System Insight

[Louis Corkern]

Good Day Everyone,

Well some of you have noticed me saying recently to be on the lookout for a new cartridge system that is going to dominate the 375/408. Well I figured I would go ahead and make a brief introductory thread about it and give credit and thanks where it is due, as this has been a long time coming and still has long time more to go.

First Thanks goes to Anthony and Gerard with GC Custom bullets for taking all the time they have in talking with myself and few others about this project. You guys took the conversation topics and made they projectile to be successful with the MV we talked about and successful at the distances we talked about..pending case design which allowed to obtain said MV lol (Prediction of 3200fps).

Second Thanks goes to Dave Viers for all the work he had already done on case design long before I ever talked to him about it personally (Anthony had done most of the talking lol) and all the leg work he has done in the area of ELR shooting. As Dave mentions on his website about upcoming announcement of 375VM..I too am in the middle of building a 375VM to begin collecting range data and have my fingers CROSSED that it matches everyones computer generated data

Third Thanks goes to Nick at Desert Tactical Arms (my boss lol) for allowing me to have a 375VM conversion made for our HTI rifle system so that we can test everything ourselves, for having same thoughts as myself in regards to making a production ELR system so people do not have to spend months and months researching what projectile, what case, what barrel maker, what rifling profile matches what bullet, etc etc etc.

This system was thought of from the ground up to have the projectile match the case design, the case design match the burn rate and on down the line. All the components compliment each other in regards to internal and external ballistic desires.

375Viersco Magnum Case
414gr GS Custom .375 Projectile
Broughton 5C 8 twist barrel at 29.5" with DTA muzzle brake is what my test platform is going to be..just waiting on Broughton to make it.
All the above dropped in Desert Tactical Arms HTI chassis!!
Custom reloading dies to be able to seat such long projectile will come from Dave Viers.

From left to right
338NM w/300gr Berger, 338LM w/270gr solid, 408CT case, 416VM which will be modified in few ways to make 375VM, 50BMG w/750gr solid
Front Row
355gr GS Custom .375, 414gr GS Custom .375

 

[KYS]

Re: System Insight

the black bullet looks painful. cant imagine hitting someone or something at 1000 yards with that! Any projected idea on what the energy will be at say 1000 yards and in?

Nice work Later.

 

[Jimmym40a2]

Re: System Insight

Looks awesome -do you have any idea of a completion date?

 

[Louis Corkern]

Re: System Insight

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: $KYshooter338$</div><div class="ubbcode-body"> Any projected idea on what the energy will be at say 1000 yards and in?

Nice work Later.</div></div>

My projection is going to be "I not even open case for something that close lol.

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Jimmy M40a2</div><div class="ubbcode-body">Looks awesome -do you have any idea of a completion date? </div></div>

Broughton advising 10 weeks for barrel. That gives us enough time to get first batch of "Test" brass and projectiles into the country.

Thanks

 

[Fredo]

Re: System Insight

The energy would be around 5,000 ft lbs at 1000.

Even subsonic the wound channel, if that tumbles even 90 degrees will be huge.

 

[Extremist458]

Re: System Insight

Thanks for the Kudos Later! Yes, this is a Ultra long range system. You would be more then welcome to shoot tin cans at a 1000m, but it's purpose-built to do 3000m+. The DTA HTI rifle is a perfect platform for this project (just love the design), the barrel is spectacular and a perfect fit (still going with Mike's additions?), Dave's VM case was a perfect fit ballistically, and the bullet is the culmination of more then 2 years of my personal efforts+ months of designing and 17 years of Gerard's expertise. To say the least, everyone said it couldn't be done: well it is, and here is just the beginning. If I could express my excitement herein, these words would give you tinnitus.

 

[Jimmym40a2]

Re: System Insight

Later-
1)what is it's case capacity?(what powder do you expect to use?)
2) Does it use a Cheytac bolt face?
3)Does it have a slightly rebated rim compared to the case?
4) Who is making the brass?
5) Is Dave going to have dies for it?
Thanks- just wondering about how difficult it will be to convert to this "if it flies" LOL

 

[Dogtown]

Re: System Insight

Excellent!

 

[Louis Corkern]

Re: System Insight

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Jimmy M40a2</div><div class="ubbcode-body">Later-
1)what is it's case capacity?(what powder do you expect to use?)
2) Does it use a Cheytac bolt face?
3)Does it have a slightly rebated rim compared to the case?
4) Who is making the brass?
5) Is Dave going to have dies for it?
Thanks- just wondering about how difficult it will be to convert to this "if it flies" LOL </div></div>

1. I do not have the finalized version of the case yet to get that number for you. I have the drawing

IIRC US 869 or I am going to import some ADI powders.
2. No it does not use CT boltface. It has a .688 instead of .640
3. Yes it is slightly rebated rim so extraction works like normal.
4. Bertram is making brass for Dave
5. I am getting my dies from Dave!



Thanks

 

[C.K]

Re: System Insight

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Jimmy M40a2</div><div class="ubbcode-body">Later-
1)what is it's case capacity?(what powder do you expect to use?)
2) Does it use a Cheytac bolt face?
3)Does it have a slightly rebated rim compared to the case?
4) Who is making the brass?
5) Is Dave going to have dies for it?
Thanks- just wondering about how difficult it will be to convert to this "if it flies" LOL </div></div>

This is what I got from Dave and Louis, if Im wrong please correct me.

1: 190gn to bottom of neck
2: No it has a .690 face
3: ???
4: Bertram brass, purchased through Dave
5: yes, dies and reamers through Dave also

 

[Wild_Bill]

Re: System Insight

Later what ADI powders are you after? the commercialy available powders are available there AR2218 the 50 cal powder is repackaged there int he US as H50BMG they do make over 100 powders and they have slower powders for military use i have a friend i shoot with that is a technition at ADI so if you want any info i can ask for you.

I also think i will have to make one as the cases will be made an hour from where i live and we import Lawton actions and barrels might have to make this my next build just called Dave so i will have to make it happen also we will be able to make them for the Australian Market if all is Ok with Dave.

 

[Louis Corkern]

Re: System Insight

WB,

I would have to talk to Anthony on the ADI number but IIRC it is 2210...We just got ordnance license so we can import and get whatever we want lol.

Thanks

 

[Black Diamond Rifles]

Re: System Insight

I am very close to the final specs on the new case.
OAL will be very close to 3.380" long.
Loaded round with the 414gn bullet 4.950" + or -

It will work in a lawton 8000 single shot or Stiller
Tac 408, you will have to do some work to the bolt face.
Lawton might offer the new bolt face if there is any call
for the actions in the future. It will however be a single
shot only. Bolt face .690

I have tested the 414gn bullet in my 375 Snipetac and achieved
3000fps, 150gns US869 powder. The 375VM should add at least 200fps to that total.

Here are some basic numbers
100yd sight in
muzzle energy 9,400#

1000yds
-15 moa 5,850# energy vel 2524 1.05 seconds

2000yds
-41.8 moa 3,465# energy vel 1941 2.4 seconds

2500yds
-59.5 moa 2,610# energy vel 1685 3.2 seconds

3000yds
-81 1,953# energy vel 1457 4.2 seconds

More to add when the specs arrive from my guy with the CAD
program.

Dave Viers

 

[Jimmym40a2]

Re: System Insight

Dave what twist is stabilizing those long bullets and any accuracy reports?

 

[Black Diamond Rifles]

Re: System Insight

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Jimmy M40a2</div><div class="ubbcode-body">Dave what twist is stabilizing those long bullets and any accuracy reports? </div></div>

Right now i am using an 1:8 lawton cut rifled barrel on the 375 Snipetac. It is throated for the big bullet, aprox .500" of free bore is needed. I have only done initial 100 yd tests working loads and chrono's. Bullet holes are round so they are stable. Groupings when i fired two of the same loads, shots were touching or a ragged hole. This weekend i hope to try 1000yds, i have a very limited supply of bullets to work with.

I have a 1:13 gained twist to 1:6.5 barrel that will be installed for a customer very soon, he ordered 375 Snipetac but now might change his mind to the 375VM.

Dave

 

[Jimmym40a2]

Re: System Insight

Thanks Dave sounds promising. What is the estimated BC on those?

 

[Black Diamond Rifles]

Re: System Insight

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Jimmy M40a2</div><div class="ubbcode-body">Thanks Dave sounds promising. What is the estimated BC on those? </div></div>

I believe Gerard estimated 1.300 or there abouts!
Anthony might have a closer estimate.

Dave

 

[Jimmym40a2]

Re: System Insight

Man that is awesome. Sorry to keep asking question but it looks like a great package. What is the estimated supersonic range?

I think I have run out of questions..........LOL

 

[Black Diamond Rifles]

Re: System Insight

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Jimmy M40a2</div><div class="ubbcode-body">Man that is awesome. Sorry to keep asking question but it looks like a great package. What is the estimated supersonic range?

I think I have run out of questions..........LOL </div></div>

Around 2 MILES

 

[Black Diamond Rifles]

Re: System Insight

Here is the CAD print for the 375 VM case. I should have brass in about 45-60 days.

Dave

 

[Louis Corkern]

Re: System Insight

Dave,

I cannot wait to get this system!! Brass should be coming in right about the same time my barrel comes in.

FANTASTIC!!!

 

[ranger1183]

Re: System Insight

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Black Diamond</div><div class="ubbcode-body">

Dave </div></div>
how does this case compare in size to the CheyTac case? What is the parent cartridge of this case?

 

[Jimmym40a2]

Re: System Insight

I think Dave is the parent. I don't think it's based off another case but I could be wrong?

 

[savage110]

Re: System Insight

I will be waiting for the release of this caliber, so long 375CT. 1.300BC HOLY SHIT!

 

[Phil1]

Re: System Insight

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Black Diamond</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Jimmy M40a2</div><div class="ubbcode-body">Dave what twist is stabilizing those long bullets and any accuracy reports? </div></div>

Right now i am using an 1:8 lawton cut rifled barrel on the 375 Snipetac. It is throated for the big bullet, aprox .500" of free bore is needed. I have only done initial 100 yd tests working loads and chrono's. Bullet holes are round so they are stable. Groupings when i fired two of the same loads, shots were touching or a ragged hole. This weekend i hope to try 1000yds, i have a very limited supply of bullets to work with.

I have a 1:13 gained twist to 1:6.5 barrel that will be installed for a customer very soon, he ordered 375 Snipetac but now might change his mind to the 375VM.

Dave </div></div>

Welcome Dave. I like your posts on other forums and hope to see more about this and your other projects.

 

[Master Diver]

Re: System Insight

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Jimmy M40a2</div><div class="ubbcode-body">I think Dave is the parent. I don't think it's based off another case but I could be wrong? </div></div>

I think the parrent case is .577 Taurannosaur AKA T-Rex.

Cheers,

Master Diver

 

[Louis Corkern]

Re: System Insight

Dave,

I have a gain twist that once I cut barrel down will come to about 6 twist at exit. I will have that barrel this week. When can I send to you for chambering and get reloading dies. I can have everything ready and waiting for the 375VM brass.

Thanks

 

[He Shoot Me]

Re: System Insight

Tag

 

[Bushmaster7]

Re: System Insight

Louis, Anthony and Gerard, Dave and Nick, you guys are my heroes on this one. LC, you are the Master Chief !!

Now does all this ass kissing get me first dibs on an HTI in 375VM???

 

[Jimmym40a2]

Re: System Insight

Master diver-I think your right here are .577 trex case dimensions- and the base diameter matches.

Parent case New Design
Case type Rimless, Bottleneck
Bullet diameter 0.585 in (14.9 mm)
Neck diameter 0.6135 in (15.58 mm)
Shoulder diameter 0.673 in (17.1 mm)
Base diameter 0.688 in (17.5 mm)
Rim diameter 0.688 in (17.5 mm)
Rim thickness 0.063 in (1.6 mm)
Case length 2.990 in (75.9 mm)
Overall length 3.710 in (94.2 mm)
Rifling twist 1 in 12 in (305 mm)
Primer type Large Rifle Magnum
Maximum pressure 65,000 psi (450 MPa)

 

[The Mechanic]

Re: System Insight

Good catch on the T-Rex. Case dimensions look close.
http://en.wikipedia.org/wiki/.577_Tyrannosaur
That will be a smokin' hot round. 414gr at 3200fps wow!

 

[Black Diamond Rifles]

Re: System Insight

The case design is being made from allmost scratch. I talked with Bertram several years ago looking for a new case larger than the 408 CT. He sugested his .585 African, similar to the Trex. I had him neck some down to 416 and hence came the 416 VM.
The rifle performed real close to that of the 416 Barrett only in a small package.
While looking for another design rifle i thought of just a simple neck down to 375, but that would leave a short neck, ok for standard bullets but i was looking at the new long bullets. I have done a 375 Snipetac with the long throat and it works good but a longer neck would be even better. I contacted Bertram and asked what was the longest brass he could do with the existing dies he has. 3.5" was his ans. So i went to the drawing board, I ended up changing most of the original specs except for the .680 case head. I added to the neck so it would come out to .750 long, this will hold any type bullet with keeping a short throat in the chamber. Basicly i can chamber for any bullet using one reamer, no separate throating steps.
Throat length will be around .200 long, this will let us use standard hunting bullets along with the 7 cal long bullets (2.62")
1:11.5" cheytac barrel and 350gn bullets, 3400fps+
1:10" barrel, 350 to 370gn bullets
Super High BC bullets 8" or faster.

You could have extra barrels for different shooting types.

I have a Lawton 8000 reciever that i am re cutting for the big case. I will be building a complete bolt for it to match the .680 case head. I picked up a blank A5 McM stock to inlet for the test rifle. I have a 10 twist Lilja, 32" bbl on hand.
The primary test bullets will be 350 SMK, 350 Predator solids, 355 GS customs.

So far everything is progressing rather fast. The test gauges will be done first of next week, then they go to Australia to get the brass made. Proper headstamps and no fire forming required.
I have the reciever ejection port opened up on the 8000 rec. I have the 17-4 bolt body fluted and heat treated. I am waiting on some 4140 for the locking lugs to complete the set up. I machined the bolt body with tight tollerances and trued up the action. Optics will be a Nightforce 8-32x56 R1 scope, 30moa rail for close work. Long range testing 40 or 50 moa base. I will have to travel out to Gillette Wyo to test past 3000M.

Faster twist barrels will be tested on the extreme bullets. I have been running tests for GS Custom in a 8 twist bbl. They are
trying to build a extreme bullet that will work in an 8 twist barrel. I am using my 375 Snipetac for the test platform, so far I can get 3000fps shooting the 414gn GS custom bullet. That is faster than a 408 Cheytac and this bullet has a killer BC. The first round of testing is complete and results have been transmitted back to Gerard in South Africa. He will be tweeking the design for the next round of tests. Eventully this bullet will go into the 375VM case. There is a lot of research and testing that goes into building a new case and bullet from the ground up! I have every confidence that this will be the new super long range set up. Hard Target capable 3500yds easy.

I will post pics of the rifle as it grows, i am thinking of the Multi Cam camo scheme, i just did one for a guy in Denmark and it turned out nice.

Dave

 

[Bushmaster7]

Re: System Insight

Thanks for the update Dave. This is some amazing work going on here. regards, Dale.

 

[Whootsinator]

Re: System Insight

It's incredible to be able to watch the development of such an amazing cartridge develop...

Keep it up!

 

[Jong]

Re: System Insight

So would you guys think it is a good idea to hold off on buying a 375/408 CT till you guys figure this out?

 

[Master Diver]

Re: System Insight

Here is my latest toy made by Dave.
Twist is 1:10.5 in rectro spective it should have been 1:10.

Next one on will be the 375VM with Gain Twist barrel 6.5 exit. I might be able to stabalize the 414 grn GSC SP in conjunction with modifications made to the bullet.

Cheers,

Master Diver

 

[i_Adam_i18]

Re: System Insight

That's one of the hottest setups I've seen. One question though, why such high rings? Needed to line up NV on that forward rail?

 

[Master Diver]

Re: System Insight

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: WASP7067</div><div class="ubbcode-body">That's one of the hottest setups I've seen. One question though, why such high rings? Needed to line up NV on that forward rail? </div></div>

You got it

Most builds do NOT take this into consideration.
I do also have a brand new set of 1" high MAX-50 34mm Badger rings if I want to mount lower.

Cheers,

Master Diver

 

[i_Adam_i18]

Re: System Insight

got it. That is definitely eye candy and I'm sure it performs.

 

[C.K]

Re: System Insight

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Jong</div><div class="ubbcode-body">So would you guys think it is a good idea to hold off on buying a 375/408 CT till you guys figure this out?</div></div>

I would.

 

[Augustus]

Re: System Insight

Dave, thanks for the update. For clarification are you reporting you fired the 414 at 3000 fps and got one hole groups at 100 yds at that velocity?

 

[savage110]

Re: System Insight

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Master Diver</div><div class="ubbcode-body">Here is my latest toy made by Dave.
Twist is 1:10.5 in rectro spective it should have been 1:10.

Next one on will be the 375VM with Gain Twist barrel 6.5 exit. I might be able to stabalize the 414 grn GSC SP in conjunction with modifications made to the bullet.

Cheers,

Master Diver

</div></div>
Master Diver, if those are USMC badger rings then the fat one goes in front, just letting ya know.

 

[Master Diver]

Re: System Insight

I knoe this, but I did not put them on. The rifle is still at Daves and will be shipped soon.

Cheers,

Master Diver

 

[Noel Carlson]

Re: System Insight

Dave,

I think it is great that you took the initiative to subcontract brass specifically for the, 6.5+ caliber, banded solids. The long case neck has some advantages, less obvious than powder column encroachment, that you will discover soon.

Good work.

 

[shoot1760]

Re: System Insight

Later, I've been talking to Dave about building a VM as well. Please keep me in the loop as you do your load development and your range work. I can use your data to develop mine and I can share my data with you as well. Im sure by now you know that revision 2 on the GS 414 will probably take the bullet down to near 380 grains with a lower BC. But it's still going to be a real screamer in the VM. My email is [email protected]

cheers,
kelly

 

[Noel Carlson]

Re: System Insight

shoot1760;

Are you kellyzier from LRH?

 

[shoot1760]

Re: System Insight

Yea Noel, it's me....Keep me in the loop on your results in the next few weeks...I've got a 10 twist inbound for the snipe tac, and Im holding a 2nd barrel cut based on everyone's data. I can have the second barrel cut and operational in a few weeks depending on what I hear from all ya'll. I'm sure it will be either a 9-5.5 gain twist or a 1-8. Dave V is really wanting to use the 1-8 platfrom for his builds for many reasons, so I hoping we can find optimum performance here.

 

[Noel Carlson]

Re: System Insight

Kelly,

I did not realize that you were interested in the monolithic solids. Most of the attention over at LRH is upon the ZA/PDT/Magazine frangibles, and I am racing to get the first 338s into production.

The 8" twist barrel is useless in maximizing 375 velocity potential on these beasts until you drop to 6.0 caliber length projectiles. A 6.5" twist works very well in stabilizing the 400 grain ZA375/6.5-M, and we had no trouble obtaining a 3,200 fps MV from the standard CheyTac case. There are huge advantages associated with the longer neck that Dave is contemplating however, which we intend to exploit in the 420 grain ZA375/7.0-M. This one can be safely fired at 3,150 fps MV, but we are still waiting on a barrel with a 5.5" exit twist. This projectile also requires a bronze alloy which may become the standard for all ZA projectiles.

You do realize that there is an eight month wait for a barrel, correct?

 

[shoot1760]

Re: System Insight

Noel,
Initially I was not...But as I have educated myself here, I've concluded that I need to have two barrels, one for hunting one for Ext Long range.

Ref the 6.5 400 gain, you said a 6.5 twist will stablize it..I take it you are talking about a standard 6.5 not a gain twist. Im not sure if Im ready to go to a gain twist.

Ref the long wait on barrels...A standard tight twist is no problem..the gain twist is the problem with lead times as I understand it...I take it you are talking about the gain twist?

kz

 

[Noel Carlson]

Re: System Insight

Kelly,

Yes Kelly, we are talking about gain-twist rifling geometries. The 14.6 caliber twist which the ZA375/7.0-M requires is 5.5 calibers tighter than even the 120mm gun that the Challenger MBT mounts. I know some versions of this gun use a gain-twist for a number of the same reasons the ZA-ULR projectile does.

First, firing into this rifling angle has a good chance of breaking the gas seal of the primary rear band, if not removing it entirely. This would cause plasma copper deposits on the bore, and these projectiles do not work well in a fouled barrel. Secondly, while not proven to have an effect on shot-to-shot repeatability, there is no question that barrel harmonics are effected. Shooting comfort is definitely enhanced with gain-twist geometry. Third, the progressive twist continouosly aligns the bore/projectile axis during barrel transit through the mechanism of engraving-band material displacement.

If you are going to shoot the extreme projectiles, you will need to put in an order for the right barrel.

Best,
Noel