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I just tried to headspace a new barrel today. At the same time I replaced the recoil lug with a SSS one. Anyway, I ran out of thread on the barrel before i get the proper spacing. Can I machine a little off the barrel nut? I haven't tried the factory recoil lug yet and really don't want to. Thanks
Is there much difference in the thickness of a factory lug compared to the one from SSS?
Simplest things first, is your hs gauge nice and flat to the bolt face, and not held forward at all by the ejector?
Yep SSS is quite a bit thicker. And I have the extractor and ejector removed.
yep you can take some off the barrel nut
There should be plenty of threads on the barrel to make room for the thicker lug. Check the barrel nut for diameter in the front undercut area. There is usually about 1/4" of thread relief in the front portion of the nut, but sometimes the diameter is too small to go over the threads. The under cut should measure 1.065" on a standard shank and 1.125" on a large.
Tried it with the stock lug, worked. So I measured the new SSS lug and the factory lug. 50 thou difference. Machined 50 thou off on the nut and all is well now. Thanks
I set up a McGowen and Jim's new thicker than factory lug on and had the same problem last October. Couldn't screw the nut on the barrel far enough to get proper headspace. I needed roughly .015 more. I bored the threads on the barrel nut .025 deep down to the root on the front side, NOT the lug side. This made the nut screw on the barrel another half turn. Deburred it and was good to go. The nut cut like butter on a lathe with carbide insert. I put tape marks on the barrel and nut to see how much more thread was needed on the barrel for the thicker lug. The tape marks were only off by about a tenth of a turn when finished. That's only .005, Sooooo close!
I just had the same problem mounting an A&B barrel on a 110.....Not having a lathe handy I turned the nut on backwards on an old barrel that I had laying around....I need approximately 1 more turn also....I measured about .050 thread on the front side of the nut to protrude beyond the chamber face....I carefully filed the end of the nut till the flat file just made contact with the barrel.....Left a nice square cut....I deburred the edge and the rest of the installation went perfect.....
Randy