If I was to venture a guess, your 2 280AI`s were factory rechambers, and the 7 Mag a custom tube. How close is the old man?
LOL! I can appreciate that.
Actually all 3 tubes were made by Paul Marquart. The 280's were
.550's with the 7 going .580.
I dug a lot of flagstone out of the ground to pay for those things! $10.00 a ton.
