Here comes a dumb question. I read lots of articles about this cartridge is better than that one because it has more capaity and consequently will hold more powder. I have yet to fill a cartridge full of powder because I always start getting signs of pressure well before I run out of room. Does cartdrige capacity allow more powder (velocity) even if the cartridge is not full? Second question. Is it the strength of the cartridge (the brass) that makes one cartridge capable of more pressure vs. another. Here is an exageration but why can't you load a .250 Savage to the same pressures as say a .300 win mag? I know tons of physics are going on here but how does that limit pressures compared to another capable of higher pressures?

There are lots of issues there, Dale - too many to answer or explain in one post. But I'll tackle a few...

Generally, when you reach maximum pressure before the case is full, you are using a powder that burns too fast. It peaks early, in other words. Try one step slower powder and see what a difference it will make. You'll be able to use more of a slower powder, and that added amount will generate more gas over a longer time - increasing the velocity without necessarily increasing the peak pressure. The ideal relationship is when a powder achieves the maximum rated pressure for that cartridge at 100% case full.

Second question, it can be either or both of the case or the rifle that determine maximum safe pressure. Sometimes, it's the design of the case (thin walls, reduced web) that limit the pressure. Other times, it's a weaker rifle design (M-94 lever, T/C Contender...) that limit it. A classic example are the MANY different rifles for the .45-70 and the three levels of allowable pressure for that round. Or the .45 Colt revolver round.

In your example, the .250 Savage was originally chambered in the Savage 99 lever gun, a great design but one that simply cannot handle as much pressure as a bolt gun. And guns chambered for the .300 Win Mag may even be specially heattreated to handle that round as opposed to a milder one like a .30-06, too.

Make sense now?

There are lots of issues there, Dale - too many to answer or explain in one post. But I'll tackle a few...

Generally, when you reach maximum pressure before the case is full, you are using a powder that burns too fast. It peaks early, in other words. Try one step slower powder and see what a difference it will make. You'll be able to use more of a slower powder, and that added amount will generate more gas over a longer time - increasing the velocity without necessarily increasing the peak pressure. The ideal relationship is when a powder achieves the maximum rated pressure for that cartridge at 100% case full.

Second question, it can be either or both of the case or the rifle that determine maximum safe pressure. Sometimes, it's the design of the case (thin walls, reduced web) that limit the pressure. Other times, it's a weaker rifle design (M-94 lever, T/C Contender...) that limit it. A classic example are the MANY different rifles for the .45-70 and the three levels of allowable pressure for that round. Or the .45 Colt revolver round.

In your example, the .250 Savage was originally chambered in the Savage 99 lever gun, a great design but one that simply cannot handle as much pressure as a bolt gun. And guns chambered for the .300 Win Mag may even be specially heattreated to handle that round as opposed to a milder one like a .30-06, too.

Make sense now?

Great explination. Thanks

Try reading the notes here: http://kwk.us/powley.html

Andy