20 TCM Project

[drewh]

Finally got back and started working with my 20 TCM. This had been a long time on the back burner. Playing around one day I had a CZ hornet mag and a 20 TCM dummy round on my desk so I tried it just for laughs. It fit pretty nice. So I started getting pieces, and a semi-unicorn showed up a left handed CZ . The barrel is a Muller Works 11 twist . The pieces all came together last week. I had a barrel on a single shot before, but that was when I lived in CA and used a fast twist barrel thinking the rotational speed would help lead free bullets come apart easier. Target 1 is all 20 TCM, Top left is 24gr NTX, rest are 32 FBHP Nosler. 2nd target top left is also NTX. at 3150, the NTX bullets could use a little more powder and the 32's seem like they would be better with a slightly lower charge. This was with Ramshot Enforcer and Win small rifle primers. Have not tried feeding from the mag yet, but feeds flawlessly through a Calhoon single shot adapter. A shoutout goes out to NorCal Mikey, I finally talked him into parting with his reamer.

 

[20 TAC]

What powder and charge weight are you shooting, if you don’t mind sharing? Velocity?

 

[drewh]

What powder and charge weight are you shooting, if you don’t mind sharing? Velocity?

Velocity is affected by the fact I chose to use a 17" barrel, for better ergonomics with the supressor. I used Ramshot Enforcer, 10.1 on the NTX and 10.2-10.5 on the 32FB . I think that's low on the NXT and high on the 32's. Plan to do more with various primers, and potentially try CFE BLK powder in it as well.

 

[20 TAC]

Have you tried any 300-MP, VV-110, H-110 type burn rates? Bowfisher has been working off and on with a little TCM based 20 cal case we built and is finding those burn rates help fill the case and optimize velocities. BUT—it has more case volume so you’re probably in a great range where Enforcer is concerned?

 

[Gabe22BR]

I like it !!!

Where do sign up ?????

 

[shoot4fun]

When I first saw the 22TCM my first thought was how it begged for a 17 caliber bullet in a 20" or so rifle.
I never got around to putting the idea to paper.
It's good to see that someone else had some ideas too.

 

[drewh]

When I first saw the 22TCM my first thought was how it begged for a 17 caliber bullet in a 20" or so rifle.
I never got around to putting the idea to paper.
It's good to see that someone else had some ideas too.

I believe there is someone on here with an AI version in 17.

 

[shoot4fun]

I believe there is someone on here with an AI version in 17.

It got my interest I guess because of all the articles I read by the likes of McPherson in the days of the VHA magazine. I miss the VHA.

 

[drewh]

Have you tried any 300-MP, VV-110, H-110 type burn rates? Bowfisher has been working off and on with a little TCM based 20 cal case we built and is finding those burn rates help fill the case and optimize velocities. BUT—it has more case volume so you’re probably in a great range where Enforcer is concerned?

Probably going to stick with the enforcer or CFE BLK if I can as I have other cases that use them.

 

[rickiesrevenge]

Here is my xp-100 in 17tcm improved

 

[L.Sherm]

Are you guys using 22TCM bushing dies with the appropriate bushing?

 

[rickiesrevenge]

I made a bushing die for mine.

Aaron

 

[Gabe22BR]

Damn cool !!!

 

[linebaugh]

Great project and thanks for sharing. I know you dont want to try other powders but lil-gun would be a great trial.
Powder conservation at its finest. Looks like it would want to feed from the pic in the mag. Keep posting.

 

[drewh]

Are you guys using 22TCM bushing dies with the appropriate bushing?

I am using Whidden dies from when they were still doing customs, not sure if a Lee or Hornady could be converted to bushing dies.

 

[rayh]

I had Neil Jones make me a sizing/forming die for the 17 M4 and 17 Javelina. His bushings really opened up wildcatting for me. His bushings are .625 OD. What makes his bushing different is they include 1/16" of the shoulder dia, 30* shoulder and then the neck ID dia needed. I had a Hornady seating die modified (they're .625 ID) , a couple spacers to elevate the bushings. I have a total of 8 bushings. They have done all my forming from 17 Squirrel to 17-204. That short 1/16" of shoulder helps prevent the shoulder from expanding during the various necking down steps. My 17 and 20 Boomers (TCU case) started from LC 223 brass. When they came out with the TCU it was a gift from God, saved so much time. After forming I blow the case out to 40*. I also make mine(TCU case) with a slightly longer neck than some here do. Back when I got my bushings from Neil they were 18.00 ea, a Redding was close 12.00 ea. Some of you are interested in various small calibers, forming dies are expensive, my forming die/bushing were fairly cheap and all fits in a die box.

 

[L.Sherm]

I made a bushing die for mine

Aaron

Resize reamer? Or converted a 22 TCM.
I've had regular FL dies converted to bushing die.

 

[rickiesrevenge]

Resize reamer? Or converted a 22 TCM.
I've had regular FL dies converted to bushing die.

Its just a neck sizing die made with the chamber reamer. Uses standard neck bushings. Eventually I either need to send for a sizing die reamer or a FL sizer.