I don't know why everyone is saying .44 mag is more "readily available" than .45 because for just about ANY pistol chambered in .45 Colt, you can buy a .45 ACP cylinder. Now that's what I call readily available, better for plinking, and cheaper. Plus, .45 Colt can be loaded just as hot as a .44 mag (Maybe not for every gun but should for most new pistols). I own a Ruger New Vaquero and it has held up for the past year of probably a 1000 rounds of hot .45 Colt + even more factory loads. And I have a .45 ACP cylinder that is awesome for plinking and cowboy action shooting.

.45 Colt Rules.

There have been a variety of answers offered from both camps in this thread, no shortage of opinion and not really a lot of hard research or test data presented to support either side. I do not claim to be an expert in ballistics or building custom loads or even shooting for that matter. I own guns in both calibers, and load a variety of power levels in both. My .45 heavy load is a 335 grain bullet cast from wheel weights in a Veral Smith LBT mold. 23 grains of 296 drives this bullet to 1160fps, as measured by an Oehler 35P chronograph ten feet from the muzzle, from a 5 1/2" Ruger Bisley. Measure power however you would like, and that is substantial.

With regards to which is the better cartridge, I would suggest that you go read some articles written by John Linebaugh. While, John is a fan of the Taylor knockout formula and I know that there are many who disagree with this theory, he has probably done more research on heavy loads in the Colt cartridge than any other person alive. Within the following links, he discusses everything from bullet weights and pressure to "weak cases" and results from pressure testing of guns to the failure point. Read what he has to say and come to your own conclusions about the two cartridges. For me, I will take the .45 Colt in a Ruger or similar gun any day of the week and twice on Sunday.

Take a look at these articles

Linebaugh's Custom Sixguns - The .45 Colt - Dissolving the Myth, Discovering the Legend

Linebaugh's Custom Sixguns - High Pressure Loads

Enjoy

Flyboy, I'm from Missouri too, so here is your hard data.
300 gr. 44 mag. bullets and 335 gr. 45 Colt bullets have the same sectional density (.234) so should penetrate the same at the same velocity.
Typical max velocities (individual revolvers may differ slightly) for these two bullets are 1300 for the 44 and 1150 for the 45, giving the penetration edge to the 44.
The heavier 45 slug does have a little more "punch." Taylor KO for the 45 is 24.8, and 23.9 for the 44 mag., a very slight edge (< 4%).
The difference in Taylor KO between the 470 NE and the 500/465 NE (the two favorite dangerous game cartridges in Africa) is 5.4%, and they are considered dead equals on game.
I don't believe any animal on earth, including humans, could tell the difference between the two rounds if hit by them. In hard cast bullets both would penetrate completely. The wound channels would be nearly identical as well, since the faster 44 bullet would have enough more rotational velocity to equate the wounding of the larger 45 bullet.

The arguments in favor of the 44 mag. as far as trajectory are fairly weak as well.
The 300 gr. 44 @ 1300 has a point blank range of 106 yds (+/- 2") with energy of 837 ft/lbs at that range.
The 335 gr. 45 @ 1150 has a point blank range of 96 yds. (+/- 2") with energy of 800 ft/lbs at that range.
This gives a slight edge to the 44 mag., but in the real world not 1 out of 10 pistoleros would be shooting at game at 100 yds. with any reliability, so the advantage is moot.

So we have a very slight edge for one or the other cartridge in several different categories which really don't add up to any significant difference for any significant purpose.
Choose the one that makes you happy. They're virtually the same.

Mag,

What art of Mo. are you from?

I was already aware of the information that you presented, but thank you for the addition to the thread. I have shot, loaded and tested a lot of loads for both the .45 and .44 for a lot of years. As a matter of fact, two of my favorite test guns are identical Ruger Blackhawks (5 1/2 stainless guns) that I use for comparative purposes. Unfortunately, the average person, myself included, does not have access to a means of measuring pressure. This is why I have referenced the articles by Linebaugh. I don't know if you have read the articles or not, but the testing that he has done in conjunction with known and respected testing labs, show that the .45 matches the performance of the .44 with less pressure, or if loaded to the same pressure levels, with much less barrel length. This, in my mind, is the advantage to the .45. The end result is pretty much the same with either cartridge, but less pressure is never a bad thing if performance is the same.

I made a post a few weeks ago detailing an informal study that I conducted comparing peoples' impression of felt recoil of two calibers loaded to equal ballistic performance (.40 S&W and .45ACP). People overwhelmingly preferred the lower pressure recoil impulse over the higher pressure, with ballistics that were identical. It made for an interesting experiment and a lively debate here on the boards. I won't get into the argument here again, but if you have not seen the thread, it can be found here recoil vs. caliber comparison

If you are near the KC area, drop me a shout and lets go burn some powder! Thanks for your input.

JW

Verginian Dragoon 44 or 45. It's not the ammo it's the gun. think out side the NORM box. Cheaper too.