Since I have been getting into this hand gun hunting stuff I have of course been harassing my little brother about doing it too (I say little but he's 27 lol)...

He has a 3.5" barrel 40 S&W and was wondering if with some of the buffalo bore ammo would it be efficient enough to hunt deer 25 yards and in?

He understands the 40 is probably marginal at best, just curious. Thanks

Should be plenty if he's proficient enough with it to put it in the boiler room. There has been a lot of game taken consistently with lesser calibers and it all comes down to making the one shot count.

Practice
Practice
Practice.

There was a guy here, silentsniper, whose girlfriend took a fallow deer with a 9mm and Hornady factory ammo. Don't see why a 40 with Buffalo Bore wouldn't work.

A lot of factory 10mm ammo isn't much warmer than a hot 40, and alot of folks swear by the 10. It is all about bullet performance and placement. Choose a bullet that will perform at the actual velocity the gun will produce and send it into the boiler room.

Ok, so would a cast bullet be better then say a JHP?

That depends on the velocity the gun can generate with the chosen bullet. If a JHP doesn't expand it won't be as effective as a WFN or even a Keith style cast bullet.

Make sure that caliber is legal for hunting in your state.

My exact sentiments. Your velocity will be limited so I wouldn't necessarily count on an expanding bullet to expand.

He is talking about shooting game within defense range...I would expect all the 40 sw ammo to still expand at 25 yards

I tested the .40 Short&Weak on deer right after it came out. Shot them with 180 Horn. XTP, 180 Gold Dot , 155 Horn. XTP, lead 170 SWC. I shot them out to 50-60 yards. The LEAST amount of hits to put one down was 3. 4 or 5 was more typical (all shoulder/lung hits), BUT one bullet did better, the 165 gr. Sierra JHC. Don't think it ever took more than 2 shots. A few were taken with one, but they ran 50+ yards.
I rarely recovered any of these bullets. The Gold Dots never expanded. The XTPs a little. The Sierra expanded the most.
I don't use this round for deer hunting. If used you need to be CLOSE!

I've never taken deer sized game with a .40 but I've carried one as hunting backup a few times. Pretty much any decent JHP will work if you put it in the boiler room, and by work I mean kill it just don't expect it to react as if struck by lightning. From my G23 I've cooked up handloads that will run a 180gr JHP to 1200 fps and 200gr hardcast to 1150 fps, warm yeah but there's not much guess on whether they'll work or not.

Ok thanks