Not to throw a wrench into the works, but you might want to consider the length of the brass that you are using (especially if you are trying to work up a load in an older rifle).
Original .38-55 cartridges were loaded with a 2.125" case. In 1926, in an effort by the federal government to standardize cartridge specifications throughout the arms and ammunition industries, SAAMI was formed. Sometime thereafter, and for some reason which remains unknown to me, .38-55 cartridge length was standardized to a length of 2.080" with a bullet diameter of about 0.3770". Many rifles made before this time were manufactured with a bore in the neighborhood of 0.379" and thus require a bullet diameter a tad larger than factory-produced ammo of today.
While you could write a book on this subject, there are a few key things to keep in mind.
1. You really need to know the true bore diameter of your rifle if you want to glean top accuracy from it. Slugging your bore with a piece of soft lead and then measuring it is the easiest way to accomplish this. With lead bullets, the best accuracy is generally achieved with a bullet that is .001 to .002" larger than the bore. If you don't want to do that, several bullet manufacturers offer "sized" .38-55 bullets in diameters ranging from 0.378 to 0.382". My 1894 Winchester was manufactured in 1920 with a barrel that slugs 0.379"; 0.380" and 0.381" bullets shoot most accurately for me in that rifle.
2. A less understood problem is chamber length in older .38-55 rifles. If you attempt to reload a 0.380" bullet in a standard, modern piece of .38-55 brass at 2.080", chances are good that it will not chamber in an old rifle. In an effort to rectify this problem, many shooters have had their chambers reamed to make them longer. An easier solution, and one that requires no modification of the firearm, is to use longer brass with a thinner neck. Currently, the only supplier for this is Starline Brass. These brass cases are 2.125" in length and have a very thin wall at the mouth.......so thin that they can be easily bent in shipping or by rough handling. These two factors allow the handloader to utilize lead bullets that better fit the rifle's bore AND will chamber without problem.
I'm certainly no expert on this subject. These are some of the problems that I've encountered--and some solutions to those problems that I've learned about--while trying to develop an accurate load in an old rifle.
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