223 wssm problems

[mike21]

The rifle discussed below belongs to a friend. I have no experience with either the rifle or the caliber. We have exhausted our troubleshooting efforts, and the comments below will accompany the rifle back to the service folks at Browning in Arnold MO if/when we send it along.

We do not know if the barrel (22") is chrome lined, but we are having a hard time believing the barrel is shot out with so few rounds fired. The factory ammo used states 3850 FPS on the box, so it's not like we have been pushing it to Mach 4 with reloads. Advice/comments concerning this rather sudden problem would be most welcome.

_________________________________________________________________
FOR BROWNING SERVICE DEPT
This Winchester Model 70, 223 WSSM (serial G2526XXX) was purchased in 2006 or 2007. The only ammunition ever fired in it has been Winchester Silver Tip/55 gr Ballistic Tip. Total rounds fired estimated to be 200 to 300.

Until recently, the rifle has consistently produced sub-MOA, 3 shot groups at 100 yd. It will now, suddenly, produce 3 shot groups no better than 3 to 5 inches. This decline has been rapid, from one shooting session to the very next and not a gradual degradation. Recent shooting sessions have been in ambient temperatures of 45 to 65 degrees F and 1-2 minutes between firings. The rifle has not been dropped or mistreated in any way. The rifle has been transported in a padded case directly to a shooting bench for its last 40 rounds.

I have attempted all of the following trouble shooting efforts with no accuracy improvement:

1. Thoroughly cleaned the bore of copper and carbon.
2. Checked that both action screws and rear trigger guard screw were secure.
3. Ensured mounts and rings were tight and secure.
4. Installed a different and proven scope.
5. Had another shooter fire the rifle which generated similar groups.

I would appreciate your inspection and diagnosis for possible repair for this unexplained and sudden loss of accuracy.

 

[MudRunner2005]

I had a Browning A-Bolt II 7mm RemMag do the exact same thing... I just put a new barrel on mine, and didn't worry about sending it off, since I was not the original purchaser, and had no idea how many rounds the previous owner(s) might have put through it. So, figured it would be cheaper and easier just to use a virtually new barrel I had laying around.

 

[Lefty7mmstw]

It happens, and sometimes it's bedding, sometimes it's carbon cooked into the barrel.... other things can do it too. I've had a couple of rifles I thought were "clean" using normal powder and copper solvents actually show up very dirty when you look down the bore. I've had to use jb bore compound on a couple of bores and scrub/ soak a couple of other bores for days until they came clean. Keep pushing; the problem is likely right before your eyes...

 

[hhack]

Awhile back I did a bit of research and pondering on getting a 223 wssm until I started running the barrel life numbers. 350 to 400 rounds of usable life according to the calculator I was using. You may need to scope the bore but I would guess by what you described is the barrel is gone.