I've recently started backpacking and like to carry a side arm for peace of mind. I'd like to load a hard cast round for extra penetration if I do need to use it, but I'm not sure if these rounds are too hot for the little shield. I've heard of some .40 shields having catastrophic failures due folks shooting rounds that are far too hot. That has me a little nervous shooting anything beyond the more common ammo? Anyone have any experience here?

Page 11 from Manual: Plus-P acceptable (may cause excessive wear). NO Plus-P-Plus!!!

Hope this helps....

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NRA Certified Pistol Inst.

Is there a SAAMI standard for +P in .40? I thought they were loaded to max already.

I lived in "big-furry-critter-that-can-hurt-you-bad-country" for many years. When out hiking, backpacking, camping I always carried a full-size pistol that could easily handle "four-legged-problem-ammo", mostly a G20. I wouldn't shoot the loads you mentioned out of a Shield.

Back when all those Shield40 catastrophic failure threads were circulating, the few 'well documented' verified instances (after weeding out all the re-posts of the same account to dozens of forums and 'a friend of a friend' stories) were indeed using hot loads. A couple of those verified incidents were using Buffalo Bore brand. Buffalo Bore seems to like to advertise being one of the hottest loads on the market. For that reason, I've steered clear of that brand.

As far as SAAMI goes... I could be wrong, but I don't believe there's a SAAMI standard for .40 cal. (added... For +P, that is )

I know a g20 would be a better option, but a shield is what I have and it's comfortable to hike with. I may just stick with fmj, at standard pressures as not to lose a hand.

You should be fine, unless you're hiking in grizzly country. In that case, I'd recommend a bigger gun.

There is a SAAMI spec for 40 cal, just not a +P. I assume that is what you meant! I believe the only handgun cartridges in the SAAMI standard with a +P spec are 9mm, 38 Special, 38 Super Automatic, and 45 automatic.

I wouldn't shoot that out of my shield.

And depending on where you backpack. ( worried about bear? Lion? Elk?) I might bring more gun, or if not more gun, at least something with a larger capacity like a Full size 40.

I can understand your desire to have a hard cast bullet for penetration, I guess I've always thought as hard cast for revolvers, not semi autos. Are the hard cast you're looking at 180 or 200 grain ?
I carried hard cast in .44 mag and .45 Colt as I live in bear (Grizzly and Black bear ) country. The .44 load has a 300 grain and the .45 has a 330 grain hard cast gas check, both at around 1200 fps.
But you are more likely to have a run in with a bad human as much as a large furry mammal. Carrying a good JHP will be a better stopper, and will penetrate almost as much as a milder FMJ range round.
I have shot some Double Tap through my Shield .40. I just happened to have a couple boxes around, and haven't got around to ordering a couple 50 round boxes of Fed HST's yet.
Mine are loaded with a 150 grain Nosler JHP at a listed 1250 fps., and they feel stout. I haven't chronographed them yet, hope to do some of that tomorrow.
But mine is the ported PC version, and even the DoubleTap loads aren't harsh to shoot.
I haven't heard of any catastrophic failures of .40 Shields, but then again I wasn't reading about Shields until a couple months a go when I got my first. Glock .40's, yes.
I wouldn't be concerned with firing a few of the DoubleTaps to check for reliability and where they're hitting on the target.
Not likely you'll ever have to use it for protection in the woods, and even then it'll only be a few more rounds. Not like you're going to be shooting dozens or hundreds of rounds of that.
I've shot close to 40 rounds of DoubleTap out of my Shield and Fullsize M&P with no problems. I doubt I'll buy any more of it though, I usually stick with Fed. HST's in all the calibers I shoot.
I'd just buy some Federal HST's or W-W PDX bonded, in the heavier 180 to 200 grain weights, they are going to penetrate as well as anything.
Don't pay $1 a round at the local store, for that same $20-$26 that you pay locally for a 20 round box, you can mail order them from somewhere like TargetSports USA and get 50 round boxes for the same price.
Shields might be "little" but are just as strong as a full size .40.
Same barrel, just an inch shorter, and single stack instead of double stack.

All of the catastrophic failures I've seen in .40S&W guns were using 180gr rounds. I've never seen one when using 165gr. I'm not saying it hasn't happened, it's just far more common in 180gr. So, for me, I wouldn't even consider a 200gr load.

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The suggestion of the Glock G20 in 10 mm is probably a very good idea, but the OP should be aware that if he decides to stay with the .40 S&W cartridge, a Glock may be the last thing he wants when firing hot .40 loads. Buffalo Bore warns against "Chambers that aren't fully supported" with their hot .40 loads, and what that means in most cases are Glocks that have a feedramp designed to facilitate more reliable cycling of the truncated .40 round. I don't know Glocks, and they may now have .40's with fully supported chambers, but it's something to keep in mind.

It may not be a function of what the Shield can take but what your hand can take or what you can shoot accurately. I wouldn't have a problem with shooting those Buffalo Bore loads out of my .40 Sigma, .40 SD or .40 M&P. I don't have a .40 Shield, but I do have a .40 FNS Compact. I just don't think I could shoot those loads as accurately or comfortably out of a small gun.