Sizer ?

[nonferrous]

In sizing for S&W 38 Spec and .357 revolvers, loaded to sub 900 fps, what would be the difference in shooting results between sizing at .357 or .358?
Would it be possible to use either size die?
Thanks.

[44man]

In sizing for S&W 38 Spec and .357 revolvers, loaded to sub 900 fps, what would be the difference in shooting results between sizing at .357 or .358?
Would it be possible to use either size die?
Thanks.
It depends on bore and throat size of your guns. They must be slugged and measured. The throats need to be from .0005" to .001" or even a little more will not hurt, OVER groove to groove size in the barrel. Then size to fit the throats.
Guns just vary too much to answer your question.

[nonferrous]

Thanks for the reply,
I have been shooting and reloading for a long time but am an absolute Tyro with regards to casting and sizing. Hopefully that will change.
I hope this question makes sense, what diameter would be cast in a factory load or a commercial reload? I have shot a lot of them and they always work in everything I own, 'K' frames, 'L' frames, 'N' frames, mod 52, etc.
Anyway, sorry to be a pest, just trying to soak up as much knowledge as I can as opposed to learning the hard way.
Thanks again

[Catshooter]

non,

You ain't bein' a pest.

The commercial cast boolits you've been using may have all 'worked', but 44man pointed out the truth. Oversize is usually a key ingredient.

I started load testing today for a 2.5 inch S&W 686. The mould I'm casting from is fat: the boolits drop (in wheel weight metal) at .363 and I size them in a .359 sizer that actually sizes them to .360.

The Smith's throats all run .356 or so and so does the bore. The Lee factory crimp die I'm using to crimp the 357s with sizes the boolits down to .359. They show no sign of being over pressure (I'm carefully measuring case head expansion as I go) so far and I've got them leaving the sixgun at over 1250 fps. Moving pretty good I thought, esp for such a short barrel and a 180 grain slug. No leading at all.

Are you totally confused yet? :)

The key (for me) is measure everything, and then make sure that I'm oversize. Every gun is different. I've got one 357 with a .3556 bore and another with a .3589, go figure.

Keeps the game interesting though.

Welcome to the forum by the way.


Cat

[nonferrous]

Cat,
What you are saying is that the load you have put together for your 686 is .003 larger than the bore after crimping. I can take it then, that this would lend itself to optimum accuracy and minimum leading.
I assume that getting a .001 reduction in diameter would need a heavy crimp, which would be called for based on the performance that you are getting I would suppose.
I am only loading sub 900 fps right now, about 3 gr of Clays with a 158 gr LSWC. I am using up my old stock of boolits but they are coming to an end. They are .357.
I am loading all my .357 and .44 magnum loads with my old stock of jacketed factory stuff that I have had for years but that is also an endangered pile of lead.
I have never slugged a barrel but it looks as if that will have to be next. From all that I have read on the subject right here, I feel as if I have already done it.
I have a 686 6", a K 38 Masterpiece, a 66 2.5", a 14 4", a shop built 67 6" with a 1" bull barrel with Bomar rib and a mod 52.
Now you have me thinking that no two of them are the same and all this time I have blamed myself for those flyers.
Thanks for the comeback and the info, looks like I better start measuring, Len

[Bob Krack]

Mostly - no two are the same.

You can use either size but in my opinion, the .358 would prolly be better. Try and see.

44man and Catshooter are giving you the true story.

Bob

[Bret4207]

Another way to tell what size you need is to listen to the gun. I think it's more accurate than slugging and measuring, but that's just me. Try a grouping with boolits sized .357, .358, 359, etc. using the same load. That is an easier way than slugging, but might get you a little leading. In the end the powder and throat do the sizing anyway, more so as your pressure increases.

In most of my 38/357's I size at least .359. Some folks report the odd gun that does better with .357 or .358 so "oversize" doesn't always work. I would think the load and alloy and boolit design play a part in this.

Remember that there is no ONE answer in this game. Going for an accurate, non-leading cast load is just like anyone pursuing any other "gilt edge" load. You're building a custom combination for that gun with that boolit with that alloy and that powder combo.

[nonferrous]

Thanks for suggesting a starting point and I think I see where this should go. I am going to the range next week and I will load up some of the .357's that I have on hand and establish a benchmark with them. From that point I will go to .358 and compare results.
Anyway, this will keep off the streets for a while.
Thanks again, Len