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Posted: 11/12/2001 10:18:53 AM EDT
I placed a Tasco Red Dot scope on my Bushmaster AR-15. I usually start zeroing rifles at 50 yards and I go for about 1" low at this distance and it generally is OK out to about 150 yards, but I have never set up a scope where the crosshairs were so high over the bore axis. Shoud I set it up to shoot 3" under the line of sight? Perhaps I should have gotten a flattop? Any help would be appreciated.
Link Posted: 11/12/2001 11:15:21 AM EDT
What is the height over bore? (center of barrel to center of reddot)

What barrel length?

What ammo are you using?

I'll be happy to run some number for you with this information, and come up with a good zero.
Link Posted: 11/12/2001 11:53:36 AM EDT
I'm sorry

16" Barrel
3.6" Center of Red Dot to Center of bore
62 gr PMP Ammo
Link Posted: 11/12/2001 11:56:36 AM EDT
[Last Edit: 11/12/2001 11:54:39 AM EDT by Forest]
Have you thought about getting a 'scout' mount like the ARMS#39 or so? It will put the sight more in line with the irons and allow you to zero at 50 yards, which gives a nice flat 200M zero (bullet stays within 2" of the LOS from 8m to 225M).

Eddited to Add:

With a 3.6" height over bore how do you get a good cheek weld?

Check out this article, I think it will help:
communities.msn.com/TheMarylandAR15ShootersSite/budgetreddotsight.msnw
Link Posted: 11/12/2001 12:19:16 PM EDT
go to cnet.com and download point blank ballistic software, its free,easy and will solve all your sighting in questions
Link Posted: 11/12/2001 12:44:36 PM EDT

Originally Posted By Glockdiver:
I'm sorry

16" Barrel
3.6" Center of Red Dot to Center of bore
62 gr PMP Ammo



Some quicky calcs based on a few assumptions.

Well, I'll have to assume it's loaded to milspec velocity, which Bushmaster lists at 2989 fps. Using a Speer FMJ BT w/cann:

50 yard zero - 0 at 50 & 290, but hits +4" at 170 yards. NO GOOD

75 yard zero - 0 at 75 & 160, +/-2" from 27 to 245 yards BEST

100 yard zero - 0 at 100 & 155 yards, +/-2" from 35 to 220 yards NOT AS GOOD
Link Posted: 11/12/2001 1:11:42 PM EDT
Fight: His velocity should be about 100-200fps slower than the Military velocity. Try it at 2839fps.
Link Posted: 11/12/2001 7:22:14 PM EDT

Originally Posted By Forest:
Fight: His velocity should be about 100-200fps slower than the Military velocity. Try it at 2839fps.



Okay.

75 yard zero - 0 at 75 & 185, +/-2" from 25 to 230 yards
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