Barrel length and bullet weight changes within a certain caliber confusion.

[Teufelhunden]

Given a fixed caliber - in this case, .40 S&W - is it better to use a lighter bullet in a short barrel or a heavier bullet in a short barrel? What about the same question for longer barrels?

In other words, will a lighter bullet work better in a short barrel since it will accellerate more quickly due to its low weight, or will a lighter bullet work worse than a heavy bullet since it won't have the barrel length necessary to accelerate it to higher speeds which are essential to light bullets?

In my instance, I've got a Springfield XD40 with a 4" barrel and a Taurus PT-140 with a 3" barrel. If your ammo choices were limited to the cartridge extremes of a 135grn bullet and a 180grn bullet, which would you use in each barrel length?

Would you rather split the difference and carry a 155grn or 165grn bullet in both?

So far I've been operating on the theory that a short barrel won't give a light bullet enough time to accelerate to its optimum velocity, so I've been carrying the 180 grainers in the Taurus, but I'd be curious to know if someone could prove me wrong.

Of course, there is the ever present argument for shot placement which I agree with, but for the moment, lets limit our replies to discussing the possible irrelevant repercussions of grain changes in barrel lengths.

-Teuf

 

[gp59]

All I can give you on this subject is my own experience with the guns i have now and all the ones I've owned before. I find that the sig229.40 likes the 180gr. rounds better. even though right now I do carry 155gr. win. silvertips in it, I have found that 180gr. rd. seem to work the best with just about any brand in this gun. my S&W m457.45acp with a 3-3/4 barrel seem to work best with 230 gr. Rd's best period. when I rotate my carry ammo for my .40 and shoot the win. silvertips up I will be changing to 180gr. carry Rd's.

 

[Ben Shepherd]

Two things are mandatory here:

1. Sufficient velocity for reliable bullet penetration/expansion.
2. Accuracy.

A lot of guns, even same make/model will shoot a different slug weight better. All you can do is test your gun.

The light/fast vs. slow/heavy debate is endless. Either will work, it's a matter of personal preference. If your gun has fixed sights, you need to pick a load that will shoot to POA, and that load may fall in either camp.

You've just got a good reason for some quality range time on your hands here, so make use of it.

 

[lycanthrope]

Heavy bullets with fast burning powder.

 

[nemesis]

Heavy bullets with fast burning powder.

That could be a formula for high chamber pressures and nasty recoil. Generally speaking, heavy bullets use slower burning powder to build up the velocity gradually but lighter bullets, with less mass, can use a faster burning powder.

My preference for short barrels is to use a lighter, faster bullet which is better suited to the limitations of the barrel. That, of course, is subject to accuracy and bullet performance.

As an example, I'll use my Springfield Ultra Compact (3.5 inch barrel) which I carry daily. I chrono'd Remington Golden Saber 185 grain standard pressure loads at 960 fps and got just a few feet per second under 1050 feet per second for the 185 grain +P's. I didn't shoot nor chrono 230 grain loads but would expect them to be well under 900 fps.

The moral of the story? I'm getting just short of 500 lbs/ft of energy and velocity which should be sufficient for good penetration and decent expansion. The 230 grain load's energy is much lower and I'm not confident that expansion would always be reliable at lower velocities.

And, for all you "hardball worked for the last 3000 years" enthusiasts; I want a bullet that stops somewhere in the selected target and not something that continues until it reaches a brick wall.

 

[lycanthrope]

That could be a formula for high chamber pressures and nasty recoil.

You would think so, but many competitors in USPSA and IDPA choose Clays powder and heavy bullets because perceived recoil is less with this combo. It also reduces any "rocket" effect and muzzle flip as the majority of powder is burnt before the bullet exits the barrel. With a short barrel, using a slow powder can actually reduce your fps as the powder never gets a chance to fully burn.

 

[BluesBear]

In a very short barrel NEITHER heavy or light bullets will attain maximum velocity.

Once the bullet has left the barrel, and the expanding gases have stopped pushing against the base, the bullet will not accelerate.
Longer handgun barrels give higher velocities, all other things being equal.
Lighter bullet weights are commonly used because in shorter barrels because it's easier to move them at adaquate expansion velocities.
The secret to success is to move the bullet fast enough for expansion while having enough momentum to penetrate.

It's always a trade-off.
There ain't no free lunch.

 

[Jim March]

The general rule of thumb is, a JHP needs velocity to expand. So as the barrel gets shorter, if you're still using a JHP you need one that's lighter to keep the speed up. In 45ACP we consistently see better results with 165 - 185 class loads in the 3" class barrels, versus failures to expand.

In some cases, esp. with a revolver, you sometimes have the option of switching to a plain lead (or gas-checked lead) unjacketed hollowpoint that'll expand at lower speeds, plus go fast because lead is slicker than copper or brass. But the necessary projectile shape means feeding in semi-autos is iffy.

Hence a lot of 38snubbie people use lead hollowpoints of 158grains instead of the more common 110 - 135grain JHPs. The same concept can work in 44Spl or 45LC.

This "old school" approach may eventually be completely trumped by JHPs that expand at low speeds, like the Gold Dot 135 in 38, 200grain GD in 44 or the GD 250 in 45LC. BUT, Bufallo Bore is claiming they'll soon ship a 158 lead 38+P that'll pull 1,000fps from a 2" barrel snub, completely stomping ALL available 38spl JHPs in terms of raw energy. If they can then transfer the same concept into bigger calibers like 44Spl and 45LC, and I see no reason why not, they'll give the newest high-tech JHPs a serious run for their money.

 

[Hal]

125 gr .38spl +P Remington Golden Saberâ„¢ clocks in at just under 1000 fps.

125 gr. .357 Mag Remington Golden Saberâ„¢ clocks in at just over 1200 fps.

125 gr. .38Spl +P Cor Bon JHP clocks in at ~ 1100 fps.

165 gr. .40 S&W Remington Golden Saberâ„¢ clocks in at 1100 fps.

The sectional density of the 125 gr .38/.357 is 0.1401
The sectional density of the 165 gr .40 S&W is 0.1473

@ .40 in in dia., the .40 starts out roughly 18% larger than the .357 in dia .38spl/.357mag. - The 125 gr .357mag has an outstanding reputation for being a "stopper". - I'd expect similar performance from the 165 gr .40S&W at a lower velocity hense a lower felt recoil and faster recovery than a .357 mag from something like a 2 to 2 1/2 in snubbie.
It should offer enough penetration (sec. densitys are very close) to get to the vitals, and sufficient expansion to do damage. Being larger to begin with, the .40S&W doesn't have to expand as much to equal the frontal area of the smaller .38/.357 round. Expansion becomes less critical.

OTOH, for the 180 gr. S&W the situation is reversed. The 180 gr .40S&W tries to "duplicate" the .45acp. Expansion becomes more critical.

I'll be the first to admit there's holes in my thinking,(biggest hole is that it's all *on paper*) so don't be all set to jump on me for it. I did do some looking into the .40 S&W as a "better" 9mm or .357mag, and this is what started me on it. 99.99% of the time, I'm a heavier is better type of person. The .357magnum and the .40 S&W are the two exceptions.