I was just wondering, did the manufactures, TRW, H&R, Winchester, lap the bolts to receivers during assembly, or is this something that is only done with non military made receivers.
I would guess that then proper lug geometry (on both bolt and receiver) would mean longer receiver life, if you're going to lap the bolt to make it mate most correctly, as that would mean less lapping.One should always keep in mind that when lapping the bolt you are also lapping the receiver.
Each barrel needs another bolt to get headspacing. That's a lot of bolts to lap in.About 200,000 to 250,000 rounds. That’s a lot of barrels.
My guess is that you are the short chambered kind. Am I right that chrome barrels need their headspace set, done by swapping bolts?......
Some owners like a better fitment of parts than others. Some like GI chrome lined barrels and others like short chambered CM or SS barrels and that's okay.
USGI bolt were precision ground between centers on a thread grinder post heat treatment to final qualification spec .So unlikely you will finds a warped one .More than likely the demill welds did this or uneven wear.Each barrel needs another bolt to get headspacing. That's a lot of bolts to lap in.
Are bolts just a scosh softer than receivers? So you lap away the cheap part?
And just how much gets lapped away? How bad is the Service Grade fit?
And another thought- While un-demil-ing a couple bolts, I noticed that the bolt faces were slightly crooked. I assume the body of the bolt had warped in heat treat. Mightn't it have warped to one side, making the lugs uneven? Or even, the receiver warped, it pushes the bolt to one side necessitating lapping for best, most consistant fit?
Radius sure, everything need to be radiused. But I think the cartridge is what centers the bolt in the bore- the end of the right lug is sticking outt in space and has a roller on the end.I might add too that not only were the lugs ground after heat treat between centers the lug shoulders that center the bolt in the barrel bore minor i.d. were ground at the same time as they dressed the stone at a 90 degree angle with .020 radius corner .I've got a picture in the SA ordnance thread.