Home Forums Hunting & Shooting Handguns .45 vs 10 mm

I may be wrong, but I seem to recall that back in the mid-70s when Whit Collins was further developing the .40G&A/10mm Police round it was based on a belted cartridge... perhaps a cut down...? I believe that the purpose of using a belted cartridge was two-fold: better head spacing and the ability to deal with higher pressures for increased performance.

Perhaps someone with a full run of GUNS & AMMO magazines can dig through the 1976/77 issues for a more definitive answer?

And, you were running that 50k PSI .45ACP brass in exactly, what, again?

I'm not a physicist, and I didn't stay at a Holiday Inn Express last night, but my guess is that they don't have the same limits for pressure. Pressure is per inches squared, and the 45 is pushing back on a greater area, so the same pressure equals more force, which is what's really beating on the gun. I'm not sure what you're saying about the gun, but if we're comparing the cartridges in identical guns, then I assume there is also going to be less margin (metal holding in the pressure) in the gun with a larger chamber. I certainly don't have a dog in this fight, I've never even had a 10mm.

My Guns better 'n ALL your guns!
So there!

ptthhhh

No and yes.

Generally the pressure limit is imposed by the handgun, not the case. In a semi-auto the limiting factor is slide force which is a function of slide mass and velocity. In a 1911 that's especially true. The .460 Rowland is a good example. It has the same case capacity of the .45 ACP but it runs at 40,000 psi. In a 1911 spring rate alone can't cut the slide velocity enough so it requires a compensator. In other designs a heavier recoil spring alone will do the job.



That's also correct. In the rifle world it's called "bolt thrust". At the same pressure a larger diameter bullet will exert more force on the handgun than a smaller diameter. Guys like to talk about the 'same pressure, more performance' in comparing the .45 Colt to the .44 Mag, but they rarely take bolt thrust into account. While it's true there is a certain amount of free lunch with the .45 Colt, bolt thrust narrows the gap.

which has more pressure on your carpet a 150 lb lady wearing high heels or oxfords, the high heels of course, the same pressure on on a smaller surface area has more force, the unit of force per unit of area.. the same reason a 38 super shooting major is worse than a 10mm , when reloading a 45 gives up nothing to a 10 mm. Have both shoot both.

You're calculating it backwards. The result (pressure) is already in pounds per square inch.

To use your analogy, you'd have to compare the high heels at 150-psi to the oxfords at 150-psi. By virtue of the greater surface area the oxfords would exert the greater total pressure.

same pressure over a smaller area doesn't change the pressure it's still applied over the smaller area. smaller area sees greater force.

My only recollection was Whit using .30 Rem brass and resizing bullets to .40 because .41 wouldn't fit, and that's how we ended up with a .40 instead of a .41 like the .41 AE. Not sure about the belted cases, he may have used them; I just don't remember anything about them.

You can type it out a hundred times, it's still back-asswards.

The units of pressure are lbs. (the force) divided by square inches.

If the pressure is the same, but the areas are different, the force must be exactly proportional to the difference in the areas.

In other words, same pressure, smaller area, yields smaller force, by definition.

It sounds like you are coming at this from both ends and meeting in the wrong place in the middle. What would be correct to say is that for the same force, the smaller cartridge would see a higher pressure.

I'm talking about factory loadings and SAAMI specs.

The first sentence is correct, but the second is contradictory. The total force exerted on one square inch at 150-psi is 150-lbs. The total force exerted on two square inches at 150-psi is 300-lbs.

The .45 ACP is perfect just the way it is. It was designed to be as low pressure as they could manage, because it�s a military cartridge and lower pressure is always preferred over higher pressure for military applications for a lot of reasons.

To create some hot-rod hunting rounds, yeah you could stuff more powder in there, but the .45 ACP was created as a combat round and nothing else; and for that purpose, it is damn near perfect.

Exactly.

As I recall early on (1970-71?) Whit started out with a cut down .38-40, and improved on it as he went along. Later (when I was at G&A) he was experimenting with other brass-- possibly custom stuff from NORMA. The last iteration I seem to remember was a belted case round that fired through a modified Browning Hi-Power.

I always felt the only advantage to the 10mm was increased accuracy at 50+ yards-- well beyond the 7-21 feet at which most shootouts occur. That being the case, I was never able to see any real-world, practical advantage that the 10mm pistol had over the .45 ACP.

From a defensive standpoint, correct?

Agreed,

What was really needed (and I believe time has proven this to be true) was bullet development of the .45 ACP (and 9mm) to give better than FMJ performance from auto pistols; essentially putting an auto pistols on equal footing with a revolver in the realm of terminal ballistics. Simply creating another auto pistol round that pushes the same bullet designs to a different velocity wasn�t likely to produce anything of substantial value. The problem was the bullet, not the cartridge.

Seems like we've more than adequately addressed those problems in recent years.

Yup. Absolutely correct. I firmly believe that the .45 ACP is the best ever Sex Crazed Zombie Stopper to come down the pike.

Agreed, with a three other "old timers" RIGHT there with it; specifically, the .357 Magnum, .44 Special, and .45 Colt.

Give any of those 4 a good bullet, load to standard specs, and stuff has a nasty habit of getting very dead, very quickly.