i have a winchester 1300 defender. older version that held 4 in the tube. with choate mag extension to make that 6 in the tube.

when i fire it, i think the barrel is moving. what makes me think this?

1. i can see marring on the barrel where the clamp for the mag extension has slid forward from its original position.

2. the mag extension clap pops my hiviz sight off as it moves forward.

now i'm thinking this is a bit strange.

i took a look at the mag extention, specifically the teeth that engage the ball bearing at the front of the, er, 'barrel hoop' and the spacing in the teech is tighter than the stock end cap. i'm thinking maybe it's just not held on all that well because the teeth aren't engaging the ball too well.

does this condition sound unsafe? what should I do?

thanks.

Sounds to me like the clamp is sliding foreward when you fire the gun.

If the mag extension is tight against the "hoop" or barrel hanger before firing, the barrel should not move foreward.

Is the mag extension still tight against the barrel hanger after firing?

To see if it is your clamp that is moving, put a mark on the barrel between the clamp and the sight with a Sharpie marker. (you can remove this later with Acetone). Put the mark on the barrel and the mag extension. If the mark on the barrel moves foreward past the mark on the mag ext, your barrel is moving. If the mark on the mag ext moves foreward past the mark on the barrel, the mag ext is moving and the threads are probably stripped. If both marks stay aligned and the clamp is closer to the mark than before you fired it, the clamp is moving. Use electrical tape on the barrel and extension under the clamp, and tighten the hell out of the clamp. That should do it.

Let us hear.
Thanks,
Lee
www.thearmsroom.com