Loading the RCBS 9MM-124-CN

[Green Frog]

I just found this mould that my late father must have bought at least 30 years ago then stuck back on a shelf without ever even cleaning off the factory grease. As the letters on the end suggest, it looks like a truncated cone, and has a single, rather hefty lube groove, I can't find Dad's copy of the RCBS loading manual so I'm flying blind here. Does anyone have any experience loading this bullet in 9mm Luger or know where I can find factory data on a website?

All help appreciated... personal experience adored!
Froggie

[Walks]

Use data for the Lyman #356402

[rintinglen]

RCBS Cast Bullet Manual No. 1
powder min max
HS5 5.7-6.2
UNIQUE 4.7-5.2
231 4.5-5.0
7625 3.6-4.1
BULLSEYE 3.5-4.0
700X 3.1-3.6

Also, Lyman lists it under 9MM in their 4th Edition Cast Bullet Handbook. p.248

[Green Frog]

Thanks, gents. I should be able to make a good start now as soon as I get some time at the casting bench.

Froggie

[Green Frog]

Not willing to leave well enough alone, I looked at the American Bullets brand commercially cast 9mms that resemble the RCBS 9MM-124-RN 401 mould. Of course as mentioned I also found a mould for the -CN 402 in the same weight. Now I’m beginning to wonder whether I should seek out the RN mould and keep on loading this style or whether I’ll be happy with the performance of the CN design(?)

Does anyone here have both, and more importantly has anyone compared them side by side? I’m thinking since I already have the CN mould I should at least try it, but everything I’ve ever shot through my S&W 639 has been either factory or reloaded RN bullets.

Opinions with experience solicited!

Froggie

[winelover]

The RCBS 125 RN GC was my first 9 mm bullet mould, over 40 years ago. Shot thousands in my Browning HP. Second mould purchased was the Lyman 356402 mould. Went this route to avoid purchasing/installing gas checks. Both preformed admirably, for many years. Then I started accumulating other brands of 9 mm firearms. Both the above mentioned moulds are only two cavities. Wanted higher production, as well as, larger as cast bullet diameters. Enter the custom bullet mould manufactures.

Both designs feed well in every 9 mm firearm I own. However, since purchasing a carbine, the conenose/truncated style has the accuracy edge from my extensive testing. Whenever, I purchase a new mould for 9 mm, I go with either a TC/CN design or a RNFP.

Winelover

[Green Frog]

Thanks, WL. I may be overthinking this. I guess while I still have a few hundred of the commercial cast bullets that are virtually identical to the RCBS RN mould, maybe I should just cast up a bunch with the CN mould and run a side-by-side comparison between those two... if the RN style gives that much better results I can start looking for a mould to buy. Once again, thanks everyone for your thoughts and suggestions. I now have a good place to start.

Froggie

[gwpercle]

I don't have both RCBS moulds but do have the RCBS 9mm-124-CN ... and Lymans #356242B (120 gr.) round nose .
I preferred the truncated cone design to the round nose .
Liked the flat point , the boolit cut clean holes and seemed to give better accuracy and most importantly ... I like the way they look !
Gary

[paul edward]

The truncated cone was the original bullet shape for the P08 as adopted by the Imperial German army. I have some WW1 dated examples in my reference collection. In 1973 I bought a 2 cavity Lyman 356402 to cast for my HP and a friend's P38. We had no problems with them feeding and concluded that the shape worked well. Sized at .356, we had such poor accuracy that I gave up on this mold and just bought FMJ. Since discovering this website, I have learned that we should have tried sizing at .358. Before ordering or using sizing equipment, it would be prudent to slug the barrels of the pistols you intend to load for, and size your boolits .001 to .002 larger than groove diameter. Plan to cast up a few for a new trial when the weather improves.

[Sailormilan2]

I have the Lyman 356402 version. 40+ year old 4 cavity mold. Unfortunately, it's one of theirs without the shoulder. So, it doesn't cut nice, neat, round holds. Other than that, it drops well from the mold, and feeds well.