I'm gonna say that it could be CVA, or possibly Traditions. The short tang is the main indicator. Investarms and most TCs have a a longer two screw tang.
Speaking as a machinist,,,,,,those Craftsman T&D sets are intended for thread chasing not cutting new threads. Buy a new die that's meant for cutting new threads, and you will have no trouble.
Don't bother with the "un-mentionable thingy" it won't save your forearm. The bbl-cyl gap will still spit hot gas and crud. If you wish to shoot those carbines with a foreward hold, use a leather Bracer/arm guard.
Blew the pic waaayy up. The Colt is a "51 and the "Winchester" ain't. The rifle is probably either a Burgess design or a Marlin, both of which were available in the early 1880s. Also the gent at the far left, is holding a TC "Hawken".;)
Don't remove the plug, drop a chunk of brass down bore. Test fit the bullet, and shake the barrel, muzzle down to remove the test piece. The brass will work as a slide hammer without harming the bore.
It's Italian, and fairly modern. Locate the proof marks, nearby will be a date code. Either a box with two letters or a X*** format (Roman Numerals). There is a thread stickied with the date codes around here somewhere. ;)
As to the trigger, if the steel you used is plain mild,,,it needs to be case hardened. Triggers should be made from at least 1045 or higher steel. The sear area (the notch on the set trigger) takes more load than you might think.
Looks to MY eye, that the stock was broken and sloppily repaired. The lock stock and barrel appear to be old. The gap between the lock plate and the barrel bolster appear to have been caused by the over use of filler behind the barrel. Pic 3 shows the forward reset of the barrel tang, and...