case sizing tolerances

[Stilgar]

Good day all,
Hey noob reloader here, my Lyman manual has specs for given cases, but I'm not finding anything about tolerance margians anywhere.
How much either way of said specs are cases allowed to be and remain safe?

[jefferson101]

Re: case sizing tolerances

Truth to tell, the only dimension I ever pay any attention to is the case length. I treat the spec length as a maximum, and trim to that or a couple thousandths less.

Other than that, a full length resizing using a resizing die that's in good condition is going to pretty much force the rest of the case dimensions to be the right size.

[Stilgar]

Re: case sizing tolerances

Truth to tell, the only dimension I ever pay any attention to is the case length. I treat the spec length as a maximum, and trim to that or a couple thousandths less.

Other than that, a full length resizing using a resizing die that's in good condition is going to pretty much force the rest of the case dimensions to be the right size.

That's what I needed to know. Thank you, Sir.

[C. M. Wolf]

Re: case sizing tolerances

Lee Reloading have done some pretty extensive compliling of info on many calibers for minimum and maximum case lengths,(and case-wall thicknesses too).

But the very best way, IMHO,(although a tad expansive), is to do a chamber-casting of every rifle/pistol that you own or reload for. This way you can guarantee yourself to get your cases within just a couple of thousands per firearm chamber. By doing the chamber casting, you can actually see and measure each chamber exactly as it exists in the firearms.
(Another added cost of this is that by firing the weapon, it will wear. The chamber casting may need to be redone every thousand rounds or sooner, depending on desired accuracy).

Generally within .003 of center-min/max recommended is fine, (* some calibers are more restrictive in "min/max" than this, and some firearms designs/makes tend to stretch/shrink case lengths at different rates upon firing each time). ...It's a "Firearm Character" thing...

IHTH

Michael