Help with choosing .357 vs .358

[martyd]

Hi,

Shooting in a Smith Mod 52 - 38 Special
Shooting in a Smith Mod 19 & 27 - 357 Magnum

Machine cast bullets I get at the local gun store measure .358

I shot some 180gr machine made .358 in the 357 mags, they seemed to be accurate and the primers were not flattened.

My sizer die is .357

I use almost pure wheel weights

I am in the process of doing a large cast and i want to size the boolits to the best diameter.

Lyman cast boolit handbook recommends .358 in the section discussing sizing

However, all of thier loads listed in the book use .357, don't figure

What is the recommendation for choosing the sized diameter and why?


thanks,
marty

[RobS]

martyd:

Welcome to the forum!!!

Actually sizing depends more on your firearm. Some revolvers have larger throats and/or larger bore diameters than others. The best way to figure out what to size to would be to slug your barrel with a soft (pure lead slug would be best) and then measure the slug. However having a S&W measuring the slug would be more difficult due to the number of grooves. If we are examining the most proper way of determing the "right diamter" then next it would be good to see if the slug you pushed through the barrel would fit through the cylinder throats.

If you are not up to slugging the barrel and checking the cylinder throats then I would go with .358 as that seemed to work to your liking with the previous bullets. You could of course try the .357 die, but you could very well have leading in the barrel due to an undersized bullet.

[462]

Slug the cylinder throats and size .001" over. S&W is notorioius for boring oversized throats, while the barrels are within caliber specifications. For instance, I have a Model 24 and a Model 624 -- '85 vintage -- both have .430" barrels and .432" throats.

[lwknight]

Revolvers do have another variable to consider compared to everything else.
Definately , slug the barrel and test the throats. Find a bullet that will pass with moderate thumb pressure. This will be the best bullet size.
If you are lucky , the cylinder throats will be .001" larger than the bore slug.

My GP-100 has .357 cylinders and slugs at .356 . I get best accuracy with .357 boolits.
I have never had ANY leading in this revolver.

[fryboy]

one has to keep in mind that alot of lyman's cast listings for both the .357 and 38 special use linotype alloy as well , IMHO this could part of it , i have to agree that the best size for you would be what your firearm dictates as stated above .

[noylj]

S&W 52: Remington 148gn L-HBWC. They are 0.358 at the head and 0.360-0.361 at the skirt. These are without doubt the ONLY bullets to shoot in an M52. Reload using Unsized case (or size in a .38Super sizing die) and crimp with a Redding Profile Crimp die or the Lee Factory Crimp Die. Reloads should NOT drop in the barrel but rather require just a little pressure to seat. The slide will do this for you and you want that cartridge/chamber alignment that a tight fit provides.
Revolver: you want bullets that are a snug fit (but not so tight as to swage the bullet diameter—just sort-of an air-cushion feel if you know what I mean) through the cylinder throat and are equal or larger than the barrel groove diameter. It is amazing that any revolvers shoot lead bullets accurately as the manufacturers don't seem to do a good job of matching cylinder throats and barrels together.
My .32-20 Colt Bisley (~1910 mfg date) has cylinder throats of 0.310 and barrel groove diameter of 0.315, with typical .32 bullets being 0.313-0.314". Guess how well that gun shoots?

[Bret4207]

I use .359 in my M-19 and M-28. My Colt OM wants .357 IIRC. Depends on the individual gun. alloy, load, boolit design, etc.

[runfiverun]

just open your sizer up and go with the 358 bigger is okay if you can chamber them.
you didn't mention what brand of sizer you have but most can be opened pretty easily.
and just because it says 357 on it don't mean it is.

[thegreatdane]

I agree with runfiverun.

what's wrong with .378 regardless? I'd go 358 just to help prevent leading. bullet fit (over-fit) is king, right?

[Bret4207]

No! Not just fat, proper size isn't just cramming the fattest boolit you can into the chamber and lighting it off. It's fitting the boolit to the gun, load, alloy and design. How far you want to take it beyond "I usually hit what I aim at, more or less." is up to the individual.

[alamogunr]

This will be of no help to the OP, but yesterday I used plug gages to check the cylinder throats of 4 S&W and 1 Ruger. One S&W had one chamber that measured .358. All other chambers on all guns checked .357. I was surprised at the uniformity.

John
W.TN

[luvtn]

alamogunr,
Where did you get your plug gauges?
luvtn

[9.3X62AL]

ENCO has sets of pin gauges for reasonable cost. They're Chi-Com made, but what isn't these days? Make sure to get the pins that are .0002 under nominal diameter for this purpose.

FWIW, my S&W 38s and 357s do their best work with .358" or .359" boolits. My Colts prefer .356"-.357". Ruger Bishawk uses .358".

Welcome to the addiction. It includes a ceertain fixation on minuteae, just so ya know.

[alamogunr]

I got mine on Ebay. It is a brand name set that had 6 or 7 missing. I took a chance that they wouldn't be ones that I would need. I guess I lucked out since the missing gauges were not close to any that I would use with guns. The missing gauges accounted for the low bid that won.

As 9.3X 62AL said be sure to get the minus set. You can find a lot of information by a search for plug gauges(gages).

John
W.TN

[runfiverun]

your alloy and load do play a very important part in the outcome also.
but the beginning guy wants something to start with.
A. he wants to make some decent boolits.
B. he wants to shoot them.
C. he wants them to be accurate.
D he wants to know why they aren't more accurate.
E. he wants to know why there is some leading in the forcing cone or bbl.
or he don't have a problem slinging ww's sized at 358 with whatever lube he found, and is happy.