Let's take the specific case of 38+P out of a 2" to 2.5" barrel, as that's one I've specifically studied as I shoot it a lot and it's my primary defensive caliber.
Don't get hung up on the weight. You have to ask, what *specific* load is worth a dang? For that, you need to do a lot of study.
Weight correllates to speed - usually
. Speed causes a hollowpoint to open. But different hollowpoints are "tuned" to open at different speeds.
Example 1: One of the loads I'd trust my life to in a 38 snubby is the 158grain lead hollowpoint +P, also known as the LSWC-HP+P, for "Lead Semi-Wadcutter Hollowpoint Extra Pressure". Made of pure soft lead with no jacket to delay expansion, these open up at the modest velocities you can hope for in a snubby (2" barrel) - about 750 - 800fps if the gun is any good (including a tight cylinder/barrel gap). If these were offered in 125grain weight, they'd go "too fast" and come unglued (fragment) in a 4" to 6" barrel, although they might actually do fairly well in a 2". In any case, the 158 pure lead hollowpoint is a primitive type of hollowpoint, one of the first designs, and it continues to work well for low-velocity applications. This round was variously known as the "Metro load", "Chicago load" or "Treasury Police load" for the various agencies that used to carry them, and they've been geekin' bad guys since Eliot Ness walked a beat
.
Example 2: Another good one (and a lot more modern) is the 130grain Winchester Supreme +P. This round was designed for 38Spl use versus 357, and has an *enormous* hollowpoint cavity. Expansion from a 2" barrel tends to be good bordering on impressive. While it's a jacketed hollowpoint (JHP), the round was tuned for the application extremely well.
Too many other 125/130grain range loads are NOT so well-tuned for the low-velocity needs of the 38, and flat-out don't work.
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In the 45ACP, as a general rule, the shorter the barrel, the lighter the round you should use. Even the very best 230grain JHPs have been known to fail when shot out of a 3" ultra-compact barrel because they're not getting enough speed to open. On the other hand, the fast 185s will sometimes break up and drop back DOWN to 45cal when shot out of a 5" tube.
If I owned a 3" barrel 45ACP, I'd carry a good 165 or 185 grain load. With a 5", I'd carry a good 230.
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There are a couple of very modern "post-hollowpoint" designs that show great promise:
Federal E-FMJ: this looks like FMJ, but instead of lead in the nosecone there's a rubber ball. The jacket over the nose is scored so that it will "squish" and flatten. Peak expansion is lower than the best JHPs, with 9mm producing .55cal worth of expansion, but it gives you that expansion more or less EVERY SINGLE TIME, without ever "clogging up" with clothes and failing to expand as hollowpoints can, and opening without fragmentation over what appears to be an extremely broad velocity range. The same load seems to work from a 2" snubby to a 16" carbine which is really unprecidented.
Downsides: Federal is only selling it in a few calibers, 9mm, 40S&W and 45ACP and aren't planning on more. They're assuming that the "easy feeding" properties will be a major selling point and it is, but revolver people could use the reliable expansion! The 124grain 9mm version could be re-sized in 38+P cases and would be a *superb* load for the snubby!
Cor-Bon Pow'R'Ball: this is a JHP with a rubber ball crammed in the nose. There's no jacket OVER the ball; the ball squishes, which starts the expansion process and then the ball falls away and typical JHP dynamics takes over.
The advantage over the Federal answer is that peak expansion is greater; the Pow'R'Ball expands like the best JHPs. The "clogproof" characteristic is as good as the Federal because it's "pre-clogged". The downside: like any JHP, it can be punched "too fast" and fragment. The 40S&W version seems to work great so far, but they loaded the same projectile in 10mm and 440Cor-Bon and it seems to be going too fast and coming apart, esp. in longer barrels.
Still, once they get this worked out (different rubber composition in the ball, guys?) the Pow'R'Ball has a LOT of promise, and Cor-Bon is promising to phase out the JHP altogether in their product line in the Pow'R'Ball's favor. Pending somebody shooting 'em into denim-wrapped gelatin and publishing the results (see also
www.ammolab.com) they'll be worth considering.
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Another solution to rounds "breaking up" is the Speer "Gold Dot" projectile. They elecrochemically bond the lead to the jacket, so that even if the jacket comes way apart and looks like an octopus, the lead will be still stuck to it instead of shredding back along the wound channel. The Gold Dot was designed as a "delayed expansion" round for "deep punch" and I don't trust them for 38snubby applications, but if you've got the velocity to make 'em work, they tend to be excellent rounds. In 45ACP they're available in 185, 200 and 230 grain weights and I'd use them in that order in 3", 4" and 5" barrels. A couple of smaller companies buy the Gold Dots as components and load 'em up nice and hot, including Georgia Arms, Proload and Black Hills (not 100% sure on BH).