not fully cycle. I loaded up to a little beyond supersonic with the 220s and the action would still not cycle. The best measurement I could get on the gas port was right around .07. Is this too small or was the powder too fast?
Reduced power buffer spring may help.
http://www.gunsprings.com/1ndex.html

[Pitt300]

Just got my M1S to cycle reliably w/subsonics by switching to CAR buffer w/original A2 spring.
M1S CAR buffer only $10 & buy CAR spring $3 @ same time in case you need it.
Also shot full load supersonics w/CAR buffer & A2 Spring & I couldn't tell the difference.