Rastus, from what ive read the 5/7 is an over penetrating beast that should only be used on the field of combat and not suitable for CCW or home defense. Plus the fact that the cost is way out there. correct me if Im wrong, I really like what ive heard but the application for this round is marginal.
It probably is an overpenetrator with the black tip armor piercing ammo...you can't get that for less than $10 a round (pre-ATF ban off the market for years) nowadays though

. I think there is, and ya'll correct me if I am wrong, a whole bunch of hype and disinformation with this thing that's been misrepresented and labeled as "cop killer". I do not carry this round as the commerically available ammo is 40 grain Vmax (SS197) at around 1,750 fps and a lighter, lead-free 28gr(?) hollow point round (SS195) at around 2,034 (probably closer to 1,850 from a pistol) and the gun is as big as my 1911 (much lighter though). Velocity is fine, capacity is great at 20 rounds (are you going to use more than 2 or 3 carrying?) but that little bullet is going to blow up when it hits something (good thing urban areas). In fact, I've heard that it's problem is that it blows up and does not penetrate....however I have also heard from L.E. that the 3 or 4 times it has been used by L.E. the perp hit the ground like a sack of potatoes....again, that's what I heard and that may be part of the mystique and not actual information.
I keep the 5.7 in the house from time-to-time because I don't think it will blast through the walls, etc. and get to family members because it is such a thinly constructed and light weight round. I believe (please correct if wrong) the 10mm, .357, .45, .40, .38, etc. will be deadly on the other side of a sheetrock wall...I don't see how the 5.7 can be nearly so destructive.
Heck, I can't even seem to find a straight answer on what the true velocity of these rounds are. I think that's on purpose for some reason...misinformation out there...mystique, whatever. I kinda liked the P90 rifle but at $1,800 I can get two AR's and have a round with "real" power. I suspect one of the reasons L.E., especially the Secret Service, uses this round is that it is not something that will go through walls and windows with a lot of knock-down power....and the S.S. probably does need to have a bunch of rounds available which you can have with this round.
I equate this round to a 22 magnum from a rifle. Somewhere near 2,000 FPS (I'm looking at handloads at 2,150-2,200) with a light bullet so I don't see how this can be an overpenetrator with lead rounds....especially if you have a ballistic tip on the bullet. But, I would really like this in a snubbie because it would be safer to bystanders in crowds. Just my 2 cents...I'm always learning so flame on back.
Have A Great Day,
Ken