375 Cheytac....getting ready!

[Hognuts]

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 , 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! gun)

 

[royinidaho]

You'll be going nuts staring at those loaded cartridges until groundhog day.

Dumping powder in the case with a scoop shovel boggles the mind just a bit.

But when that 350 SMK smacks something it certainly smacks with noticeable authority. Way more impressive on rocks and stuff than 338 RUMs, Lapuas and edges.

When you get'r together I'll send you my Lat/Lon coordinates to send a projectile Idaho way and we'll verify terminal performance on one of my goats (If I can get it to hold still for long enough.)

 

[Hognuts]

You'll be going nuts staring at those loaded cartridges until groundhog day.

Dumping powder in the case with a scoop shovel boggles the mind just a bit.

But when that 350 SMK smacks something it certainly smacks with noticeable authority. Way more impressive on rocks and stuff than 338 RUMs, Lapuas and edges.

When you get'r together I'll send you my Lat/Lon coordinates to send a projectile Idaho way and we'll verify terminal performance on one of my goats (If I can get it to hold still for long enough.)

Yeah, that is no doubt, I am already rocking back and forth like Rain Man waiting for that action! It never fails when I have a build going, or a scope ordered, or some other piece of gear that I think I can't live with out it is like they have to wait on a special order of ground up unicorn antlers before they can complete the order!

 

[songdogslayer]

If you don't mind me asking,what did the dies set you back? I am really considering doing this build instead of a 338

 

[Hognuts]

The prices are on the website for Viersco, they were in the $300 range, I don't remember exactly, I try to stay vague on stuff like that so that when questioned by the wife I have plausible deniability! Dave @ Viersco was very good to deal with.

What I see on his site is $289 for a set add $50 for micrometer seating die.
Shell holder $17.00
This seems to be in the ballpark of what I paid for mine. I have the Lee 50 BMG press I am using for this caliber. Good luck....I am still waiting on an action for my build!

 

[songdogslayer]

Did you go with the 1.450 or the 1.600 stiller? And is there any advantage to either.

 

[Hognuts]

I went with the 1.60", just to make things "Beefier" My thinking was just more mass to support the large caliber and heavy contour barrel that I am running.

 

[Colcalcipherol]

Does anyone know the actual load data, other than just COAL, from CheyTac? Mine was test fired by the smith with CheyTac loads and it fired extremely well. Just curious . . .

 

[Hognuts]

Does anyone know the actual load data, other than just COAL, from CheyTac? Mine was test fired by the smith with CheyTac loads and it fired extremely well. Just curious . . .

I have seen very little out there, I have heard that RL25 is a good powder, I didn't have any, but I am running 133 grains of H-1000. No signs of pressure, not sure on Velocity yet. Going to run an OAL test tomorrow, started on the lands out to .050" off in .010" increments. 6 rounds each (two 3 round groups) see if any of those is a "happy spot". This thing is badass!

375 Cheytac built on a Stiller TAC 408 action, Jewel trigger, Benchmark 1.250" no contour barrel finished at 30", Ross Schuler 5 port brake, McRee Chassis, Alpha type 5 mag, Atlas Bi-pod, Multi-cam finish on the chassis by Custom Gun Coatings, NF 8x32x56 scope.

(the barreled action is going to get cerakoted OD green with black inside the flutes, but I HAD to play for awhile first!)

Here she is:
















Aint she a beauty!

 

[JeffVN]

Hopefully Augustus will see this thread. He runs a 375 Chey with great precission. He uses US869 and has great results.

RL-50 and RL-33 might be in your wheel house. RL-33 is great in my 338LM Improved (124 gr. H2O) under 300 gr. smks or 300 gr. Scenars.

Jeffvn

 

[etisll40]

Any thoughts on going Cheytac Improved? Hard to find information on this cartridge for me.

 

[royinidaho]

Any thoughts on going Cheytac Improved? Hard to find information on this cartridge for me.

The 375 SnipeTac and 375 Allen Mag are nearly, if not, identical improved Cheytacs.

A considerable amount of MV is gained. i.e., 350 SMK @ 3250 MV w/142.5 gr Retumbo.

Its a bit hard on Jamison brass. I reduced to 141.5 gr to reduce problems. Velocity still well above 3200. @ 41*F and below she's pretty sweet.

Will switch to Bertram brass one of these days and get'r back up to the higher velocity. But so far I don't see a need.

I'm running the 375 AM.

I don't have enough data yet to determine the temperature sensitivity of Retumbo but the full charge was a bit much in warm Montana weather. The main consideration seems to be neck thickness of Jamison brass vs that of Bertram brass as the reamer was designed with a brass similar to Bertram. Wild cats are funny that way. . .

Just an oh by the way, a 370 or a bit better weigh offering sure would be sweet. It would make the 375 extreme mags stand up to expectations over 338 extreme mags. Just my tho'ts. . .

 

[Hognuts]

I found a load with the H-1000 that shoots, probably better choices out there, but its what I have on my shelf. These were 100 yard groups.





I found that the Ivey rings wouldn't work for the type of shooting I do, they would require some tinkering nearly after each shot to keep everything tight, I don't have time for that ****! I took them off and put my Barrett X-rings on there adjusted to 40 MOA with the 20 MOA base on the Stiller action. That set-up with the NF puts me 20 MOA high at 100 which should give me about an 1150 yard zero. Going to go out next weekend and beat up my AR500 elk target at 1150 and see how the load does at distance.







AR500 ELK TARGET