Ok, so I conceal carry a full size 20 10mm in the winter and currently use Corbon 135gr JHP that push 1400fps/588ftlbs as my main rounds. But I also have a fear of being carjacked and do a lot of driving in the city which has had its fair share of violent crime and it’s not unusual to have addicts people walking up to your vehicle for change. Armed bank and convenience store robberies that happen locally are a daily occurrence are nothing new so are home break-ins. If I have six Doubletap 200gr WFNGC Hardcast that push 1300fps/750ftlbs and then the 10 corbons in my gun and happen to use it in a self-defense scenario could it be used against me in a totally justified situation? And would the hardcast penetrate my car door better if need be?
I've read about everything I can find to read on the subject of ballistics, penetration and expansion. Still, I'm not an expert and I didn't stay at a Holiday Inn Express last night, so take this as you will.
Heavier bullets will penetrate barriers better, period. FMJs will penetrate barriers better than HPs, period.
If I were you, I would dump those 135gr rounds anyway. 135gr round, at that speed, is going to come apart or deform, and will underpenetrate in any circumstance that you could need it. 135gr rounds aren't even advisable in a .40, from a ballistic standpoint, and other than creating a "low recoil" .40 round, which doesn't perform well either, I don't know why anyone bothered making that light of a bullet in this caliber.
165gr are better in .40, and ok for 10mm, but I still prefer 180gr bullets, at a minimum, in 10mm because those are rounds that will expand and penetrate reliably. 200gr are better. Double Tap's got some nice 230gr "Equalizers" too.
I've been giving the subject some thought recently and was considering Federal's new "Guard dog" EMFJ, but they only make it in 9/40/45 and it's not exactly a stunning performer.
Shooting through the car door would definitely be ill advised and problematic at best. Depending on where you place the shot, it might have to try to go through the plastic door panel, the steel behind it, the window or window track, the steel "side impact" crossbar, any lock/handle rods it encounters, an electrical harness and then through the exterior door skin. Not likely to happen.
If you are serious about the possibility, you need to pull your door panel, find the path of least resistance and mark it on the door panel. You should be able to find a spot or maybe a couple of spots, where it's just the plastic door panel and outer skin, unless the window is down, in which case you should be shooting through the open window.
Shooting through the side window shouldn't be that big of a problem, regardless of the round, though a typical HP may get clogged with glass. The window will shatter, but tempered glass is designed to shatter immediately on impact and all the little pieces then fall to the ground, in the car, in the door.
Shooting through a windshield, you would want a heavy bullet to go through with minimal deflection. At the range you would be shooting through it, I would think it would have still have sufficient energy to reduce deflection even more. Since it is two panes of laminated glass, it won't shatter like the side or back windows.
So, at this point, you have to consider the likelihood of each scenario based on where and when you travel. From that point, I would either stack a few, 3-4, FMJs, whether you use the 200gr DTs or something else, followed by good HPs (maybe even matching 200gr DTs or you might look at the WFNGCs in 230gr backed by the DT 230 Equalizers) or start with FMJ and then alternate FMJ/HP for several rounds, or 2 FMJs and then alternate, or 2 FMJs followed by HPs.
It's going to come down to the most likely scenarios you could encounter and what you consider the best pattern to win those scenarios.
I'm still working out my own plan, which I have to do for several calibers, but I think by the time I'm done, I'll have FMJs in the chamber, or be going to Hornday Critcal Defense or Critical Duty in the chamber, so that no matter what I may need to shoot through, I don't have to worry about good initial penetration.
I'd suggest the Critical Defense for you, but they only make it in 165gr in 10mm, probably because that's what they offer in .40 as well, and they don't expect enough demand for a bigger 10mm round.
If they eventually offer the Critical Duty in 10mm, which is probably not going to happen, that would be a good choice...or if they make the bullets available and you reload, that particular 175gr (odd size, but still) would make a nice 10mm.
If cornered however, I will take whatever action is neccesary to stop the threat.
+1. Especially in Castle Doctrine states. It's practically a public service.
