Recoil is felt differently by all of us, but I've found little difference in felt recoil between bullets in the 125-158 grain range when fired in a J-frame snub nose, airweight or steel frame. All these guns kick noticeably regardless of the ammo used, though maybe a little more with +P loads.
I don't think you can do better than a 158 grain cast loading in the .38 Special because such loads often shoot close to point-of-aim, may be more accurate than lighter bullets, and seldom is a heavy bullet a disadvantage for a defensive gun. Bullets in this weight range is what the .38 Special was designed for and it's still right.
You can get bogged down with FBI, jello shooting, heavy clothing, textbook esoterica, etc., but learning to shoot well (almost always overlooked in these threads) is a far more important consideration. Ammo selection is really very secondary.
It may hard to do now with the shortages, but consider trying four or five ammos and go with what works best for you, standard pressure or +P loads. I still like the 158 grain HP cast standard pressure or +P loadings (only if +P worked better for me than standard pressure).
If you are already a very proficient shooter or become one and want to delve into all the peripheral gimcrackery, you've certainly earned the opportunity, but you may lose all interest in it if you shoot well.
I do not think the ability of the shooter to shoot accurately is “often overlooked”, it’s just intentionally ignored by shooters who:
- don’t shoot well; and or
- have not learned the basics and practiced enough to ensure they will put the front sight on target with the sights more or less aligned under extreme stress; and or
- ignore the second point entirely as most police officers are not well enough trained to use their sights under extreme stress and thus feel it’s a waste of time.
They just feel they can buy better performance without having to put in the training or trigger time. They are dead wrong on that.
I agree completely that bullet placement matters far more than bullet design and terminal performance.
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That said, I don’t entirely agree with your “cast bullet” assessment.
All three of the major FBI loads used a swaged lead bullet made from very soft lead with a BHN of 8-9 or less.
The average cast lead commercial bullet intended for .38 Special has a BHN of about 12 and for the 38 +P it BHN around 15 (more or less Lyman no. 2 alloy). The .357 Magnum uses harder bullets with a BHN around 18 (more or less Linotype alloy). None of them expand all that well at the 800-1000 FPS velocities attained in even a .38 +P.
Most folks won’t notice expansion or lack there of, but they will notice leading that occurs when either the bullet is 1) too soft for the operating pressure of the cartridge and strips in the rifling, or 2) is too hard to obturate and fill the bore at the available cartridge pressures and leads due to gas cutting around the base of the bullet.
Consequently you see the above ranges for hardness in commercial cast bullets, and all of these “hard cast” bullets are well known for excellent penetration and almost no expansion, even in a hollow cavity design.
When I want a hollow point bullet that will expand at .44 Magnum and .357 Magnum velocities around 1400 FPS I’ll use a 50 % Lyman no 2 alloy (or an equivalent made from 9 pounds of wheel weights and a pound of 50/50 bar solder) and 50% pure lead. The resulting alloy is around BHN 11, soft enough to expand at that velocity, with enough tin to still fill the mold well and enough antimony to avoid stripping in the rifling.
At .38 a+P velocities around 950-1000 FPS I’ll use a 25-1 alloy using 12 pounds of pure lead with 1 pound of 50/50 lead-tin bar solder. The BHN is down around 9 for decent expansion and there’s enough tin for it to cast cleanly in the mold there isn’t any antimony however so it’s a bit more sensitive stripping in the rifling. I have a 3” 686 that loves it and a 2 1/2” 686 that will key hole with it at 5 yards despite lower velocity. The difference is in the chamber and bore dimensions.
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Hornady’s 158 gr LSWCHP has a BHN of 8 and it can perform quite well at .38+P velocities in a FBI’esque handload but it needs a fairly heavy coat of liquid alox on top of the lube Hornady uses to prevent leading.
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In short, it’s tricky stuff. A 158 gr LSWC is a better choice than a LRN for terminal effects, but commercial cast LSWC bullets won’t expand. A truncated cone or round nose flat point is probably a better choice as you get the large meplat plus easier reloading than you get with the sharp shoulder on a LSWC.
For that matter, if you handload, it’s hard to go wrong with a plated lead RNFP bullet. No leading, soft swaged lead core, and decent manners in a reload.
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But…to Rock quarry’s main point, the major advantage is low cost, allowing you to shoot a lot more, and it’s the increased practice, proficiency and improved bullet placement that will pay off in the end in the (unlikely) event you ever have to shoot.