Explanation of Co-Witness

**Chessbay** · 04-10-08, 20:03

So, I just got my Troy flip up BUIS in the mail today.

I have a cheap BSA Red Dot Scope mounted on my weapon right now as well.

Unfortunatley, I can't kick out for a better optic right now so I would like to make do with what I have for now if possible.

As it's mounted my optic is too low to have a true cowitness. The BUIS are almost looking over the top of the optic. They are at least in the upper third of the optic.

Is there a scope mount that I can use to fix this? Some type of shim?

Or am I SOL until I purchase a new optic.

Thanks for the help.

**Chessbay** · 04-10-08, 21:05

I've also noticed that my gas block sits about 1/4" lower than the flattop. This seems like it could create problems. Maybe not????

Man, I hate being completley new to something. I guess that's what site's like this are for.

Also, please correct me if I use the wrong terminology.

I've taken some pictures I'll try and post in the am.

**Shihan** · 04-10-08, 21:06

You would have to use a riser of some type. If you are planning on getting another optic in the near future I would just leave it as is and not waste the money.

**Oscar 319** · 04-10-08, 21:25

The Troy BUIS is good to go. Sight it in and roll with it (or use what came on the gun) until you can afford an EO, Triji or Aimpoint on a decent mount. You may want a 1/3 co-witness, thats what all the cool kids are using these days. I still like my dot on top of my front sight post (true co-witness). No worries, no hurries. Sounds like you have the gun. Go out and shoot the hell out of it and master the iron sights while you are saving up for an optic.

**Chessbay** · 04-11-08, 06:43

Originally Posted by Oscar 319

The Troy BUIS is good to go. Sight it in and roll with it (or use what came on the gun) until you can afford an EO, Triji or Aimpoint on a decent mount. You may want a 1/3 co-witness, thats what all the cool kids are using these days. I still like my dot on top of my front sight post (true co-witness). No worries, no hurries. Sounds like you have the gun. Go out and shoot the hell out of it and master the iron sights while you are saving up for an optic.

Your right......good advice.

Do I need to be concerned that the top of the rail on the gas block is about 1/4" lower than the flat top rail?

Will this have an effect on sighting the rifle in? Should they not be mounted at the same height?

**BC520** · 04-11-08, 10:23

That should only matter if you have a folding or detachable front sight that is designed to be installed on the top of a FF Rail system. If you post what you have for a front sight that will probably make it easier to clear up if its a factor or not.

**Chessbay** · 04-11-08, 10:58

Alright, I hope the pictures work.

Sorry for the poor quality, but when I resized them the quality went down.

So, as you can see from the pictures I don't have a picatinny rail on my handguard. I only have the rail on the gas block, which is not level with the rail on top of the reciever.

I'd rather not buy a new handguard if I don't have to. I'd prefer to save my money for a better optic. Plus I would prefer to not dump tons of money into this gun because it's inexpensive and my first.

So, can I purchase a new gas block with a higher rail? What's the best fix?

**nickdrak** · 04-11-08, 12:52

I would see if you can send the Troy front sight back, and get the MI gas block front sight that I linked above. They will work perfectly together. And you will actually save some cash as the MI is about $30 less than the Troy front sight.