Accuracy Loss

[Orange Dust]

I concur and I really feel like its something simple

ButterBean and susquatch. Completely agree with you both. I also think the rifle is fine to take on the hunt. Mostly a confidence thing on the part of the hunter. I went on a lot of expensive, successful trips with a rifle that shot no better than his is shooting now. For the OP, shoot the rifle at the maximum range you plan to take a shot and see what you get. You might be surprised. 100yd groups really tell nothing, esp with VLD bullets. My current rifle shoots groups just as good at 300yds as it does @ 100 with ELDX's.

 

[slikmrc]

Looks like you might have some throat erosion and your load is getting out of its accuracy node. Velocity check might shed some light on the issue. Hope you get it figured out.

 

[Wedgy]

How long between shots ??

As far as erosion goes 550 rounds on a WM is nothing

 

[Tulsa Reiner]

aghunter: Give us a report on your hunt next week, with pictures. Don't forget to tell us how long your shot was.

 

[new2mud]

How long between shots ??

As far as erosion goes 550 rounds on a WM is nothing

Given the minimal firecracking visible in the bore scope photo, throat erosion would indeed seem highly unlikely.

 

[Bob Wright]

The last scope I had repaired was for the parallax adjustment.
Assuming you are adjusting for parallax and not just "focus". Sometimes the adjustment for focus may be slightly different than zero cross hair movement.

 

[LRNut]

As mentioned by others, I have come to learn the action screws are the first thing to check, followed by scope rail screws.

I recently had a gun go down to 2.5 MOA, with one group at 1 MOA. When I got home I discovered the front action screw (which had been torqued to 65 in-lbs) was MISSING. I have no idea how that thing even shot an MOA group.

In my experience, the scope rail screws are the first thing I check. One of my 28N's started throwing bullets all over my 24x24 inch gong at 905; previously it held less than 1/2 MOA vertical. Bullets kept drifting to the right as well. Got back to Phoenix and decided to check the scope. I could actually feel the scope moving slightly; the base screws were not even finger tight. This has happened to me on a Lapua as well. I use blue loctite when I mount them, but...

 

[LRNut]

I see a lot of comments about loss of accuracy nodes, lot changes, etc. A truly accurate rifle isn't going to suddenly go from 1/2 to 2" due to a changes like these IMO. I can take my custom guns and vary charge, seating depth, powder lots, etc - may not be as good as my ideal load, but the groups are not going to open 4X. I think it is mechanical. Any chance the carbon fiber is somehow not bonded to the barrel? Really out of my element with that question.

 

[Susquatch]

In my experience, the scope rail screws are the first thing I check. One of my 28N's started throwing bullets all over my 24x24 inch gong at 905; previously it held less than 1/2 MOA vertical. Bullets kept drifting to the right as well. Got back to Phoenix and decided to check the scope. I could actually feel the scope moving slightly; the base screws were not even finger tight. This has happened to me on a Lapua as well. I use blue loctite when I mount them, but...

The single biggest reason for recalls in the auto industry is fastner failures. Usually because of incorrect torque but sometimes bad design.

I have nothing against blue loctite - it works. Nuff said.

But a good torque driver is worth its weight in gold. I really like the WiHa adjustable torque screw drivers. They are pricy, but WAY better than the cheap torque driver alternatives sold at gun shops. Properly installed and properly torqued, I've never had one come loose.

 

[Stammster]

Looks to me that you have a 1MOA gun that shoots 1/2 MOA occasionally and 2 MOA occasionally.

 

[donwill]

I have seen several occasions where the scope rail has come loose on the frontend and caused this type of issue. it is almost impossibe to see or feel the movement. Blue locktite is the answer with the proper torque. A friend had a similar issue and was about to sell the gun. I fired 5 shots at 25 yards and 100 yards and could see it track across from left to right. although the scope felt secure when it was removed the front screws were found to be loose.

 

[Tulsa Reiner]

I think aghunter said his Aoudad hunt was tomorrow (3/7), so I'm hoping he got the problem solved and nails a big one.
We should hear a report next week.

 

[aghunter]

Ok guys thanks for the all the comments. Sorry for being MIA but wanted to catch this post up.
A couple comments alluded to chasing the lands which I hadn't previously done. I thought I'd measure to touch again to compare to my base line. I use the wheeler method and as I started measuring I noticed I could "feel the lands" much shorter than previously measured. But wait this should be impossible right? Back to basics as something was obviously not right. After some verifying, my sized brass length was at 2.616. This is under the sammi max of 2.620 but over the trim length. I thought this was ok but found it was tight in my chamber and only noticeable on a seated case with the firing pin removed. After trimming brass back to 2.605 I could now properly measure that the lands had grown .012". I took my standard load without making it longer back to the range and shot two 4 shot groups at roughly .7" (didn't pull the target). This tiny bit of length appears to be the root of my problem. I had planed to head back to the range and verify one more time Saturday morning before updating you all but woke up with no taste or smell. You guessed it, I am now sitting at home Covid positive and had to forfiet my hunt. What a couple a weeks! Thanks again to all who commented to help me work through my issue.

 

[slikmrc]

Hoping you have a quick recovery!! Take care and be well