You've asked a couple different questions here. First, from your description, I think you did hit that elk, but perhaps never found the exact spot where he'd been when you searched. It's not easy to find that exact 5 sq ft spot where an animal actually stood when you took a shot at him at 200 +/- yards. You are not the first hunter to hit and never find an animal, nor will you be the last. It is unfortunately a part of hunting, for better or worse.

As far as your .300's trajectory, for a 200 yard zero shooting a typical 180gr load, your rifle should be sighted in at 200 yards to ensure it is. As far as the trajectory at both 100 and 300 yards, your rifle should print @ 100 yards, about 1.5" high and @ 300 yards about 6.5" low figuring a 200 yard zero. On an elk sized animal this would allow you to hold center of chest and still keep your shots within the elk's kill zone. All hunters are responsible for knowing where their rifle is printing at any range they expect to shoot at. Simply put, familiarity with rifle and load.

As far as an uphill or downhill angle added to the situation, there is no reason to compensate for the angle (up or down) until that range also exceeds your MPBR. Shooting uphill or downhill at a significant angle will actually shorten the distance that trajectory will affect your bullet. The actual range for the trajectories in these cases is shorter than the line of sight distance, being what that distance would be, if the animal was actually placed on the same plane as you for that shot.  

In other words, until such distance as you would need to compensate for ranges longer than your MPBR (line of sight), you do not have to worry about the angle of your shot.

When I was lining up the shot I knew there had to be some bullet drop if I'm sighted in at 100 so I had dead center barely above half way up the shoulder and my 200 dot was in the vitals still and most people have told me I shot high on the bull or shot over completely which just doesn't make sense to me. And I figured 5-10 ft in elevation wasn't going to be a big enough factor. And luckily enough the ground was soft enough so I could see exactly where the bull was standing when I shot and his lovely spinning in circles tracks. Looks like I'm gonna have to go sight this rifle in myself like I wish I had.

If you did hit the elk it sounds like you may of hit him in the gut.  If you hit them there they might be a blood trail and there might not be one it all depends. 

You are making the right decision in sighting in the rifle yourself and if you can find a range that you can shoot 200 yards on and then you will know right where the rifle is shooting.  The big question is did the shop that put your scope on just bore sight it or did they actually go out and shoot it?  Along with what kind of ammo did they use?  If they used a different grain of bullet or at times a different brand of ammo it may shoot differently than what you are shooting.  As far a putting a muzzle brake on it you still will not be able to watch the bullet hit after shooting and anyone near you will cuss you until their hearing returns or as soon as your hearing returns.  The brakes are nice while shooting at the bench but in my opinion have no place when out in the field. 

One thing about the shot at the elk.  I have made a few bad shots and every time that I did I would cuss the scope out just knowing that something had happened to it.  But as soon as I would take the rifle to a bench to check it out I would find out that it was me that didn't get the job done and that the scope was sighted in right where it had been and should be. 

I don't think I got it in the gut... I was aimed more on his shoulder than behind it. And I'm almost positive the place that sighted it in just did a bore sight. I had just put that scope on my 30-06 and a week before the hunt my dad took it to the range to make sure it was on and the spring that pushes up the next cartridge up went out so you could only single load and no one could get it fixed in time so I drove 4 hours up to salt lake and met my dad at Cabelas and I bought the .300 then headed back to St George so he took it in for me to put the scope on and sight it in. So once we got up to Montana I put 10 rounds through it before I took the shot at the bull.

Sounds like a gut shot to me also. I don't like how you have your rifle sighted in. Your not making use of the trajectory it has to offer. These scopes that correct everything for you have come and gone on a regular basis over the years. I'd suggest you sight in your rifle for MPBR at an 8" target.

I have two charts here figured with a 180gr bullet at 2950fps and a BC of .452. You may or may not match all these things but this will be very close to what your doing.

MPBR 8" target

50 yds               +1.4"                                                                                                  

100yds              +3.2"

150yds              +4"

200yds              +3.4"

250yds              +1.4"

300yds              -1.9"

Zero range is 274yds  Max Point Blank Range is321yds. At 321yds the bullet will be 4" low"

What you have

50yds              -.2"

100yds             +/- 0

150yds            -.9"

200yds            -3.1"

250yds            -6.7"

300yds            -11.8"

Zero range is 100yds.  bullet is 4" low at about 220yds. At 300yds bullet passes under the elk with a center of the chest hold or just grazes the belly.

With the first set of number's you hold on the center of the chest with no elevation adjustment and you will score a good hit at something over 320yds if you do your part. With the set for what you now have with the same hold, you'll clean miss at 310yds and might wound at 300yds using a center of chest hold!

I think if you take your rifle out and try shooting at targets at these distences you will find these figures afull darn close, both for the way you are now and with the MPBR method!

The next problem you have is shooting off hand at 200yds. While you might believe your pretty good off hand at that distence, the reaction you described says to me "gut shot". Very very few people are good enought to pull off a 200yds shot on a game animal off hand. Guessing at range unless you practice a lot is an iffy thing to do. Finding the spot the animal was standing if only 200yds off should not have been that hard. Could be you did find it but as mentioned earlier a gut shot may or may not have left blood. Bad shots do happen but you can lessen the chance a good deal with shooting technique and off hand is the worst possible position to shoot from.

Ya I'd much rather shoot with sticks or have something to rest the rifle on but I just got caught in a small opening with no trees to rest on and I kneeled down to take the shot but the tall grass was showing up in the scope and of course my dad had my shooting stix 200 yards down the hill. The gun was bought 5 days before the hunt cause I ran into issues with my 30-06 so my dad just took it somehwere and had the scope put on and they just bore sight it to 100 yards and said the .300 shoots flat enough that I'd be fine to 250-300 yards but I knew it couldn't shoot that flat

I'd guess that was your problem. Bore sighting get's awful close sometimes. I say sometimes but not all that often. With a colminator I think it sets the sights to get a bullet on paper at 100yds, someone will correct that if wrong. It it got the paper at 100yds but was way right or left, add that to the problems involved in shooting offhand and ya got it. Tuff lesson but I doubt you'll do that again!

Friend of mine did the same thing several years ago with a 223. On the way back to my place we saw a coyote about 50yds off the road. Stopped and he got out and the thing just stood there looking at him. Looked at him for two shots and left. Got to the house and my target frame and went out and finished sighting it in. Didn't take a lot but was out enough to miss at 50yds!