TC Contender pellet gun.

A friend approached me with an idea for a pellet gun of sorts. He had an old Crosman .177 cal BB gun barrel that was about .430" OD and 10" long. He was thinking about chambering it for some small caliber and driving pellets with a primer alone. I had an old .44 mag Contender barrel I've shot 20 rounds through about 10 years ago and it's sat since. Turns out that the nominal bore dimensions for a .44mag is .417". So I put the Crosman bbl in the lathe and turned the muzzle to .4165", the breech to .413" and ±.400" in between.

I made the breech .413" so I could counterbore a piece of .44 Magnum cartridge brass with a Z letter drill and glue the Crosman barrel into it. I also drilled/bored the primer pocket to .243" to hold flanged 209 shotgun primers and chamfered the primer pocket to clear the 209's inside radius between the flange and the primer body.

So it's not my prettiest work and this was just a proof of concept. Testing supports that the concept is valid except that standard thin/soft pellets will be stripped of their skirt and the head will be ejected. So the concept might be more appropriate for .22 caliber barrels or a more robust pellet can be cast or purchased. It is interesting to note that the .177 pellet head alone will penetrate 1/2" of pine 2x4 at 3' standoff; perfect for plugging popcans in the back yard.

https://s33.postimg.org/dpqf9s3n3/TC_177b.jpg

https://s33.postimg.org/fuasatuz3/TC_177a.jpg


Improvements are to thread the Crosman barrel breech end and machine a permanent steel flanged piece for headspacing the barrel and the 209 primer.

An extractor for the primer should be made since the dimensions of 209 primers-on-hand vary and might become an interference fit. A positive extractor would make 'reloading' much easier.

.22 and .177 Crosman barrels are available for $20 or less on fleabay and come in 7", 10" and 14"+ lengths and they have real rifling last I checked.

Anyway that is how I entertained myself for an a couple hours last night.

Pretty cool idea. I had no idea that barrels like that were available at reasonable prices, might have to try something like that.

I agree with the round lead ball, especially in .22 or .25.

209's should have plenty of snap to send that ball flying.
Cost is still likely going to be more than .22lr but it is an interesting project.

I appreciate the heads up on ebay barrels. I just ordered a 24" 177 barrel for a contender project. I have a bunch of old RWS 4.5 mm (0.177") bulletless caps. Some time ago, I found an early 357 HotShot barrel. Idea is to make a 177 liner chambered for the 4.5 caps and use regular lead pellets. A 'parlor pistol.'

Had a minute this morning to test a pellet I filled the back of with RTV. The skirt stayed on but I don't think it stabilized. At 2 yards standoff the pellet went through a milk jug full of water and one layer of a cardboard box that was placed behind the jug. The old Crosman barrel's in such bad condition there's virtually no rifling to stabilize pellets anyway. For a production piece I think a .22 cal barrel would be a better option.

I found when loading 22 cal pellets in 22 hornet cases ( I was testing various makers primers in std magnum and match by chronograping velocity of the pellets) loading the 22 cal pellet skirt forward worked better for me. Other wise a skirt would occasionally stick or blow off. I didn't have as much issue with the 22-250 case used testing LRPs possibly due to the increased volumne softening the primers blow, but still loaded into neck skirt forward.
These loads made for some interesting shooting as they were right on line with most 22cal pellet guns. In a custom set up barrel without using a case velocities should increase a little and may casuse more skirt deformation from the force and brisance of the blast. Buta 177 or 22 cal barrel with a short leade cut and "chamber" for a primer should be very consistant as to velocity and pressures. With the flanged 20d an extractor could be cut to remove them easily. the Large rifle or pistol and small rifle or pistols being a cup will be harder to remove.
Accuracy should be very good with the right pellets and leade into the rifling. I had a tool made up that matched the recess in the skirt and was .310 OD above it. This allowed consistant loading of the pellet into the case. It would also iron out the skirt or small imperfections. I have on that's 90* also for loading my 177 rws pellet gun.

I found an OLD Benjamin 9gr .177 pellet and shot it unmodified, it exited just fine and there's no visible skirt in the 'chamber'. Flipping the thinner 7gr pellets around is harder to load but they seem to work that way too. They pop a water-filled tin can open pretty well. The Benjamin pellet went through 2 pop cans, and a milk jug full of water. Seems like plenty of oomph. :D

For a .177 project you might consider trying the .18 size BB shot made for shotshell loads.
The .177 Gamo round balls I've tried are very inconsistent in diameter with an unacceptably high percentage of deformed BBs.
Using the Lead .18 BB shot with a forcing cone should provide better accuracy.

Interestingly there was a CO2 powered .22 replica of the Thompson Contender marketed years ago. These occasionally show up on Ebay or in the classifieds. They don't have a good rep though. IIRC the brand name was Ampell.

There are extra heavy .22 pellets made for use in the HPA PCP guns, some are basically just slugs.
A greased card wad behind slug or round ball might improve performance and lube the bore for following shots.

The original BB Cap was just a piece of bird shot packed in a musket cap.

Crossman Premiers should work for you. Their skirts are thicker and generally a much tougher pellet.

I think you have WAY TOO MUCH power in the shotgun primer.
Large pistol primer may well be plenty of oomph

I doubt it, I have pushed regular .22 pellets over 2100 FPS using nailgun blanks.

http://castboolits.gunloads.com/atta...3&d=1512009203

Years ago another gunsmith tried 22 pellets with 209 primers and the skirts would be stuck in the barrel. We had discussed the problem and came up with the idea that 209s were just a bit to much for pellets. Maybe using a cartridge case with a little space to sort of cushion the pressure would work better. I played around with wax bullets in a 38 special using 209's and found out the hard way that it would penetrate sheet rock . Barrel liners are available in many calibers, including 17. T.J.'s makes barrels for the airgun crowd up to 58 caliber so there are lots of possibilities.

The 9gr Benjamin pellet survived a .209 primer. Its skirt was noticeably thicker than the 7gr ones I also tried. I didn't manage to recover the Benjamin pellet though. Its skirt may have been stretched, but it did not remain in the breech end. Thinner, softer pellet skirts will be stripped from the head. Again the unstabilized 7gr pellets would penetrate 2 pop cans and a gallon milk jug of water; the pop cans would burst too . That's a LOT more power than the old .177 air rifle I had as a kid.

I prefer the notion of the 209 primer since it has a flange that can be used to extract the primer in the field. A large pistol primer's hard to remove without having a turned-down piece of brass or something else to hold a LP primer.

I use pellets in my 223 contender barrel, modified a 223 case to accept a 209 primer, Stuff a pellet in the case neck, load and shoot. No broken skirts, no problems at all, been doing it for years, have shot thousands of them. Something to do in the cellar/load room, especially in the winter.

You should look for one of these...

Attachment 208760

Quote:

---

Originally Posted by Stilly

You should look for one of these...

Attachment 208760

---

Yes, That is a Converta-Pel. I think they came in 22 Hornet, 222, 223, 22/250 and 220 Swift. I have the swift and the 223. Powered by a 209 primer (a 157 actually fits better) they are quite effective. A friend living in the city limits poached 50 some crows one winter with one in 22/250.

Currently not available

http://convert-a-pell.com/

http://convert-a-pell.com/22-centerfire/

I'd think you could make one with a donor case, if you carefully drilled out the primer pocket and then the area for the collar on the 209 primer? Not simple drilling but doable.

The trick in using 209 primers is to ream the chamber so that the pellet drops in to sit about 5/8" to 3/4" away from the primer face. I haven't had a blown out skirt with any of the pellets that I have tested.

https://www.youtube.com/watch?v=Z6GSa7JaN_w

Check out the "Zimmerstutzen." The Germans were doing this over a 100 years ago. The one I inherited from father uses pistol primers.