ORIGINAL: Pglasgow
In spite of the many reports of good performance with the 295 PB, there seems to be a myth circulating that they just can not penetrate. Even, in spite of reports of people like srwshooter where exits occur even when coupled with scapula entrance wounds. Sometimes it helps just to contextualize the subject with something else, for example, another projectile one has confidence in.
For this comparison I have chosen a .530 PRB propelled with 90 grains 2f Goex. The 295 PB load is propelled with 60 grains RS. There ballistics are below.
At the muzzle, the PRB is superior in energy, but at 40 yards the two projectiles have equivalent energy. Beyond 40, the 295 PB exceeds the PRB in impact energy. Now at 40 yards, the first thing one notices is that the velocity of the PRB exceeds the 295 PB. Given the velocity of impact, the hollowpoint of the Powerbelt aids expansion. Having shot the 295 PB's into compacted sand at velocities of 1250 fps, I found them to expand to around 3/4" (just under 3/4 in places and around 13/16 in others).
Lets just say that at 40 yards and a velocity of 1173 fps the 295 PB expands to 3/4". The expanded bullet has a sectional density of around .095. This is pretty poor sectional density, but is it enough to penetrate?
How about the PRB? I don't know how much it may expand, i just know it does. Lets say it expands to 2/3 of an inch. Given the greater impact velocity, I would suspect it to expand more than that but if it only expands to 2/3" its sectional density declines to .09. Basically the sectional densities would be nearly identical with the powerbelt having only a slight edge.
When one thinks about it. The expanded 295 powerbelt is kind of like .575 roundbal expanded to 3/4 inch.
The energies are the same at 40 yards but there is 15% more momentum in the 295 powerbelt. So the powerbelt should penetrateas well as the .530 PRB, perhaps better. The question then becomes, can a .530 PRB penetrate? I think it can. I think at 40 yards it can enter between the neck and shoulder, pass through the vitals, exit the bottom of the deer and then break its hind leg. I also think the at 40 yards, a 295 PB propelled by 60 grains RS can do the same thing.
Phil,
I am getting out of my league here, but I believethis article:
http://www.snipersparadise.com/tsmag/July03/july03.htm
speaks to your theory/calculations and in particular this statement:
The long time theory has held that all else being equal, a bullet with higher SD (more weight per diameter) will penetrate deeper. Thus, a 180 grain .308 bullet with a sectional density of .271 should penetrate deeper than a 165 grain .308 bullet with a sectional density of .248. IF all else is really equal, the theory works out pretty well.
So the PB with more weight per diameter will penetrate deeper, all other things being equal.
He also says in this in the article:
A useful rule of thumb is to select bullets having a reputation for finishing their work with a profile roughly as long or longer than the bullets frontal diameter. In contrast, bullets that end up resembling a "pancake" are to be shunned.
This is what I think is going on with the PB, they are "pancakes" usually 1 or 2 inches below the skin (I read that somewhere). Therefore their frontal area is too large. I can't prove any of this, just my theories as to why their terminal performance is not as good on bone hits as with rib hits. Sorry I started a PB war again.
Chap Gleason Va