rcbs sig mold

[barnabus]

do yall think the rcbs 9mm-147fn would work for my 357 sig? i would powder coat.i have range lead and wheel weights. how fast would these be pushed..or would the rcbs 9mm-124 rn be an option thanks im finishing up the last of my montana bullets

[Bigslug]

Just looked at the blueprint for the round. A short neck and short OAL. Going from the max OAL of 1.14" to the back of the neck gives you .425" of bullet length to work with if you want to keep the base of the bullet totally contained by the neck.

That is about the length of 90-100 grain .380 bullets. Methinks they weren't thinking of cast when they drew up the round.

[20:1]

They weren't thinking of cast bullet shooters. 357 SIG was developed originally for Air Marshals, and other Law Enforcement personnel. It was actually designed around a single bullet weight as well, 125 gr. jhp. The best mould I've found for it is the Ranch Dog 135 gr 9mm bullet. I have used Lymans 356637 with some success, but I feel the bullet has too much taper in it. 357 SIG needs parallel sides for crimping to the necessary length.

[justindad]

I’ve done it. The COAL is 1.170”, so make sure it can fit in your magazine. The round nose helps fit longer boolits, whereas a WFN has to be shorter to fit in the same magazine.
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You will need to use compressed charges of AA#9 or Enforcer. This boolit fills up too much of the case in order for Enforcer to give good performance, but it did burn clean. I got up to 10.2 grains of AA#9 (compressed), and there was some flattening of the primers (which is normal for .357 Sig ammo).
Do not consider the 10.2 grains of AA #9 to yield safe pressures. Find good data and work your loads up.
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You must use compressed charges because you will have at least one lube groove in the already tiny neck length.
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RCBS makes a 124 gr TC mold (which I believe NOE cloned) that will require ~1.155” OACL and Saeco makes a 122 gr that fits within the standard 1.140” OACL. I have not loaded with the Saeco design yet.

IMG_1056.jpg

[justindad]

One other thing I had to do, since my boolits were lubed, is seat & half crimp in one step. The grease creates an air-tight seal and seating the boolit generates pressure, which pushes the boolit out like a piston. So seat & half crimp in one step, followed up with the collet style Lee FCD for the real crimp. And don’t over-crimp - that’s counter-productive.