Looking for some input on the importance of a crimp groove.

[Leatherhead Bullets]

I am looking to add a new .45 mold to the lineup, and need a little help. Wanting to add a 200 grn RNFP. I coat with Hi-teck, and am wanting to go with a smooth sided bullet. This is in attempts to make a multipurpose mold. to be used in the 45 ACP, LC, and levergun. Not having a levergun yet (in the near future for sure), how important isthe crimp groove? Should it be included in the design? Will it interfere with the ACP application?

I appreciate your input.

[pietro]

The crimping groove is very important, in keeping the boolits in the cartridges in the magazine from being driven deeper into the case under recoil - which can compress the powder enough to give quirky velocities.

Feeding of cartridges from the magazine may be problematic if the OAL of the loaded cartridge is too long/short.

Also, some powders/propellants require some resistance to boolitt movement for best ignition.


.

[williamwaco]

I think the crimp groove is almost mandatory for the lever unless it has a rotary or box magazine magazine. ( That is not a recommendation. I don't even know if such an animal exists.)

It is a bad idea for the ACP.

See if you can seat the ACP loads to a depth where the entire crimp groove is inside the case then crimp the mouth just enough to remove the flare. The case wall should be straight with no inward curve. ( Look at a factory load to see what it needs so look like.)

Some people recommend a taper crimp. That is OK but in most cases requires a separate die.

[TXGunNut]

Hard to imagine one boolit working well in a 45acp and a levergun in 45 Colt, that would be a nice bonus but it could happen. I used to crimp the mouth of a 45 Colt case into the top lube groove of a 200 gr SWC for some pretty accurate plinker loads. I didn't know a .452 boolit wasn't supposed to work in a .454 bore, neither did my Ruger Blackhawk. Couldn't hurt to put in a crimp groove as long as it gave you a good OAL in the levergun and the acp. I would design it to use a taper crimp above the groove for the acp application.

[KirkD]

I used a Lee Factory Crimp die for a 38-55 bullet that had no crimp groove and it worked just fine. How it works for a 45 bullet, I cannot say.

[Dan Cash]

I use a 230 grain truncated cone bullet at .454 in the Colt and the ACP cartridge. They are both taper crimped and the Colts get fed through a Rossi 92 clone as well as various Colt and S&W revolvers. The crimp is not heave and the setup works well in all with no bullet movement from recoil or magazine spring pressure. I also feed a pair of Marlin 336s in .30-30 with cast and paper patched bullets. I use and extra sizing die to, in effect, taper crimp the cartridge enough to remove the belling done by the M die. Again, no bullet setback. These rifles are carried on motorcycle and in pickup trucks as working guns, not range rifles.

[ReloaderFred]

Just about all my .45 acp and .45 Colt loading is done these days with the Magma 200 gr. RNFP bullets. It works just great for both of them, and it does have a crimp groove.

There are no drawbacks to using this bullet, and the upside is you get more bullets per pound of alloy. I've shot some impressive groups in both calibers with this bullet, and I've won some 100 yard matches with it using my .45 Colt Marlin CB. You won't go wrong with this design and weight.

Hope this helps.

Fred