Just slugged my barrel

[sapper_eng]

Just slugged my Lee Enfield No 4 and it came in at a few different measurements. A The most common measurement is coming in at .308. But I also got a reading of .312. Whats up with that? It seems to differ based on where I measure it from? I'm taking all measurements on the land.

[sapper_eng]

I just did the process again, with another 00 buck shot to see if I could duplicate the results. I've checked the shot with my calipers and am getting readings consistently of .3115 and .312.

Now, I have 5 land and 5 groves within my barrel which makes it difficult to measure since I don't have anything on the opposite side - I have to go off of the edge of each land to measure. I'm thinking my measurements are a bit off. When I roll the slug gently between the calipers I get resistance up until .312, but at .3125 the resistance is gone.

Based off of this should I be casting with the Lyman 314299? Or should I use the Lee C312-185-1R?

Looking for some advice on how to proceed on this one from you more experienced members.

[MtGun44]

Calipers are not accurate enough to do this measurement with any consistency. You need a
.0001 reading micrometer.

Also, there is a good bit of technique in this, very easy to damage the slug with a touch too much
pressure, or leave the mic a touch too loose. With the five groove bbl, you need to span
the edges a bit and this adds a large dose of uncertainty, too. You can wrap a piece of
.001 or 002 shim stock around the boolit and measure that, then subtract twice the
thickness.

Expect .312-.314 for groove diam on most of those.

Bill

[GhostHawk]

Sapper I'm using the Lee .312185 in my 2 Mosin's and my Yugo SKS.

Mosin's both slugged at .312 the Yugo SKS came out a bit like your readings, from .312 to .314

I have been sizing to .311 to put gas checks on.

For the SKS I read somewhere that it likes the bullets set LONG, so I have been doing so.
They still fit in the original steel magazine, but they look pretty long.
It all seems to be working like a charm at this point.
I have not done any long range shooting yet, but at 25-50 yards it shoots cast EXACTLY where I point it. Using IMR 4895 in both, 20 grains for the SKS is easy on the shoulder but performs well.

[Larry Gibson]

Wrap a strip of shim (.002-.003 is best but you can cut a piece from a thin aluminum can) tightly around the slug and measure that. Subtract twice the thickness of the shim and that will give you the proper groove diameter or very close to it. As MtGun44 mentions your 5 groove should be in the .312 - .314 range.

Larry Gibson

[milsurpcollector1970]

.314 worked good in the enfield #4 I had