Why might my rifle have lost zero

[ARK_Ginger]

Any random debris in the barrel channel?

 

[ResearchinStuff]

Seekins rings are known to crack and reported to shift from side impacts. They're the known weak link in your system, so any troubleshooting needs to start there.

 

[stan_wa]

Seekins rings are known to crack and reported to shift from side impacts. They're the known weak link in your system, so any troubleshooting needs to start there.

That’s great to know I thought people generally thought of them as one of the best rings so I’ll check that

 

[Fireflyfishing]

I like the idea of trying a different scope and see if there are the same issues. Just because you have a Trijicon doesn’t mean it can’t have a problem.

How about not using a bipod and shoot off bags or a backpack and see if there’s issues there?

Another thought is to chrono your loads on different temps to see how the temp does or does not affect your groups and their locations.

 

[Wrench]

The hard thing about this is I’ve gone on probably four range trips with the scope and proven that it did hold zero in the same set up and then suddenly it didn’t which is concerning so I can’t directly test it because the response can be erratic

You can set up a tracking board and run the square.

 

[stan_wa]

Checked all scopes screw and they are all tight
Checked scope rings no cracks I could see
Checked muzzle break it was snug
Couldn’t see any junk in barrel channel
Would need to disassemble to be 100 % sure

I like the idea of trying a different scope and see if there are the same issues. Just because you have a Trijicon doesn’t mean it can’t have a problem.

How about not using a bipod and shoot off bags or a backpack and see if there’s issues there?

Another thought is to chrono your loads on different temps to see how the temp does or does not affect your groups and their locations.

I have shown that bag and bipod have a indistinguishable affect, bench vs prone does certainly cause a shift

Once I re-zeroed my ballistic solver gave good hits at 700 so I think that shows mv temp sensitively is not a major issue . I would
however like to use the ab mv temp correction so when o get a chance I’ll do that

Anyone think the rear ring position being too far aft could be the problem ?

 

[ResearchinStuff]

Your front ring looks like more of a problem than the rear ring, can you get it further forward?

 

[Castle Rock]

Anyone think the rear ring position being too far aft could be the problem ?

That is a very strange thing to say, grasping at straws

It is more likely either your technique or the scope has shifted, they are not all perfect
My money is on you

 

[stan_wa]

Your front ring looks like more of a problem than the rear ring, can you get it further forward?

From the pic it’s hard to tell but the front ring about centered, I’m definitely grasping at straws.

That is a very strange thing to say, grasping at straws

It is more likely either your technique or the scope has shifted, they are not all perfect
My money is on you

I would agree but when I was shooting the 2 nd zero i changed form far more than I could ever change it accidentally and couldn’t replicate that a change near large enought.

 

[Fireflyfishing]

What about action screw torque?

Agreed. I don’t think you answered this question yet.

As this thread goes on, I feel like you should change scopes and compare with another.

 

[solarshooter]

I believe he addressed action screw torque several times already, Seekins recommended 55in/lbs and he installed with torque wrench and blue loctite.

I think doing a mini drop test on this scope would be the move. If you observe a shift, swap to another known good scope and drop that one. If the shift persists, its a rifle issue, if not, its a scope issue.

 

[Fireflyfishing]

I believe he addressed action screw torque several times already, Seekins recommended 55in/lbs and he installed with torque wrench and blue loctite.

I think doing a mini drop test on this scope would be the move. If you observe a shift, swap to another known good scope and drop that one. If the shift persists, its a rifle issue, if not, its a scope issue.

Ahh, fair enough. I couldn’t recall. Thanks

 

[solarshooter]

Thinking more about it, I'm not sure a drop test would be useful yet. The zero moved after a hunt, during pretty light treatment. I would recheck action screw torque, really all torques on all fasteners, and test zero.

 

[stan_wa]

i’ll take the whole thing apart and reassemble de grease and Loctite all fasteners and use applicable torque spec per best practices. Next time I take it to the range, I’ll do a mini drop test and see where I can learn.


I’ve seen a product that is something like scope grip tape, but I haven’t seen anyone on here advocate for it

 

[ResearchinStuff]

All the tape in the world won't fix the rail clamping on those rings.

 

[LaHunter]

I may have missed it, but what cartridge is your rifle chambered for? If it is a 'barrel burner' your barrel could be spent, or getting close to the end of its life, depending on strings of fire over its life.
Also, it has been suggested a few times about trying a different known scope on this rifle. This would be my next step, since it sounds like you have checked every screw / torque. All scope brands / models can fail.
Also, is this factory ammo or hand loads? If factory, same lot or new lot? If hand loads, then there is another list of things to check.

 

[Shortschaf]

Seekins rings are known to crack and reported to shift from side impacts. They're the known weak link in your system, so any troubleshooting needs to start there.

This is the first I've heard of this, and curious if you could share the source. Ive always been a fan of them

 

[ResearchinStuff]

I've seen a cracked set, form has posted that he has too, and he's mentioned the loss of zero from side impacts.

 

[Shortschaf]

I admit I asked about that because I know formidilosus had a previous typo and blamed PMR rings instead of PRO rings for zero losses.

Outside of that typo I'm not aware of losses of zero reported from PMR's

The broken rings you share are undisputed, and I would check for cracks also if I saw that happen.

I think the OP's plan for his rifle is proper. Reassemble and reassess

 

[stan_wa]

I don’t have a another reliable scope that I could use and considering they’re all over $1000 it’s a pretty penny to ask lol I could probably borrow one from a buddy, but then I can’t beat it up too much to see how well it holds cause I know under light use and normal range strips. It seems to be doing fine.

I got a 28 nos with about 700 rounds in it running retumbo estimated barrel life at 1 k

The Seekins rings are made from 7075, which is in my mind is good material choice because it’s more prone to crack than stretch. And has great strength