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Old December 1, 2019, 02:28 AM   #1
Tinker Pearce
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.251 TCR- wildcat revolver cartridge

.251 TCR (Tinker Centerfire Rimmed) is a straight-walled .25 caliber cartridge designed to fill all the various roles of .22 Rimfires, from gallery loads to exceeding .22 Magnum performance, in a reloadable cartridge with centerfire reliability. It's intended primarily as a recreational/hunting cartridge, but it may also have some utility as a defensive cartridge.



The parent case is .22 Hornet. The finished case-length is .980" with a .275 outside diameter and rim approx. .35" in diameter. The test gun is an Uberti 1973 Black Powder (their C&B version of the SAA for countries where cartridge firearms are difficult to own.) I used some TJ's .25 ACP barrel-liner provided by Magnumwheelman, who also provided the initial .22 Hornet brass to get things rolling. I bored through the cylinder and filled the chambers with 4140 round bar, and after the barrel liner was fitted I line-bored the chambers. I was limited to a 3-1/2" barrel because that's what I could do with the tools on-hand. I'm OK with that because if I can hit my performance benchmarks from this short barrel a longer barreled handgun will only improve things.



At some point I'll fit a modified ejector and housing, but for now I just pull the cylinder and punch the empties out with the cylinder pin. Initially I was testing with 35gr. Gold Dot hollow-points, 50gr. FMC and swaged 38gr. LSWCs. The Gold dots can be driven to up to 1450+ fps. pretty easily, but unfortunately they aren't stabilizing well; at 7 yards I'm getting yawing and even keyholing, and accuracy is not good as a result.

The PPU 50gr. FMC on the other hand are very accurate; of course it wouldn't be me without a flyer...



The 38gr LSWCs are similarly accurate.

So far I've loaded rounds in the .22lr and .22 WMR range, and some that exceed .22WMR from a 3-1/2" barrel. I've used Unique for some of the LR-equivalent loads, but I am mostly focusing on Power Pistol right now, and I'll be experimenting with Red Dot next. Interestingly even the most potent of the Power Pistol loads are not producing the somewhat obnoxious muzzle bast associated with .22 Magnum from short barrels.

I'll be using some .25 caliber airgun pellets, seated deep like a wadcutter, for the gallery/pest loads, but right now I am exploring the mid-to-upper range loads. One of my favorites so far is the 65gr. LSW at 1038 fps. producing 155 ft./lbs., with a standard deviation of only 15 fps.!

Fun project and it seems like a genuinely useful round. My expectation for this round is that I will have a lot of fun playing with it before it vanishes into obscurity, but hey- a fellow has to have a hobby, right? Doesn't stop me from fantasizing about a .251 TCR Ruger Bearcat, or a 7-shot airweight J-frame...
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Old December 2, 2019, 01:23 AM   #2
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Interesting project. Does the liner have a 14" twist? What is the length of one of the keyholing Gold Dot bullets? I am wondering if they are long for their weight or if they just don't handle dropping into the transonic velocity range very well.
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Old December 2, 2019, 01:40 AM   #3
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Interesting project. Does the liner have a 14" twist? What is the length of one of the keyholing Gold Dot bullets? I am wondering if they are long for their weight or if they just don't handle dropping into the transonic velocity range very well.
Yes, it's a 1:14 twist. I haven't got one of the Gold Dots handy to measure, but they are short, with around half of the bearing surface that the 50gr FMC bullets do. Even the 38gr LSWCs have significantly more bearing surface, and they seem to stabilize properly.

With a limited amount of brass I have been focused on chrongraphing loads, so now I am going back to check more of them for accuracy/stability.
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Old December 2, 2019, 09:53 AM   #4
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It's odd. Short bullets normally need less twist, but if they are light enough for their length, that can change.
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Old December 2, 2019, 11:08 AM   #5
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It's odd. Short bullets normally need less twist, but if they are light enough for their length, that can change.
That was my thought too. Given the bullet was designed for velocities around 800 fps. I may be over-driving the bullet at these speeds; the jacket is quite thin. I may shoot one into water so I can recover a bullet to have a look.
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Old December 2, 2019, 01:58 PM   #6
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Well I hope it does well on charging mutant ninja squirrels!

Looks like a fun project but I felt compelled to put (at least my sense) of Midwest humor in.

I do think think the T should be amended to Tinkerer with a double intendre or some such play on words.
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Old December 3, 2019, 02:33 AM   #7
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More testing today-

38gr. LSWC 2.5gr Power Pistol, CCI MSPP

875 fps 65 ft/lbs SD: 26.3

Cookie-cutter holes, good accuracy. Going to push the velocity up a bit, but these are pretty soft lead. Probably not going to take them over 1000 fps.

57gr JHPWC, 3.8gr. Power Pistol, CCI 550 MSPP

1078fps 147ft/lbs SD: 13.4 fps.

This load yielded mixed results; most hit the target squarely with good accuracy, but occasionally one would yaw or keyhole. I'm pushing the sound barrier here- maybe the odd faster than average bullet is hitting trans-sonic turbulence? I think this bullet shows promise; I'm going to back off the velocity slightly.

31gr. JHPWC 2.5gr. Power Pistol, CCI 550 MSPP

726 fps 36 ft/lbs SD: 44.5

Since the 31gr. GDHPs weren't working out I swaged some of them into hollow-point jacketed wadcutters. I've started with a modest charge just to see if they would stabilize, and at this low velocity they have. Cookie-cutter holes with good accuracy. Time to start bumping up the velocity.
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Old December 3, 2019, 12:43 PM   #8
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It continues to be an interesting experiment. Please keep reporting.
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Old December 3, 2019, 02:16 PM   #9
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Am curious why you chose .251" over the .257" common for rifle bullets. Was it just to use .25acp bullets? or was it just the size of the liner you could get?
Something else??

am thinking that with a .257" bore, a 60gr cast slug it would be a dandy small game round, and wouldn't need swaged down slugs to fit a .251" bore
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Old December 3, 2019, 02:41 PM   #10
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Am curious why you chose .251" over the .257" common for rifle bullets. Was it just to use .25acp bullets? or was it just the size of the liner you could get?
Something else??

am thinking that with a .257" bore, a 60gr cast slug it would be a dandy small game round, and wouldn't need swaged down slugs to fit a .251" bore
The .251 is intended as a pistol cartridge to cover the range of .22 rimfires; as such I wanted to use bullets designed for pistols. I'm actually swaging 1/4 lead wire, and some cut-down .243 jacketed bullets- swaging these up rather than down.

With the intent of making gallery/pest loads the ability to use .25-caliber airgun pellets was another attraction. For pest control some of these pellets should make excellent quiet/low flash rounds.
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Old December 3, 2019, 02:56 PM   #11
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Thanks for the explanation, I thought it might be something like that. I can see where using .257" bore would lead some people to thinking they should use .257 rifle bullets, and the round should be powerful enough to do that successfully, etc., which is clearly not your vision.

next question, CCI 550...?

the case isn't huge, you're using very small charges of powder, is there a reason you're using the magnum small pistol primer??
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Old December 3, 2019, 03:20 PM   #12
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Thanks for the explanation, I thought it might be something like that. I can see where using .257" bore would lead some people to thinking they should use .257 rifle bullets, and the round should be powerful enough to do that successfully, etc., which is clearly not your vision.

next question, CCI 550...?

the case isn't huge, you're using very small charges of powder, is there a reason you're using the magnum small pistol primer??
I was using Federal 100s, but they aren't tough enough for some of the maximum loads; they were actually pushing into the firing-pin hole. They appear in the lighter loads because I was too lazy to change them out.
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Old December 3, 2019, 06:46 PM   #13
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OK, now there is an Gallery Load-

31gr H&N Grizzly hollow-point pellet, 1.0gr. Power Pistol, Federal #100 SPP

257fps., 4.6 ft/lbs, SD: 27.5

They leave the barrel, fly straight and punch holes in paper with decent groups at 15 feet. Not loud either; about right for an indoor gallery load.
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Old December 3, 2019, 11:59 PM   #14
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Good brass life, too, no doubt.
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Old Yesterday, 12:13 AM   #15
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New load- I think this one is a winner! Accurate, no keyholing, punches neat mini-wadcutter holes in the target.

38 gr. LSWC, 2.0 gr. Red Dot, Fed #100 SPP
1214 fps., 124 ft./lbs., SD 18.7

Kinda' rough on the primers. I'll switch to CCI; they handle high-pressure loads better.
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