Loading the .45 Colt for Rifles
Although Mr. John Linebaugh is partial to WW-296 and H-110 for upscale loads in the .45 Colt revolvers, I think a somewhat slower burning powder that has a wider workable pressure range would be more accurate and would produce better results in rifle length barrels. These slower burning powders should be bulkier per grain weight. Also, they should burn at lower temperatures than WW-296 or H-110 and fill the case to the base of the bullet.
H-4227 or IMR-4227 may give the desired results we are looking for. The custom 292 grain DKT/LFN cast bullet I am using only has a seating depth of .360". This leaves .738" of room inside the .45 Colt case for powder if the case is trimmed to 1.275". Because WW-296 and H-110 should be used with 90% or more of that space filled for best results, too much pressure and velocity can be created for our purposes. Actually those 2 powders would work best slightly compressed according to Mr. Linebaugh. Because of their physical form, granule size, grain for grain H-4227 and IMR-4227 would occupy more room inside the case than H-110 or WW-296, therefore creating a higher loading density without excessive velocity or pressure.
I am looking for a very accurate load in the 24" barrel of the Marlin Cowboy using the 292 grain bullet at 1150 to 1300 fps velocity. It is possible that these powders, IMR-4227 and H-4227 could be used in charge weights that would fill the case to the base of the bullet and still give permissible pressures and velocities. It is a known fact that if powder charges have enough room to wander around inside the case, pressures and velocities may not be consistent. By filling the case to the base of the bullet, we eliminate the wandering around syndrome and would hopefully produce more consistent pressures and velocities, which should produce greater accuracy. Along with filling the available space in the case, the ideal powder should be insensitive to it's position in the case. Filling the case to the base of the bullet with a specific powder to obtain a specific velocity is known as shape charging.
The Hornady manual states that 2400 and IMR-4227 proved most consistent in their experiments. This manual also shows 21 grains of IMR-4227 and a 300 grain bullet w/WLP primer at 1200 fps in a 10" Contender barrel. Also, 21 grains of XMP-5744 got same velocity; may burn different in longer barrel.
The Hodgdon manual shows 22.3 grains of H-4227 w/WLP primer in a 7.25" barrel at 1202 fps (29,900 CUP). Other loads in this paragraph are 25,000 CUP or less. All of these loads are with jacketed 300 grain bullets. Our 292 grain cast bullet would probably post less pressure with the same charges as the jacketed bullets. It is estimated that the 24" barrel of the Marlin Cowboy would produce 150 fps more velocity than the 7.5" to 10" revolver barrels. Therefore, maximum charges for these powders could be lowered somewhat to keep velocities within the required limits. Hence, in Marlin:
292 grain bullet, 21 grains IMR-4227, Starline case, Fed 155 primer = 1350 fps.
With above suggested loads, cut powder charges to obtain 1250 fps. Therefore:
In recent tests performed at the Silhouette range at Pala, California it was determined that the Federal 155 LPM primer produced cleaner burning characteristics when used with WW-296 and the 292 grain bullet in the .45 Colt caliber Marlin rifle, than did the Winchester WLP primer under identical circumstances. Also, more consistent results were experienced using .45 Colt cases with factory primer pockets rather than those that have been uniformed with the Lyman tool. This tool reams primer pockets for rifle primers. This is too deep for pistol primers, and could cause inconsistent ignition that can be detrimental to accuracy. Also, newer lot #'s of WW-296 are more consistent than older lot #'s of this same powder.
Also, in this test at Pala, 115 rounds were fired in the Marlin .45 Colt using Winchester and Star-line cases, 292 grain bullet (20-1), Bubba Lube #2, 19 grains of WW-296, and Winchester and Federal primers in warm weather conditions without experiencing any leading in the barrel or on the case mouth as was experienced with 15 grains of AA #9 and the Federal 155 primer when used with the Laser-Cast 300 grain bullet. I recently changed to 16-1 lead to tin mix. This change has enhanced accuracy. Also, I have changed bullet lube from Bubba #2 to SPG+.
It has been stated in reloading manuals that the same powders that produce top velocities in revolver length barrels will produce top velocities in the rifle length barrels. This may be true, but I have not chronographed top loads to check this out. What I am saying is that slower burning powders that are bulkier per grain weight and fill the case to the base of the bullet may produce more consistent results in rifle length barrels (20" to 24") for the velocities that they produce. As I have said before, in the silhouette game we are not looking for high velocity, we are looking for extreme consistencies in velocity, pressure, accuracy and clean burning characteristics. Ease of extraction and positive feeding are not to be over looked, either. In reviewing past loads shot in matches, it appears that loads using the WW .45 case shot higher scores with the 292 grain bullet than loads using the Star-line .45 case with the same bullet and powder charge (19.0 grains of 296).
Regarding XMP-5744, Accurate Arms claims that this powder is insensitive to position in the case. It bulks up good and in most cases pretty much fills the case to the base of the bullet. Use magnum primers with this powder.
This powder will leave some unburned grains in barrel, but other wise shoots relatively good. A load of 20.0 grains of this powder with the Laser Cast 300 grain bullet in WW .45 cases with Fed 155 primers was tested at Pala on 7-13-02 to no avail. Only scored 22/40. The bullet was seated to the second crimp groove for an overall length of 1.642". This load shot dirty, velocity was too high for this game, really heated up the barrel, and was a shade too long after barrel was fouled. I should try this same bullet seated to the forward crimp groove (COL 1.570") with 18.0 or 19.0 grains of this powder.
Best loads so far are:
The loads using WW-296 were from a new lot# of WW-296. A load that used an old lot# of WW-296 only scored 24/40.
The Lyman bullet 452651 GC will cast 20-1 at about 325 grains including gas check. With these bullets sized .452" and cast of 16 parts lead to 1 part tin, try this loading with 19.0 grains of WW-296 or 19.5 grains of H-110 in Star-line cases with Fed 155 primers and Bubba lube, or Javelina or NEI pistol lube.
Use a COL at 1.572". The load using this bullet and 19.5 grains of H-110 was reported by Mr. John Taffin as turning in very good accuracy in revolvers. Taffin also reports superior accuracy using 17.0 grains of VV-N110 with the above mentioned Lyman bullet, in a revolver. 19.5 grains of H-110 produced 1109 fps in revolver tests or 1259 fps in a rifle barrel. 17.0 grains of VV N-110 produced 1113 fps in revolver tests, 1263 fps in a rifle barrel.
Loads to try:
Sighting equipment has been changed from the stock Marlin open sights with 1/16" gold bead to a Marble tang sight with smallest aperture and a Williams .450" high front fire sight.
Note: A full length article about the .45 Long Colt for rifles can be found on the Rifle Cartridge Page.
Copyright 2003 by Dave Thornblom. All rights reserved.