Luke said:I think he saying that the .308 booster hole is slightly larger than a half of an inch, whereas the 30-06 hole is .718. If your gun is all perfectly square and machined to fine tolerances, assembled perfectly and ETC. it will work with the .718(30-06) type booster. Hell he might be right! But I find it hard to accept that the Israelis(they engineer some cost efficent, well made and functioning things) would bother modifing the front booster unless they were experiencing cycling/reliability issues. Having said all that if my gun with a 30-06 booster worked I would use that and I might think my gun is better made than one that requires more power(smaller booster hole) to cycle the action. All I know is all 3 of my 1919's work well and I have alot of fun with them. Again thanks Lobo for your fine tutorials!
The Israelis went with a smaller orifice because they wanted a much higher cyclic rate.