New IMR "Trail Boss" Smokeless Powder

By Chuck Hawks


This week a flyer from the IMR Powder Company came in the mail. It announced a new powder named Trail Boss, intended specifically for reloading cowboy action loads. It is primarily a pistol powder, but can also be used for pistol cartridges chambered in rifles.

According to IMR, Trail Boss is a new technology smokeless powder developed exclusively for use with lead bullets at low velocity. This new powder allows very high loading density, flows well through powder measures, and is stable across a wide range of temperatures. In most calibers Trail Boss will nearly fill the case, making double charges unlikely or impossible, an important safety feature.

Along with announcing their new powder, IMR included a number of loads for their new powder for pistol cartridges ranging from the .32 S&W Long to the .45 Colt. Examples of loads for some of the more popular calibers and bullet weights are reproduced below. You can find more complete loading data on the IMR Powder web site at: www.imrpowder.com/data/handgun/trailboss-feb2005.php


.32 H&R Magnum

STARTING LOAD - Case: Federal / Primer: Fed. 100 / Barrel: 5" / Bullet: .314", 90 grain LSWC / Powder: 2.4 grains Trail Boss / MV 751 fps / MAP: 10,700 CUP.

MAXIMUM LOAD - Case: Federal / Primer: Fed. 100 / Barrel: 5" / Bullet: .314", 90 grain LSWC / Powder: 2.8 grains Trail Boss / MV 785 fps / MAP: 11,300 CUP.

.38 Special

STARTING LOAD - Case: Win. / Primer: WSP / Barrel: 7.7" / Bullet: .357", 158 grain LSWC / Powder: 2.7 grains Trail Boss / MV 661 fps / MAP: 11,400 PSI.

MAXIMUM LOAD - Case: Win. / Primer: WSP / Barrel: 7.7" / Bullet: .357", 158 grain LSWC / Powder: 4.2 grains Trail Boss / MV 804 fps / MAP: 13,700 PSI

.357 Magnum

STARTING LOAD - Case: Win. / Primer: WSPM / Barrel: 10" / Bullet: .357", 158 grain LSWC / Powder: 3.2 grains Trail Boss / MV 754 fps / MAP: 16,500 CUP.

MAXIMUM LOAD - Case: Win. / Primer: WSPM / Barrel: 10" / Bullet: .357", 158 grain LSWC / Powder: 4.2 grains Trail Boss / MV 865 fps / MAP: 20,400 CUP.

.38-40 Winchester

STARTING LOAD - Case: Win. / Primer: WLP / Barrel: 5.5" / Bullet: .401", 180 grain LRNFP / Powder: 4.5 grains Trail Boss / MV 694 fps / MAP: 7,300 PSI.

MAXIMUM LOAD - Case: Win. / Primer: WLP / Barrel: 5.5" / Bullet: .401", 180 grain LRNFP / Powder: 5.5 grains Trail Boss / MV 800 fps / MAP: 9,900 PSI.

.44-40 Winchester

STARTING LOAD - Case: Win. / Primer: WLP / Barrel: 5.5" / Bullet: .430", 200 grain LRNFP / Powder: 5.5 grains Trail Boss / MV 723 fps / MAP: 7,800 PSI.

MAXIMUM LOAD - Case: Win. / Primer: WLP / Barrel: 5.5" / Bullet: .430", 200 grain LRNFP / Powder: 6.5 grains Trail Boss / MV 826 fps / MAP: 11,900 PSI.

.44 Special

STARTING LOAD - Case: Starline / Primer: WLP / Barrel: 8" / Bullet: .430", 240 grain LSWC / Powder: 4.0 grains Trail Boss / MV 673 fps / MAP: 9,700 CUP.

MAXIMUM LOAD - Case: Starline / Primer: WLP / Barrel: 8" / Bullet: .430", 240 grain LSWC / Powder: 5.2 grains Trail Boss / MV 763 fps / MAP: 11,700 CUP.

.44 Magnum

STARTING LOAD - Case: Win. / Primer: Rem. 2 1/2 / Barrel: 8.275" / Bullet: .430", 240 grain LSWC / Powder: 6.0 grains Trail Boss / MV 828 fps / MAP: 19,100 PSI.

MAXIMUM LOAD - Case: Win. / Primer: Rem. 2 1/2 / Barrel: 8.275" / Bullet: .430", 240 grain LSWC / Powder: 7.3 grains Trail Boss / MV 917 fps / MAP: 21,600 PSI.

.45 Colt

STARTING LOAD - Case: Win. / Primer: WLP / Barrel: 7.25" / Bullet: .452", 250 grain LRNFP / Powder: 4.5 grains Trail Boss / MV 606 fps / MAP: 8,800 PSI.

MAXIMUM LOAD - Case: Win. / Primer: WLP / Barrel: 7.25" / Bullet: .452", 250 grain LRNFP / Powder: 5.8 grains Trail Boss / MV 727 fps / MAP: 12,700 PSI.




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Copyright 2005 by Chuck Hawks. All rights reserved.



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