OK I am going to hold back from calling you an idiot douche bag and many other funny yet insulting names.
Nope I am going to give you FACTS.
1. You should have at least 1000ft lb of energy at the point of impact to kill large game animals like Deer.
2. Deer are a lot tougher than your normal everyday bad guy getting shot while trying to take your car. Most SD shooting take place at 7 yards or less. that is 21' if you didn't know.
3. Lets look at the specs of your 40 smith at 20 yards. OK this is for Speer Gold Dot 180gr factory SD Ammo.
As you can see from the above pictures the 40 S&W IS not suitable for hunting at any distance. Could it kill a deer maybe. Should you do it NO. Why because as a hunter you should be out to respect the fact that a game animal is going to give its life to help feed you and your family. The fact that that animal is giving up its life to keep you and yours healthy you should have the utmost respect and try to cause as little pain and suffering as you can. Also run a Hornady HITS calc on the 40 smith and tell me what it comes out too. I did and got 288 it says 500 and under is for small game only.
Also if you look at the above chart, how much hold over are you going to need to hit a 6" bull on a deer? Oh yes my chart says 22 clicks. You don't have clicks on glock sights.
4. What is your accuracy with your glock at 20 yards? Can you put 100% of your shots in the 6" target that is the kill zone on a deer? I would suggest you get to where you can shoot 3 to 4" groups at 25 to 30 yards with your glock before you trying hunting.
I don't care how big a deer is. I have seen small deer shot with a 30-06 with a 165gr hunting bullet take a shot to the lungs and run off for over 300 yards.
I have seen coyotes take a hit from a 22-250 or 243 at 200 yards pouring blood out its chest and still run 300 yards before dying.
So please think twice before doing what you talk of doing.