won't stay closed

[grant ross]

My SBT opens up when fired it locks up tight with no play but opens up when shot??

[Harry Gietler]

Originally Posted by grant ross

My SBT opens up when fired it locks up tight with no play but opens up when shot??

That is called a ''Self Opener'', Some Guys payed extra money for that ''Feature''
With all Kidding Aside, What make of S.B.T. ARE YOU TALKING ABOUT?

[grant ross]

Parker SBT SC grade

[Harry Gietler]

What position is the Lever in when you Snap the gun closed, and how long have you owned it? Did you or some one replace the ''WEAR'' Plate on the locking bolt? If the answer is yes, it may not be fitted properly.

[B. Dudley]

It is usually a bolt bite issue. Or a weak/broken top lever spring. But usually the bolt.

[grant ross]

thanks I'll contact previous owner and find out as much as I can about previous work etc

[grant ross]

forgot to ask what is the bolt bite

[Jeff Christie]

My SC does that on occasion with 3 dram 1 1/8 oz loads. My shoulder can’t stand a steady diet of 3 dram shells so I am delaying getting it fixed. I load very light 3/4 or 7/8 oz. Loads and never have an issue. Score is not a big issue with me but comfort and pain is.

[Frank Good]

I assume an SBT "wear plate" is something along the same lines as the locking plate in something like a 101, Citori etc. and not shaped like the locking block in my Perazzi's?

[Researcher]

Parker bolting from a 1930 catalog.

Bolting from the 1930 Parker Bros. catalog.jpeg

The fit of the replaceable "bolt plate" is critical as well as the strength of the top-lever spring.