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Lostinidaho
11-19-2017, 10:37 PM
I am looking for a new long term project.

My father somewhere obtained a rolling block action that some one tried to make a pistol out of. The lower receiver tang has been trimmed. And the barrel cut short.

I like rolling block and I like guns with changeable barrels.

I was thinking of a having a two barrel system (50-45-400 and a 20 gauge shotgun). I want the barrels to slide in and fixed with a thumb screw. Is this possible?

Thanks in advance

Cap'n Morgan
11-20-2017, 10:16 AM
I was thinking of a having a two barrel system (50-45-400 and a 20 gauge shotgun). I want the barrels to slide in and fixed with a thumb screw. Is this possible?



If the barrels are inserted from the front you'll need some sort of locking device to keep them from moving forward due to pressure and recoil. A thumb screw wont do unless in connection with a cross pin or two. It should certainly be possible to machine the receiver to allow inserting the barrels from the rear, like a giant rimmed cartridge, but of course it would require removing the rolling block and hammer when changing barrel. Also, inserting the barrel from the rear may work with a plain shotgun barrel, but not so much with a rifle barrel with sights!

Gewehr-Guy
11-29-2017, 09:53 AM
Perhaps you could use an interrupted thread system, like the takedown system of a Win. mod 12 or 97.Then maybe a spring loaded plunger inlet into the forearm,that locks into a corresponding hole in the trigger guard. I wouldn't trust it to shoot 400gr. loads if converted this way, but something like .44-40 and 28 gauge black powder sounds like fun.

country gent
11-29-2017, 04:05 PM
There are several ways to do this. CPA uses a hand tightened barrel and a set screw to time and lock the barrel in place, this set screw has a 60* point machined on it and a mating surface in the barrel shank. Another would be the hand tightened barrel and a cross pin thru the barrel receiver junction, this pin would have a detante ball to hold it in place. Last would be a swap barrel like bench rest and some others do with a witness mark and using a barrel vise and action wrench to change out the barrels. Keepin mind that unless cartridges are the same head dia extractors will need to be changed out also. Most of the Rem rollers are square threads so a long stub could be turned and a barrel nut made similar to savages system. wont be as flowing a look. My choice would be between the cpa and bench rest systems.

TCLouis
11-29-2017, 09:58 PM
Any interest in a barrel nut not unlike the Savage system

Lostinidaho
11-30-2017, 12:11 AM
I didn't know what a Savage system was till I looked it up. That would be slick.

Am I right thinking with the Savage system you could adjust head space?

Over the Thanksgiving Holiday, I got to give the rolling block receiver a very close look.

It has a crack running from the breech block pin to the top of the receiver. Maybe that is why it was turned to a prop wall hanger.

John Taylor
11-30-2017, 10:01 AM
With the corse thread on most rollers it might be best to just screw the barrels in like a Steven 44. You could make a frame extension like a Winchester 1885 with a sliding lock to keep the barrel from moving. Cutting interrupted threads on a barrel is not to hard with the right equipment but doing the frame would be a bit tricky. You would also need a different extractor to go with the barrel. Sounds like an interesting project. I might just have to steel your idea and make up a multi barrel setup on a #5. I could do 25-35, 30-30 and 38-55 and use the same extractor. The breach block would need to be removed to swap barrels but that's no big deal.

country gent
11-30-2017, 01:43 PM
On the Savage system with barrel nut it can be used to adjust headspace if there are no sight cuts or mounts on the barrel. Actually with the not really due to the extractor cut and relief cut for the block on the back of the barrel, these have to stay in alighnment also. On a round barrel with no cuts sights of other things yes it can adjust head space. On the rollers the extractor cut, relief cut and forend screws all determine timing also.

john.k
11-30-2017, 07:54 PM
With the cracked reciever,the best you could safely use it for would be 22 rf.In which case,a cross pin would be quite sufficient.