What's an extreme ricochet? I've heard of extreme skiing and snowboarding but not an extreme ricochet.
So is your argument with using a pistol or not using frangible ammunition? After all, there is far more variety of frangible pistol ammo than rifle.
Sorry, been away stalking.
An 'extreme ricochet' is one that comes off a solid surface such as a piece of flint or tarmac! It makes that noise that we've heard so many times on the old cowboy films, and when it happens to you for real, it makes your but cheeks clench so tight, that if you had a piece of coal between them at the time, you could probably create a diamond!

It happens occasionally in Suffolk where somewhere behind a deer with a seemingly perfect backstop, lies a piece of black flint at about 45 degrees! However, if you shoot bullets at roads, you will get this pretty much every time! The trouble with a standard pistol bullet, is that it is fairly low speed, and even if you hit the deer, the bullet retains almost 100% of its mass and a good proportion of its energy depending upon numerous factors such as size of deer, surface type, angle, and whether you even hit it, etc.. This is why the police would rather grant a .177 HMR to a novice rather than a .22 LR despite its higher velocity, as the ricochet risk is negligible in comparison.
The OP used a relatively small soft point bullet, which will still ricochet as it has nowhere else to go. However, he is less likely to miss for a start. The bullet will begin to break up on impact with the deer. Upon exit it will break up further into even smaller pieces when it hits the road worst case. If you can get a frontal shot to the brain with the neck behind, this is perfect as you may not even get an exit with any bullet which would be textbook stuff! This is why a shotgun is the weapon of choice on a hard surface, as the load is already broken up before it is even fired! If you watch slow motion footage of how bullets and shot behave, you will see that shot almost turns into liquid/dust! This video shows it perfectly, and also how bullets seem to turn to liquid when hitting a surface straight on. Fascinating! The lead shot is near the end:
I wasn't aware that you could get frangible bullets for pistols as such? If you can, then that would add a lot of weight to using one for HD as it at least shows recognition of risk and how to minimise it. Once again though, at sensible HD range, a .410 pistol using standard No.6 shot at about 11-16 grains will have the same effect on a deer as a solid slug, but without the risk of 'extreme ricochet'! If anything, it is even more effective as it spreads slightly and then disperses at various angles to destroy a larger section of the head. Shotguns up close are devastating!
I'm interested to hear about frangible bullets? I know they have been designed for use inside passenger planes without the risk of cabin rupture. Maybe this is the answer?
As I've said previously, I have no issue with pistols. It is just their effectiveness and safety, along with those that desire to own them for the benefit of themselves, rather than the welfare of deer.
Firing at any hard surface, even at 90 degrees is foolish!
MS