Can I "slug" a S&W bbl?

[Packnteacher]

I understand from all y'all that all S&W bbls are non-symmetrical -- i.e. they have five lands not 6, and so there's a groove directly opposite the land. And sure enough, there is. Makes measuring rather difficult. So to find the "true" size of my bore, do I just trust that the grooves are .004 deep and do the arithmetic?

Wait. Back up. Since the whole reason to do this is to eliminate leading of the bbl, is there any good reason not to just order my moulds and sizing die in .358? Come ta think of it, this is the main question. Why not just cast .358? Any ideas?

Grateful for the advice.

 

[nevadabob]

I slugged my M&P 9mm, it came out at 0.356. Order the slugs from Dardas. You then can send the sized slugs to him and he'll measure them at no cost and send you an email. My 0.356 slugs measured the same with him. He recommended using 0.357 bullets. I placed an order. Pretty simple, life is good.

 

[Packnteacher]

Now that's what I'm talking about!! Thank you, NVBob!

 

[LAGS]

I have never had a problem Slugging a S&W Barrel.
If I can not get what I feel is a good accurate measurement, I drill a hole in a piece of metal, and use a tapered reamer to hog it out to the size that fits the Slugs that you ran thru the barrel, then measure the hole in the metal template.
And for the second dimention, I use a Brass mandral that will fit the smaller diameter of your barrel. then measure the mandral.
But I dont think being off .001 is really going to make that much differance, and lead slugs are generally cast to .001 or more than your bore's largest diameter.
My Lee Molds cast at .358 with Lyman #2 lead, but you still have to size them to make sure they are perfectly round.

 

[Packnteacher]

Thank you, LAGS. I may resort to that. I'm wondering if Lee sell a .358 mold.

 

[LAGS]

If you look at the ID numbers for the molds like the Lee the first number is the size they are made to cast
Like for a Lee .357 the mold is a C358-158SWC
The C is for a Gas Check bullet design, the .358 is the size it casts, and the rest is the Weight and nose shape.
And a Lyman gives the caliber it is for, and the bullet cast Diameter
Like 38-158 but lists the diameter as .358

 

[USSR]

If you are talking about a revolver, you want to slug the cylinder throats, not the barrel. For example, my S&W 25-5 has .4545" throats and I shoot .455" cast bullets in it without leading. Doesn't matter that my barrel is .451" or .452", the bullet will slug down to the barrel dimensions.

Don

 

[rcmodel]

+1

Fit the bullet to the chamber throat, not the bore.

rc

 

[Catshooter]

Mmm. Well, if you want to measure your five grooved slug, wrap a .001 feeler gauge around it, measure with your micrometer and subtract .002.

Do you need to measure? Only if you want to know. I've measured 357s that ranged from .355 to .3595, all quality guns.

Using a .358 will probably work well, as long as the cartridge with a bullet of that size seated in will fit into all your chambers.

With a revolver, you want to measure the throats and the bore. If the bore is .358 and your throats are .355, it might not be good. Your throats will size your bullet down and then they'll rattle down the bore, usually leading as they go. Throats & bore matter.

There are some Ruger 45s with tiny throats and large bores. Bad combo.

I have a Smith 45 with a .452 bore and the throats are all .455. I cast a .457 bullet, size it too .456 and they shoot wonderfully with zero leading.

Good luck. If you want to learn more, go here:http://castboolits.gunloads.com/index.php

The best site on the web for casting.


Cat