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Posted: 10/20/2005 5:04:23 PM EDT
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I recently put together a parts gun ( Bushmaster 16" patrolmans barrel, mated with a White Oak armaments flatop, mounted on an old SGW/Oly lower I had lying around). Couldn"t get to a range for a while, so I bore sighted the BUIS (Bushy BMS) and EOtech 552 (mounted directly to flatop) to point of aim with a laser boresight ( only at 15 yds , don't want the neighbors to freak). Finally got to a range (unfortunatley limited to 25 yds) thinking everythings cool and had alot of problems. Started with zeroing the BUIS and groups started at 6" high which I got to point of aim after about running after turns on the front sight post (bottom of sight about above the floor of the front sight post). Then the EOTech was a disaster as at 25 yds I was missing the paper shooting over the top. Finally got that to my point after massive amount of turns (4 or 5 complete turns) of the elevation screw. I guess I can fix the BUIS issue with by getting taller .40 front sight post, but I thought that was only necessary with Colt parts. My real concern is with the EOtech as the manual says that only fine tuning of elevation should be necessary, but the manual does mention shimming. Does anyone have experience on how to shim the EOtech? Will putting the EOtech on a Larue mount fix the problem? Could this be a problem with barrel to upper fit? Will a proper distance range to re-zero make this nightmare disappear? The range only allowed for 25 yd shooting |
| 25 yards should be fine for zeroing your EOTech. It sounds like you were able to get your EOTech zeroed - if not and your iron sights are zeroed you can co-witness and use your iron sight picture to get your EOTech very close. Keep in mind that if your sights are zeroed and the reticle is co-witnessing low on your sight picture, you'll need to turn the adjustment screw in the "down" direction (not "up"). Using a Larue mount will raise your EOTech by about 1/4" which will put the co-witnessed sight picture in the lower 1/4th of the EOTech view window. Any more height and you may not be able to co-witness. Some folks like the additional 1/4" height (myself included) while others seem happy with the sights sitting a bit higher in the window. However, the Larue mount also allows you to mount and remount the EOTech quickly and easily (while preserving your zero). |
| Thanks for the replies. I probably should have zerod the EOtech first, as I ran out of ammo without being satisified with my results (used most of it on the irons). With the EOtech, my results were about 1 1/2" to 2" within my point of aim at 25 yds. I was shooting off a bench and I'm thinking I should be shooting better with that EOtech. As I was using BMAS low profile BUIS, I could only adjust elevation with the front sight post (A1 type on M4 16" barrel) and the top of the post is level with the side wings of the FSB (seems like I'm about out of elevation). I'm hoping that getting a taller front sight wil do the trick or I guess I end up getting the BUIS I should of got (ARMS 40). I was hoping not to spend anymore money on this gun as I got my eye on the new CMMG 14.7 lightweight upper. |
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