Savage 440 locking problem

[shaune509]

I have a Savage 440 12ga O/U [Fabarms] that the breach unlocks upon firing a round. Breach lock looks good and is clean with out disasambling the action for a closer look. It seems to lockup solid before firing, but will just unlock after ward. Shells were Win 1-3/4oz #6 2.75". Any ideas as to why? Thanks in advance for the help.
shaune509

[DLCTEX]

Is this a new to you gun or is this a recent occurrence? My grandson's Handi Rifle (243) did the same And I found that it wasn't moving the locking bolt far enough into battery. A few touches with a file on the end of the bolt let it move farther. If this is a new problem, disassembly and cleaning may cure it.

[shaune509]

Thanks for the responce. It has only happened with heavy loads, so you might be correct, the lock bolt are clean but I will try to determine the engagement stroke.
Shaune509