Pressure for .45 auto rim & .45 acp target wadcutters

kcub · January 6, 2013, 09:52 AM

Looking for low pressure ammo for a S&W triple lock and a mkV Webley, both converted from .455.

.45 auto rim I understand has lower pressure than acp
.45 acp target wadcutters 185 grain 750 fps bound to have much lower pressure than standard 45 ball 230 grain

Thoughts?

Two Old Dogs · January 7, 2013, 07:15 PM

SAMMI pressure standards:

.45 ACP 19,000 cup or 21,000 psi
.45 Auto Rim 17,000 cup
.455 Webley Mk. II 16,000 cup

You are correct stating that the .45 ACP has a higher allowable pressure than the .45 Auto Rim and the .455 Webley Mk II (the caliber your pistols were originally chambered for).

Modern Reloading by Richard Lee has several pages of .45 Auto Rim loading data and indicates the pressure of those loads which will provide you with acceptable reloads in a safe pressure range by loading the.45 ACP with .45 Auto Rim data.

Also check Hodgon's Reloading Data Center for 230 grain loads for the .45 ACP that are in an acceptable pressure range for your pistol. There are probably numerous other internet sights that can provide loading data for pressure ranges in the 16,000 cup range.

Using .45 Auto Rim data for loading .45 ACP cases is not a problem since the case capacity of the .45 ACP is 22.87 gr's of water and the .45 Auto Rim capacity is 22.92 gr's of water per The Handloaders Manual of Cartrildge Conversions by John Donnellly.

kcub · January 8, 2013, 07:58 AM

Thanks for the response!

Per this table 45 auto rim is 15K cup.

http://www.leverguns.com/articles/saami_pressures.htm
Do you think the loads I mentioned are safe in my guns?

Two Old Dogs · January 8, 2013, 01:27 PM

I stand corrected. I failed to check current SAMMI specs on the web and referred to my copy which is a few years old. Obviously SAMMI had reduced
the max level allowable. However, Lee in Modern Reloading is showing loads for the .45 Auto Rim exceeding 16,000 psi. C.I.P. (Europe's SAMMI) lists the .45 Auto Rim at 1200 atmospheres (17,635 psi).

I do not recommend specilfic loads that I use or comment on the safety of loads of others due to liability but refer you to published loading manuals.

Lee in Modern Reloading shows numerous 185 grain jacketed loads in the 900 fps range at pressures below 16,000 psi. Hodgon's Reloading Data Center (on the web) lists .45 ACP, 230 grain FMJ loads with velocities in the 750-800 fps range at pressures below 15,000 CUP.

I would consult other published data (both web and print) to determine the proper load for your needs.

kcub · January 9, 2013, 09:00 AM

Academy is clearing out Federal premium gold medal match .45 acp 185 grain @ 770 fps. $35 @ 50 rounds, so I bought the ten boxes they had. Seems like this ought to be safe for both guns.

kcub · January 12, 2013, 12:13 PM

Shot both guns today. Triplelock keyholed blackhills 255 swc but still made a fist sized group at 25 yards, the mark v loved this ammo. Too bad it seems discontinued.

The federal 185 swc shot tight groups in both guns though low to point of aim in the triplelock. Very low recoil in both revolvers.

January 6, 2013, 09:52 AM	#1
kcub Senior Member Join Date: October 24, 2010 Location: Austin, Texas Posts: 3,318	Pressure for .45 auto rim & .45 acp target wadcutters Looking for low pressure ammo for a S&W triple lock and a mkV Webley, both converted from .455. .45 auto rim I understand has lower pressure than acp .45 acp target wadcutters 185 grain 750 fps bound to have much lower pressure than standard 45 ball 230 grain Thoughts?

January 7, 2013, 07:15 PM	#2
Two Old Dogs Member Join Date: November 28, 2012 Location: Eastern SC Posts: 68	Low pressure .45ACP loads SAMMI pressure standards: .45 ACP 19,000 cup or 21,000 psi .45 Auto Rim 17,000 cup .455 Webley Mk. II 16,000 cup You are correct stating that the .45 ACP has a higher allowable pressure than the .45 Auto Rim and the .455 Webley Mk II (the caliber your pistols were originally chambered for). Modern Reloading by Richard Lee has several pages of .45 Auto Rim loading data and indicates the pressure of those loads which will provide you with acceptable reloads in a safe pressure range by loading the.45 ACP with .45 Auto Rim data. Also check Hodgon's Reloading Data Center for 230 grain loads for the .45 ACP that are in an acceptable pressure range for your pistol. There are probably numerous other internet sights that can provide loading data for pressure ranges in the 16,000 cup range. Using .45 Auto Rim data for loading .45 ACP cases is not a problem since the case capacity of the .45 ACP is 22.87 gr's of water and the .45 Auto Rim capacity is 22.92 gr's of water per The Handloaders Manual of Cartrildge Conversions by John Donnellly.

January 8, 2013, 07:58 AM	#3
kcub Senior Member Join Date: October 24, 2010 Location: Austin, Texas Posts: 3,318	Thanks for the response! Per this table 45 auto rim is 15K cup. http://www.leverguns.com/articles/saami_pressures.htm Do you think the loads I mentioned are safe in my guns?

January 8, 2013, 01:27 PM	#4
Two Old Dogs Member Join Date: November 28, 2012 Location: Eastern SC Posts: 68	I stand corrected. I failed to check current SAMMI specs on the web and referred to my copy which is a few years old. Obviously SAMMI had reduced the max level allowable. However, Lee in Modern Reloading is showing loads for the .45 Auto Rim exceeding 16,000 psi. C.I.P. (Europe's SAMMI) lists the .45 Auto Rim at 1200 atmospheres (17,635 psi). I do not recommend specilfic loads that I use or comment on the safety of loads of others due to liability but refer you to published loading manuals. Lee in Modern Reloading shows numerous 185 grain jacketed loads in the 900 fps range at pressures below 16,000 psi. Hodgon's Reloading Data Center (on the web) lists .45 ACP, 230 grain FMJ loads with velocities in the 750-800 fps range at pressures below 15,000 CUP. I would consult other published data (both web and print) to determine the proper load for your needs.

January 9, 2013, 09:00 AM	#5
kcub Senior Member Join Date: October 24, 2010 Location: Austin, Texas Posts: 3,318	Academy is clearing out Federal premium gold medal match .45 acp 185 grain @ 770 fps. $35 @ 50 rounds, so I bought the ten boxes they had. Seems like this ought to be safe for both guns.

January 12, 2013, 12:13 PM	#6
kcub Senior Member Join Date: October 24, 2010 Location: Austin, Texas Posts: 3,318	Shot both guns today. Triplelock keyholed blackhills 255 swc but still made a fist sized group at 25 yards, the mark v loved this ammo. Too bad it seems discontinued. The federal 185 swc shot tight groups in both guns though low to point of aim in the triplelock. Very low recoil in both revolvers.