I don't get it.

People say that if I want to shoot .44 mag, I should load with 2400 or H110 (amongst other magnum powders).

I have Accurate #2, and I use about 8 grains under a 245 gr. LSWC. It makes a big boom and a big impact.

If I'm after 800-900 fps, what does a slow powder do that a fast powder does not do?

I understand that if I want to squeeze everything out of a .44, I'm going to use jacketed bullets and 2400, but for cast bullet shooting, how does #2 disadvantage me?

Sometimes it's hard to see an accidental double charge when you're only putting in 8 grains of powder in that big case. With a slower powder because it fills more of the space, a double charge is much more visible.

In my .44 Mag a full case produces better accuracy.

For your loads (low power) fast powders are fine. The slower powders like H110 give high velocity with relatively low pressures. The point is that you cannot duplicate the high power loads with vast quantities of a fast powder. You could even try AA#9 for that matter.
peter.

To achieve the maximun velocity from a given cartridge one needs to load a powder that has a burn rate such that as the bullet moves down the barrel the powder burns to keep up the pressure on the bullet all the way. The more the powder matches this requirement the more you will achieve velocity.....which translates to power.

A very fast powder will create the pressure that the cartridge is designed for but fails to keep the pressure up on the bullet as well as a (usually slower) powder. We tend to use slower powders in magnums because we want the powder to continue to burn all the time the bullet is in the barrel.....thus keeping up the pressure.

The key to velocity isn't therefore how much pressure the powder creates.....it's HOW LONG one can keep that pressure on the bullet.

Different cases have different capacities and different bullet diameters create greater capacity to fill as the bullet travels down the barrel. It's a quite complex mathamatical problem but rest assured that using the correct amount of the powder with the right burn rate for your cartridge will create the performance differences you will see.

quote:

People say that if I want to shoot .44 mag, I should load with 2400 or H110 (amongst other magnum powders).

I don't.

quote:

I have Accurate #2, and I use about 8 grains under a 245 gr. LSWC. It makes a big boom and a big impact.

quote:

If I'm after 800-900 fps, what does a slow powder do that a fast powder does not do?

Slow powders are inappropriate for the velocity ranges you quote. H110 is especially inappropriate. Stick with your "fast" powders. If you want to fill the case with a fast powder whilst using cast bullets try SR4759. But hey, it's not like you're looking for sub MOA groups out to 300 yards. Any of the faster powders will work well enough for casual plinking etc.

quote:

I understand that if I want to squeeze everything out of a .44, I'm going to use jacketed bullets and 2400, but for cast bullet shooting, how does #2 disadvantage me?

Your understanding is a bit skewed but that's already been covered for the most part. What hasn't been directly addressed is that the .44 Mag performs as well with cast as it does with jacketed bullets, probably a bit better actually. I don't know if H110 is good with cast bullets, but it is definately superior to 2400 with jacketed bullets. Li'l Gun is superior to both with cast bullets. In fact, a full dose of Li'l Gun under a 300 grain cast bullet is probably the best combo you'll find for the cartridge, unless you're paper patching, then that's number 1. JMO

If you like using "fast" powders in big cases, far be it from me to tell you otherwise. When asked, I recommend med. to slow burners in large case because they fill more of the case, usually giving better accuracy & little to no chance of a a dbl. charge. I only use AA#2, WST, etc. in 9mm & .45acp, even then, I really prefer something a bit slower like Unique.