Tracker, sorry to hear about your gun problem. After reading your opening post, I was wondering if you are referring to a NEW Huntsman,or one of the older H&R's?
I assume that it is a new Huntsman and a few things come to mind that I would check,should it happen to me.
1) Remove forearm and check slowly the opening/closing response and how it pivots on the barrel lug/receiver pin (assuming both surfaces are clean and lightly oiled. Install forend and see if everything remains the same...or if causing action to close with more difficulty.
2) Insure that breech plug is screwed in all the way and not interfering with the receiver recoil face. Check also with a primer carrier to see if anything changes.Also check that firing pin is retracting properly.
3) MOST IMPORTANT...Double check the mating surfaces of the locking mechanism,to insure that they are clear of powder fowling,etc. and lightly oiled. (barrel lock shelf and under surface of latch on receiver.
Plunger the latter with your finger (barrel off) insuring that it has free spring movement and not cruded up (check lower hidden surface with a cleaning patch on your finger tip.(only good way of reaching under and into that small area of latch...for me :roll: )Clean this area well.
I know that you have probably done all of these things ...and probably a few that I'm not thinking about,already.
I cannot imagine,however, that the receiver hinge pin got bent, to cause any permanent distortion to impede lock-up. Only thing that makes sense would be fowling to the latch surfaces and mechanism that sometimes escapes a good cleaning/oiling, or the breech plug not screwed in far enough.
On a long shot...some change to the forearm end cap that places friction onto the mating surface of the receiver front....but usually that area only makes closing/opening more difficult due to excess friction.
I know how frustrating this is,and sorry that I don't have more to offer.