408 Cheytac initial loads

[JOCSWFL]

So, I have a rifle from Mirage ULR. He recommended a starting load of 140gr of either N570 or 50bmg with a 400gr Cutting edge Laser cut bullet, but I went with a 450gr bullet. Started with 135gr of both powders, with a 136 gr follow up. The N570 at 135gr got a velocity of 2850 fps, a bit over Desert Techs 447gr claimed 2730. I did not try the 136gr at this time. The 50bmg powder seemed 300fps slower. Odd
I got a big jug of N570, and ordered 150 more projectiles. Right now I am just collecting data. I plan to dial in the round after I get a 50bmg suppressor. I shook the range ceiling and caused rain with every shot.

 

[secondofangle2]

Personally, I can manage recoil better sitting behind rather than beside the rifle.

You did not post nearly enough information for us to help you decide if you velocities are at below or above expected. We need to know, barrel length, cartridge, overall length, distance from lands, many other variables.

408CT is among the rarer of the ELR cartridges these days, but I’m sure some others such as my buddy in Arizona will chime in with some experience.

We can put the data into quick load, but again we will need more input variables

Personally, I am always a little, wary, when my velocity exceeded the factory ammo or the published data or the predicted data significantly

 

[Dogtown]

I haven’t had a .408CT since 2010, but a starting load of 140gr of N570 sounds too high to me. Give us some more info and we can give you some better ballpark numbers with QL

 

[JOCSWFL]

Personally, I can manage recoil better sitting behind rather than beside the rifle.

You did not post nearly enough information for us to help you decide if you velocities are at below or above expected. We need to know, barrel length, cartridge, overall length, distance from lands, many other variables.

408CT is among the rarer of the ELR cartridges these days, but I’m sure some others such as my buddy in Arizona will chime in with some experience.

We can put the data into quick load, but again we will need more input variables

Personally, I am always a little, wary, when my velocity exceeded the factory ammo or the published data or the predicted data significantly

It’s got a 31” barrel, 1:9 twist. OAL is 4.605, about 0.02” off the landing. I’m in the south Florida swamp so it’s always hot and humid here.

 

[Dogtown]

 

[secondofangle2]

for a CE 450 laser at 4.600 COAL, starting pressure ~3500 (not jammed), case capacity 169 grains H2O, N570, QL thinks the max load is 144.5 n570, with 63000 PSI, which it predicts gives 2905 fps from a 31" barrel. 101% case fill

For 136 grains N570, It predicts 51,000 PSI and 2732 fps at 95% case fill
For 136 grains H50BMG, it predicts 43K PSI and 2500 fps at 98% case fill

This is pretty typical of QL, a bias towards higher pressure and lower velocity with the Cheytacs.

Because of this, what I often do to assure I'm below pressure is make sure I'm below the velocity predicted for the max pressure, or here 2900 fps.

You're probably OK at 2950 if you don't have pressure signs on brass or bolt lift (check your primer pockets next time you load them, if they've loosened at all, you're over pressure). You can also check CE data for that bullet, or others' results online.

FWIW, you're way faster than I am in a 375 cheytac with a 390 ATIP and a 35" barrel. My velocity is 2915 at 135 H50BMG. QL thinks I'm 56,500 PSI and 2810 fps velocity at 98% case fill; to hit max, I'd have to push up to 139.9 grains, 101.3% case fill, 63744 PSI, velocity 2913. This is why I have stopped at this load, even though there's not a hint of pressure, because I'm at a velocity that corresponds with what QL thinks is a max pressure charge. (It's also a super accurate load with single digit SD.)

ETA, Dogtown beat me to it, I type too slow

 

[JOCSWFL]

for a CE 450 laser at 4.600 COAL, starting pressure ~3500 (not jammed), case capacity 169 grains H2O, N570, QL thinks the max load is 144.5 n570, with 63000 PSI, which it predicts gives 2905 fps from a 31" barrel. 101% case fill

For 136 grains N570, It predicts 51,000 PSI and 2732 fps at 95% case fill
For 136 grains H50BMG, it predicts 43K PSI and 2500 fps at 98% case fill

This is pretty typical of QL, a bias towards higher pressure and lower velocity with the Cheytacs.

Because of this, what I often do to assure I'm below pressure is make sure I'm below the velocity predicted for the max pressure, or here 2900 fps.

You're probably OK at 2950 if you don't have pressure signs on brass or bolt lift (check your primer pockets next time you load them, if they've loosened at all, you're over pressure). You can also check CE data for that bullet, or others' results online.

FWIW, you're way faster than I am in a 375 cheytac with a 390 ATIP and a 35" barrel. My velocity is 2915 at 135 H50BMG. QL thinks I'm 56,500 PSI and 2810 fps velocity at 98% case fill; to hit max, I'd have to push up to 139.9 grains, 101.3% case fill, 63744 PSI, velocity 2913. This is why I have stopped at this load, even though there's not a hint of pressure, because I'm at a velocity that corresponds with what QL thinks is a max pressure charge. (It's also a super accurate load with single digit SD.)

ETA, Dogtown beat me to it, I type too slow

Many thanks for the input. I’m just starting, and probably won’t dial it in for accuracy till I get a can on it. Maybe I will spend some time at a lathe and use my last tax stamp.

 

[secondofangle2]

Well, for whatever it is worth, after having it about eight years, I took my elite iron can off of my 375 and threw it in the junk box

I need better recoil control than a suppressor can provide. If they made a good one with an anchor break that reduced recoil as well as my T5 terminator brake, I would consider buying one. But for now, the only thing on the market is that enormous 50 caliber can from thunder beast and I just can’t stomach 22.5 inches and $6000

If you look at the king of 2 mile competition, there is hardly a single competitor running a can. I think that’s because of recoil, and they want to use any additional length to increase their barrel and get free velocity.

 

[blackened]

Thanks for posting! I just got my .408 CT and I ended up with 100 MTAC 420 MAX bullets and Peterson brass. There isn't many people posting online about 408 CT reloading these days, and as soon as I decide which magnum press to go with I'll get to work and share my results also.