Yes, the Green Mountain "drop-in" barrels will fit the Lyman trade rifle (not Great Plains) as well as the T/C Hawken. With either rifle one may sometimes have to do a bit of fitting, perhaps remove a bit of wood around the underlug and sometimes the rib needs to be cut an 1/8 of an inch shorter to fit the individual rifle. Some drop in, some require a bit of help regardless whether Lyman or T/C.