375 DCM, 375/408imp

[Frank7mm]

First shots with the 377 CEBs

These bullets are very sweet to load. The "ring" takes all the fun out of it.

Loaded 3 with 139 gr of Retumbo and fired for effect.

Group was 1/4 MOA wide and 1+ MOA vertical speed.

However velocity averaged only a little over 3000 FPS MV. (With 350 SMK this load gives 3225 with no pressure signs.)

These three exhibited pressure sign by extraction and bolt lift. What I'm not certain of is these cases may have been fired "hot" previously. They were tough resizing and there was "some" pressure necessary to chamber them.

Maybe I should go with 50 BMG with this bullet? If so what would be a close starting load. Hate to waste any of these precious offerings.

Any tho'ts????

Did you get a good ES? I shoot the CEB350's at 3200fps and have unbelievable ES (less than 5fps).

 

[ragnarok]

First shots with the 377 CEBs

These bullets are very sweet to load. The "ring" takes all the fun out of it.

Loaded 3 with 139 gr of Retumbo and fired for effect.

Group was 1/4 MOA wide and 1+ MOA vertical speed.

However velocity averaged only a little over 3000 FPS MV. (With 350 SMK this load gives 3225 with no pressure signs.)

These three exhibited pressure sign by extraction and bolt lift. What I'm not certain of is these cases may have been fired "hot" previously. They were tough resizing and there was "some" pressure necessary to chamber them.

Maybe I should go with 50 BMG with this bullet? If so what would be a close starting load. Hate to waste any of these precious offerings.

Any tho'ts????

I had the same problem in my 375VM2, I had to set my bullets deeper in the casing, I needed a jump of 0.035" from the rifling/chamber throat to the seal tight band. that took care of the pressure signs.

now I seat them so the "ring" is just barly visible. according to CE you can seat the bullet 1/3 down the neck, but you have to remember to use the case "reamer" flaring tool a little extra to make sure you don't scrape of the seal tight band.

what I had original was the recommended 0.020" jump, and I got a really stiff bolt. once I added a little jump everything was cool, but I also lost 50FPS, but that doesn't matter to me as they shoot incredible good.

 

[Lovetohunt]

I had the same problem in my 375VM2, I had to set my bullets deeper in the casing, I needed a jump of 0.035" from the rifling/chamber throat to the seal tight band. that took care of the pressure signs.

now I seat them so the "ring" is just barly visible. according to CE you can seat the bullet 1/3 down the neck, but you have to remember to use the case "reamer" flaring tool a little extra to make sure you don't scrape of the seal tight band.

what I had original was the recommended 0.020" jump, and I got a really stiff bolt. once I added a little jump everything was cool, but I also lost 50FPS, but that doesn't matter to me as they shoot incredible good.

Ragnarok,
What velocity are you shooting those bullets at now with the 50 fps drop in velocity? And I assume you are shooting the 377gr CEB's ?? Barrel length please?

And RoyinIdaho, yours is a 375CT? Barrel length please?

Thanks guys.

Jeff

 

[ragnarok]

Ragnarok,
What velocity are you shooting those bullets at now with the 50 fps drop in velocity? And I assume you are shooting the 377gr CEB's ?? Barrel length please?

And RoyinIdaho, yours is a 375CT? Barrel length please?

Thanks guys.

Jeff

I shoot these CE 377gr bullets at 3300 fps, using 163 gr of vith 20n29 powder. I had 3358 with the same load but 0.020 jump, which gave to much pressure. im using a 38" barrel.

 

[ragnarok]

here is one ready to go. And some chronograph shooting. And a picture taken this winter shot at 1225meter with the CE377Gr bullets

 

[Lovetohunt]

Ragnarok,

That's awesome performance at 377 grains and 3300 fps. Are you the guy that's in Europe with that rifle from Dave Viersco? And I am wondering, how is the shock wave / concussion wave from that powerful 375 VM? I did the math and you are getting just over 9100 ft-lbs kinetic energy at the muzzle with that load. And how is the anti-material penetration with it? Have you tested that yet to see how far out you can shoot through 1/2 inch or thicker AR-500 steel??

Jeff

 

[ragnarok]

The muzzle blast is quit large, somewhat a good amout over a 338 lapua.
Ar 500 plates under 10mm gets dentet, ill guess to shot in the same hole/aera might go through at 600 meters. ive shoot through 1" of hardened steel plate at 200 m and 3/4" soft steel at 400m.

the rabbit I shot at 300 yards and It broke, and left a pretty large dent in it. I dunno what kind of steel it is but it could take all my rifle shots at 100 yards without issues.
and the plate is a 3/4" freehanging plate at 500m, almost went through.

so a 1/2" AR plate your good to go beyond 500m, but still it will make a small mark from the bullet tip out to 1200m, you can see it on the other pictures I postet if you zoom in on the hits. in my shooting club at home they have a dedicated plate for me to shoot so I don't wreck their steelplates. not only does is damage the plates, the small shackels and chains it hangs in snaps after 1 or 2 shots.

 

[royinidaho]

Ragnarok,

And RoyinIdaho, yours is a 375CT? Barrel length please?

Thanks guys.

Jeff

Mine is a 375 Allen Magnum. Barrel length of 30"

I'm running 149.5 gr of H-50 BMG for about 3150 FPS MV (That's what the Shooting Crony says at 12 feet.

I can push a bit more and get over 3200 FPS but projected case life due to primer pocket expansion indicated maybe 4 or 5 rounds case. I'm not gonna do that.:roll eyes:

Besides it's actually hard to find a shooting place to max out the cartridge with that bullet and velocity. Idaho simply isn't big enough.

 

[Kiwi Greg]

Mine is a 375 Allen Magnum. Barrel length of 30"

I'm running 149.5 gr of H-50 BMG for about 3150 FPS MV (That's what the Shooting Crony says at 12 feet.

I can push a bit more and get over 3200 FPS but projected case life due to primer pocket expansion indicated maybe 4 or 5 rounds case. I'm not gonna do that.:roll eyes:

Besides it's actually hard to find a shooting place to max out the cartridge with that bullet and velocity. Idaho simply isn't big enough.

Find some RL50 & give it a try, should perk it up a bit

 

[ControlledAnger]

Wow mate, you have this build.

I'll be keeping a close eye on this thread.

 

[7mmShooter]

Sounds like an awesome build Greg! Definitely keeping tabs on this one.gun)

 

[royinidaho]

Greg,

W/the 375 Allen Mag where would a decent starting point be with RL-50 and the CEB 377s.

And what kind of velocity should I expect out of the Pac Nor 10 twist 30" barrel?

 

[Kiwi Greg]

Greg,

W/the 375 Allen Mag where would a decent starting point be with RL-50 and the CEB 377s.

And what kind of velocity should I expect out of the Pac Nor 10 twist 30" barrel?

I don't have my data on me sorry & haven't shot the 377s.

If you have H50BMG data it will be very similar.

It is pretty easy to extrapolate data with the CEBs as the bearing surface doesn't change between projectile weights.

 

[7mmShooter]

Greg, you've run the CE range from 350-425gr. In another thread you said they are all pretty identical ballistically. What combo do you find to be the best? I have a feeling the 400 and 425s might I've a little better barrel life (could be wrong!) Also, what have you found for a BC on those 450gr Lazers? From what I've seen the 425gr MTH is right around .495 G7. Bryan Litz tested the 352gr MTAC at .408 G7. Keep up the amazing work!!