Originally posted by Lost Sheep
Quote:
Originally Posted by Webleymkv
It's not a bad loading as it delivers ballistics similar to a 9mm +P. The main disadvantages are that it will have less penetration than a heavier bullet and will likely shoot low in fixed-sighted revolvers (most .357's come from the factory sighted in for either 125grn or 158grn bullets). Also, very light revolvers like the S&W 360PD often have trouble with very light bullets jumping crimp under recoil. S&W actually reccomends against the use of bullets lighter than 120grn in their Scandium J-Frames.
Webleymkv, you should probably review your physics. Very lightweight bullets have less inertia than heavier bullets, therefore have less of a tendency to jump crimp when subjected to heavy recoil from its siblings earlier in the firing rotation. Its the HEAVY bullets with heavy loads in a LIGHTWEIGHT gun that bullets pulling out of their cases is a concern.
What you're forgetting is that the lighter bullet, for a given caliber, is typically also shorter than the heavier one. Because of the relatively small allowable variation in OAL, the heavier bullet must protrude farther down into the case. This means that there is more area for the case to grip the heavier bullet and hold it in place. This is why 158grn bullets are not as hard of the forcing cones of a K-Frame .357 as the lighter 125 and 110grn Magnums are: it takes longer, and thusly burns more powder, for enough pressure to build up to overcome the case's grip on the bullet. Honestly, I doubt that the recoil of a WWB 110grn .357 Magnum would be enough to cause the bullets to jump crimp unless the shooter had a very weak grip on the firearm, but the recoil of a Cor-Bon 110grn .357, which has a muzzle velocity over 200fps faster than the WWB, might have issues.
Originally posted by Tipoc
There is sometimes a gap between the theoritical and the actual.
Due to advances in bullet construction of self defense loads in the last 20 years a 110 gr. JHP bullet from a .357 will penetrate and expand as deeply (within an inch or so) as a heavier JHP bullet also designed for self defense. The same advances in bullet design also led to better rounds for self defense in other bullet weights which have largely relegated the 110 gr. loads to the position of an afterthought. Cor Bon makes a 110 gr. load at 1500 FPS. Because that bullet is well made it does not break apart. Neither does it expand too rapidly and inhibit penetration. This is simply a fact.
I agree that differences in bullet construction will make a larger difference than energy and momentum as far as penetration is concerned. That is why I chose Remington loadings of almost identical bullet construction to compare in my previous post.
The concept that velocity and energy inhibit penetration is a misunderstanding of some concepts I believe. Easy enough to do. The problem that some have though is in explaining why a 9mm 115 gr.JHP bullet of good construction penetrates and expands deeply but a 110 gr. would not. Fact is they both act about the same. Bullet construction makes a difference.
The difference is that of bullet construction. Both the WWB and Remington Express 110grn .357 Magnum loadings (two of the most common) use bullets of rather dated design (1970's) while many 9mm loadings use bullets of much more modern design with more emphasis placed on penetration rather than the greatest possible expansion. The problem with explaining it away with bullet construction is that given two modern 9mm loadings, a 147grn JHP with less velocity and less energy will often both outpenetrate and match or exceed the expansion of a higher velocity, higher energy 115 or 124grn loading with comparable bullet construction. This is illustrated in the following link (choose your 124grn +P, 127grn +P+, and 147grn T-Series bullets for comparison).
http://www.winchester.com/SiteCollectionDocuments/flash-SWFs/law_bullit.swf
When the higher energy round (110 at 1400-1500 fps) strikes the wet newsprint mentioned above it will shed it's energy more rapidly. But it also has more energy to shed. In doing so it will likely disrupt more of the tissue in making it's way through the newsprint than a heavier round. This is the actual result of it's shedding it's energy more rapidly than a 158 gr. round. Both though will be effective.
When the lighter, higher velocity bullet strikes the wet newsprint, it sheds its energy through either losing mass (fragmenting) or losing velocity. Assuming that the bullet is of good design and does not fragment, it will shed its energy through velocity rather than mass. Energy is not what causes a bullet to penetrate, momentum is (the definition of momentum is the tendency of objects in motion to stay in motion). Assuming that we have two bullets of roughly equal energy, the lighter, faster on will be much more reliant upon velocity than the slower, heavier one to achieve both its energy and momentum. Once those two bullets start shedding velocity, the lighter one will penetrate less because the velocity being shed it what it was most reliant upon for its momentum. The heavier bullet, on the other hand, will continue to penetrate more deeply because even at its reduced velocity, the extra weight allows it to retain more momentum. While it is true that a light bullet at very high velocity with vastly more energy and momentum will often outpenetrate a heavy one at very low velocity (say a 110grn .357 Magnum as opposed to a standard pressure 158grn .38 Special), we're talking about .357 Magnum loadings exclusively and the ones we're discussing all have relatively high velocities and fairly similar amounts of energy. High energy does not necessarily equal shallow penetration, but high energy with low momentum does.
If we were looking at different types of bullets, a semi wadcutter round for example, then in that case the heavier round would penetrate more deeply than the lighter. But modern JHP rounds for 158 gr. loads are designed to not penetrate too deeply, only to about 12-14". This is the same as the 110 gr. loads.
So long as we compare JHP's of equal or similar construction, the heavier bullet will still penetrate more deeply. Also, .357 Magnum JHP's are often much more penetrative than you might think. In Brassfetcher's testing, the 125grn Speer Gold Dot loading penetrated in excess of 16" in bare gelatin and, while somewhat dated, Winchester 145grn Silvertips, Federal 158grn Hi-Shok, and Federal 158grn Hydra-Shoks all penetrated in excess of 15" in bare gelatin (the Hydra-Shock actually penetrated 24.7" but expanded very little likely due to the reduced velocity of being fired from a short barrel).
http://www.brassfetcher.com/Speer%20125%20grain%20Gold%20Dot%20hollowpoint.html
http://www.firearmstactical.com/ammo_data/357magnum.htm
I mentioned before that I prefer the 145 to 158 gr. loads as self defense loads in the .357 and this is because I shoot them faster and more accurately than the hot 125 gr. loads. With the heavier there is less muzzle flash and less felt recoil. I also feel that momentum makes a difference and the heavier rounds actually deliver a heavier blow. This last may not be actually correct but I believe they do.
While I too prefer the 140-158grn loadings, it is not because I think the penetration of lighter bullets is inadequate. While the 110 and 125grn loadings don't penetrate as deeply as the heavier ones do, they still penetrate plenty deep enough for my purposes. The reasons I prefer the heavier bullets are that the flash and blast of them is less offensive, they lose less velocity when fired from short barrels, and they are more friendly to the forcing cone of my K-Frame S&W.
