Lots of folks, me included, hate the idea of a barrel being supported by a single grub screw. Yet FX continues to make $2000 guns with that system, even as they develop innovations like the Maverick and M3.
I'm no engineer, but I think the answer is that the grub screw doesn't 'support' anything. Its job is to LOCATE the barrel by, in combination with the locating pin that mates with the notch in the transfer port, controlling fore-and-aft movement and rotation of the barrel. In firearms terms, it controls headspace. In fact, last week after a cleaning I noticed a big drop in POI and the chrono showed a 30+ fps drop. I had seated the barrel assembly just a hair short of fully. Shoved it back in place, tightened grub screw, problem solved.
Ahead of the brass transfer port section is the steel segment Ernest calls the adapter. It has two raised bands which very closely fit the channel in the rear block. Very closely. After I bent my barrel sleeve (the outer blued tube which contains the liner) I found that I could not re-insert the barrel assembly into the rifle until I had rotated it to a certain position. When I went t replace the bent sleeve, even though I was careful, I caused a subtle burr on one of the bands on the adapter. I could not get that gun back together until I looked at the adapter under magnification, the oh so carefully smoothed away the burr with a fine Arkansas stone.
Then of course there are the O-rings in the forward and rear blocks, and on the transfer port. So all in all I think there is quite a bit of support, and quite precise at that, and the grub screw just keeps things from falling out.
I'm no engineer, but I think the answer is that the grub screw doesn't 'support' anything. Its job is to LOCATE the barrel by, in combination with the locating pin that mates with the notch in the transfer port, controlling fore-and-aft movement and rotation of the barrel. In firearms terms, it controls headspace. In fact, last week after a cleaning I noticed a big drop in POI and the chrono showed a 30+ fps drop. I had seated the barrel assembly just a hair short of fully. Shoved it back in place, tightened grub screw, problem solved.
Ahead of the brass transfer port section is the steel segment Ernest calls the adapter. It has two raised bands which very closely fit the channel in the rear block. Very closely. After I bent my barrel sleeve (the outer blued tube which contains the liner) I found that I could not re-insert the barrel assembly into the rifle until I had rotated it to a certain position. When I went t replace the bent sleeve, even though I was careful, I caused a subtle burr on one of the bands on the adapter. I could not get that gun back together until I looked at the adapter under magnification, the oh so carefully smoothed away the burr with a fine Arkansas stone.
Then of course there are the O-rings in the forward and rear blocks, and on the transfer port. So all in all I think there is quite a bit of support, and quite precise at that, and the grub screw just keeps things from falling out.
