Originally Posted by davery25
I didn't mean it as in the shortened barrel length means everythings different and he'll have to find another load, rather my concern is that if the barrel is too short for a powder and that powder doesnt finish burning and hence muzzle flash is produced then that load doesnt do what he intends for it to do as the pressure levels never get quite high enough.
of course the load might still shoot well, but its a concern.
or am i still off on that train of thought?
Your train is partially on track and partially off.
Muzzle flash and inefficient use of the powder because of incomplete burn is all true.
"Pressure levels never quite get high enough" is off track. The pressure levels peak in the very early part of bullet travel, so unless you're talking about a barrel that barely extends beyond the end of the chambered round, you're going to get peak pressure.
The idea that the powder that produces best velocity in a long barrel will also do it in a short barrel is generally
true up to a point. It's generally true if you go from 24 to 22 or 20, for instance, but it might start to change if you get down to 15" or 12" for example, such as in an Encore handgun that shoots rifle cartridges.
On the other end, it's also usually true that the powder that produces the best speed in a short barrel will also do it in a longer barrel, such as going from 3" to 6". At some longer barrel length, that rule breaks down too and if you think about it, those two points converge at some approximate barrel length where they are each no longer true and the other becomes true, depending which direction you're going.
Clear as mud, right?
Still happily answering to the call-sign Peetza.
The problem, as you so eloquently put it, is choice.
He is no fool who gives what he can not keep to gain what he can not lose.
-Jim Eliott, paraphrasing Philip Henry.