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Posted: 6/2/2004 4:45:27 PM EDT
| Ok, the TA31 et al, series allow for the use of the BAC as well as the magnified optics. Now if I zero the scope at 100yds, how does it impact the BAC function at say 25yds? |
| Ah, this is the question that I was wondering about. I'm thinking that my problem lay in the fact that I had zeroed it a 100yds, then if I used it at CQB distances it sucked badly. So I was stuck between a rock and a hard place. If I zeroed it for CQB then I was screwed if I went out to distance. Not a problem now though. Dang it. |
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The only problem you'll have at CQB distances is the normal holdover for the AR15 series of weapons. I usually hold on the hairline at 7-10yds and under. Your zero won't affect BAC; but using BAC will give a different point of impact from your zero that will vary for each person due to their stance, eyes, etc. If you wait for the scope to "zoom" though, you'll eliminate that issue and if you are close enough you can't wait, the difference won't be enough to matter. |
AT CQB distances it makes no difference for a COM shot. You have a 8" diam zone there 2" off is still well withing 'the zone'. Note many spec ops guys are mounting their Aimpoints 4" over the bore which makes aiming more interesting. If you're worried about the 'headshot' into the 4"x2" zone - all you have to do is aim high and inch or two With training/practice this comes naturally. Note there is NO zero you can do at CQB distances where you will not have to offset the aiming point at a specific distance. If you zero for 12y then when the target is at 24 you will be high over two inches high, if the target is at 6y you will be over an inch low. If you use the 100y zero then the round only travels 1" high from 0 to 25y. Thus at CQB distances if you always use the SAME offest you'll be good to go (this is easily practiced). [for those using the IBSZ you get a similar offset with a elevation travel of only 1.4" - also transitioning from the BAC equipeed ACOG to the another rifle using the IBSZ you don't have to change where you train to aim] Using the 12y zero the round travels 5.5" in elevation from 0 to 25y. That requires changing the aiming point depending on the distance to the target - tagets closer than 12 require one point, targets a but further may require another. This is much more difficult to train for, and once trained the offsets only work on rifles so zeroed. |
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No, with the TA31, zero the top surface of the donut at 100 meters. Then follow the prescribed BDC positions in the reticle for 200, 300, 400, etc. As others have said, at 0-50 yards, you have normal hold-over. The axis of the scope is about 2.6 - 2.8" higher than the bore axis, and the bullet is rising to the first zero. -z |
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