stevegun 1 Wrote:Thanks rasp65, good link. If I'm reading right, a RLGS is the way to go. After reading the link, I'm still not sure of the correct gas port size for the barrel? It sure sounds like an adjustable GB is the smart way to go with the Grendel.
From rasp65's link, I think this is your answer for an 18":
Bill Alexander Wrote:Our examination of the 18" barrel has shown that the mid gas system while a little enthusiastic can be easily mitigated by reducing the gas port size. Typically the port is 0.073" for the correct operation and the slight change in duration of pressure at the port actually helps reliability.
FWIW, I had a MLGS 18" with a gas port that measured ~0.082", and it ran fine with a standard gas block using powders of yesteryear. Other 18" barrels that I've tried had gas ports measuring 0.090"+, and an adjustable gas block was absolutely needed.
Until recently, RLGS on ~20" barrels didn't seem to need adjustable blocks. But with new powders like CFE-223, adjustable gas blocks make sense. 129gr bullets using CFE-223 powder will operate a system much differently than 107's with 8208 powder.
Drifter