Looking at ordering some 158gr SWC bullets, and noticed they allow a choice between .357 and .358 diameter bullets. If I'm loading for 38 spl, 38 spl +P, and 357 magnum powder charges, which should I choose, and why? Thanks in advance.

The guy I get mine from says his are .3575. I am not sure it matters.

Given a choice I would chose the .358. Most knowledgeable bullet casters* recommend sizing bullets at least .001 over bore size.

*Ed Harris bullet caster par excellance & past NRA Reloading Tech,
Phillip Sharpe, Sleeter Skelton, John Taffin, ETC

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Semper FI

get you two very small pieces of paper and write .357 on one and .358 on the other and put them in your hat and shake them thoroughly and pull one out. That is the one you should order. you'll never know the difference.

I've cast a fair number of bullets myself and others from time to time so sometimes I have one size and sometimes the other so I use whichever is handy. Occasionally I only have a few of each and get to shoot both on the same day.

.358 for the S&W is what works best for me. One of my Colts dos as well or better with .357 cast, go figure.

There are several reasons it would matter. IF, and this is a stretch, you bore/throats are huge and the bullets are too hard. A bullet that is too small and too hard will lead as easily as a bullet that is too soft that is pushed too hard.

So, since ALL firearms are individuals and blanket statements seldom fit, you need to slug your throats and bore to find out what size you need.

Here is what I have learned in the last few years I have cast my own bullets. And, this works in everyone of MY firearms. Bigger is better and matters more than hardness. I have pushed the same size bullets, at different hardnesses at the exact same velocity with the exact same results.

Bigger for me.

Use the fattest ones that will chamber in your gun.

I usually order cast bullets sized to .358" because most cast bullets are sized that way. It's a general rule jacketed bullets are .357" and cast bullets are .358" for the 38/357...

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Freedom is never free!!
SWCA #3437

For S&W, if those are the only choices take the .358. Prefer .359.

.357 cast bullets are for people that don't know any better, or they are loading for a Colt, which can have groove diameters as tight as .354.

I shoot volumes of lead WC's and SWC's for PPC / Action pistol with a tricked out PPC 686 and a couple of other stock barrel L frames. I have found that when I shoot .357 lead bullets I get way to much leading (one brand leaded so bad I had to stop and brush to finish the 150 round match) but it seems to be very minimal with the .358 diameter bullets so I stick with the 358's.

I'd order the .358 because based on my unscientific observations when it comes to cast bullets a little large causes less problems that a little small. I even size my 9x19 bullets .358.

I just slugged one of my 27's and the cylinder throats came out .3584" so .358 would be the better of the two choices if it were my gun.

EXCELLENT INFORMATION!!! Just the type of info I needed to make a decision on this issue. I really appreciate the responses, since I like to learn as much as possible on matters relating to my S&W's.

This is only one part of the puzzle of lead bullets. I suffered through so much talk of "hard cast", "sized this or that", and "gas checked or not" that I almost didn't want to figure out casting. If you don't read up on how lead bullets work in YOUR gun then you will be eternally lost in the lead bullet madness. But, if you read up on matching the bullet diameter to throat/bore, alloy to bullet hardness, bullet hardness to pressure used on said bullet, proper lube to pressure on the bullet, and a few more things, then you will know why there are so many that still swear by casting their own and get amazing results from them.

Or you can just shoot jacketed and be happy with whatever the latest factory offering is.

It's really not that hard even though it may sound like a lot to absorb at first. I don't for a minute claim to be an expert, but I have made some stellar ammo that has given me the best accuracy ever in all of my guns so far.

I guess it just depends on how deep into the hobby you want to get. The more of the "mass market factory line" you remove from your shooting, the better your shooting can get. And only hand loading your own ammo with loads made for YOUR gun will ever give you the best your gun and you are capable of getting.

Give the "Lyman Cast Bullet Handbook" a read and you can also read through this:

Cast Bullets For Beginner And Expert - Joe Brennan

There is so much more to a lead bullet than .357 vs. .358...

No, despite what your friends say, size does matter. :-) An undersized bullet will lead & can even tumble & keyhole as it leave the bbl. You want your elad bullets at least ).001" larger than groove dia &/or cyl throat dia. If you are not going to slug or measure, then always go with the larger bullets.
As Maxi notes, there are other things to consider, but you don't get many choices when buying commercial. Getting the right sized bullet can make up for short comings in alloy or lube, but not the other way around. I buy some commercial & cast for all my guns. It's an anjoyable hobby in itself & the results can be quite amazing to the novice shooter.

. 358 for sure.... my smith 586 likes the larger projectile, and its no big deal for a revolver to squeeze a slightly larger bullet thru the barrel.. only a couple of hundred pounds i believe..( its lead ) so it will swage in that barrel really nicely, giving much better results. Thats what i think anyway :-)
Just casting up some 158 lee flat nose , and they come out of my mold at .359, ( range lead ) so i lube them, and resize to .358.. .. i have had some problems with local hard cast lead projectiles.. .357.. not working too well at all !

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Gidday from Downunder ;)

+1. I always go with .358.
Semper Fi!

I fall in with the crowd that said the biggest that will chamber. in a 38/357 you want .358 or .359

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Shoot fast & live long
Warren

That would be correct. It is important to 'fill' the barrel as the bullet enters to keep the flash from going passed it and causing excessive leading. This is true with lead bullets, not necessarily jacketed. It doesn't sound like much, .001 of an inch, but lead, when heated upon firing will tend to fill to the grooves anyway, so why not help it along. Most knowledgeable casters size to .358 in 357 caliber bullets for that reason. JMHO.