Re: Borden bumps.
I don't understand the no clearance while woking the bolt statement you made? The bushing takes up extra clearance but still leaves some, and when the bolt is worked the bushings at the rear are actually withdrawn from the bolt bore completely and the original bolt body clearance forward of the bushings has plenty of clearance. I don't like the idea of bushing the front end tho, I think you're just asking for a binding condition just as soon as the bolt is withdrawn far enough that the rear bushings leave the bore. If it were me, I'd build up the rear bolt body with a Tig in several spots and turn it back down to the exact diameter it needed to be. All one really needs is maybe a bump on top and two on the bottom to keep the bolt centered in the cocked and uncocked position both. I haven't asked Dave yet what he'd charge me to put the bumps on, but he agrees it's a better idea than bushings and would take a lot less time.
I agree, I don't like the idea of anything soldered either, soft or siver. Bolt handles included. I like the bumps design that leaves clearance for grit to escape into.
I don't see the need to have damn near zero clearance on the "whole" bolt body itself, except for fast cycling on a bench gun, just the opposite in the field is what I want.
How much "accuracy" is gained by this mod? I've got no idea, but I do think it's slim to none. If the bolt body allows the lugs seat square when sear spring pressure is released and the bolt face is paralell to the lugs, the thrust from the casehead is more than enough to seat the lugs firmly upon firing, thus no out of square caseheads ever develop. JMO at this point.
From what I gather, the BAT and some of the other customs are machined too tight to be 100% reliable in the field, that's the impression I get from people who own them anyway.
When Dave puts this 30-338 Lapua in the stock for me, I'll have him put the bumps on my bolt and find out what he has to charge to do it.