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Posted: 11/5/2012 3:43:40 PM EDT
| I have an "optic ready" flat top M4. Right now I have MBUS front and rear pop-up sights. It shoots low, and I can't crank the front post up enough to get it to hot at 100 yds. In my limited experience, the only thing I can think of is putting a 1/2" riser on the front and then install the front MBUS on the riser. Is this my only option? Any thoughts or suggestions, are greatly appreciated! |
| Sorry! That woudl be too easy. It's shooting about 4' high. Therefore I need to being my POI down. Sorry about that. Withe the post so high that the plastic piece in the MBUS won't go any higher to the the post from turning. It's mounted on the rail that is at the gas port. |
| First of all, the MBUS isn't designed to be mounted to the gas block. Its polymer and the gas block is one of the hottest parts of the rifle. It could end up melting. Second, is your gas block the same height as the receiver? From what you're describing, it doesn't sound like it. If it isn't, this is your problem. You need a sight that is designed to be mounted to railed gas blocks that are shorter than the receiver. |
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Not to make it sound like you don't know what you're talking about, but are you sure the gas block rail is the same height as the flat top upper? The reason I ask is my S&W M&P15s are all optics ready models and you can flip them upside and lay them on a flat surface and see the gas block rail is lower in height. Without doing that if they look as if they are the same height.
If that is your case then as already said you'll need a riser. And that sucks because all the risers I can think of raise 1/2" which would almost (in my mind) put your sight post at the lowest position. |
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There are rail height GBs but not many. Typical GB rails are .300" lower than receiver rails.
If your POI is that far off, I would hazard a guess that your GB is not rail height. Get a front sight designed for the GB. There are a bunch of them out there, unfortunately not the MBUS. Joe |
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