.300 win mag stopped grouping proven load

[petasucks]

my tc encore has decided to drive me crazy i have benn shootn 77 gr of h1000 under a seirra 180 pro hunter for 10 yrs it shoots 3 holes that touch each other previously now its throwing a 6" group the load is correct i checked it over very carfully im seated at 2.932 which is 4-5 thou. off the rifling.i have decopperd and cleaned the barrel then fouled back with 5 shots. could the scope be jumping to cause this? as always thanks in advance for all yalls great advice

 

[alaska]

Check your forearm screw

I replaced that pivot pin with one that didn't shift.

 

[Rick Richard]

Check the 'pin' that holds the receiver and barrel assembly for excess movement.

Also, make sure the 'ears' on the forearm stock is not touching the receiver.

 

[barefooter56]

Check the 'pin' that holds the receiver and barrel assembly for excess movement.

Also, make sure the 'ears' on the forearm stock is not touching the receiver.

petasucks,
IF you have had to set the bullet out of the case some , chasing the throat . You MAY have gotten off your velocity accuracy node. As you set the bullet out it opens up more case capacity and can lower your pressure in the case which in turn can lower your velocity. See if you can get back to your velocity node by going up in charge 1/10th of a grain at a time. You may want to do this after checking the mechanical s of the rifle as mentioned if you are still having this accuracy issue after addressing them.

 

[petasucks]

have a .005 over pin driven in fore arm is good will try hotter load thanks

 

[RockyMtnMT]

I did not see that you changed your seating depth to chase the lands? I would look ant the scope for such dramatic change in poi. Is it possible that the crown may have been damaged?

Steve

 

[6x6 elk]

Whenever I have had a big change in accuracy from a proven gun, it has almost always been in the scope, or the rings /bases are loose. You may need to put a different scope on it to see if that inconsistentcy is there or not. It's a pain in the behind, but you could be chasing your tail otherwise

 

[mark fox]

throat, change your seating. should fix the problem. also check your cases have they grown and are now getting spikes. the 300 win mag is a fast grower. and this cause lots of problems. but first check your scope, bases & rings

 

[alaska]

Encore Accuracy Locker Hinge Pin

Pivot pin for encore

 

[petasucks]

it was the scope but kudos to leupold full warranty ive had it since 1992 they said send it back and we will replace or fix it if possible thanks to everyone for all the help

 

[mark fox]

If you got 13 year out of a leupold your lucky. I cant seem to get more than 3 years if that.