Group issues long range

[huntsd]

zeroed my rifle at 100. First 3 shot group was .5 moa and an inch high and right. Made the adjustment and my 2nd 3 shot group was .4moa dead on.

Drop back to 300,400 & 500. Groups all opened way up. Elevation was generally good but they were wide apart. Also all groups were 4-8 inches right. Ironically there was a right to left wind (7mph).

Any guesses on why 100 was great and my groups went to hell at distance? Shooting 180 grain 300 wm off an atlas bipod with a rear bag.

Picture shows 100 yard group and 400. I was aiming at large blue tape. Farthest impact is 8inch away from center closes impact are about 4 inch away
Thanks!

 

[NSI]

Shoot a ten round group at 100 (as slow as you like), post it here and we’ll be able to diagnose. You’re suffering from sample size issues right now.

-J

 

[PineBrook413]

Like NSI said above, re-confirm zero but with 10 shots.

That will tell you if you are actually zeroed or not. Also will give you a better baseline on the level of precision your rifle is at the moment.

 

[Sadie]

Tagg

 

[nobody]

I’ll echo the comments above, more data>less data. 10 round (or more) group to confirm ACTUAL rifle capability, zero from that, then start diagnosing and critiquing to improve outcomes at distance. There’s a very high chance your zero isn’t where you think it is, and I’ll bet $50 your rifle is nowhere near a true .4 MOA system. Probably 1.5-ish MOA is my guess, especially for a hunting weight 300 WM.

 

[ResearchinStuff]

so many potential causes, no where near enough info to diagnose. but - did you by chance switch boxes/lots of ammo at some point while you were shooting?

 

[EdP]

I'll echo the above with a couple of points unmentioned so far.

Your 10 shot "group" can be done in two 5 shot groups at different bulls on your target and provide the same data (as long as the bulls are identical).

You don't mention how fast you shot or whether you allowed the barrel to cool between shots. My standard practice is 3 minutes between shots and I try to keep the sun off the barrel. You can get away with 2 or 3 shots in fairly rapid succession if that is all you are going to shoot. I don't do that. Even if shooting to confirm zero after travel I am going to give 3 min cooldown between shots in case I need to do a sight adjustment. Note: I'm not saying 3 min is the magic formula, it is just what works for me and it is easy to track with an egg timer.

Keep your ammo out out of the sun.

Make sure all your ammo is the same.

Shoot every shot over a chronograph so you can tell if something other than group size is in play. In my .30-06, the POI shifts up and to the right as velocity increases.

Don't let a round sit in the chamber to cook. If you don't get a shot off in the normal time after loading, pull it and set it aside to cool.

 

[huntsd]

so many potential causes, no where near enough info to diagnose. but - did you by chance switch boxes/lots of ammo at some point while you were shooting?

All the same lot. I run Barnes vortex and always shoot a pretty good group. .5-.75 moa. Will try the 10’ shot group as suggested and see what happen s

 

[wapitibob]

Benchrest guys are shooting .1 and .2 at 100 and 90% aren’t shooting 1 moa at 1,000.

 

[Axlrod]

Benchrest guys are shooting .1 and .2 at 100 and 90% aren’t shooting 1 moa at 1,000.

Not even remotely true. Have you been to, or seen the scores from a 1000 yard BR match?

 

[wapitibob]

Not even remotely true. Have you been to, or seen the scores from a 1000 yard BR match?

My bad, I meant F Class.

 

[eric1115]

I'll echo the above with a couple of points unmentioned so far.

Your 10 shot "group" can be done in two 5 shot groups at different bulls on your target and provide the same data (as long as the bulls are identical).

You don't mention how fast you shot or whether you allowed the barrel to cool between shots. My standard practice is 3 minutes between shots and I try to keep the sun off the barrel. You can get away with 2 or 3 shots in fairly rapid succession if that is all you are going to shoot. I don't do that. Even if shooting to confirm zero after travel I am going to give 3 min cooldown between shots in case I need to do a sight adjustment. Note: I'm not saying 3 min is the magic formula, it is just what works for me and it is easy to track with an egg timer.

Keep your ammo out out of the sun.

Make sure all your ammo is the same.

Shoot every shot over a chronograph so you can tell if something other than group size is in play. In my .30-06, the POI shifts up and to the right as velocity increases.

Don't let a round sit in the chamber to cook. If you don't get a shot off in the normal time after loading, pull it and set it aside to cool.

I have a little bit different perspective on this...

If a friend were engaged to a girl and he was having trouble keeping her from having psychotic meltdowns when she's hungry, or tired, or stressed out, would you advise him to figure out how to make sure she's always fed, rested, and relaxed? Or would you advise him to maybe rethink marrying her and try to find someone that doesn't lose their mind when things aren't going great?

Not saying it can't have an effect, but if leaving my ammo in the sun or shooting five shots in a minute causes me to go from "all good" to "measurable problems", the system is no good. Either I'm loaded way too hot, or my barrel isn't stress relieved and of good quality, or whatever other issues might be, I'm going to work toward fixing the rifle and/or ammo rather than try to walk on eggshells trying to keep my rifle happy.

Edit to add:
OP, do you have a scope level (installed correctly)? If no, cant could account for part of the R-L shift at distance.

Much more likely though, is what multiple people have said. If I were in your shoes, I'd shoot a 10 round group at 100 to verify zero, and if it's spot on then shoot what you think you need for elevation, 10 round group at 500. Do it slow if you want, there's a big gray area between waiting 3 minutes per shot and ripping off 20 shots in 2 minutes.

Those two 10 round groups will tell you more than 10 different 3 round groups making adjustments in between.

 

[Formidilosus]

I have a little bit different perspective on this...

If a friend were engaged to a girl and he was having trouble keeping her from having psychotic meltdowns when she's hungry, or tired, or stressed out, would you advise him to figure out how to make sure she's always fed, rested, and relaxed? Or would you advise him to maybe rethink marrying her and try to find someone that doesn't lose their mind when things aren't going great?

Not saying it can't have an effect, but if leaving my ammo in the sun or shooting five shots in a minute causes me to go from "all good" to "measurable problems", the system is no good. Either I'm loaded way too hot, or my barrel isn't stress relieved and of good quality, or whatever other issues might be, I'm going to work toward fixing the rifle and/or ammo rather than try to walk on eggshells trying to keep my rifle happy.

Astute analogy.

 

[EdP]

Not saying it can't have an effect, but if leaving my ammo in the sun or shooting five shots in a minute causes me to go from "all good" to "measurable problems", the system is no good. Either I'm loaded way too hot, or my barrel isn't stress relieved and of good quality, or whatever other issues might be, I'm going to work toward fixing the rifle and/or ammo rather than try to walk on eggshells trying to keep my rifle happy.

There is certainly validity to this viewpoint, but I think it is more applicable to higher end equipment rather than the average $800-1200 hunting rifle. That average hunting rifle will do the job needed by accurately shooting 1,2, or 3 shots in succession. Barrel heating never becomes a problem. Nor does taking out a 20 box from an air conditioned vehicle, laying it in the sun on the bench, shooting the first cold and subsequent rounds as they heat up. I wouldn't call that system "no good" if it serves it's purpose in taking game. It is also what I believe most hunters are using, if not what we would all like to have in every rifle we own. I have and use some of both.

 

[Shraggs]

Completely agree 10 shot group to zero minimum. Myself, if it’s a hard recoiling I’ll go up in zero rounds or do multiple 10 shot because I’m liable to be in error.

I’m also not in support of cool diwn between shots, I used to think that but comparing myself resulted in zero measurable difference - after seeing the cold bore test here.

Mirage from a hot barrel could be a consideration on optic effects as well as unseen wind.

 

[mxgsfmdpx]

Hey OP...

The answer here is "D" not enough information. Start from the start... Review the thread below carefully, tear down your gun if you have to in order to ensure it's correct. You need to eliminate variables, and in general shoot way larger sample sizes. I realize this sucks sometimes with hunting weight guns and 300 win mag, but you need more field information here. What is your action, barrel, scope, and scope mounting system in detail?

You need to start here...

Scope mounting to maintain zero

After multiple requests for an explanation of how to mount a scope in order to have the lowest possibility of loss of zero, a discussion of a scope mounting video, and the latest thread about scope bases and action screw coming loose, I took some pics of what I do with a rifle when I get it and...

rokslide.com

Once you know your gun and scope are properly mounted and are not likely to shift off your 100 yard zero, then we start moving forward and diagnosing. If you are using a known "problem" scope and/or mounts in 300 win mag chambering, issues can be seen very quickly a lot of the time. Provide some more information and several folks will be glad to help.

 

[TaperPin]

At 500 your 7 mph wind drift is what - close to 3 moa? So you’re dialing 15” into the wind and it’s impacting 4-8” off? 6” error is only about 3 mph, no?

Unless I don’t understand something, my prediction is you’ll find the wind speed at various points on the range differ from the shooting benches and has a few mph of variability.

I also predict your rifle is shooting well and the ten shot group won’t add anything useful.

At distance, wind makes women do crazy things, I mean bullets. Lol

 

[Macintosh]

Elevation was generally good but they were wide apart

I could not tell what the second target photo represented, could not tell what was what with no holes and all the random tape, but if your 100 yard 10-round group is generally “round” as opposed to “strung out horizontally”, and your longer-distance groups are generally sized roughly as expected vertically, but they are strung out horizontally, highly likely thats wind.

 

[Sadie]

Some loads will shoot extremely well at 100yds but fall apart at longer ranges. I work up loads at 100 and then test at 500.

 

[mt terry d]

Will try the 10’ shot group as suggested and see what happen s

Results?