We'll, I may have gotten a bit carried away after reading some comments about how little effort was required to hold the reamer from turning (some smaller in stature individual mentioned if he could hold it anyone can!). :-) I could, like Tozguy said, use some rubber material like maybe the round thingy for getting a better grip on a jar top. I could also just add a drill rod out one side (I was trying to avoid that). This reamer holder is 1.1" in diameter. I was originally thinking of making it something like 1.5" in diameter. Would be good to somehow know what I should do what it will take to keep it from turning before I start chambering. I'd hate to have to remove an already indicated barrel out of the head stock to do some other work!!!!
That would be me. 5-8, 170 lbs, and not all of it muscle. Mine is 1.5 dia, the gripping portion is 1-1/8 long, and the knurl doesn't cover all of that. Held between the thumb and first finger only.
I've chambered several .308's with it, a 6.5x55, a .284, a couple 22-250's, and a number of puny little things (.223 and .222). Like I said before, no idea if I'd get away with doing a belted mag this way.
How to hold it without deflection? It's stuffed into a bored hole with a taper matching the reamer. I kind of doubt I could pull it off center if I tried. May have to actually try that someday and see what happens. At worst, I think it would oversize the chamber a bit, but probably stay true.
As for slipping in your hand, it's one of those things you don't pussyfoot around with and let go at the first sign of distress. Hang onto the damn thing. You'll get a feel for how hard to feed. Always surprises me how hard you can feed it, and it's never spun in my hand ... yet (knocking on wood). *
I would not use this if the chamber weren't bored to match the body taper of the reamer. I'd use another knurled collar with a thru hole and guide the reamer with the tailstock center. And then go back to this once it's established.
You also need to figure out how deep to bore so the body contacts first, with the throat and neck clear of the bore. I cheat. I have CAD ;-)
* Actually, I take that back. Had one reamer, I think the 6.5x55, that would not cut at all on the body. Wedged into the hole like a Morse taper. Had to send it back to get the margin reduced on it.
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