Originally Posted by mattL46
Hello all. New to the firing line and glad to be here. Not really new to reloading just a little in experienced which is why I'm here. Any who my question is along the topic of substitutions. I'm sure this question has been asked before. What are your thoughts,suggestions,do's,don'ts about case substitution. For instance alliant's freebie guide lists for the 45Colt so many grains of green dot with this primer and this bullet etc etc. But it uses all speer brass (which I was unaware speer made case brass) I have a ton of winchester brass I'll be using. So is this a no no or could I reduce the load (which I would do anyway considering all of alliant data is maximum and suggests to do so anyway) and work up to my desired performance. Please give your thoughts and opinions. Thanks folks.
The main thing about substituting brands of brass is the case volume. More to the point, the volume inside the case under the bullet at whatever seating depth you are using. And this is even more important the more the case is filled (free volume vs occupied volume). With a large case like the 45 Colt (originally a black powder cartridge), the relative volume differences between brands is less than the volume differences between, say, a high-efficiency cartridge like the 40 S&W.
My opinion: You have little to worry about.
Other factors might come into play, like case wall thickness and the elasticity of the brass at the case mouth, which will cause the neck tension on the bullet to vary.
My opinion: Little to worry about here, either, as SAAMI specifications keep everything fairly uniform.
Yes, do work up your new load from a mid-range charge weight.
: Consult a variety of loading manuals and sources. One source is the Loadbooks' "One Book One Caliber
" manuals. For about $10, you buy a book that is the compiled copies of many different manuals, but only the recipe pages for the titular chambering. They have one book each dedicated to all the popular calibers, about 5"x8" and 30-40 pages or so and a spine bound so the book lays flat on your loading bench. A really nice concept and fairly well executed.
Good luck, Matt.