What the heck is .251 TCR? Well, lemme tell ya...

[Tinker Pearce]

.251 TCR stands for 'Tinker Centerfire Rimmed.' It's a straight-walled .25 caliber case designed specifically for revolvers, and it's a passion-project of mine.

Back during the .22 shortages a fellow known on the forums as Magnumwheelman had a single-six made in .25 ACP, sort of as a re-loadable .22 LR replacement, and it worked out pretty well. In fact I planned doing my own conversion in .25 ACP, but I got to thinking, and that's where the trouble began. The tiny ACP has a very limited case capacity and a relatively weak head, so there are limits on how much you can hot-rod it. What if I did a rimmed cartridge, made of stouter stuff and with more case capacity? Ideally it could be loaded anywhere from indoor gallery rounds to somewhat hotter than .22 Magnum.

Magnumwheelman was on board right away, and sent me some .22 Hornet brass as a parent cartridge, then later sold me some leftover .251 barrel from TJ's. I got some .25 ACP dies and was off and running.

I started with the sizing/de-priming die. I made a replacement for the de-priming pin, a .250 hardened-steel rod with a well-rounded point on the bottom end. Using a .22 Hornet shell holder I ran the .22 Hornet into the die and squeezed it in over the pin to form a straight-walled case. I had to take off the bulge at the rim of course; quickly and easily done with a fine file and a hand-drill. chuck the case up in the hand drill, spin it and apply the file... easy-peasy. then I shortened the case to the desired length.



The brass has an outside diameter of .275″ and is .980″ long. The rim diameter is approximately .350″.

Naturally I needed a gun to test-fire it from. I had picked up an Uberti 1873 Black Powder cheap; this is a percussion version of the Single Action Army, mainly made for countries where owning cartridge firearms is problematic. I had to change the breech and firing pin. I bored the cylinder through and press-fit 4140 rod in to fill the chambers. I bored out the barrel and inserted the .251 liner, a press fit with Loctite Red. I'd wanted to leave the barrel at 4-5/8", but had some issues with tools that required me to cut it to 3-1/2". I line-bored new chambers, then reamed the and chambered them with a .275 reamer for the new cartridge. Works a treat. I slab-sided the barrel to give it a distinctive look.


Now that I had a test gun it was time to start reloading and get the chronograph out. I swaged some 38gr LSWCs, and bought some PPU 50gr FMC. I also picked up a tin of H&N Grizzly 31gr. LHPs and a couple hundred 35gr. Gold Dot JHPs. I loaded some of the LSWCs over Unique, and got about the energy of a hot .22 LR from a 4" barrel. I branched out to Power Pistol and Red Dot, with excellent results from these latter two powders. Then I discovered Rimrock Bullets Hard-cast 55gr. LRNFPs and grabbed 500 of those. I've done a lot of experimenting and have been giving my new Chronograph a workout.

So far I've developed gallery loads with about 5 ft./lbs. of energy all the way up to loads giving around 170 ft./lbs. from my 3-1/2" test gun; the cartridge is proving every bit as versatile as I had hoped.


I've even put together a second project gun- an 1849 Wells Fargo (reproduction) cartridge conversion in .251.

(No, the sheathed spur trigger is not a feature of the original gun.)
Anyway, I'm having a ball playing around with this and thought I'd stop lurking and start sharing.

[45workhorse]

Nice!
What kind of velocities?
What kind of accuracy, are you getting?
Rimrock has good bullets.

[Tinker Pearce]

Accuracy is fine, though the 35gr. GDHPs don't like to be pushed too hard; they seem to want to keyhole at 1460 fps., then of course accuracy is out the window. The PPU FMC are good with high-pressure loads, and I'm really liking the Rimrock 55gr., but I haven't had a chance to chrono those yet. I expect them to perform well in some of the more powerful loads. The 38gr. LSWCs do well across a range of velocities, but they are pretty soft; not sure I can push them much further than the 1215fps. I've hit with the latest load. Primers have been an issue- I've been using Federal #100s, but the hotter loads are tearing them up. CCI Magnum Small pistol primers handle the pressure much better, and I've been told to consider CCI small rifle primers.

If anyone is really interested I can put up some load data.

[salty dog]

I would like to see data. The idea of a flexible round in the 22/22mag power level is attractive.

[dverna]

I admire the ingenuity and workmanship.

Not for me, but still interesting to see what others more talented are able to accomplish

[Tinker Pearce]

I would like to see data. The idea of a flexible round in the 22/22mag power level is attractive.

Here's what I have tested so far; values given are generally rounded up or down to the nearest whole number. All loads were fired from the same 3-1/2" test gun.

31gr. H&N Grizzly LHP- This is actually an airgun pellet shaped like a bullet.
1.0gr. Power Pistol 257 fps. 4.6 ft/lbs SD: 28 fps.
Gallery load. Flies straight and groups well at 15 feet

2.5gr. Unique 843 fps. 49 ft/lbs SD: 79 fps

2.8gr. Power Pistol 1104 fps. 84 ft/lbs SD: 57 fps

35gr. Gold Dot Hollow Point
2.7gr. Power Pistol 769 fps. 41 ft/lbs. SD: 41 fps

3.5gr. Power Pistol 1214 fps. 115 ft/lbs. SD: 38 fps

4.0gr. Power Pistol 1464 fps. 167 ft/lbs. SD: 54 fps.
Bullets yawed or key-holed, poor accuracy at 7 yards

35gr JWCHP- These were swaged from the GDHP listed above.
2.5gr. Power Pistol 726 fps. 45 ft/lbs. SD: 45 fps.
Need to see how hard I can push this bullet. The greater surface area might keep it stable.

38gr LSWC- I swage these from ¼” lead wire.
2.0gr. Power Pistol 698 fps. 41 ft/lbs. SD: 41 fps.

2.5gr. Power Pistol 875 fps. 65 ft/lbs. SD: 26 fps.

2.7gr. Power Pistol 912 fps. 70 ft/lbs. SD: 24 fps.


2.0gr. Red Dot 1214 fps. 124 ft/lbs. SD: 19 fps.


50gr. PPU FMC
2.7gr. Power Pistol 831 fps. 77 ft/lbs SD: 13

3.5gr. Power Pistol 1108 fps. 136 ft/lbs SD: 21

57gr SPJSWC- I swaged these from cut-down .243 JSPs
3.8gr. Power Pistol 1078 fps. 155 ft/lbs SD: 13

65gr. LSWC- Swaged from 1/4" lead wire
2.8gr. Power Pistol 1038 fps. 155 ft/lbs SD: 15

Currently I am working up more loads with Red Dot, and I'll be doing more with the Rimrock 55gr. Hard Cast LRNFPs; what with work and the holidays I haven't been able to devote a lot of time to this recently.

[Wolfer]

Very interesting.

[tbx-4]

Neat little cartridge and the Uberti 1873 conversion is way cool and well done. I like it!

[Tinker Pearce]

makes me ask why, as the 25 hornet kind of makes it redundant.

It really doesn't; comparing this to the .25 Hornet is like saying a Corvette makes a Ford Transit redundant; they are intended for entirely different uses. .25 Hornet is a rifle cartridge, and considerably more powerful. The .251 TCR is designed for revolvers, and sized so that it will work in even a quite small platform. A Ruger Bearcat could easily be chambered in .251 TCR; you couldn't do that with the Hornet. If you could it would under-perform and have a ridiculous muzzle-blast, being designed for rifle-length barrel.

[40-82 hiker]

I have to wonder how hard (easy ?) it would be to convert most any .22 mag revolver to this cartridge (maybe lengthen the casing a little to match the .22 mag length of 1.055" ?)? Have to modify the firing pin... Replace or bore the barrel... Cost prohibitive for me, but then again, no more headache of .22LR unobtanium situations. Bullseye and Unique could shine in this, I would think. Many possibilities...

[missionary5155]

Good Morning
Nice idea and far better than the 22RF. That 65 grain load would do some real hurt on troublesome 4 legged critters.

[Tinker Pearce]

I have to wonder how hard (easy ?) it would be to convert most any .22 mag revolver to this cartridge (maybe lengthen the casing a little to match the .22 mag length of 1.055" ?)? Have to modify the firing pin... Replace or bore the barrel... Cost prohibitive for me, but then again, no more headache of .22LR unobtanium situations. Bullseye and Unique could shine in this, I would think. Many possibilities...

This is something I have thought about, and any .22 LR or WMR with an adequate cylinder would work fine. The outside diameter of .22 WMR is .242" or so, so there'd be no issues with chambering. Just run a .251 reamer in, then a .275 reamer to the correct depth for the .251. Myself, I would bore out the existing barrel and line it so issues with chamber alignment would be minimized. How difficult it would be to adapt the ignition system for centerfire would depend on the specific gun, but it's doable. This might be a future project for me if a suitable donor-gun shows up at a good price. I think this would be a pretty cool round in an airweight J-frame too...

[tbx-4]

...25 Hornet is a rifle cartridge, and considerably more powerful. The .251 TCR is designed for revolvers, and sized so that it will work in even a quite small platform...

I think your .251 TCR would work great in a little carbine too! Even in a single shot but a pump or lever action would be very cool.
Having a six shooter and long gun in the same caliber ain't a bad thing. Small, light and packable. I like it!

[Tinker Pearce]

I think your .251 TCR would work great in a little carbine too! Even in a single shot but a pump or lever action would be very cool.
Having a six shooter and long gun in the same caliber ain't a bad thing. Small, light and packable. I like it!

Hmmm... I think this may be a future project as well. The barrel won't be too expensive; about $120. Something like this rolling block .22 I made last year on a 10/22 barrel:

[harm]

I opened this expecting a necked-up 22 TCM, but this was a pleasant surprise. I really admire the work you did on those pistols. If I ever catch up on projects.. this is something I'd consider pursuing as a new one.

[Tinker Pearce]

I opened this expecting a necked-up 22 TCM, but this was a pleasant surprise. I really admire the work you did on those pistols. If I ever catch up on projects.. this is something I'd consider pursuing as a new one.

If you ever need information, dimensions etc. hit me up.

[harm]

Absolutely, I really like the idea. Should be a really flexible round to load for, compared to 25 ACP.

[dverna]

Curious why you did not go with a .32 S&W Long?

[Tinker Pearce]

Curious why you did not go with a .32 S&W Long?

I love .32 S&W long, and have a couple of them. It's accurate, and can be a fine small-game cartridge. But the goal was a re-loadable alternative to rimfires, and .32 really doesn't do the job of replacing the whole spectrum of .22 rimfires, especially in the field of super-light gallery loads. This cartridge can be loaded to emulate .22 Colibri or 6mm Flobert at the low end, all the way up to hotter than .22 Magnum at the high end. It's just a better fit for the mission than .32 S&W Long.

[uscra112]

This seems a mighty good idea for revolvers if you can build your own or have one made.

This is the exact route some people are following to make a reloadable .25 Stevens Rimfire, for which countless thousands of boys' rifles and Stevens 44 small game rifles still exist, but for which ammo is so scarce as to bring over $1.00 a round on Gunbroker. Just trim the swaged-down Hornet case to 1.125" and use a 65 grain .258 cast bullet. (Yes, I know Barnes says .251 but all the Stevens and Remington barrels I've collected are .257 plus or minus.)

Occurs to me to add that, before the advent of smokeless high velocity .22s, the .25 Stevens was considered the acme of small game rimfires, so a centerfire recreation of it is very much in order.