6X45 vs. TCU differences?

C

CastleRocker

New member
Well I've been wondering, searching, and reading about this new 6x45. So what is the difference between this and my old 6mm TCU that I've been loading for around 30 years? I'm just curious as I'm thinking about getting one.

Thanks in advance!
 
Your 6mm TCU is a improved design.
This is why you need fireforming loads instead of just resizing the necks. The TCU should have more velocity and use a little more powder.
 
Those rounds are just the .223 (5.56) and .223 Ackley necked up to .243. It may be easier to see the differences by looking at the parent cartridges.
 
Originally Posted By: WileE.CoyoteThose rounds are just the .223 (5.56) and .223 Ackley necked up to .243. It may be easier to see the differences by looking at the parent cartridges.

So my TCU has an Ackley shoulder? Thanks for the info as that's something I did not realize. I've always just necked up 223 cases and fireformed them. I've actually never thought to measure the angle of the shoulder.

I have been seeing a lot of interest in the 6x45 cartridge lately and was just really curious as the what the difference was.

All I know for sure is that the TCU has been, and contiues to be one of the most intrinsically accurate barrels I own. Heck it even shoots great when I'm fireforming the brass.

Thanks for the info!
 
Here are the drawings:

6x45.jpg


6TCU.jpg


I currently have three 6x45s and one 6mm TCU. For the life of me, I just can not beat the 6x45 with the TCU by more than 25 fps or so. From my field shooting with these cartridges, any difference in accuracy is not noticeable. Either one will do the job of the other.
John
 
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Originally Posted By: CastleRockerOriginally Posted By: WileE.CoyoteThose rounds are just the .223 (5.56) and .223 Ackley necked up to .243. It may be easier to see the differences by looking at the parent cartridges.

So my TCU has an Ackley shoulder? Thanks for the info as that's something I did not realize. I've always just necked up 223 cases and fireformed them. I've actually never thought to measure the angle of the shoulder.

I have been seeing a lot of interest in the 6x45 cartridge lately and was just really curious as the what the difference was.

All I know for sure is that the TCU has been, and contiues to be one of the most intrinsically accurate barrels I own. Heck it even shoots great when I'm fireforming the brass.

Thanks for the info!

Yep. IMO, if you're going to the effort to fit and chamber custom a custom barrel for a non-standard cartridge, you might as well go for the gusto and get the TCU.
 
Could you talk a little about your brass prep and fire forming experience and brass life with he 40deg shoulder. I am assuming you are using bolt guns. I wonder what the rounds potential in an AR would be, I would think you would need to bump the shoulder back for AR's to ensure reliable feeding/chambering.
 
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The forming process is to simply FL size in the TCU die and then fire form. Accuracy from the fire-forming load is usually pretty good as well. Accuracy from my TCU is nearly identical to that of the 6x45. Velocities are normally about 25 fps better at the same barrel length and equivalent pressures; though I only have a strain gauge on the TCU barrel and not a transducer. Brass life is good with the TCU and I tend to loose very few case in fire-forming. Typically I use a full power 6x45 load to form (shooting gophers or p-dogs).
John
 
Actually, I used my TCU back in the late '70 through the late '80's for shooting handgun silhouette out of a Contender and later an XP-100. My 6mm TCU is the most accurate one I have, but I did shoot my 7mm TCU a lot as well, as it knocked down the ram a bit more reliably.

Both are exceptionally accurate, and brass life is... well...put it this way; I always took brass out of rotation that reached 10 loadings and then quit counting. I wish now I had kept track, as I'm sure some of them have been loaded 15 to 20 times.

Now I'm actually considering getting a barrel for my AR...
I'm thinking the velocities would be considerably better than out of my handguns.
 
TCU = Thompson Center Ugalde
Wes Ugalde worked with TC to develop these rounds.
They excel in the contender but are fabulous in the AR.
Bob Milek did load development with the 6x45 long ago.
 
This has been going on for 7 years.... amazing.

I have nothing to contribute other than I have a 16” MGM Contender barrel chambered in 6TCU and its impressive. I’ve loaded it with everything from 58gr Vmax to 87gr HPBT. All shoot MOA or better. It loves 65gr Vmax and a healthy dose of H322.
 
... and it's still got a lot of years left in it as long as contender shooters keep getting into TCU chambers and AR shooters keep finding the benefit of exploring beyond the 5.56.
The fun will never end.
I personally prefer a parent case with a bit more storage space for propellant.
[img:left]https://flic.kr/p/2hmjNtF[/img]
 
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