375 CheyTac loading data

jwoolf

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I'm hoping to find some starting load information... ( there isn't much out there and, not too many posts here )

Let's say I'm going to begin loading the Lehigh 330gr solids, possibly the 350gr match kings and/or the 355gr GS solid ( I think it's 355, maybe it's 350 too )

Anyway, I'm interested in all the powders you guys use but, I have retumbo on the shelf I shoot out of the 300wm.

I'm guessing to start around 130gr of retumbo but, I'd like to know where your sweet spot is on this round.

Also like to hear what kind of velocities you're getting from the 350s. Mine will have a 1:10 twist and 30" bbl.
 
M

milo 2.0

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Re: 375 CheyTac loading data

This guy might be able to give you some info.

www.blackdiamondrifles.com

This guy builds alot of these big boys.

I know some people who shoot the Rocky Mtn 375gr bullet, with 50BMG, and VV N570.
The "sweet" spot is in an individual gun, don't ever take anyones pet load and run with it. Start lower and work up.
Is your barrel a Lost River bore, or normal? I have been told not to shoot solids through a regular barreled rifle.
 

jwoolf

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Re: 375 CheyTac loading data

This rifle will not have a lost river bore but, I can't imagine what would be different about a lost river bore other than maybe the twist rate.

The twist on mine has 1:10 twist which is fast enough to stabilize the long 350gr solids. The "standard" twist is 1:11.5 which will not stabilize the 350gr solids but, will stabilize the 350gr SMK. I wonder if that is what you're talking about? Also, the viking bullets require a 1:8 twist to stabilize the really long bullets. I'm somewhere inbetween with a 1:10 but, that is fast enough for the solids in the 350gr range... BC of .941 on the Lehigh 330gr (wheeeeeee) I've heard folks here are getting 3200fps out of that thing.

Yeah, the sweet spot is the accuracy node for your rifle but, I was wondering where everybody is loading this beast up to. I want to start -10% from there and work my way up and there just isn't much information out there ( including here )... I'd be interested in knowing how far they're jumping or jamming etc. also.
 

pyrofx

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Re: 375 CheyTac loading data

I'm loading 130 retumbo. MUST use mag primers. 1 sec hang fires with standard primers. 132 gr was a bit hot . I got 3 minutes less elevation needed with lehighs v/s the smk @1760.

Greg
 

hognuts

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I just loaded up my first 30 rounds to do load development once my action shows up! (was scheduled for November, now pushed back to January)

I am building a 375 Cheytac on a Stiller TAC 408 action. Benchmark 1/10.5 twist. Will finish at 30", 1.250" no contour barrel/truck axle :). McRee chassis, which is now being coated in Multi-cam by Shortbus, Jewel trigger, BAT brake, NF 8x32x56 NXS with zero stop and high speed turrets, Ivey 150 MOA rings. Running the Sierra Match Kings, 350 grains.

Started with H50BMG powder as that is what I had on the shelf. Started at 128.5 grains and went up in .3 grain increments and stopped at 130 grains for now. Used OAL that I jacked from Cheytac's site, their "factory ammo" is loaded to 4.303" so I started there. Will toy with that once I get a few rounds down the tube. Used Tula Large Rifle Magnum primers. Got dies from Dave at Viersco, running the Lee 50 BMG press. Looking forward to burning some powder with this one and hopefully getting it pounding nails before next elk season and find myself a nice high vantage point! :)

I am hoping I can find a load that it likes with the H50BMG as I have 24lbs on the shelf!
 

VJJPunisher

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That is exactly the type of quality technical response that I was hoping for! It is filled with both constructive cristicism and yet oozes sophistication, well played sir! :)

relax nancy, i said that jokingly since i just bought a .375 cheytac, and it is a funner way of tagging this thread for future info rather than saying some gay ass comment like "tag for later"
 

hognuts

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I was just jabbing back, so one of us needs to relax.... :) The powder/water comment is like I said, Invaluable! :) I really hope that I can make the H50BMG work, so I don't have to add yet another breed of powder to my standard order list! I am sure it will go bang, and I will go from there I reckon.
 
M

milo 2.0

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Mine was a comment, not a technical recommendation.
Can anyone point me to cartridge and chamber drawings? Is it a necked down .408cheytac?
It is.

Bill,
I don't know why BMG wouldn't work, RL-33, and RL 50 should work also. I had a 338 snipetac, bmg was too fast, settled on VV 20N29, but that was seriously overbore, so slow worked better. Stay away from US 869, it's a ball powder and your fill ratio will be low, = hangfires!

The old man, grandpa of the kid that won that shoot here, has 2 375's, runs VV N570 and Rocky mountain 375's, he swears by it. Both high dollar components, but I do recommend buying at least 1 box of RM 375's, they'll be the most 100 accurate rounds to go through your gun.
Dave Viers at Black Diamond rifle's might be the premier expert in the country, Kirby Allen also, might look to those guys. Chuck Mac has built quite few also, it's tough when there's no published data.
 

hognuts

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It is.

Bill,
I don't know why BMG wouldn't work, RL-33, and RL 50 should work also. I had a 338 snipetac, bmg was too fast, settled on VV 20N29, but that was seriously overbore, so slow worked better. Stay away from US 869, it's a ball powder and your fill ratio will be low, = hangfires!

The old man, grandpa of the kid that won that shoot here, has 2 375's, runs VV N570 and Rocky mountain 375's, he swears by it. Both high dollar components, but I do recommend buying at least 1 box of RM 375's, they'll be the most 100 accurate rounds to go through your gun.
Dave Viers at Black Diamond rifle's might be the premier expert in the country, Kirby Allen also, might look to those guys. Chuck Mac has built quite few also, it's tough when there's no published data.

Thank you sir.

You getting around alright after the surgery?

I bought my dies from Dave Viers, I was able to find a few posts (had to use google search to find posts that were on here that didn't show up when I used the site's search engine) where he had made some suggestions. I have my first 30 rounds loaded now with the 350 SMK's and the H50BMG and will atleast be able to get it sighted in and send a few rounds, his recomendation was Retumbo for powder. I will have to try to get my hands on some of those RM 375's you speak of! :) Hope all is well with you and yours! I will (hopefully if my action ever shows) bring my new toy up when I come for WTRC next summer and we can play around at Chuck's range and see if I can hit anything with it! :)
 

hognuts

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Just sent an email to the folks at Rocky Mountain, I see they're in Darby Montana, when I worked for the Cat Dealer in Missoula, we did a job down there in the Bitterroot mountains above Darby, that was a blast from the past! :)
 

Alphabet

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Jun 17, 2014
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I just loaded up my first 30 rounds to do load development once my action shows up! (was scheduled for November, now pushed back to January)

I am building a 375 Cheytac on a Stiller TAC 408 action. Benchmark 1/10.5 twist. Will finish at 30", 1.250" no contour barrel/truck axle :). McRee chassis, which is now being coated in Multi-cam by Shortbus, Jewel trigger, BAT brake, NF 8x32x56 NXS with zero stop and high speed turrets, Ivey 150 MOA rings. Running the Sierra Match Kings, 350 grains.

Started with H50BMG powder as that is what I had on the shelf. Started at 128.5 grains and went up in .3 grain increments and stopped at 130 grains for now. Used OAL that I jacked from Cheytac's site, their "factory ammo" is loaded to 4.303" so I started there. Will toy with that once I get a few rounds down the tube. Used Tula Large Rifle Magnum primers. Got dies from Dave at Viersco, running the Lee 50 BMG press. Looking forward to burning some powder with this one and hopefully getting it pounding nails before next elk season and find myself a nice high vantage point! :)

I am hoping I can find a load that it likes with the H50BMG as I have 24lbs on the shelf!


How is that BMG powder working for you??