Accuracy Loss

acourvil

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Joined
Apr 30, 2011
Messages
134
Location
San Jose, CA
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

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Joined
May 22, 2020
Messages
401
Location
Houston, Texas
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.
 

Will Gray

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Joined
Feb 21, 2013
Messages
308
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.
 

jgs8163

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Joined
Sep 27, 2011
Messages
1,190
Location
Southern Arizona
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

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Joined
Mar 23, 2008
Messages
738
Location
N. Central Indiana
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

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Joined
Jan 14, 2021
Messages
98
Location
Meeker colorado
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.
 

BrienM

Active Member
Joined
Jan 22, 2021
Messages
38
Location
WV
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..
 
Last edited:

jrg

Active Member
Joined
Sep 3, 2013
Messages
37
Location
N.East Texas
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

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Joined
Aug 10, 2014
Messages
46
Location
North Dakota
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

Member
Joined
Feb 4, 2021
Messages
13
Location
Texas
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

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Feb 5, 2012
Messages
3,248
Location
West Terre Haute Indiana
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
 

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