Odd S&W 629 bore size: sizing question

[Jumping Frog]

OK, I've read just enough to be dangerous without really knowing what I am doing.

I slugged the 6 chambers and the barrel for my .44 Mag S&W 629. I cast some pure lead bullets and then smacked the nose with a hammer to make them a slightly oversized diameter. Then I drove them through with a wooden dowel. Each chamber got its own slug and I slugged the barrel twice. I could see where I had shiny lead circumference from being sized as I pushed each slug though.

The chamber sizes came out to:
.4290
.4287
.4288
.4290
.4290
.4291

However, I am concerned about the barrel. It slugs out to .4233!!! I started the slug at the muzzle and pushed it through to where the cylinder would normally (I had removed the cyclinder).

Seems awfully small to me, however, I cannot find anyplace with google that lists what the barrel bore should be, so I don't know.

Now, I bought a .430 sizing die but it seems to me that a .423 barrel is going to be a problem.

Can anyone help enlighten me?

 

[243winxb]

five-land-and-groove rifling is hard to measure. Normal is .429" to .430" Bullets are the same.

 

[ClarkEMyers]

I'd start with 429 sized bullets -

I'd start with 429 sized bullets - I see little to be gained by taking a .430 bullet and sizing it to .429 in the chamber throat.

On the other hand I might lap the chamber throats to a uniform and larger size. I would look very closely at bore diameter at the barrel threads - many S&W barrels are in effect choke bored through the frame where again the bullet is squeezed down early and continues undersized through the rest of the barrel. Best not to resize the bullet except through a tight fit in the barrel itself and never to open up larger after squeezing the bullet down.