12 Gauge A-Bolt - Bolt won't open after 3rd shot

[dsh1106]

Was just at the range testing several different brands of slugs in this gun.
Remington
Winchester
Federal
All loads were 2 3/4 designed for rifled barrels.

Of the factory loads nothing seemed to group well past 50 yards except the Federal Truball loads.

While shooting the Truball rounds, the gun locked up. The bolt would operate, move from the closed to open position, but would not unlock and open.
After playing with the gun for 5 minutes or so the bolt was able to cycled open. The casing didn't look any different than any of the other that were shot from the gun. After cycle the gun a few times and looking things over, I mounted the gun in the lead sled and shot more than 10 rounds remotely (Remington and Winchester), the gun fired and opened as it should. I loaded gun with 3 rounds of the Truball, and after firing the gun three times the bolt locked up again. It appears that this gun doesn't like these Truball loads.

What say you, anyone have any ideas?

Scott

[Rich/WIS]

Not familiar with the round but possible that the brass base is soft and expanding more than the other rounds. Suggest miking the bases before and after firing and also do the same with the others as a comparison. If this is the problem a call to Federal is in order and talk to them. May be a bad lot.

For accuracy you might try some of the Brenneke type slugs, found they were much more accurate that the US Forster style slugs. Not sure who makes them now but think they are still available.