Cooey mod 60 and blowback

[bessiedog]

Dug out my uncles old mod 60 repeater. Spent ALOT of time cleaning it up and got the action working on it so it cycles properly.

Shot it 5 times last week. No problem.
Took it hiking with the boys today. Loaded it up and fired 7 straight shots. Shot number 8 went and I got some blowback. Stuff got me in the forehead ( no damage) and I ... Stopped shooting.

I've taken everything apart and cleaned it well.


Any ideas what's causing it. None of the parts seem fouled or worn.

Thanks

[6.5x47 lapua]

you should have the headspace checked.