Mold sizing

[Oregon Coot]

I have just acquired a new S&W model 69 in 44 mag. I also own an older Model 29. Throats on the 69 are just under .430 and the 29 runs .432.

I am about to order up a new Accurate mold. Are there any issues in specifying a mold to throw bullets at .432, knowing that they will need to be sized down .002 for the smaller throats of the 29?

Alloy used is WW plus 2% tin.

Also, is there any issue with driving .432 cast bullets through .430 throats? Assuming rounds can be chambered, how much oversized can a bullet be before pressure issues raise their head?

Appreciate the input.

Jim

[Outpost75]

Band diameter on the drawing is usually the MINIMUM dimension, with the tolerance being +0.002

On some designs where fit of the front driving band ahead of the crimp groove is critical, to permit fast reloading with speed loaders for IDPA and such, you may see a note which says "Nose Tolerance Negative", which means that the bore-riding nose and front band dimension stated on the drawing, ahead of any crimp groove is MAXIMUM, and the tolerance for that specificied area is then -0.002"

In your case to fit two revolvers, I would order the mold at .430 to fit your tightest revolver, and at mid-point of normal tolerance the .431" normally expected should shoot fine in either revolver without sizing. At maximum tolerance the fit will be perfect for the 29 and for best accuracy you would want to size to fit the 69, but as long as bullets are not so large as to impede free chambering, any pressure increase will not be dangerous.

Ideally you want bullets about 0.0005" smaller to not more than 0.0005" larger than cylinder throat size. A slight squeeze of 0.0005" is not noticeable in terms of velocity, or accuracy. In some guns, a very slight squeeze is beneficial, but you cannot overdo it. My S&W Model 544 Texas Commemorative .44-40 has .4285" cylinder throats and .429" barrel and shoots wonderfully with soft cast bullet bullet .44-40 loads. I and my friends use the Accurate 43-230G in a variety of .44-40 and .44 Magnum revolvers and rifles, Colts, S&Ws, Rugers, Marlins, H&Rs and Winchesters and it is as close as I have found to a "one size fits all .44 bullet. The double-crimp groove is handy, using the front groove to deep seat in the .44 Magnum and .44-40, and the rear groove to seat out longer in the .44 Special and for single-shot .44-40s or long cylinder revolvers, like the Rugers, which are not sensitive to overall cartridge length. If you wanted a heavier bullet Tom has several of similar shape in different weights, or a GC heel could be added to this one, or the base band made wider.

149440 149441

[44man]

Good advise, .431" is where I would want to be in the 29 but even if the boolits come out .430" they will be OK in both.
I never found a need to be exactly throat size. All my revolvers shot great with just groove size as long as throats were larger then groove.
I owned 5 or 6 29's over the years and all shot .430" just perfect.
My SBH has .4324" throats and my best boolit is .430".
Seems all you need is an ogive that will align the boolit to the forcing cone.

[Oregon Coot]

Thanks for the input guys. It is appreciated.

Jim