Undersize Bore

[ncbearman]

I slugged a S&W .357 AirLite w/2.5" barrel today and I got readings of .351, .353 Groove specs on a .357 are .356 and .357 on a 38 Special. I am planning to size to .354. Is this going to be a problem for me? I slugged twice and got the same results both times.
Russ

[R.M.]

The Smiths have an odd number of grooves, which make measuring a slug tricky.

[bhn22]

The Smiths have an odd number of grooves, which make measuring a slug tricky.

Aye. The slugs really need to be measured in a fixture. Some guys have devised some magical way of doing it using shims, but I can't get my mind wrapped around the process. Size to fit the throats, and you should be fine.

[ncbearman]

Ah, that explains alot. I didn't notice that. Thanks for pointing that out RM. Well, as I rotate the slug while keeping slight pressure on the calipers I get the same reading as I do at the throat. Not completely accurate, but it is closer than the first way of measuring and it's closer to spec now too.

[williamwaco]

I have never seen a Smith that will not work perfectly with .357 or .358 bullets.

Try it. You will like it.

[Fishman]

Ah, that explains alot. I didn't notice that. Thanks for pointing that out RM. Well, as I rotate the slug while keeping slight pressure on the calipers I get the same reading as I do at the throat. Not completely accurate, but it is closer than the first way of measuring and it's closer to spec now too.

That way works ok with calipers but its just an approximation. Take your slug and "upset" it a bit by striking it with your hammer on a hard surface. This will ensure you are gettting to the bottom of the grooves.