375 cheytac load info.

[pondskipper]

So, I've been looking everywhere to find solid load data but everything I've found has been all over the map as far as charge weight goes for 350-377gr solids for the standard cheytac cartridge, only thing that was consistent was the powder type which seems to be unanimously Retumbo. Also velocities seem to be all over the place as well from what I've been reading.

Does anyone have and good data to go with for charge weights and velocities that were obtained? I will be running a 32" Broughton 1:9 5c barrel and I'm hoping to hit 3150fps

 

[Deleted member 46119]

Exact bullet and COAL needed.

 

[Deleted member 46119]

The 375 Cheyenne Tactical is kinda a proprietary cartridge.

Hodgdon does not have reloading data for it.

https://www.longrangehunting.com/threads/375-cheytac-load-data.110001/
https://www.calguns.net/calgunforum/showthread.php?t=1328186
http://www.longrangeonly.com/forum/showthread.php?1555-375-Cheytac
https://forum.nosler.com/viewtopic.php?t=12555&p=87031

 

[pondskipper]

350smk at 4.1"
350CT at 4.3"
377CE at 4.4"

Just looking for starting points charge wise and will work up from there. Not looking to push it super hard, hopefully the barrel length will help a bit in that department.

I've read basically all those at least 3 times. I was looking to see if anyone here had any good info to share and what their experiences have been.

 

[nmbarta]

I'm running 133 retumbo and a 350 rmb. Getting 3075 out of 30" lawton barrel (LRB)
bertram brass. No pressure signs, but I'm guessing it's getting close to max, I haven't pushed it any harder.
I think the smk runs about the same. As you know, start low.
I'd feel safe starting around 128-129, but that's me, and this is the internet.
It's tough to find good info on this cartridge, hopefully this helps.

 

[pondskipper]

Now that sounds about right to me.

 

[Deleted member 46119]

I "reverse engineered" Cheytacs 375 load for the SMK 350gn and the Chy 350gn. It was Retumbo powder.

After adjusting my weighting factor for the 375 CheyTac in QL I am within %1 of @nmbarta 's velocity.

If it were me: with those COALs
SMK 350: start at 128gn of Retumbo max 136gn range and that is "hot"
Chy 350: start at 126gn of Retumbo max 134gn range
CEB 377: start at 124gn of Retumbo max 132gn range

For the 377 you might get more speed from RL-33 or H870 but they are very temperature sensitive.

 

[Deleted member 46119]

BTW, my 375 this time will be a 375 HE. I make the reloading dies and shell holders for @hubel458 projects so I want one for myself.

 

[pondskipper]

Awesome, thanks for the info! When the rifle is finished I will measure the max oal in the chamber and see what I will be able to achieve, I'm probably going to have mirage ULR put it together for me and it will likely be in one of their chassis. I'll have to make a modified case that will allow me to check it with my Hornady gauge but shouldn't be too bad.

 

[LR3]

Not much help but with my .375 Snipetac and 12 twist with Retumbo at 134 gr and 350 SMK I get 2900 fps and with my 375 AM and 141 gr I get 3270 fps but that is quite hot and the bolt is tight with some dimpling of the casing.

 

[Fotis]

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