Service Rifle Sight Adjustments at Perry

[Major Buzz]

Looking for some advice. I just returned from Perry and shot the Individual Trophy Match with my AR. Naturally I had all my zeros set from here at home (Old Colony 200, Copitut for 300 and Reading for 600). Shooting the match I was so low it was embarrasing. The groups were very good, just low right and mostly outside the rings at 2 and 3. Finally attacked the sights at 600 and went 3 1/2 MOA above my zero to start and still had to come up more. The wind was another story, but its the elevation I am worried about.

The question for you guys that go there often. Is this normal? Do you have to come up a lot more than usual at Perry? The only thing different from the ranges at home is the light. We are under cover at Old Colony and in the shade elsewhere. Advice needed and suggestions welcome. Will be reestablishing zeros to make sure something did not break, but a good White Oak is probably not the problem. THANKS!!

 

[Admin]

Is your barrel floated?

 

[Major Buzz]

Hi Derek; Yes fully floated White Oak Upper with 1/4 by 1/4 sights (pinned) 1/7 barrel, wilde chamber.

 

[bpm990d]

Nailing down a zero is a very hard thing with a service rifle. Probably a little easier with the AR than the M-14, although I never have been off by 3 1/2 + min. at 600.

Did you change anything? New can of powder or primers. Also do you count clicks, or do you have a mark on the sights? With 1/4s there are just too many to count. You should have a witness line on the sight. Sometimes my zeros move around a little but it should be within a minute and a half.

Another issue you can have is a club where the actual range is only nominally 200, 300 & 600. I never had much difference shooting between Reading & Perry though. Never shot at Old Colony though.

The groups were very good, just low right and mostly outside the rings at 2 and 3

Can you clarify? Seems like this is contradictory.

HTH,

B

 

[Brent]

I personally have noticed that my zero's at Reading, MA... Hamden, ME... Nashua, NH are all the same but at Perry, I have to bring them up a Minute at 200, I think 1.5 mins at 3 and I cant remember at 6. But yea. Perry for me has different zeros.

Correct me if I am wrong, I am positive that it is mostly a result from the fact that the targets at perry are at a higher elevation from the ground.

I was shooting nothing but Black Hills 75gr both years from the same case/lot.

 

[PatMcD]

I was 1/2 min up from my normal at 200. My 300 and 600 elevation zeroes were exactly the same as here at home.

 

[bpm990d]

Typically the effect of shooting up or down hill is that the bullet will strike higher (requiring you to come down on your elevation or shoot low).

B

 

[Cledus J. Crabb]

I found I had to come down 7 clicks (1/4 x 1/4) for 600 from my Reading zero. I'd imagine that 7 o'clock wind had some thing to do with it.
I was right on for 200, a little high for my sitting rapids as were my rapid prones.
Can't wait for next year.

 

[Major Buzz]

Ok, first answer is that the " 2 and 3" above is reference to the yard lines. I took a bad shortcut in writing, sorry. I did hit low right at 4-5 O'Clock just outside the scoring rings most of the time at 200 and 300 yards. A few in the rings at 200, but no points at 300 with a very good tight group that my scored said would all be in the 10 rings if not low right.

The only difference in my ammo is the primers. I paracticed with Winchester Small Rife and used Remington 7 1/2's for the match. Powder was R-15 and the same lots and loads. Brass was Lake City military, but factory cleaned and trimmed, sized, once fired, versus my practice which is Lake City military brass also reloaded about 5-7 times so far.

I plan on some range time to check zeros at 200 next week and comparing the practive ammo and the leftover match ammo to see if there is a difference.

Thanks to all for the input so far. I appreciate the help. bz

 

[PatMcD]

When you say "outside the scoring rings" do you mean outside the 5 ring, as in a pile of miss'? If so, that is WAY off at 2 and 300 yds.
I'm guessing you meant your groups were just outside the 10 ring.

I don't see how a primer change could have that much difference at the short yardage lines (from 10-ring to visible miss's).
That being said, am I to assume you went all the way out to camp Perry with ammo you hadn't shot before???
Any changes in your loads want to thoroughly tested before any important match.

I would be interested to hear if there is any difference in elevation once you test the old vs. new.

 

[Major Buzz]

No, they were all misses outside the 5 ring. The only change to my ammo was a different primer. Loads, bullets all the same. Just newer brass of the same type I have been using all along. Only change was the primers. Hopefully will get some range work this week and see whats going on. Its almost like the sights broke it was that much of a difference. Quite dissapointing. I actually shot better with the rack M16 on the SAFS than with my own custom. Just another challenge to overcome.

 

[PatMcD]

Wow. I'd say it would have to be something other than your ammo.

 

[bpm990d]

Thanks for the clarification. Yeah, something is really wrong. Could be any number of things.

Changes due to light or other stuff like that, we are talking about getting moved from the center of the X ring to the edge of the ten ring maybe. Completely missing the scoring rings, that is something like the barrel coming unscrewed or using the wrong powder. Best of luck. I'd be super careful with any left over ammo. I'd disassemble it.

B

 

[charliet]

Its the primmers...you cant change anything, it will vary your load. I know for a fact that just changing primmers will take you from the x ring to the 7 at 600yds...Whinchester primmers will shoot HIGH...they are hotter.

 

[Admin]

Good to know

 

[Major Buzz]

So here's what we've got from 3 hours of benched 200 yard range work. I used several different loads with both types of primers (WSR, 7 1/2s). The initial 3 round string with what I made up for the match went right where they all were at during Perry. Low right, just outside the 5 ring. No adjustments, but used the practice ammo, slightly higher but the same place. All 3 round strings throughout, by the way. Started adjusting sights for windage and elevation. By the time I got done, I had all the various types and loads into the 9 and 10 rings, mostly 10 and X's. Slight changes in powder and either primer just made a slight difference of not more than 1/4 MOA elevation or so. Did a countdown to base of the sight and came up with the same count as at Perry give or take a click or 2. Windage on a hot humid no wind day was about the same as well. I now believe that I had all my notes wrong on the sights as everything was off on elevation around the 25 clicks for a full rotation on the wheel. Had to be buck fever/nerves/stupidity or whatever. It was the nut behind the wheel so to speak.

THANKS for all the good input. I will be starting from scratch on the sights and re-establishing zero's. By the book....logged into the book.

 

[tdeon221]

Are your sights marked with paint? Could you have been off a complete revolution? So instead of around 60-70clicks up from mechanical zero, you were 45-50? For 600. I'm usually 91/2 to 10 min up from 300 with a 6 oclock hold to 600. Remington 71/2s are hotter than wsr, which if they're the new (copper colored) ones aren't recommened. Stick with the 71/2s or CCI small rifle or CCI 450 magnums, the cups are thicker and are less sensitive to piercing and slamfires. This is from experience, friends don't let friends blow primers and melt pin tips. Changing primers in short line loads might move you around the X ring a little, back at 600 could be more of a difference, maybe the 10 ring.