OK folks, after a not s olong hiatus a car wreck, and major surgery on my leg, I'm back, and with yet another question.  As everyone knows i'm putting together a parts gun Trapdoor Springfield for BPCR competition.  I have a 45 cal #3 taper Green mountain barrel blank, a disassembled (but I think it's complete) breechblock, and what should be the rest of the action assembly but we have a not so small problem.  I have no idea how all of it goes together and what the clearances and tolerances for a trapdoor are.  Anybody can point me in the right direction?  Where's Dick?

well, looks like I need to call midway and order a new book.  I'm not tackling the barrelling myself sowould anyone care to chime in and tell me how to put this thing together as it will probably be a while before the book comes in the mail?

Hello Don,

As far as I know, there are just a few things to look for when putting a trapdoor together from parts:
1) there are wide recievers and narrow recievers. If you are using an original stock, make sure the stock width matches the reciever width. Reciever with a serial number over 100,000(?) are all wide recievers.
2) A two stage tumbler requires a sear cut for a two stage tumbler. I prefer a three stage, in which case the sear must be cut for a three state tumbler. 
3) when you remove a lock from a trapdoor, make sure you put it on half cock. Otherwise you run the risk of chipping the wood at the bottom of the lockplate.
4) before removing the action from the stock, loosen or remove the lock plate screws.
The lock is just like a muzzleloading lock. A special mainspring clamp is handy but a vise grip pliers(locking) will also work. 
Some firing pins are made for a small return spring, others are not. I prefer the ones without,I think either one will work in any rifle. 
Cut down original  wood is not that hard to find. If there is enough wood on the forend, you can make a nice sporter out of it with no inletting. The parts will all drop in. (assuming you have wood that matches the reciever width.).
Cadet stocks and buttplates are narrower, If narrower is OK, not a problem. Otherwise you are in for some sanding and grinding to make things match up. 

I hope this is helpful. Good luck with your project. Joe S

Hi Nobears. Sorry, I've been gone for a few weeks.  The basic info the guys are giving you is good. The books mentioned have enough meat in them to be a larnin' ya how ta be puttin' thet thar trapdoor together.  If you do have any trouble, I'm always willing to put it together for you, gratus. Put together a specific list of what you have in parts and we can go from there. For barreling the action, the best advice you got was John McGlothin. I'm getting ready to send him two actions for my projects right now. If you can't find contact info on him, let me know. Your project can't be any goofier than what I've sent him. He humors me a lot. Give me a shout here or PM. Look forward to hearing from you.

Dick

Be glad to walk you through it NBY. How far dissassembled is the action? Breech block stripped?  The firing pin drops in with the slot on the bottom. Screw holds it in. There is a small coil spring behind the thumb latch. Set that in place and the latch rotates into position and is held by a second screw. Hardest part is getting the breech block back in the action. Trick... after setting the ejector pin,  spring & ejector in place, start a long drift or punch in from the right side. Use this as a fulcrum, lever the block and ejector into position while starting the hinge pin from the left. Once the hinge pin starts to enter the ejector, tap it in and the drift out all in one motion. Let me know if there's any other way I can help. I understand the accident you had in a fashion. Mine broke my neck in 4 places, my back in two, broke both shoulders and turned an inch & a half of my left leg to dust. So stay with it NBY, you'll make it. My prayers and blessings go out to you.

Dick

All I lost was a muscle out of my left thigh, and 1 rib on that same side (they say it just got turned to dust) but otherwise I'm not doing too bad, aside from the pin they put in my femur telling me when it'll rain.  Thanks for the assistance guys, Dick, you may end up doing this one if my book doesn't hurry up and get here.

I'll let you know.

It sure would, I'm using a number 3, but what you have to do is get rid of the points that stick out past the front action ring.  I'm just going to turn my round for an inch or so.