Home Forums Reloading Handgun Reloading 255gr SWC in 45 Auto and 45 Auto Rim

I bought some 255gr SWC to use in my 45acp and 45auto rim.
I loaded the first rounds last night and shot them today. I loaded the acp with 3.5grs of Bullseye and the AR with 4.0grs.
Both bullets loaded to the crimp groove.
Shooting them thru the chronograph today they both averaged 680 +/- fps. But there were huge velocity variations on both loads. They both shot well. The revolver AR rounds had several cylinder fulls where there were 3-4 rounds cutting one hole at 15yards off hand.
I’m looking for any suggestions on lower the extreme spread.

I’m weighing each charge and using a Redding profile crimp die.

I know there is some room to increase the powder charge or change powders.

Does anyone have any experience with this combination that can offer some advice?

Don't worry about extreme spread if you're getting good accuracy. As a suggestion, however, shoot benchrested groups at 25 yards as it's much easier to find the most accurate load this way. At 15 yards, almost everything tends to be accurate. I've used the Lyman #454424 SWC at about 255-260 grs. in the AutoRim case with Unique, HS-6, Power Pistol, and 231. The most accurate load was with 5.5 grs. 231 for a muzzle velocity of about 815. I think these figures were taken using a 5" 625 revolver, but my notes don't have that listed. I don't think I'd use this charge in a semi-auto, but I'd have to review data to be sure. I taper crimped the .452" bullet. I didn't care for the extra recoil attributed to the heavier bullet, so I stick with the 200 gr. SWC that I've used for years.

Can you quantify huge variations? Over 100fps? What is your yardstick for huge?

If a load is shooting well I don’t stress over velocity variations unless they are really significant.

150 and over, out of 13-16 shots. I read more on my crimp die and I’m gonna turn it down some more.

These are really mild loads so I may bump it up some. I have some +P data for the auto rim from load data.Com that I start on the low end with different powders.

Consistency depends on consistent crimps. Consistent crimps depend on consistent case length. For most of my handgun ammo I don't worry about it and tolerate inconsistent crimps as I hate trimming. But some batches get greater care.

Lee Factory Crimp die

some will laugh......others that have used it won't

https://leeprecision.com/reloading-dies/hand-gun-dies/lee-carbide-factory-crimp-die/

My favorite bullet in the acp for bowling pin shooting and carrying around the farm looking for wounded deer after the neighbors get done spraying and praying is the RCBS 255 Kt SWC. I load over IIRC about 5.5 grains of Unique. Seat so that about 1/16" is in front of the case, taper to standard diameter and it feeds in almost every 1911 I've tried. Will shoot through a deer and takes pins off the table like a sledgehammer. Not high pressure and I don't think it is very fast. Haven't felt the need to chrono.

The factory Double Tap +P version 875fps advertised.

YES


And YES

.45 Auto Rim data.

Warning! Notes: test gun: Smith & Wesson 1955 6", WLP; never reduce stated overall lengths; THESE ARE MAXIMUM LOADS - DO NOT INCREASE THESE CHARGES!

Be Alert: Publisher cannot be responsible for errors in published load data.

Wt. Bullet Powder Manufacturer Powder Charge Velocity (FPS) Favorite?
250 Round Nose Flat Point Alliant Unique 6.1 900
Remarks: OAL: 1.170
250 Round Nose Flat Point Hodgdon HS-6 8.5 925
Remarks: OAL: 1.170
250 Round Nose Flat Point Hodgdon HS-7 9.2 905
Remarks: OAL: 1.170
250 Round Nose Flat Point IMR 800-X 6.2 840
Remarks: OAL: 1.170
250 Round Nose Flat Point Alliant Blue Dot 8.9 895
Remarks: OAL: 1.170
255 Semi Wad Cutter IMR 800-X 6.2 863
Remarks: OAL: 1.200
255 Semi Wad Cutter Hodgdon Universal 5.8 868
Remarks: OAL: 1.200
255 Semi Wad Cutter Hodgdon HS-6 8.5 899
Remarks: OAL: 1.200
255 Semi Wad Cutter Hodgdon HS-7 9.2 910
Remarks: OAL: 1.200
255 Semi Wad Cutter Alliant Unique 6.2 910
Remarks: OAL: 1.200
255 Semi Wad Cutter Alliant Blue Dot 8.9 915
Remarks: OAL: 1.200

I would be very careful with that data... seating depth changes everything and it's an issue with 255 gr in the ACP