when were the single barrel traps made?

[Don Kaas]

You are probably right Bill, one of the 5 SCs I've had was an early one with the access screw and it had 34" Acme barrels...

[Autumn Daze]

Bill and Don ....My first SC serial 180115 was a 32" straight grip gun with the access hole. It had Titanic barrels.

Also I checked the Serialization book last night and there were guns listed in the the 158,s. Does this make any sense? Seems way early to me too.