200 yard grouping problems

H

hounddawg

New member
First off apologies if this question should be in the handloads section, the rifle section seemed more appropriate

I have a .223 that shoots consistent sub MOA groups at 100 but I cannot seem to get dialed in at 200. The upper has a DPMS 1 in 8 20 inch barrel.

So far I have tried 55 grain SP Hornady, 68 grain Sierra and 77 grain Sierra with various loads of TAC powder. Like I said all will consistently group .5 - .75 MOA at 100 off a rest with scope but as soon as I move out to 200 it is all over the target. This even occurs on windless mornings. I do my load workups at 100 then move out to 200. I am looking for a good cost effective round for 200 yard practice shooting and if I can get 4 inch groups at 200 I will be happy.

I have a chronograph in shipping right now and a box of 75 grain A max sitting on the bench which I will try this weekend if weather permits. I guess my main is does the load differ between 100 and 200, I just cannot fathom how a load could shoot really well at 100 then go to pieces at 200 in a no wind situation or conversely shoot bad groups at 100 then pull in at 200.

Thanks in advance for any suggestions or tips.
 
Assuming that the guy pulling the trigger has previously demonstrated an ability to shoot at 200 yards, I would guess you have a stability problem with the heavier bullets. 1:8 is a fast enough twist, I would think, but we'd have to know the velocity to be sure.
 
It sounds to me like you have an issue with your scope. Are you using the same scope settings at both ranges? Do your cross hairs block out the bull so you can't hold as accurately? It may be that you can only really tell with a stationary rifle vice. By stationary I mean one that holds the rifle securely AND is fastened so that it doesn't move from the bench. Unless your load is transitioning between sonic and subsonic between 100 and 200 yds (most unlikely) nothing else makes sense to me.

Good luck
 
well the guy pulling the trigger shoots 1.5 - 2 MOA 5 shot groups prone unsupported at 100 with iron sights so I don't think it is a trigger pull issue.
When I mean they are not grouping at 200 I am referring to groups of 24 inches or better at 200 shooting off a Caldwell Rock rest with a sand bag at the back and a 20X scope sitting on top. This is not a one time thing, I have been playing with this gun for a few months now, shoots like a champ at 100, go out to 200 and I might as well be throwing rocks at the target.

The subsonic transition crossed my mind but according to the load book I should be cranking over 3000 FPS with the loads I am shooting. Can't see it slowing that much between 100 and 200. I just checked the UPS site and the chrono will be here tomorrow so by the end of week should have some accurate data. Oh and the same scope, same load was used at 100 and 200 within 5 minuter time periods. Scoped off the rest it shoots . 5 to .75 5 shot groups at 100 then I just swivel over to the 200 with the next clip and here come the lousy groups. So same conditions on everything except distance. I have done minimum to maximum load workups on each bullet, but have only tried the "sweet spot" loads at 200.
 
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Yep they will vary from X ring and track up and to the left, with maybe 1 or 2 low right of the X. Are you thinking barrel heat up? I tend to shoot fast but this is a heavy barrel AR and the issue does not ever occur at 100 which is what has me so confused. I am not shooting any faster at 200 than at 100, if anything I am shooting slower
 
Ramshot shows max of around 3,100 with 60gr bullets in a 24" barrel. I would think you're max velocity would be in the 2,750 range with the 77gr.

Anyway, JBM predicts good stability with that setup down to less than 1,800 fps so I doubt it's a stability problem and you certainly wouldnt have stability problems with the 55s. They'd be OVER spinning if anything.

You used the same scope but did you CHANGE any settings?
 
On the speed I was referring to the 55's which was what I was shooting last weekend. 24.5 grains loads so I guestimated + 3000. According to the TAC guide 23.4 and a 55gr Sierra= 2966 . On the scope setting I brought it up 12 clicks (1/8 inch per click). Pretty much all I did was load another clip, swiveled the rest to the 200 yard target and brought it up those 12 clicks then shot. If it was just the 55's I would chalk it up to instability but this has happened with three different weights now.

I curious to see what the 75's do. i have a buddy that swears by them in his rifle which has the same barrel length and twist.
 
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How long between shots? Did you go to 200 after shooting a lot at 100? Like you said, you shoot fast- that MIGHT have something to do with it.
 
24" groups would not be attributable to barrel heat unless there is something DRAMATIC wrong with the gun. Even if there were, there's no reason why it would show up at 200 and not at all at 100.

Something is happening with the bullets or the scope.

You should get 24" groups at 200 yards shooting from the hip!

I would guess that it's possible that the 55gr are overspun and tiny imperfections are causing instability that doesn't manifest until beyond 100 yards. Unfortunately, that doesn't explain what happens to the other bullet weights.
 
Yeah, if this was 55s only, I'd say it was jacket shedding. I had that with a 1x7 Colt AR that I eventually sold off.
But 68s and 77s...those should be running fine,as fast as you can push them.

Absent deep visible jacket scoring, I would say that perhaps you have a scope issue, since you are apparently dialing between 100yds and 200yds, correct?

It's possible that you scope has a weak set of erector springs, and your initial adjustments aren't "taking" for a few shots. This leads to more and more and more adjustments, putting it all over the paper. Any chance this is happening?
 
Clarity question: Are you adjusting the scope when you move from 100 to 200? If you are, try not adjusting it and see what happens (besides shooting an inch or two lower).
 
Might seem counter-intuitive for you but with your twist any bullet from 40 to 75 grains should work for you. back off a little bit on your load and see if it settles down a little. I find my most accurate loads are hot but below maximum and I go more for max accuracy then I do for zip and git bullet speed. Can't hurt and might help.
 
++++++++1

Good tip shooting the 200 yard target and leaving the scope alone.

I would like to hear how that goes if you try it.

Geetarman:D
 
thanks for all the ideas folks, here is what I decided to try. Tomorrow I am going to size, trim and prime 100 cases and make a small portable reloading bench out of a couple of layers of 3/4 ply and some C clamps so I can carry my press to the range.

Friday, weather permitting, I am heading the range and working up loads as I shoot. I also plan on just shooting at 200 yards. Maybe start at 150 if it is cloudy since I have a hard time spotting those little .22 holes at 200 if the light is wrong

anyway I will bump this thread Friday evening or Saturday with a range report
 
I would also recommend not adjusting the scope elevation to 200 yards and just aim a couple inches higher. At the very least you would be able to take scope adjustment out of the equation.

Also that mirrors my advice as far as getting a final resolution, do your best to isolate and change only 1 variable at a time, at some point you should be able to find your gremlin.
 
decided to eliminate the scope entirely at least at first. Just going to use the irons off the rest until I start getting decent groups, then put the scope on to fine tune
 
Friday, weather permitting, I am heading the range and working up loads as I shoot. I also plan on just shooting at 200 yards. Maybe start at 150 if it is cloudy since I have a hard time spotting those little .22 holes at 200 if the light is wrong
Click to expand...

Changing variables before you start may cause you to "lose" the problem without knowing what it was that caused it to go away. If it were me, I'd shoot several shots at 100. Then I'd move to 200 without changing anything including my aim point (I don't remember the chart exactly but you should only be 2 inches or so lower using .223 unless you are running an unusual load). Fire several more shots. Check the group. Then adjust the scope to 200 and shoot another group. This process should help identify where the wildness is coming from.
 
Have you checked your reloads for runout? Also, have you shot factory loads in the rifle to see if they have the same phenomenon?:confused:

I need a do-over, after thinking more about it, I cant imagine a rifle changing it's bullet dispersion on target so dramatically from 100 to 200 yds, I put my money on the scope adjustment either elevation, focus, or magnification causing the weird groups.
 
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