Re: Powder for short barrel 243?
That depends on what caliber he used and what gr wieght he used and if he stayed with the same caliber/gr through the testing. If it was that easy there would only be one powder based on each casing. It just aint that simple. Nor would there be a pistol powders that have a really fast flash point and exclleration burn point.
This is a good example. When I was a bit younger I had a H&R handi rifle in 357 mag with a 22 inch barrel. I had a friend of mine who was a gunsmith fresh outta Murray State. He helped me find a load I liked on a chronograph. It shot fine, but being a 20 year old I wanted my handi rifle even handier. So, he cut the barrel back to 18.5 and when we chronied again, much to my surprise I had gained about 14fps.
It is a tit-for-tat science and for everything you change, you have to change something else. Barrel length, bullet wieght, bullet length, ect, ect. Thats why there are so many powders available. But, one would have to take note that this is ever evolving and has boomed only in recent years.
Now, that is a loose example. It hardly ever happens in normal rifles, unless you completely mess up and use some crummy stuff, or, your barrel is extremely long. Will a fast burning powder in a short barrel be even faster in a longer barrel? Yes, but a slow-er, more effeciant burning powder will go even faster than that in a longer barrel. However to say that slower burning powders have no effect on a shorter length barrel is a moot point. They do for a fact. As someone else stated, you can't burn all of it off and it sends alot of it out of the muzzle. Why? Because it burns slower. Not to mention some of the slower burning powders can play a part in throat errosion on small, high speed calibers. It is hard on'em to cram that much hot powder down a small hole.