corneileous said:
But no, I really wouldn’t think that even a 165 grain hollowpoint would have a hard time passing through this truck door, or even through the much thicker door on my fairly brand new ram pick up. I guess that’s just differing opinions over lightweight bullets compared to the heavyweight ones.
You're dealing with the trade-off between mass and velocity. Keep in mind that energy is what expands a hollow-point. Energy increases linearly as the mass increases, but exponentially as the velocity increases.
The reason +P is wasted in short barrel pistols is that you need barrel length to allow them to get up to full velocity. These new "short barrel" self-defense rounds only started coming onto the market maybe two or three years ago (or so), in response to the growing sales of small, concealable pistols with short barrels. These new rounds are specially designed for optimum performance out of short barrels. The specifics will vary from one manufacturer to another but, in general, the characteristics are different bullets, designed to expand at lower velocity, and (probably) faster powders, to allow the bullets to achieve more velocity before exiting the short barrel.
You can do the math to compare actual muzzle energy, but the Sportsmans Guide web site publishes the velocity and energy for all the ammo they sell. So, for example, look at Remington. In .45 ACP, the regular 230-grain Ultimate Defense has a muzzle velocity of 875 fps and a muzzle energy of 391 ft-lbs. The 185-grain has a muzzle velocity of 1015 fps and energy of 423 ft-lbs.
But those are both out of a "standard" barrel, which for .45 ACP typically means a 5" 1911 barrel. The "Compact" 230-grain has a muzzle velocity of 725 fps, and energy of 268 ft-lbs.
Several years ago, before the advent of this short barrel ammunition, I did some informal comparisons to see how much velocity I was losing by carrying a 1911 Commander (4-1/4" barrel) or Defender (3" barrel) compared to a full-size. Depending on the specific ammunition (I tried several different types), the loss in velocity ranged from 9.45% to 12.85% going from a 5" barrel to a 3" barrel. The highest loss was for the round with the highest velocity out of the 5" barrel, and the least amount of loss was for the round with the lowest velocity out of the 5" barrel.
The formula is E = 1/2 M x V^2 [V squared]
For those Remington rounds, then let's say we reduce the muzzle velocity of the standard 230-grain by 10% for your short barrel. The new velocity would be 788 fps. The resultant muzzle energy would be 317 ft-lbs.
"But," you might say," that's more than the velocity of the short barrel ammo of the same weight." Yes, it is -- but the short barrel ammo has a bullet that's designed to expand
reliably at lower velocities. We don't know how reliably the standard 230-grain bullet will expand at 317 feet per second. The muzzle energy will be reduced by 18.9% -- that could be significant.
Looking at the 185-grain standard load, if we reduce the muzzle velocity by 12% we get 893 fps. The resulting muzzle energy is 328 ft-lbs., a drop of 22.5%. It's still more muzzle energy than the short barrel, 230-grain load ... but is it enough to reliably expand the bullet? I don't know. If we want to assume (always dangerous!) that the standard 230-grain and 185-grain bullets are similar in construction, the reduced muzzle energy of the 185-grain bullet is about 16 percent less than the muzzle energy of the standard 230-grain load. Is that enough drop to cause the expansion to become unreliable? I can't answer that.
For what it's worth, in my Officers ACP (3-1/2" barrel) I carry the standard Remington 230-grain. But ... I had it before they came out with the short barrel stuff. When it's time to resupply, I will probably go with the 185-grain ... primarily because I alternate between the 3-1/2" barrel Officers and a 4-1/4" Commander, and I think the standard ammo is better suited for the Commander-size pistol.
For a 3" barrel like a Colt Defender, I would probably go with the short-barrel ammunition. For me, the odds are that I'm a lot less likely to be shooting through a car door than I am to be shooting through nothing other than an asailant's clothing.