[Lemarc]

Good morning to all,

Long time reader first time poster!

I have a few questions regarding the performance of a new T3 Varmint in 300WSM purchased recently.

Took it out yesterday to break the barrel in and get it on paper, cleaned the barrel completely before first shot, first 3 shot at 50mtrs were key holed. Then cleaned barrel again, second 3 shot opened up! This continued until it was shooting about 3 MOA after 4 of 5 cycle.

This would not be of concerns except for the fact that i have broken quite a few barrels in and typically get quite consistent results that get better with Load development, bedding etc, to this i also own a T3 Varmint in 204 that followed the normal lines of performance during the breaking process and now after some additional work shoots .5MOA all day long.

Is anyone aware of barrel issues?
Do 300WSM barrels take longer to break in?
Has anyone else experienced this?
Should i put more rounds through and give it time?

Thanks in advance,

Marc

 

[Mainspring]

Accuracy will/should come, but the keyholing may be troublesome.

I would check for an enlarged bore at the muzzle, and also check for damage to the crown and rifling. If these are reloads, then check for correct velocity and bullets.

 

[MikeG]

I think you have a bad crown or bad barrel. The fact that it is getting better suggests that there is a burr on the crown that is wearing away.

The bedding, scope, etc., would not make bullets keyhole.

 

[fred243]

I agree with both posts above and would say to check the action screws and make sure they are torqued properly and not loose. Shouldn't keyhole even when brand new ! If you have a bore scope or can borrow one I would do that before I shot it again or at least look down the barrel the best I could with lights if possible.
Welcome to the forum, Lemarc !

 

[firebird]

No new rifle should key hole and the advice given so fa was good advice. The only other thing I can think of would be an extra long bullet for the rifling twist and that should not be an issue with factory ammo.
I would be inclined to not shoot it any more and return it to where I bought it and talk to the people there about the problem. It could be a quick fix by a factory gunsmith. Don't take a chance on playing around with anything that could void the warranty.
An accuracy problem can happen but a key hole is an indication that there is a bigger problem that should be tackled by a gun smith. Better on their tab than yours.