What to do?

[cornchuck]

I have a Christensen Arms Mesa in 300 PRC. I bought it brand new and did the recommended barrel break in from Christensen. The only thing I changed was the muzzle brake from the factory radial brake to a self timing 5 side port brake from MuzzleBrakesandMore. As I was doing the break in, I also was fire forming new Lapua brass. After I got that done, I started load development at 100 yds. Load development consists of Barnes 190 LRX and Hornady 190 CX. Both are all copper bullets with H1000 and H4831sc. Doing load development for an upcoming Aoudad hunt. I even tried Hornadys factory 190 CX ammo. I CAN NOT get anything to group. Its more like MOB. Minute of Barn. There are 239 rounds down the barrel. I have checked the scope rings, base, and action screws. Everything seems up to spec. This is the first rifle I can't get at least moa at 100 yards. Does this warrant a return to Christensen to have it checked out? Or is there something else I need to look at?

Jason

 

[cohunt]

Try cleaning out the copper to bare bore and shoot just 1 of the mono bullets again.

Often times mixing mono bullet types and or guilding metal bullets will muck up the bore.

 

[gillettehunter]

First of all try a different scope. Always a possibility that it needs service. Thats the first item. Next is a change of components. Perhaps a different bullet or powder would make a difference. If that doesn't help then I'd say Christenson needs to look at it. Good luck.
Bruce

 

[Bob Wright]

Copper monos can require more jump. I'm not sure how much you've tried. Start at .050 off in three shot groups and further as you go.

 

[PBramble]

Do the easy stuff first. Replace the scope with a known good one and ditch that brake. Just put a muzzle protector on it to remove a strike from the equation.

 

[dcloco]

Also, have somebody else shoot the beast.

I would shoot off of short bipod and a rear sandbag.

 

[338 dude]

Once you ruled out screws, loose rail or bad scope, as mentioned above, clean to bare metal and try a different bullet look at the difference a bullet change made for me!

 

[tobnpr]

As said, obvious stuff first.
Rings, mount, scope- all tight. You didn't say whether the optic is new, or off another rifle. If it's new, swap it out to rule out it being defective. Make sure your action screws are tight as well- nothing should move.

I've had a few customers let me know of heavy fouling from solids during "break-in". I'd do as suggested and make sure the bore is stripped clean before the next testing. I'm assuming you don't have a bore scope- and if you don't know what you're looking at anyway they can cause unnecessary worry. That said, if you have a local smith I'd call him to stop by for a quick scoping of the chamber and throat. If the chamber wasn't cut concentric with the bore (he can tell easily be looking at the start of the throat) it will cause this type of inaccuracy. When the bullet isn't launched perfectly straight into the rifling, bad things happen...

If all that's negative- go back to your reloading. I'll second that every rifle likes something different- both bullets, as well as powder types. I just re-read your post- if you're just above MOA and not shotgun patterns- it's probably not a scope problem or something loose. That usually means you need to do more load development. I have an AR-10 that wouldn't group 168's inside 1-1/2"- but shoots 175's under 1/2" all day long. Go figure...it's all about harmonics.

 

[cornchuck]

Thank you for all the input. The scope was new. Vortex Viper PST 5-25x50. The first 100 rounds down the barrel (barrel break in fire forming brass) was with Hornady 200 gr eldx. The other 139 rounds were Hornadys 190 cx and Branes LRX. Maybe I didn't get all the copper out when I'd clean the barrel. I usually clean after every range session.

I do have a Lyman bore scope. I know it's not the best tool, it doesn't get used that much. I did clean the barrel a little extra this time. When I ran the bore scope, I didn't see any copper in there.

I ordered a box of Hornadys 212 gr eldx and 225'eldm to see if my gun just likes heavier bullets. The plan is to shoot 10 of each with the side ported muzzle brake and 10 of each with the radial brake that came from the factory. I want to see if there is a difference. I might even switch out the trigger.

Jason

 

[338 dude]

Thank you for all the input. The scope was new. Vortex Viper PST 5-25x50. The first 100 rounds down the barrel (barrel break in fire forming brass) was with Hornady 200 gr eldx. The other 139 rounds were Hornadys 190 cx and Branes LRX. Maybe I didn't get all the copper out when I'd clean the barrel. I usually clean after every range session.

I do have a Lyman bore scope. I know it's not the best tool, it doesn't get used that much. I did clean the barrel a little extra this time. When I ran the bore scope, I didn't see any copper in there.

I ordered a box of Hornadys 212 gr eldx and 225'eldm to see if my gun just likes heavier bullets. The plan is to shoot 10 of each with the side ported muzzle brake and 10 of each with the radial brake that came from the factory. I want to see if there is a difference. I might even switch out the trigger.

Jason

 

[jpd676]

I have a ridgeline in 300wm. I had to send it back twice. They put a total of three barrels on it. Now, it will shoot but it was MOB prior to the third barrel (the second one they put on wouldn't shoot at the factory so they did the third immediately).

 

[slikmrc]

@338 dude, Lots of good info in the pics. What Publication is that?

 

[cornchuck]

I have a ridgeline in 300wm. I had to send it back twice. They put a total of three barrels on it. Now, it will shoot but it was MOB prior to the third barrel (the second one they put on wouldn't shoot at the factory so they did the third immediately).

Each time you sent the gun back, how long did they take?

Jason

 

[338 dude]

@338 dude, Lots of good info in the pics. What Publication is that?