PDA

View Full Version : Floating bolt head



Mr.Snerdly
02-02-2020, 03:33 PM
They say this is an advantage due to machining tolerances and if everything isn't perfectly square the bolt head can flex enough to contact both lugs, which makes sense. The thing I wonder about if it isn't machined right and the head has to twist a few thousandths to get perfect contact, wouldn't the area that contacts the cartridge not have square contact? It would be better to have everything perfectly square but if this isn't possible, would it be better than having a solid bolt that isn't making perfect contact with the lugs but is still square against the cartridge?

sharpshooter
02-02-2020, 04:30 PM
I think your assumption is correct, but the chances of bolt head and the lug abutments being out of square is very,very slim. The front end of the receiver is machined in one fixturing, so the lug abutments, the receiver threads and the face of the receiver is all square to one another, at least on actions made on the new machinery.
It would be very difficult to deliberately make them out of square. The bolt heads are the most consistent components for holding tolerance, but most will suffer from a slight dish in the bolt face from the vibratory polishing operation. Typically this dish is less than .002", and doesn't hurt accuracy, but sometimes it will contribute to primer cratering.

old110
02-06-2020, 06:36 PM
I think your assumption is correct, but the chances of bolt head and the lug abutments being out of square is very,very slim. The front end of the receiver is machined in one fixturing, so the lug abutments, the receiver threads and the face of the receiver is all square to one another, at least on actions made on the new machinery.
It would be very difficult to deliberately make them out of square. The bolt heads are the most consistent components for holding tolerance, but most will suffer from a slight dish in the bolt face from the vibratory polishing operation. Typically this dish is less than .002", and doesn't hurt accuracy, but sometimes it will contribute to primer cratering.
I would have to agree with this statement.

Texas10
02-07-2020, 09:10 AM
If you're concerned about the trueness of the bolt face, you can send the bolt head out for bushing the firing pin hole. The bolt face will be trued up and you'll have no problems with cratering primers. It's not expensive, nor does it takes long.
https://www.gretanrifles.com/product-page/bush-firing-pin-hole-turn-pin