I bought an old 1899 basket case. I fitted a new bolt and replaced a couple of items. While putting it together this afternoon I noticed the round cavity in the receiver, where the rotor lives, is slightly tweaked. It's hard to notice until installing the rotor. Before I find a socket that's about the right size and pounding it in, I thought I'd ask for other ideas. I think finding a mandrel like is used to stretch exhaust tubing would probably be a better idea but I'm having trouble finding one that will fit.

Thanks.

Pounding in (!!??) a hardened socket seems a bit excessive for fixing what sounds like very minor distortion, (most likely distorted by being clamped in a vise, or dropped?). I'd choose fine tapping with a brass hammer on the outside, or hardwood wedges inside. The receiver steel is not that hard,

The socket idea is not likely to work, because the body of the cavity is larger than the aperture, at least on any I have examined. I like the idea of the expanding mandrel, and often thought of making one, but so far the solution is disproportionate to the problem. I thought of making a hardwood cylinder the diameter of the spindle head, splitting it down the middle and driving wedges in it to expand it. Must be able to retrieve the wedge, however, or the headache just got worse. Also, the propensity to yield will be at the thinnest part of the wall, not necessarily where the damage is. Just my 2 cents worth.

Sam

Well I'm glad I asked first

I'll think through the suggestions. I think I found a expanding mandrel that should work. When I get home I'll take apart q non-tweaked 99 and take better measurements.

Hmmm. "Tweaked"? Just how so, and how bad? If bad enough to have tweaked the receiver a few thousandths out of true would it effect the geometry of the moving parts inside of it?

Something I've often wondered about: being that the receiver walls are so bloody thin and susceptible to stretching if the elasticity of the steel alloy is exceeded, if that may be a cause of increased headspace issues (especially in the early guns made before their metallurgy was changed to accommodate the .250-3000)? Sure, the bolt nestles firmly against a big blob of steel in the back but what's that steel ultimately supported by - the receiver walls. Purely an academic question as obviously practically the rifles have chugged along without breaking a sweat for 100+ years. I sure would like to examine a 1899/99 that failed due to a horribly egregious overload or tested to destruction with increasingly stiffer loads, just to see how/if the receiver walls reacted and/or failed.

I've often said the 99 receiver, while hell for stout, has to flex/stretch a lot microscopically at the instant of discharge and might possibly explain why brass life can sometimes be less than the same brass fired in a tightly breeched bolt gun or single shot. Try as we might otherwise, all steels are limited by their tensile strength and elasticity.