On another board that I visit daily the subjuct came up again. Now I was always under the impression that the problem was the contact between the barrel and the forearm. Not nessesarly... so claims Bill in PA.
Heres what we were discusing....
Bill said...
The problem with the forends is where it bears against the receiver when closed, trying to force the barrel forward and down. The easy solution is to relieve it. Use sandpaper and a dowell or a Dremmel tool with a sanding drum and give it enough clearence,when closed,you can pass a piece of paper between the receiver and forend. Yes it will seem loose when the action is open, but that doesn't matter. There isn't a way of "floating" since the forend is attached to the barrel. Installing an "O" ring masks the problem to some extent, but dosen't eliminate it.
WDO said...
I've never heard that one. As far as I know, the "O" ring thing is so that the fore-arm does not contact the barrel. I use a washer cut out of a coffee can lid. This way when you tighten it down it's always the same thickness. Unlike a regular "O" ring that deforms.
Bill said...
Well, after doing a few NEFs, 'bout 50 or so, I've learned a thing or three. I do more triggers then anything else, but always the first question asked is how to make them group better. Using a spacer, O ring or whatever does in fact help move the forend away from the barrel, but doesen't do anything for the binding between the receiver and barrel stud/screw. If you want to try something interesting, shoot it without the forend resting the receiver on the front bag. If it groups the same, the action/forend clearence is OK, if not ......
Then bill replyed...
Here is a pic of the area to check. Some show very heavy rub marks with the action closed. It can cause some very heavy pressure between the receiver and forend screw/stud, doing bad things to the barrel when its fired.

Interesting to say the least....just when I thought I did the deal all figured out. WDO