The differences between 115, 155/165, and 180 grain bullets in .40 S&W

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Emin

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I went to a range yesterday and took a box each of CCI Blazer TMJ 180 gr. and Speer Lawman TMJ 155 gr., both in .40 S&W. I basically wanted to test how my gun behaved with both of these rounds trying to pick up the best in accuracy and everything else. At the range, I also got a box of FMJ 180 gr. factory reloads for a "third party" comparison.
The accuracy of all the ammo was roughly the same -- I'll probably have to shoot much more rounds just to see any difference. What I felt, however, was significantly stronger and sharper recoil with Speers 155 gr. as compared to both "reloads" and Blazer which recoiled exactly the same. Each shot with Speers, moreover, was noticably louder as well. Does anyone know a good source of info on why it is like that, what factors change based on a bullet's weight such as speed, recoil, etc? A web link would be just great, but any personal info or experiences are welcome too. Thanks.

Emin
 
The 180's have less recoil because they have less of a powder charge than the 155's you were shooting. On the accuracy issue, I have found the 180's more accurate than the 165's.
 
I'm guessing that you made a typo with the 115 grain 40 S&W. Seems like you'd sacrifice a bit of accuracy for a gain in speed.

I personally like the 155-165 grain bullets best. I hear the 135gr can wear out a barrel a bit quicker than most. I think The 155 keeps the necessary velocity for reliable expansion and "accaptable" length for accuracy, and the 165 should be used for more reliable penetration. If I wanted 180 grains, I'd buy a 45ACP. The 185gr .45's rock.

Ben

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Ben, you're right, I've meant 135 -- I've recently ordered several boxes of Federal Hydro Shocks HP 135 gr, the kind Federal calls "Personal Defense" in its Hydro Shock line. I'll use one or two boxes to see the way it shoots and keep the rest as my defense ammo. Now, I'm thinking that perhaps I shouldn't have rushed and get 155 or even 165 gr Federals instead. It's just that I imagine 135 will have even more recoil and noise. Can you say anything in favor of 135 HS or otherwise? I definitely value accuracy more than speed -- unless, of course, there're certain factors in defensive shooting I'm simply not aware of which are benefitted by speedier bullets. Thanks.
 
There's a whole science involved to answer your question. Normally, if an important factor of operation - chamber pressure - is the same between 2 different bullet weights in the same cartridge case, and they're both fired out of the same gun, with the same tension on the grips and throughout the arm muscles, the heavier weight bullet should have more felt recoil due to physics. In your case, the 155gr felt sharper than the 180gr. It could be the 155 had more momentum imparted to it (mass times velocity) by the burning of, undoubtedly, a different powder brand. This powder may also have had a much shorter burning time, and reached its peak pressure in a much quicker time than the powder used to drive the 180. The difference isn't much, measured in a few thousandths of a second, but it translates into "felt" recoil. The 155 ammo may have been made to operate very near the SAAMI maximum pressure rating for the cartridge, by its manufacturer and the 180 ammo may have been loaded to more of a midrange pressure rating of the SAAMI specs, due to this bullet having the greatest accuracy at that pressure as determined in testing by its manufacturer. Noise level.... it's all due to the different powder types and burning rates between the two cartridges. SAAMI is the shooting industry's "specifications" institute which sets the standards for the manufacturing & operation of commercial ammunition (just one of the things they do).
Hope this helps out.
Wayne
 
Noise:
The 180s are almost certainly subsonic, the Speer 155s are almost certainly supersonic. There's a downrange bullet "crack" component involved identical in causation to the sonic "boom" of a jet fighter. This is a higher pitch impulse which can really get reflected and reverberate all over the place if you're shooting at the typical cinderblock/concrete slab indoor range.
 
Another factor to consider is that your reloads are more than likely a bit on the light side. I have only had the opportunity to chronograph a couple of commercial reloads, and they all are slower than new. This may be due to liabilty factors. The .40 S&W does have a high pressure rating and the potential of catastrophic case failure does exist.
Your choice of Federal Personal Defense ammo is excellent. Very accurate with exceptional expansion and very good penetration, as long as you're not shooting through metal or glass.
 
Thanks, everyone, for the answers! I guess I'll just stick with whatever feels comfortable to my hand -- on my experience, sharp recoils as well as noise add up substantially to the already existing recoil anticipation and flinching problems that I'm fighting vigorously. It's getting better, I think...

Emin
 
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