SB, You are lucky that the Hornet barrel fit perfectly without having to be fitted to the action. Starting with the "B" actions, they changed internally from a striker system to a hammer system. With the early striker systems, they cocked when the top lever is moved to the right to open the action. Any barrel (early or late) will work with them. The hammer system guns have a spring loaded stud at the bottom right rear of the barrel lug that engages a cocking lever in the right rear bottom of the action and cocks the hammer when the barrel pivots open. Check your new Hornet barrel, and I believe you will find this stud missing. You have two options....save the Hornet barrel for an early striker action, or....the stud assembly can be found on Ebay and sometimes from Numrich Arms. The assembly has 3 pieces, hollow stud, spring, and retaining screw. The barrel lug would have to be drilled and tapped for the assembly. Anyone can tell at a glance whether any M219/220 action is a striker or hammer model. The striker actions have one large pin and the hammer models have two large pins. As to the Hornet barrel being hard to open.....The barrel lug to locking lug measurement could be different from the original barrel. I have found a lot of these guns that show little use are very tight and hard to open. A competent gunsmith should be able to adjust the barrel lug on the Hornet so that it is not so hard to open (If you decide to modify it and leave it on this action). I suggest advising him NOT to change any dimension of the locking lug as this could make a change in the way the original barrel locks up. I hope this is some help to you.
