I'll interject a touch of theory and a bit of truth on part of this.
I'll label this "a touch of theory": IF I wanted to use a fast rifle powder to take advantage of the longer barrel, I would do it "after" a lot of reading and ciphering. You see, there is nothing new under the sun. It has all been done. Simply a matter of research to find who-dun-it and what their results were. I have not done it specifically with the 45Colt, but I have done it with other rifles for which there was no data in the mainstream manuals for the powder or bullet weight that I wanted to use. Error on the side of caution and work up. Some powders are very forgiving when loaded light, and others are not. Reading will help locate a similar round, similar case capacity, maybe the same or different expansion ratio - have to be careful there. Part of the joy of handloading is such as this.
I'll offer this for "a bit of truth": Some loading manuals are placing a seperate data set for some pistol cartridges to be used in rifles. Usually there is a disclaimer to "not use in revolvers due to higher pressure" or some such verbage. So, from the pages of my handloading journal; Let's take a load from the "revolver data" that was worked up properly in a particular revolver to pretty near the max for a certain mainstream loading manual. This load works as a 200meter ram load on a IHMSA shooting range for several years. All is well. Some time later, a rifle is purchased in the same caliber. Several boxes of light to medium loads are fired and the rifle is dialed in and shooting is fun. As a matter of decision, a box of the 200meter ram load is matched to the rifle for a day at the range, prepping for some possible hunting. The first round ends the day with a case head seperation, and a trip to the gunsmith. After removing the "rest of the case", the 'smith asks about the ammo used. I showed it to him. We pulled a bullet and verified the load and cross-checked with his manual. All is well. Inspection of the brass shows no signs of weakening in the brass, but, just in case, some new brass is sized, trimmed and loaded with the same powder charge and bullet. We both go to the range. Again, the first round gives a case head seperation. We concur that the revolver data, which is good in the revolver with it's cylinder gap, is actually too high for the rifle with it's closed chamber and long barrel. The powder was in the middle of a can of W296 and had showed no signs of being erratic before or after. Mag primers were always used and loads were kept near the top of those listed, per Winchester's instructions. I've always had to load this rifle below "book max" in the "revolver section" of the book to keep the cases from seperating in the chamber. The rifle chamber is proper spec and smooth, and the barrel measures correctly. I've adopted the policy of loading the middle ground of the "revolver section" for my rifle and working up from there, and basically leaving the "rifle section" unused, except where other powders may have been used "to take advantage of the longer barrel". Then I start at the suggested starting charge and work cautiously. I've not had another case head seperation with this rifle. Noted the later manuals show either the same loads or lighter loads for the rifle as compared to the revolver, so I guess a few light bulbs came on.
Regards,
Sweetwater
