50yrd AR-15 Iron Sight Zero

[kurtm]

Well that sounds a bit stout. I do believe the DPMS rear sight is about 1.15 M.O.A. per click when the sight moves on out the barrel (this is the sight I use), and it is designed for a 300 yard zero...hence the 3/6, but the numbers really don't mean much as the sight is for a 14.5" carbine (less velocity) with a 62 grain bullet and if you like to count clicks feel free but it is hard to do with a timer in your head!

It also sounds like you got one of those super tall carbine front sights that makes up for the lack of a "F" marked carbine front sight (don't worry about any of this it is just why) and that is why you had to cut it down. I usually use a stock A2 front sight post and chuck it up in a drill and file it down to what ever diameter I like ...usually around .040-.045, and then hit it with cold blue.

For a 20" gun with the front sight out by the comp..."IN GENERAL"...W/ 55 grain bullets in the 3100-3250 range, and that rear sight, you would be looking at 3" high at 100 yards, 4" high at 200 yards and zeroed at 300 yards. this alows you to hold right on at 300 and if you are shooting at a MGM flash target at 400 you hold the bottom of the flash card in the center and hit the plate.

Remeber there is no right or wrong on this stuff, it just has to make sense to you and it needs to be effective on the clock, It also has to be tested out to any range you are going to shoot, cause the charts LIE!!!!

Edited May 24, 2011 by kurtm

[Nuke8401]

KurtM,

Thanks for the info, since most of my shooting is at 200 and under I will most likely stick with a 200 yard zero. I must be wrong on my numbers but I got .4 MOA per click on the DPMs with a 25" sight radius? I think I’ll shoot a group at 100 yds, add 24 clicks, shoot again at 100 yds and get a rough MOA per click number from that as a data point. Based on yours and other recommendations I would rather start with and stay with a 300 yd zero and learn those holds so I don't have to change later.

I’ll be shooting AM at the AR15/Rockcastle match and will try to sign up for your seminar.

David E.

[cardiackid]

It also has to be tested out to any range you are going to shoot, cause the charts LIE!!!!

That's a huge factor right there I didn't realize until I started shooting a lot of precision rifle. While the charts give a ballpark guideline, I'd venture to say it's virtually impossible to have that kind of predictability 100% of the time (especially on an AR). Even if you generate a bunch of charts for various atmospheric conditions, etc. you're still going to have variables with each weapon and shot/round that are unpredictable. While you might think a PDA/computer with ballistics software on there will give you up to date information on trajectories based on current conditions (altitude, temp, humidity, wind - all the factors) it's still going to vary slightly with each round (slightly varied muzzle velocities, powder that may have temperature sensitivities, slightly varied ballistic coefficients of each bullet, etc.) There's a reason I am entirely complacent with shooting steel at distances and haven't gone down the benchrest/high power paper road. I have seen it drive reloaders crazy and I don't have that kind of patience. One guy had gone to the detail of figuring out that each individual granule of powder he was using weighed .02 grains and measured his powder throws out to the hundredth and also used the water drop method to measure his case capacities - not my cup of tea

[Jadeslade]

Well that sounds a bit stout. I do believe the DPMS rear sight is about 1.15 M.O.A. per click when the sight moves on out the barrel (this is the sight I use), and it is designed for a 300 yard zero...hence the 3/6, but the numbers really don't mean much as the sight is for a 14.5" carbine (less velocity) with a 62 grain bullet and if you like to count clicks feel free but it is hard to do with a timer in your head!

It also sounds like you got one of those super tall carbine front sights that makes up for the lack of a "F" marked carbine front sight (don't worry about any of this it is just why) and that is why you had to cut it down. I usually use a stock A2 front sight post and chuck it up in a drill and file it down to what ever diameter I like ...usually around .040-.045, and then hit it with cold blue.

For a 20" gun with the front sight out by the comp..."IN GENERAL"...W/ 55 grain bullets in the 3100-3250 range, and that rear sight, you would be looking at 3" high at 100 yards, 4" high at 200 yards and zeroed at 300 yards. this alows you to hold right on at 300 and if you are shooting at a MGM flash target at 400 you hold the bottom of the flash card in the center and hit the plate.

Remeber there is no right or wrong on this stuff, it just has to make sense to you and it needs to be effective on the clock, It also has to be tested out to any range you are going to shoot, cause the charts LIE!!!!

This is a Gold Standard-thanks for posting. This info is hard to come by sometimes.

[mike4045]

I zeroed 5" high at 200 yd since no range was available to me. I was able to make all hits to 500 yds at the Tx Multigun. I will be working on getting my new iron gun sighted in this week and shoot it this weekend at a couple of matches. I did not bother to adjust my rear sight for the 500 yd shot just figured how much to holdover and plate fell. It did take me 2 shots though.

I went with Kurt's recomendation and have my front sight just behind my comp. It really does make a difference. I am beginning to think he really does know what he is talking about.

Mike

[Nuke8401]

Just an update on some range time with my extended sight gun.

My link

David E.