Hi everyone, I'm thinking about taking advantage of Bushnell's rebate and buying a TRS-25 Trophy. I have a couple of questions before I buy. I have been looking for a red dot for my pistol AR and M4 clone for some time now and I think this sale is as good a time to buy as any. I will post my setups below.

AR-15 Pistol -

7.5 inch barrel with MagPul MBus flip up sights. I am looking at the UTG Med-pro Compact Riser Mount, 0.83" High, 3 Slots Will this setup co-witness with my sights? If not, what size riser do I need?

AR-15 M4 Clone

My rifle I am using a rear MagPul Mbus pro flip up sight. I think it is called the pro. I am looking for a riser that will co-witness with my rear flip up sight and front sight post. I am looking at the UTG Hi-Profile Compact Riser Mount, 1" High, 3 Slots Will this setup co-witness with my sight setup? If not, what size riser do I need?

Thanks everyone.

The UTG high profile 1" provides a lower 1/3 co-witness.  I have two of them with the TRS on the AR with fixed front sights.  My third TRS came with a riser that is also lower third.  

The rest of those words you wrote, I didn't read.  

Usually the Medium will be a "True" co-witness (Red dot in center of view will on top of the post instead of above it (lower 3rd view)...

Assuming you have sighted in both optics...

As said before, the high risers are usually lower third view...

I'm new to optics and I am watching some videos trying to learn.

Would going lower third be better? If I would go lower third I'm guessing I should go with the high riser? I'm guessing my flip up sights will all still co-witness and give me a sight picture if my optic went down and I couldn't take it off in that moment.

I got my red dot scopes in and I have it mounted on my AR-15 pistol. Frankenstein (the name I have given the pistol) is looking good. It says its lined up and I can see that its right on the front sight. A little left so I will figure out how to adjust it and then go and shoot it.

The Bushnell TRS-25 is the  one with the white lettering and the problems that I have seen mentioned in videos I have not noticed yet. Low settings are really low. High is really high. Once I get it in the outdoors I will know what settings work the best. I have found inside 5 and 6 are good when dark.

I think I have it mounted in a good area on the receiver. I may play around with it a bit. I went with co-witness on the pistol. I will go lower 1/3 on rifle. The UTG riser is really nice and well made. I installed it all in about two minutes.

I want to play around with the risers. I did notice that the backup sights with the medium riser might be a little low. I need to look at it again tomorrow. I am way to tired to mess with it. My first red dot scopes and I think I will enjoy them.

Why is this in the precision rifle forum?

I had it in the pistol section. I guess they thought it didn't belong there. I was looking for red dot setup for AR pistol.