Accuracy Loss

[acourvil]

One more mechanical item: check the barrel channel and make sure that you didn't get a piece of gravel or something in there that is making contact between the barrel and stock.

 

[Stammster]

Check velocity.

It's been cold lately. Maybe your load is shooting a little slower and took you out of your accuracy node.

Or your barrel sped up for some reason...with same result.

That combined with a little throat erosion could be the issue, and a minor tweak in both seating depth and charge weight will get you back where you were.

 

[22250imp]

See if you can find some Wipeout bore cleaner and clean according to instructions. Will get rid of any copper build up. Might have to do it several times.

 

[Will Gray]

I clean and coat all the screws with anti-seize compound (you know lube allows more force holding the part at the same torque). I use a bore snake to clean using Hoppie's No. 9 to be sure there are no obstructions (mud dauber) in the bore to make it easy to bore sight the rifle. I never scrub the bore. All my barrels shoot just fine.

 

[JAYgs8163]

Crown and brake look good.
Action screws didn't budge at 55in/lb so they have not come loose. Barrel is not contacting stock.
Double checked picatinny rail and it was tight. Just had it bedded not long ago.
Powder charge correct from deconstructed bullet
WOW what a difference the bore scope makes in really knowing if your clean or not. Check out the before and after pictures. I used c4 and Iosso.
Will shoot tomorrow and let you guys know if there is any improvement.

It'd be nice to see 2 before and after pictures from the same photo profile or view. The one picture here of it being dirty shows some debris in the barrel. Unburnt powder maybe? Is this a new batch (lot) of powder with these loads, new batch (lot) of primers? When you loaded these rounds could you have possibly loaded them with a non-magnum rifle primer, causing a varying degree to the rate of burn on the powder?

 

[esshup]

With the elimination of the mechanical issues I would check velocity and check the jump to the lands/grooves if you haven't done anything to the load from beginning to end. One more thought, even though you are using the same load, has the powder lot # changed?

One more thought, I have seen different fps/group size with different neck tension. I now anneal before sizing for every batch that I load for my long range gun. Double check case length to ensure they aren't too long.

 

[Jim’s Hunt]

Crown and brake look good.
Action screws didn't budge at 55in/lb so they have not come loose. Barrel is not contacting stock.
Double checked picatinny rail and it was tight. Just had it bedded not long ago.
Powder charge correct from deconstructed bullet
WOW what a difference the bore scope makes in really knowing if your clean or not. Check out the before and after pictures. I used c4 and Iosso.
Will shoot tomorrow and let you guys know if there is any improvement.

 

[Wedgy]

It almost looks like brass in there, did you check the trim length ?

 

[BrienM]

That is sometimes when i loose interest and replace the barrel. Components are hard to find/replace. When i loose trust in a barrel, it's over for me.
I bet the nice cleaning job you performed on it will help though.

Edit to clarify: When a barrel starts acting funny and i go through all the steps to identify why it's not repeatable, if i cannot diagnose the problem (loose screws,base,rings,scope etc.) is when i loose interest and replace..

 

[hunter0528]

Did you change
1) powder lots
2) primer lots
3) bullet lot?

 

[jrg]

I am attempting to diagnose a sudden loss of accuracy in one of my custom rifles. I have an Aoudad hunt coming up this Sunday and am in dire need to get it back shooting properly. The rifle went from 1/2 MOA to 2MOA in the span of 1 shooting session. The rifle is a 300WM with Proof Carbon barrel. It has 546 rounds now and went bad right at 500. I have cleaned the rifling during this period with no improvement. I have eliminated the scope and rings by trying a proven optic from a different set up and still have issues. The ammo is hand loaded so nothing has changed on that front. I have been researching the elusive carbon ring and this is what I see through the bore scope. Do you think this could be causing my issues? I have not seen any noticeable pressure signs. Any other ideas that I can quickly try? Let me know what you see.

If you removed the carbon & copper from your barrel when cleaning, you may just need to refoul your barrel. I would shoot 10 or so foulers & then see where you are!

 

[Squatch]

Check the crown of your barrel for any nicks or issues. I shoot suppressed the the carbon build up on the crown after 350 started causing issues similar to what your are describing.

 

[aghunter]

One more mechanical item: check the barrel channel and make sure that you didn't get a piece of gravel or something in there that is making contact between the barrel and stock.

Checked and all clear

It almost looks like brass in there, did you check the trim length ?

I do have a fired piece of brass in the chamber on the before pic. I think that is what you are seeing.

Did you change
1) powder lots
2) primer lots
3) bullet lot?

No lot changes on any.

 

[ButterBean]

Checked and all clear


I do have a fired piece of brass in the chamber on the before pic. I think that is what you are seeing.

No lot changes on any.

If all is mechanically good and you know your scope is good to go Once again I'm gonna suggest you start sending rounds down range and see if it fouls up and straightens up