Bullet diameter ?

[rebs]

I have a smith and Wesson model 19, what do I need to slug the barrel to find what size bullet will fit my barrel the best ?

 

[res45]

Slug the cylinder throats there generally larger than the groove dia. of the bore. You could use an appropriate lead ball or just measure the inside dia. of the throats with a pair of calipers.

 

[black mamba]

What you really want to slug are the chamber throats in the cylinder, and use bullets just that diameter or .0005 under.

 

[Dufus]

Once in a blue moon, you might find a barrel that is larger than the cylinder throats. If that be the case, Brownell's have reamers that will enlarge the throats. Good rule of thumb is to have the throats larger than the groove diameter.

This is the reason to measure the cylinder throats and the bore.

 

[Paul B.]

Measure the cylinder throats plus the bore for groove diameter. S&W barrels have 5 lands and groove which make measuring difficult but you can make a reasonably educated guess. Say tour groove diameter is .358" (Most of mine have that groove diameter) and the cylinder throats are 359" to .360". Be best to size at .360". Most of mine run .359" and one runs .358". I just size all bullets to .359".
Paul B.

 

[mikld]

Know your gun! Measure the barrel; slug and measure with micrometers. Slug or use pin gauges for the cylinder throats, and measure with micrometers. Calipers have small flats on the edges of the jaws so getting a measurement with the inside radius of the cylinder throat may not be accurate, and may flex in use. As Dufus mentioned on very rare occasions a barrel's groove diameter may be larger than the cylinder throats, but it's still best to make sure. Besides getting dimensions, slugging can show restrictions (Many Rugers are "tight" at the barrel/frame junction) or bulges (big "spots").

I size all my cast bullets to the same diameter as the cylinder throats. Doin' it for years and it eliminates most leading...

Update; I've been seeing some discussions on bullet sizing in the last couple weeks. I guess I'm in the minority on this subject, I like to know all I can about my guns, the important dimensions, and I use micrometers capable of .0005" and measure. It seems many reloaders would rather guess at bullet diameter to gun fit rather than know accurately the diameters of the barrels and bullets. I guess that's OK for them, it's their guns, their ammo, and their time...