• Frank's Lesson's Contest

    We want to see your skills! Post a video between now and November 1st showing what you've learned from Frank's lessons and 3 people will be selected to win a free shirt. Good luck everyone!

    Create a channel Learn more
  • Having trouble using the site?

    Contact support

Recent accuracy issues?

STI_1911_Guy

Sergeant
Supporter
Commercial Supporter
Full Member
Minuteman
Feb 1, 2011
1,554
205
36
Michigan
Hello, I have a dpms LR-260 and up to this point it has been a great shooting rifle out to 600 yards but now all of a sudden it has went from about .5-.75 moa to bouncing around. I will dial 12minutes on my dial and center punch the steel then the next round will go 8" high then the next back to center. Then if i stop and go back to it i will shoot 5 shots in that .5-.75 moa range. Im pretty certain its not me as i have not had a problem up to this point in about 500 rounds. Im thinking it may be an ammo issue as i have been necking down 7mm-08 but i recently got some remington 260 brass. i also thought it might be a scope issue so i switched it to my leupold VXIII but same thing. Any suggestions?
 
Re: Recent accuracy issues?

When was the last time you cleaned it? Do you have another shooter you could put behind the rifle to check and verfiy it isnt you? I would definitely check your velocity with a chrono. Also look at ANYTHING you changed from how you shot it when it was doing well to now. Any item you changed etc.
 
Re: Recent accuracy issues?

Yes I do have a chrono. I can check it but what am I looking for? Something I forgot to mention which is very odd is that the more I shoot it the less minutes I have to dial on the turrets. I check zero and then I started dialing 13 minutes then 12 now sometimes to center it I have to go to 11.5. What the hell is going on? I looked at the crown and I can see where it looks like there might be a scratch on the inner edge of the crown. So minute I had to look for 2 minutes to see it. Could this be it??
 
Re: Recent accuracy issues?

It's good that you changes scopes, that would be my first choice too. I'm not sure what your comfort level is, but now would be the time for a complete tear down and inspection. From your symptoms it seems that some part has gone out of tolerance or vibrated loose.
 
Re: Recent accuracy issues?

I had that happen with 223 brass and it was because too many loadings had make the necks weird. Crazy neck tension issues.

Otherwise I would check to see if someone had come loose. Barrel crown is a possibility but when I've had issues with that it went from being consistent to all over the place 100% of the time.
 
Re: Recent accuracy issues?

I am going to have the crown touched up just so I can eliminate that issue. Got a smith down the road and can have it done immediately so why not. It will only shoot about 25% of the time good then the rest it's throwing them all over. The reason I am thinking this is because I have tried my necked down 7mm-08 brass and new 260 Remington brass. I have put probably 200 rounds down range since this trying different brass and making sure everything is good but same issue. My last group at 300 yds was over 6in
 
Re: Recent accuracy issues?

Your problems sound alot like a scope that has gone bad, or a mounting system that is loose, worn, or broken. My first suspect would be the scope. However, just to be cautious, I would check:

1. Muzzle device to insure it is tight and not wobbling or has come out of alignment.
2. Gas block to make sure it hasn't suddenly started wobbling around.
3. If your barrel was installed properly, the gas tube should keep it locked into position, but it wouldn't hurt to check to make sure.
4. Insure that the forend is tight. Depending on the method used to secure the forend, if it has come loose, the wobble can affect things.
5. Check underneath your muzzle device to see if you have alot of carbon buildup that causes a false crown. If you have a buildup of carbon, that can really wreak havoc with how the bullet's base gets pushed as it exits the bore.
Obviously, if there is a buildup, carefully clean it off to get back to the fresh clean crown.
6. As you have probably eliminated the scope as the problem, check your mounting system starting with the base. Make sure that the base is tight, then that the rings are tight. Insure that the rings hold the scope tightly enough. If any one of those three aren't tight, problems develop. Remember that the rings should be pushed to the front of the rail when mounting as that is where recoil will seek to drive them anyhow.
7. Lastly, suspect the barrel. It is always possible that you just have a bad barrel. If that is the case, and DPMS built the rifle, return the rifle to them to have it fixed.

Many manufacturers (some much more than others) will seek to either blame something you did, your ammo, or anything other than admitting that perhaps they had a manufacturing glitch. That always struck me as odd as simple logic says that if you make enough of anything, eventually something will go wrong. I believe that the positive customer good will of admitting to an occasional problem and promptly fixing it would far outweigh telling the customer it is their fault, or saying something that comes across as "We never make mistakes because we are perfect", so it has to be your fault.

I had a manufacturer blame a magazine for problems with extraction, over pressure and other items that were clearly the result of a short throat. When I could extract unfired rounds, you could see the lands engraved onto the bullets that weren't retained in the bore. A gunsmith at the range even verified what the issue was. I returned the rifle, and it got the throat fixed, but I was told that it was a bad magazine. Yeah, sure....

It seemed only reasonable that if you chamber and throat 10,000 rifles, eventually one will get short throated, or have some issue with the chamber. To blame a magazine was embarrassingly illogical for that company.
 
Re: Recent accuracy issues?

tn.jpg

when i got home from work i decided to take the rifle apart and check everything which i did then put it all back together while not finding anything other than maybe a little extra gas coming out of where the tube goes into the gas block but i thought it looked fine still. Then this followed.So......... i just reloaded some more ammo. During witch i watched runout and careful process and then cleaned the rifle. After wich i shot 5 fouling shots. with previous knowledge i know it takes 10-15 rounds after a cleaning for this rifle to fall back in. So Group 1 was shot as not the greatest being that it was only 8 rounds total. Group 2 and 3 were shot immediately following and both are fairly good. Im starting to think this is not a crown issue like i thought before. Maybe something was up with the rifle and when i tore down and put it back together maybe it corrected it?????? Or maybe it is the ammo. I am going to try more tomorrow and see but for now does anybody have any input??
 
Re: Recent accuracy issues?

Shoot some factory ammo like FPGMM to eliminate the ammo, crown, scope issues firest befor going any further.
 
Re: Recent accuracy issues?

I will order some factory ammo but after sorting through reload last night and shooting the two groups like that back to back then I think the bad reloads may have played a role
 
Re: Recent accuracy issues?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: jlow</div><div class="ubbcode-body">Shoot some factory ammo like FPGMM to eliminate the ammo, crown, scope issues firest befor going any further.</div></div>

I have also found FGMM to be a good tool for eliminating variables when tracking down accuracy problems. If a rifle won't shoot consistently with FGMM, there is very likely a problem with the rifle itself.