What twist for a re-barrel .375 CT ?

[mdslammer]

Hello guys,

Hope you all are well.

So I have my .375 Cheytac back at SAC for re-barreling. My current barrel had a 1:10 twist rate when it was fabricated in 2016'.
I want to be able to shoot not only the .350 grain pills but the heavier ones .
I read that guys are now using a 1:7" twist rate for heavier pills. I see .408/.416 is available. Maybe others as well. I've been
away for a while.

What twist rate would you recommend? It will be a 32" barrel once finished.
Thanks in advance.

Mark

 

[Matthew488]

I went with a 1 in 7 twist Bartline 5R in mine for the 400gr solids once done with fireforming. Easily shooting sub moa with factory seconds 350gr SMKs at 1000k yards on the fireforming loads.

 

[MACHTECH]

1:7 with the 400 laser as mentioned above.

 

[gnochi]

Reminder: if you’re going to use high-BC monolithic bullets, you need a faster twist. If you’re going to use jacketed bullets, you might not be able to use the faster twist.

Edit: adjusted “cannot” to “might not be able to”

 

[Esoteric Junkie]

We are using 8 twist barrels and the 350gr Matchkings are holding up and shooting good groups at 1k yards at slightly over 300k rpm's. If you are only going to shoot Matchkings I would recommend sticking with a 10 twist and throat accordingly. If going with solids go with an 8 twist. Impact signature is a big advantage of lead core bullets.
EJ

 

[mdslammer]

Hello Esoteric Junkie. Thanks for the info.
So you're saying you have good luck shooting both the .350gr MK AND a
the heavier solids with the 1:8" twist?
I see where Cutting Edge has projectiles ranging from .375gr. - .450gr. Have you
tried any of these heavier pills for your loads, and if so, how did they perform?

 

[Esoteric Junkie]

Hello Esoteric Junkie. Thanks for the info.
So you're saying you have good luck shooting both the .350gr MK AND a
the heavier solids with the 1:8" twist?
I see where Cutting Edge has projectiles ranging from .375gr. - .450gr. Have you
tried any of these heavier pills for your loads, and if so, how did they perform?

Yes, I have shot a "few" Cutting Edge Bullets. Currently, I shoot on the CEB ELR team. Several of the guys on the team are shooting Cheytacs , however most have moved up to 416 or larger. The Cheytac size case works best with 350-375gr bullets, however some are shooting the 400gr Lazer. If it were me, I would limit the bullet weight to 375gr and under in the Cheytac case. Limiting bullet weight to 375gr and under will yield a little more velocity which affords one a little more trajectory error at distances where hit percentages are the highest, 1800 yards and in.

EJ

 

[GIXXER2000]

I got my Cadex Shadow 375CT with the Bartlein 1-7 32in barrel from the factory and shot very good. I now have a 34 in 1-7 the Vestal did for me. When we talked he said the 1-7 is to fast for the 350 smk when you get toward max load and they come apart. My friend shoots a Tubbs gun with a 1-8 33in and has no issue with 400 lazer's. I have shot the Berger 379 and CE 377 MTAC also and both were good.

 

[mdslammer]

I went with a 1 in 7 twist Bartline 5R in mine for the 400gr solids once done with fireforming. Easily shooting sub moa with factory seconds 350gr SMKs at 1000k yards on the fireforming loads.

Hello Matthew,
Thanks for the info. Can you tell me how far you've stretched out shooting both the .400gr and .350gr. pills?
And what kind of accuracy you were getting as well.
I've shot out to .2200 yards with my older barrel that had the 1:10"consistently.
Thanks.
Mark

 

[Matthew488]

Hello Matthew,
Thanks for the info. Can you tell me how far you've stretched out shooting both the .400gr and .350gr. pills?
And what kind of accuracy you were getting as well.
I've shot out to .2200 yards with my older barrel that had the 1:10"consistently.
Thanks.
Mark

I've had a lot of obstacles in getting out as often as I'd like so still working on fireforming my brass to the chamber. Mine is a 375 BAS from Robert Vestal. Fireforming with 131gr of Retumbo gives me 3000fps. Haven't even purchased the 400gr solids yet but will most likely be the Laser Tips from Cutting Edge.
How far do you end up having to drive to shoot to 2200yds? Not as easy as most would think to find a good spot to shoot that far in AZ and NV once you factor in people wondering into your firing line.

 

[GIXXER2000]

I live in Bullhead City and with have a couple of places 15 to 20 min drive from my house. We can shoot out to 4k. We were out this morning testing some rounds at 2805 yards. I am shooting the 400 CE Lazer with 131.5 N570 getting 3068 with an SD 5.6
My friend was testing some round in his 50 bmg single shot.

 

[mdslammer]

I've had a lot of obstacles in getting out as often as I'd like so still working on fireforming my brass to the chamber. Mine is a 375 BAS from Robert Vestal. Fireforming with 131gr of Retumbo gives me 3000fps. Haven't even purchased the 400gr solids yet but will most likely be the Laser Tips from Cutting Edge.
How far do you end up having to drive to shoot to 2200yds? Not as easy as most would think to find a good spot to shoot that far in AZ and NV once you factor in people wondering into your firing line.

I live in Las Vegas. Short 25 minutes from my house to the desert. Can get out to 1.5 miles.

 

[Matthew488]

Nice! I'm in Chandler (SE valley Phoenix) and drive 1.5hrs. I've gone to 1100 yards there so far but occasionally have someone come across the line of fire so makes me hesitant to back up much farther at that location.

 

[mdslammer]

Nice! I'm in Chandler (SE valley Phoenix) and drive 1.5hrs. I've gone to 1100 yards there so far but occasionally have someone come across the line of fire so makes me hesitant to back up much farther at that location.

If you're ever headed out this way, shout. We'll shoot a mile, then some.

 

[wheels2487]

I live in Bullhead City and with have a couple of places 15 to 20 min drive from my house. We can shoot out to 4k. We were out this morning testing some rounds at 2805 yards. I am shooting the 400 CE Lazer with 131.5 N570 getting 3068 with an SD 5.6
My friend was testing some round in his 50 bmg single shot.

View attachment 7395305

What is twist rate on yours?

 

[GIXXER2000]

My 1st 2 barrels were 1-7 32in then 34in. My new barrel is 36 in and is 1-7.5 I could have even gone 1-8 at the 36 in length. It shoots really good 1/2 MOA if I do my part. The load is virtually the same as the 34 in barrel but this one shoots better. The first 2 were Bartlein and this barrel is an K&P is about .0002 tighter than the last Bartlein barrel.

 

[wheels2487]

I have a 1:7 Bartlein 34” Ackley Improved. About finished up firing forming brass and starting to look around at bullets and starting loads, etc. going to be using N570. Let me know if you have any thoughts and appreciate the reply

 

[dttheliman]

I got my Cadex Shadow 375CT with the Bartlein 1-7 32in barrel from the factory and shot very good. I now have a 34 in 1-7 the Vestal did for me. When we talked he said the 1-7 is to fast for the 350 smk when you get toward max load and they come apart. My friend shoots a Tubbs gun with a 1-8 33in and has no issue with 400 lazer's. I have shot the Berger 379 and CE 377 MTAC also and both were good.

@GIXXER2000 with the Berger 379's what powder did you use and did you get a fps out of that 34" tube , I found a bunch of them recently , but have been too busy with 400 CEL's and RL50 to try them.

 

[GIXXER2000]

I will look when I get home but not sure what the load was.. Hope I didn't delate the load from my Excel spreadsheet. If its still there I will be happy to share with you.

 

[GIXXER2000]

Here is what ia had.
Bartlein 34in 1-7
Powder N570 130.8
PRIMER 215M
BRASS PETERSON
BULLET BERGER 379
AVG FPS 3072
SD 4.9
ES 10.0
It was 15 shots to get the avg info

Hope this helps

 

[dttheliman]

Here is what ia had.
Bartlein 34in 1-7
Powder N570 130.8
PRIMER 215M
BRASS PETERSON
BULLET BERGER 379
AVG FPS 3072
SD 4.9
ES 10.0
It was 15 shots to get the avg info

Hope this helps

Thanks bud , appreciate it