Matech BUIS question

[Coronach]

I'm familiar with how to zero the Matech rear sight, but here's something I don't know: what ammo is it calibrated for?

I ask because I'm thinking about plopping it onto an M4gery that I'm setting up to run Hornady 75gr TAP 5.56 ammo, and I'm wondering what that will do it its elevation adjustments. I could just throw it on there, sight it in and see, but I could burn through a lot of TAP (read: $$$$) just fiddling with it. I'd prefer to figure out what it will "probably" do, and just dial it in and confirm.

Anyone know what the best zero procedure would be under these conditions? I'm thinking about using range ammo to zero at 25m, then set the rear sight to 300 and use range ammo to get on paper at 300m, and from there using the spendy stuff to dial it in. After that, I may try running it in and out to various ranges to see where the shots land, again using TAP. One way or the other, I'd like to keep the TAP-burning to a minimum, so if this is a dumb idea, someone please say so.

Mike

 

[taliv]

sounds like a plan,

nice post count, btw

 

[waterhouse]

I'm not sure if this will help at all, I followed the instructions for zeroing mine a few years ago with Radway Green 62 grain stuff, and found the ranging lever to be accurate to 400 yards, which was the farthest I ever got to shoot with it.

I'm doubt it was designed to work with Radway Green specs, but it seemed to do well with it.

 

[Jenrick]

Hmm does Hornaddy have a cheap ammo line designed to mimic the ballistics of TAP (i.e. Lawman and Gold Dot)?

Do any of the ballistic tables out there match up to TAP with something cheaper?

Call Matech and ask them what the sight is supposed to be calibrated to, then find that ballistics chart.

-Jenrick

 

[Coronach]

I'm doubt it was designed to work with Radway Green specs, but it seemed to do well with it.

RG stuff is nato spec, and I found that the Matech is calibrated m855, so I don't see why it wouldn't. IIRC, the 62gr Radway stuff is M855, but that's from memory.

Hmm does Hornaddy have a cheap ammo line designed to mimic the ballistics of TAP (i.e. Lawman and Gold Dot)?

I think they have a training line, but it's still pretty expensive, and it's not made to mimic the 75gr TAP 5.56.

Do any of the ballistic tables out there match up to TAP with something cheaper?

Not that I'm aware of.

Call Matech and ask them what the sight is supposed to be calibrated to, then find that ballistics chart.

It's M855. Now, all I have to do is find a chart for that...

Mike

 

[possum]

i would think that the buis would be best with 62gr, liek what we shoot. the m855. i have the same rear sight on my ar but i haven't been able to test it out as far as the sight allows, as there are no ranges around that allows for a shot that far.

 

[Coronach]

OK. I used the ballistics table for M855 and overlaid it with the ballistics table for 75gr TAP. At first, they don't look encouragingly similar. Then I went through and used the sight-in distances indicated on the Matech BUIS. Assuming I'm using the appropriate distance (eg, the 200m setting for a target ~200m out) the difference in POI between the two rounds is always 1.75" or less- usually way less, with the vast majority being under 1".

For a BUIS? That's quite good enough, thanks. I will never know the difference.

Mike

 

[Onmilo]

I agree with Coronach.
55 to 77 grain ammunition is so close in ballistics for the ranges one would practically utilize iron sights that it won't really matter what you choose to sight the rifle in.

Every single type of ammunition will hit within 18 inch vertical dispersion at 300 meters and that is minute of bad guy accurate.

The closer you get, the tighter the vertical spread.

 

[taliv]

i dunno...

as a high power shooter, i'm pretty comfortable shooting irons out to 600 yrds. granted, i'm accustomed to shooting large black circles on 6'x6' white sheets of cardboard and not guys hiding in bushes wearing camo.

still, all my BUIS are the precision flavor. if i have to take a 300+ yrd shot with my micro red dot, i'm pretty well screwed. I'd switch to irons even if the primary sight is functioning as normal because my eyes can't really tell where the dot starts and stops, but i can still focus on front sights.

eta: i'm not knocking your strategy there, Coronach, just offering an alternate perspective. using irons as primary for long range, backup for short range, and 1x optics as primary for short range, backup for long range