Looking For Ideal twist for 6mm TCU

[grahamugalde]

Building a 6 TCU, have a nice Sako l461 action for starters, now working on barrel selection, will be mostly varmint shooting but would like to be able to use as a deer rifle also, will be shooting 70-80gr Sierra HP's, but would like be able to load a little heavier for deer, any suggestions on what twist would be Ideal?


Thanks, Graham Ugalde

 

[pdog2062]

I have a 6x45 with 1-8 twist and it shoots the 75 grain vmax very well but it doesn't like the 58 grain bullets at all.

 

[SDWhirlwind]

Don't you have a relative who can answer your questions concerning the TCU???

T-Thompson
C-Center
U-Ugalde

Edit to add that mine has a 12 twist Douglas. Wished now I had went with a 9 or 10 but at the time had the 12 in hand and a bunch of Sierra 60HP's and Sierra 70gr MK. Haven't tried to shoot anything heavier than the 70's.

 

[JohnHenry]

I would think a 1 in 10" twist.

 

[Kermit in Va.]

I've got a 6x45 9 twist and it shoots everything from 55 to 85 good. Ain't tried anything heavier yet. It has shot the 70 SMK's the best so far.


Kermit

 

[grahamugalde]

Thanks for the input, I really appreciate it, I would love to have the option to ask my uncle Wes Ugalde for his input, but he lost his battle with cancer in 2006, my cousin Chet who is the son of Wes has taken over his gun smithing shop & I havent asked him as of yet, but i was advised to come to this site & figured this would be the place to find some 6mm experts. 1:9 or 1:10 sounds like a pretty good twist rate for the range of bullets I plan on shooting.

Thanks again, Graham Ugalde

 

[bheadboy]

the silouet shooters use 9 twist for the heavier bullets above 70/75, for deer if you go up to 100 you need the twist to be under 10.

Bob

 

[grahamugalde]

Thanks Bob, I appreciate it.

 

[Randfal]

I have a 6x45AI which is almost the same as the TCU. It's shoulder is a tiny fuzz longer than the TCU. I don't know why people always think the 6x45 and the TCU are basically the same. That like saying the 22-250 and a 22-250AI are the same. Anyway, I am shooting it mainly with 55, 58 and 68gr bullets in a 22" 1:14twist Krieger. I fire formed with a bunch of 75gr Hornady hollow points and the gun loved them. I lobbed a couple groups at my 600yd target and it shot two groups around 4.5" (calm day) with no load development etc. Just saying this in case you were considering a 1:14 twist barrel. It will stabilize the 75gr Hornadys just great.

 

[Kermit in Va.]

Yep, the 6x223 and are different BUT just how much differance is they as far as twists and bullet weights ?


Kermit

 

[Lumpa]

I have a 6x45AI which is almost the same as the TCU. It's shoulder is a tiny fuzz longer than the TCU. I don't know why people always think the 6x45 and the TCU are basically the same. That like saying the 22-250 and a 22-250AI are the same. Anyway, I am shooting it mainly with 55, 58 and 68gr bullets in a 22" 1:14twist Krieger. I fire formed with a bunch of 75gr Hornady hollow points and the gun loved them. I lobbed a couple groups at my 600yd target and it shot two groups around 4.5" (calm day) with no load development etc. Just saying this in case you were considering a 1:14 twist barrel. It will stabilize the 75gr Hornadys just great.

Hi Randal,
Mate you say the 1-14” twist stabilised the 75 gr projectiles well. I’m wanting to run the 58gr vmax and 70gr blots king projectiles weights only until I pick one and go with it.

We’re you able to obtain any velocity data please mate. I’m very interested to know as most people are saying 8,9 or 10 twist but I want fast as I can get reliably.

 

[thatguyshm]

I would go with a 9 twist . I went with an 8 twist for my 6x45 and it does fine with all weight ranges but the 55s shoot best at lower velocities which translates to lower RPMs. It's not the best shooter out there with a multitude of bullets, but it does very well with the 70gr Nosler BT around 3000fps. Doing it again I would probably choose a slower twist.

 

[Hammer500]

I built mine on a 10 gain twist. I shot everything up to 95 gr with great results.

 

[BenPerfected]

Check out the Berger Twist Rate Calculator . It should get you close.
Ben

 

[PRR1957]

Thanks for the input, I really appreciate it, I would love to have the option to ask my uncle Wes Ugalde for his input, but he lost his battle with cancer in 2006, my cousin Chet who is the son of Wes has taken over his gun smithing shop & I havent asked him as of yet, but i was advised to come to this site & figured this would be the place to find some 6mm experts. 1:9 or 1:10 sounds like a pretty good twist rate for the range of bullets I plan on shooting.

Thanks again, Graham Ugalde

Dose your cousin have a web address for the smithing business ? I would like to check it out.

I used to shoot a 7T/CU in IHMSA in a 14” T/C that was the cats meow. With 140 gr Nosler BT it was almost boring to shoot 40x40 scores along with 200 yard chickens in a shoot off. Love that little cartridge.

 

[centershot]

My 6mm TCU is a 9 twist. Very happy with the accuracy. I have shot up to 87 grain bullets with it. Go to is a 80 gr. Nosler for prairie dogs.

 

[GrocMax]

Don't be afraid of the faster twists (8"-10") and light varmint bullets. 300K RPM = Snertability (as long as they stay together). Go 3 groove, throat will last forever. A 58vmax at 3600+ FPS out of an 8 twist makes for a good show.

 

[k80skeet]

Don't you have a relative who can answer your questions concerning the TCU???

T-Thompson
C-Center
U-Ugalde

Edit to add that mine has a 12 twist Douglas. Wished now I had went with a 9 or 10 but at the time had the 12 in hand and a bunch of Sierra 60HP's and Sierra 70gr MK. Haven't tried to shoot anything heavier than the 70's.

The 80 & 85 grain shoot lights out and great hunting bullets.