Choosing a sizing die

I would like some advice from those who have a bit more experience than I with regard to bullet sizing.

I have a new to me H&G #251 mold which casts double ended 38 spl wadcutters specifically for the S&W 52. I measured some bullets from the mold and found diameters from .3579 to .3595 depending on where on the bullet you measure, both along the length of the bullet and direction of the diameter. All 4 cavities cast bullets in this range. 

I size and lubricate using a Magma Star Lube Sizer.

I will be using the bullets in a S&W 52-2. I have slugged the barrel and it measures .355.

My present 38 die is .358 and has been fine for bullets from my other mold which is a H&G #50 and casts about .359 to .360. I believe it is a bit large for these bullets.

I am wondering whether to get a .357 die or a .356. I originally thought to go with.357, but read that Gil Hebard got best results in the Model 52 with .356, and the barrel is tight at .355. So now I am on the fence.

Anyone have any experience with the difference or generally with choosing the sizing die?

Any advice would be appreciated.

The old rule of thumb was to size bullets to .001 over groove diameter.  But each gun is different.  Due to the cost differential, you could try a Lee sizing die in .356 and see if that diameter shoots better.

I would load 3 rounds  at  the .358"  bullet  diameter,  to see if they will chamber in the M52.  If they do, load more for a test on accuracy. 

I dont have a M52 , so just my guess as a caster for many years.

I have tried the.356, .357 and .358 sizing dies for my M-52-2.  I have never noticed any difference but then the farthest I shot all of these were at 25 yards.  My bore  slugs smaller than .355 and believe it's something like .3546 if I remember correctly.


Virgil

Just to rain on your parade, Star made a sizing die that was .3565 for the Model 52 shooters. One was on sale recently on E-bay and it went for a premium.
I would go for .001 to .002" over actual bore.
I just tested some groups in my M-14 this past weekend.
My .358 sizing die was actually .3577. My bore size was .3570 and I could not get groups less than 2 1/2" with the .3577 die/bullets. I honed it out to .3582. Groups were about 1/2" bigger with the .3577 sized bullets compared to the .3582 bullets.
I honed out my Star sizing die with a drill and sandpaper. I took a wood dowel and took a hack saw and cut a slot in the end. I rolled up some sandpaper and used that to hone the sizing die. I started with fine sandpaper and it done nothing. IIRC I went with 100 grit paper to remove material and then 400 to polish. It took a good hour to remove .0005". That said you could buy a .356" and then hone it up,if the gun does not group at .356".

The same die may produce different finished diameters, per the lyman website. I have not noticed it or know if its true?

Greetings,

Star dies were actually honed with a taper. Tight at the top and wider at the exit. Only a few tenths; but, measurable with a bore gauge.

Alloy will have an effect on bullet diameter. Linotype "springs" back and measures larger than the marked die size.

Pure Lead sizes close to actual diameter as it does not spring back.

Another thing to consider is hydraulic pressure. If you size and lube a soft alloy bullet and give it a shot of grease, the bullet is swaged under the pressure of the lube and stretches. It also makes the diameter smaller in the middle. This phenomenon puzzled me for a long time when I started shooting Black Powder rifle.

Most Star dies I own are slightly smaller than the etched diameter marked on the die to allow for "spring back" as most of use cast with wheel weights in the "good old days".

The old guys at Star were pretty clever. I miss them.

Cheers,

Dave