I did not catch which Red Dot sight you were using.
Most that are made in China are junk.
If you are not all that impressed with your Red Dot you probably are not using an UltraDot.

I would go with a 30mm MatchDot II or 30mm UltraDot if buying new. If you are shopping used you can live with a 1" UltraDot (25mm) if you cannot locate a 30mm one.

The UltraDot Sights are very well made in Japan.
They have a Great Reputation for not breaking.
They Track very well.
The 25mm and 30mm UltraDot's have a 4 MOA dot size. The Red Dot covers up 4" at 100 yards.
The 30mm MatchDot II has multiple reticles. To me only 2 of them are important, 4 MOA and 2 MOA. Where this becomes important is in low light. You get Bloom on a Red Dot in low light. The 2 MOA set on 1 in low light has less bloom than a 4 MOA Dot set on 1. The 2 MOA Dot only covers up 2 inches at 100 yards. Smaller Dot equals less bloom.
Why 30mm over the 1" (25mm). Pretty simple, you can see more ground through the larger tube.

My first UltraDot was a 1" one that I still have. The last 4 that I have purchased have all been 30mm. Below is the order that I have acquired them:

1" (25mm) UltraDot
30mm UltraDot
30mm MatchDot II
30mm UltraDot 6 (AR 15 Carbine version of the MatchDot II Sight)
30mm MatchDot II

I wish you luck on your journey into handgun hunting. My advice is to use 158 XTP's and stay away from 110 grain bullets. The 110 HP's will kill a deer but the chances of an exit hole are not very good. If it runs off you will probably have a pitiful blood trail to track.

Bob