1898 Headpsace Out of Whack

[browningautorifle]

Let us know how this works out...

[Potashminer]

As alluded to in earlier posts, the Go and NoGo gauges are used when installing a barrel. To check if rifle is still "within spec", then one uses a Field gauge, which is longer than the NoGo gauge. I have no experience with the Krags, but I believe the "Field" gauge, either pass or fail, is the "test" for whether a rifle's headspace is "safe" for continued use or not. British, American, Russian, German, etc. If it fails, then investigate why (Receiver lugs set back? Bolt lugs worn? Chamber worn or stretched) and respond accordingly. Several of these issues mean the receiver, bolt, or barrel, or all of them, are trash.

[butlersrangers]

It use to be a practice among some professional and amateur gunsmiths to 'Lap' the rear of the single lug on the U.S. Krag Bolt.

The intention was to allow the rear of the Bolt's 'Safety/Guide Rib' to make contact with the receiver, when the Bolt was closed.

(Danish and Norwegian Krag rifles were manufactured to have this 'rib' contact. U.S. Krag Bolts had a few 1/1000" clearance).

IMHO - This 'Lapping' may have made the U.S. action slightly stronger, but, it also likely introduced more 'head-space' or 'free-travel'.

[browningautorifle]

This 'Lapping' may have made the U.S. action slightly stronger, but, it also likely introduced more 'head-space' or 'free-travel'.

Agreed, opens up the headspace.

[butlersrangers]

IMHO - A U.S. Krag bolt should show some clearance, (approximately .001" to .004"), between the rear of the Bolt's 'guide rib/ safety-lug' and the receiver. This appears to be how Springfield Armory built them.

If the rear of the 'Safety Lug' bears against the receiver, it is likely there is locking-lug wear, 'lapping' of locking-lug, or 'movement of metal'.
Head-space should be checked with a Field Gauge.

[skeet1]

If you are a handloader you could always load some fire forming rounds by loading a bullet in the lands of the rifling to hold the case against the bolt face and then fire form. These cases would then be for this rifle only and would require neck sizing only.

Ken

[browningautorifle]

to hold the case against the bolt face

Can also be achieved the way .303 guys do it...use a tiny rubber "O" ring around the case at the base. Holds the base against the bolt face and then neck size...

[skeet1]

Jim,
I had forgotten about the "O" ring trick. You are right , that would work very well!

Ken

[browningautorifle]

"Last On 10-10-2019 @ 03:36 PM"



He didn't tell us if all worked out or not...