375 Cheytac Loading advice needed

[Pahighlander]

Well my Turban press finally arrived so I can start reloading for my new cheytac. with the shortage of Retombo would H1000 be usable? I have a large supply of H1000 on hand. Im using 407 bergers, Peterson brass 7" twist 32" barrel shooting 1780 yards and longer is the plan. Has anyone used this combo?
Thanks again

 

[Sleepertruckguy]

Well my Turban press finally arrived so I can start reloading for my new cheytac. with the shortage of Retombo would H1000 be usable? I have a large supply of H1000 on hand. Im using 407 bergers, Peterson brass 7" twist 32" barrel shooting 1780 yards and longer is the plan. Has anyone used this combo?
Thanks again

I will do a test and let you know. I just purchased the same rifle/barrel/twist set up from euro optic. I'll pick it up in a few days from my FFL and start load development. I have h1000 and retumbo on hand. I believe the cartridge was originally developed using RL25.

 

[Dogtown]

With a 407gr bullet, I would seriously consider a slower powder like N570 or RL33, if possible. You can use H1000 but you'll hit your pressure limit around 90% fill ratio, where RL33 would let you get much closer to 99%.

I used RL25 for many years for .408CT and later .375CT, but it was a bit fast for the 419gr .408 bullets and better suited to the 350gr .375s.

 

[ZiaHunter]

Retumbo and certainly H1000 are too fast for the bullet you plan on shooting. Options would include US869, RL-33, BMG50. 24N41, N570, 20N29.

 

[Sleepertruckguy]

Found some N570, starting at 131.5g (407g berger) seated .008 off the lands. I'll post the data on Thursday or Friday.
140g of RL33 (407g berger) = avg 3009 FPS. SD 7.

 

[Sleepertruckguy]

Berger 407g
N570 - 131.5g
Avg speed 2,943 FPS.
SD 5.5
EXCELLENT GROUPING (1/4 moa)