375 Viersco Mag

#51
Re: 375 Viersco Mag

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Jimmy M40a2</div><div class="ubbcode-body">Great info. I really dig this case. What was the velocity in the snipetac case for the 414? </div></div>

I was running them right at 3000, 148 US869 It was highly accurate out of my 31" Gain twist bbl. 16 to 8 twist.
With the longer barrel i am looking at 3150 to 3200 for the 414 in the VM. This is what the case was designed for.
I would like to get another gain twist barrel, but its at least a year to get one.
The loads i publish are not hot loads, case life is very important to me and my customers. I worked very hard with
Bertram Bullet Co. to make the changes to the case that i thought that would give them the best life.
The 375 Snipetac will not be replaced by the VM, its just a step up for those who want to push the envelope a bit more. The smaller Snipetac case will have an advantage by not needing the longer barrels to get top performance in lighter carry rifles.

Dave
 
#52
Re: 375 Viersco Mag

Thats an important note worth highlighting... you dont really get much advantage over the cheytac/snipetac UNLESS you have a 34"+ barrel to go on the VM... So if your looking for a lighter weight, somewhat more portable rifle with a 32"bbl or less, then the snipetac is still a better choice.

 
#54
Re: 375 Viersco Mag

Dave
thank you for the information. As always your notes are informative. I'm glad to see that you pushed for superior brass for you new cartridge. I have held off building a rifle using the 408 case specifically because of the brass issues and quality.

I like the idea and use of the longer barrels to get a more comnplete powder burn and increased velocity. Do you think there is a point of diminishing returns on barrel length, where the length, weight, and flex of the barrel outweigh the utility of the powder burn?

I do have a couple of questions about the differences in day one and day two.

Are you talking celcius for the temperature or fahrenheit? 15C = 59F; 15F = -9C.

Was there any reason that you loaded 153 grains of US869 for day two tests instead of the 155 that you used on prior day?

You were low at 550, and close to 5 MOA lower than expected by the published elevation chart at 1,150. Do you think that the 35-39 fps velocity change accounst for the 5 MOA difference at 1,150? I would think the velocity difference would drive less than a 1.5 - 2 MOA difference in elevation.

I look forward to your continued reporting on your results. Keep up the good work and reporting.

JeffVN
 
#55
Re: 375 Viersco Mag

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: groper</div><div class="ubbcode-body">So if your looking for a lighter weight, somewhat more portable rifle with a 32"bbl or less, then the snipetac is still a better choice. </div></div>

Imagine a 375VM in a DTA HTI chassis! I will be getting an ELR rifle within the next year to 2 years. (it will take me that long to save up for one) This cartridge looks VERY good thus far.

Viersco, you need to call Desert Tactical Arms and make sure they set up their HTI to work with this cartridge. The bullpup design would allow a nice long barrel without making the rifle too unwieldy.
 
#56
Re: 375 Viersco Mag

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Jeffvn</div><div class="ubbcode-body">Dave
thank you for the information. As always your notes are informative. I'm glad to see that you pushed for superior brass for you new cartridge. I have held off building a rifle using the 408 case specifically because of the brass issues and quality.

I like the idea and use of the longer barrels to get a more comnplete powder burn and increased velocity. Do you think there is a point of diminishing returns on barrel length, where the length, weight, and flex of the barrel outweigh the utility of the powder burn?

I do have a couple of questions about the differences in day one and day two.

Are you talking celcius for the temperature or fahrenheit? 15C = 59F; 15F = -9C.

Was there any reason that you loaded 153 grains of US869 for day two tests instead of the 155 that you used on prior day?

You were low at 550, and close to 5 MOA lower than expected by the published elevation chart at 1,150. Do you think that the 35-39 fps velocity change accounst for the 5 MOA difference at 1,150? I would think the velocity difference would drive less than a 1.5 - 2 MOA difference in elevation.

I look forward to your continued reporting on your results. Keep up the good work and reporting.

JeffVN </div></div>

Jeff,
The temps here are fahrenheit.

On barrel length, i would think that 35" would be plenty to burn the powder, Deminishing returns is
hard to predict without massive amounts of testing. I doubt 40" would see much improvment or detrement.
Extra long barrels might require a bbl block or V block of some sort. 36" bbl would be just fine in standard
type bedding.

The elevation chart called for 23moa at 1150yds, i added 2moa but the group was not measurable as it was vertical
from bottom to top 2 moa. If you split the difference from the highest hit to the lowest then the group was on center.
The US869 loads were not usable due to the hang fires, vel was 200fps slower than the day before. I am shooting up hill
just a bit, a couple hundred feet i supose.

The reamers are going back to have a few adjustments made, The sizer die reamer needs a bit more restriction, and i am
shortening the neck as i dont need the full .750 long for the larger bullets. The new neck will be a full half inch long
still capable of holding the bullet straight in severe conditions. R&D time. This case can be necked up for larger calibers,
408,416.

I sized the 5 cases again from last test yesterday, I still havent bumped the shoulder and primer pockets are very tight.

Dave
 
#57
Re: 375 Viersco Mag

Dave,
by any chance ,is it a 577 Tyrannosaur case necked down? <div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Viersco</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: XLR</div><div class="ubbcode-body">I am so excited to see the development of this round! Good stuff!


Dave can correct me if I am wrong but the bolt face is .678"

edit: Just read on his site that a bolt face of .690" is required. </div></div>

VM takes a .690 bolt face. Case head is .678 base of case is .680
Cheytac is .635 bolt face .650 on most actions.

Dave</div></div>
 
#59
Re: 375 Viersco Mag

Later,
Sorry i missed your question. I really didnt want to use BMG primers as they are inconsistant and hard to get at times. The only issue i had was with US 869 and extreme cold temps.

I just started a new round of tests with V V 20n29 powder. I shot in temps right at zero degrees and had no issues at all with ignition. This powder is working very well with the heavy bullets, i tested some 414gn GS and 425gn Jacketed prototypes. I got the new 8 twist barrel installed last week, it finished out at 35". At 3100fps with the 425gn bullets the recoil is very mild, still some room for velocity increase as the bullets are supose to be shot in a 10 twist barrel. Pressures were moderate at best, load was 162gns. I have a small tweek that needs to be done to the size die reamer, it is set too close to chamber specs and its not giving the brass enough room for expansion and spring back.
I just talked to Dave Kiff and went over the new specs for the reamer regrind. Its just a minor thing that can cause issues.
Now that i have the brass fired and tested i will get one sent off to THOR.
I am also working with Kyle at XLR Industries in designing a Bull pup stock that works with the Lawton 8000 or Stiller TAC 408 actions. It will shorten the OAL of the rifle by 6".
This will be great for hunters and dont want that long barrel getting in the way. First models will be single shot only. It will take some work to fit the trigger linkage and the magazine system on repeaters.

guns_089_crop.jpg


This photo is just pics of some prototype stocks that Kyle has done. The Bull Pup stock i am having him work up will be similar to the one above. As with any prototype there will be some changes made during testing. Once the specs has been finalized they will be available for purchase.

Dave
 
#62
Re: 375 Viersco Mag

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">Now that i have the brass fired and tested i will get one sent off to THOR.</div></div>
Why?
 
#64
Re: 375 Viersco Mag

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Jimmy M40a2</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">Now that i have the brass fired and tested i will get one sent off to THOR.</div></div>
Why?</div></div>

They are one of the several companies looking to offer the 375VM in mfg system.
 
#66
Re: 375 Viersco Mag

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Jimmy M40a2</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">Now that i have the brass fired and tested i will get one sent off to THOR.</div></div>
Why? </div></div>

Later is building a rifle chambered in the 375VM
 
#68
Re: 375 Viersco Mag

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Viersco</div><div class="ubbcode-body">By the looks of the fluting </div></div>

That's why I thought so.

Sorry for the misunderstanding... thought those were your sticks.

John
 
#69
Re: 375 Viersco Mag

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Jimmy M40a2</div><div class="ubbcode-body">So is Thor doing a "windrunner" barrel for this?</div></div>

I am doing one as a test platform for ME first lol
 
#71
Re: 375 Viersco Mag

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Jimmy M40a2</div><div class="ubbcode-body">Are you modifying a 408 bolt to use for it?</div></div>

That is what they are wanting the case for, to see if it can be done or if they need make new bolt. I am mechanically declined to I figured it better for them to have case in hand to do all the measuring and figuring lol.

I have the gun already so makes for easy test lol
 
#76
Re: 375 Viersco Mag

Wow, 3000 yards. Im sure at that range, HTI is out of the question but damn. Very cool. If you can get a decent avenue for brass avail and ammo avail, I would buy one. Also a repeater action with readily avail mags would be on my list. See what you can do and lets talk.
 
#77
Re: 375 Viersco Mag

Do you think a EDM .50 BMG action would be able to magazine feed this round? (I'm guessing the 408 action would not work due to the extra length).
 
#78
Re: 375 Viersco Mag

A 40" tube has a shit load of weight so does one need a barrel block and free floating action to hold a 40" bull barrel or run bedding compound 1/3 up barrel to support the extra weight on the action if it is not floating the action ? I know Barnard make a 50 cal action that could probably hold this tube but they dont often do custom size bolt faces -the question will be asked though as their action would be perfect for this caliber and tube length.
I look forward to LATER reporting back on his new rifles ability once finnished and fired.
 
#79
Re: 375 Viersco Mag

See 375VM bullet development is planned down under:

http://www.snipershide.com/forum/ubbthreads.php?ubb=showflat&Main=216405&Number=2468391

Bet Berger, Hornady, Barnes, or others may have .375 plans in time as is proving to fly best. While have seen no formal public plans yet they tend to work in private, and often it takes a government / NATO contract for them to know the volume will be there to fund new development before plans go.

Proof by prototype is often critical to winning government contracts. The 375 VM seems to be taking off, and is great to see testing with partnerships moving forward.
 
#82
Re: 375 Viersco Mag

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: XLR</div><div class="ubbcode-body">I am in the final stages of the custom bull pup chassis designed specifically for Mr. Viers and the 375 VM. It will be available for inquiring eyes very soon!

-Kyle ~ XLR Industries </div></div>

A bullpup!!
cool.gif
 
#83
Re: 375 Viersco Mag

Be great to see the Bull Pup platform ! I myself am most interested in the projectile and hope Groper or one of the other members comes out with a projectile stable through all distances -thats what I really want to hear about !
 
#84
Re: 375 Viersco Mag

the projectiles are already stable and have been so for quite some time... the problem is accuracy, they will not shoot 0.5MOA regardless of any load and i have tried quite a few in the 375CT.

I may give up on this concept in favour of a conventional design projectile soon, as it simply may be impossible to get this sort of accuracy from an assymetric projectile...
 
#85
Re: 375 Viersco Mag

Thats a real knock back Groper as you have obviously put time and dollars into this testing .How is it a projectile can have stability but not accuracy ?is this a barrel twist problem-gain twist /not gain twist?
 
#88
Re: 375 Viersco Mag

Groper,

"I may give up on this concept in favour of a conventional design projectile soon, as it simply may be impossible to get this sort of accuracy from an assymetric projectile..."...

Now you can begin implementation of design solutions that have a reasonable chance of success.

The Fall ULR demonstration is still being planned/coordinated by an objective third party, so you have time to prepare. It has been decided to limit projectile caliber to 338 in order to include the maximum number of participants, therefore it would be best if you prototyped that first. All the major jacketed contenders will be represented through proxy. Even two of the highly visible, albeit reluctant, solids manufacturers will be drafted for participation in absentia.

With all of the information clutter surrounding this class of projectile, it will be an ideal opportunity to deliver on substance.
 
#89
Re: 375 Viersco Mag

Ok people, heres a pic of what scorpion projectiles is all about...
410gr.jpg


They shoot subMOA repeatably out to very long ranges and the BC is ridiculous. I can not get them to shoot 1/2MOA however... I still havnt given up on this concept just yet, maybe the next revision will see a consistent 1/2moa reality projectile.

In the 375VM, the possibilities for this type of projectile/rifle system will completely change the way we think about ELR shooting.
IMG_0272.jpg
 
#91
Re: 375 Viersco Mag

" I can not get them to shoot 1/2MOA however... I still havnt given up on this concept just yet, maybe the next revision will see a consistent 1/2moa reality projectile."...

Will you make a commitment to subject the Scorpion to independent validation this Fall... whatever the final configuration may be?

If all that you can come up with by then is a 375, I do have a ZA375 that you can compare against.

 
#93
Re: 375 Viersco Mag

groper said:
Ok people, heres a pic of what scorpion projectiles is all about...
410gr.jpg


They shoot subMOA repeatably out to very long ranges and the BC is ridiculous. I can not get them to shoot 1/2MOA however... I still havnt given up on this concept just yet, maybe the next revision will see a consistent 1/2moa reality projectile.

In the 375VM, the possibilities for this type of projectile/rifle system will completely change the way we think about ELR shooting.
IMG_0272.jpg
[/quote

Far out Nick , thats some Star Trek stuff you got going on there -wow! i wiould have to wonder if you cant get .5 moa because they are far more sensitive to wind as they spin and eat the wind with the tail twist situation ?? cool anyway ansd I hope you get a break through soon
Click to expand...
 
#94
Re: 375 Viersco Mag

Chandalar,

I am not in charge of the event, however; I am certain that nobody will question the qualifications, or the objectivity, of the individual that will oversee testing.

Date, and place, will be announced at Sniper's Hide when details are formalized. I can tell you that all manufacturer's specifications will be followed in preparing for evaluation of their products.
 
#98
Re: 375 Viersco Mag

This right here is the only reason I visit this sight.

God only knows what kind of crazy crap you'll see or hear next. I applaud you for thinking outside the box. I bet you were the kid in kindergarten with the square peg and hammer.
 
#99
Re: 375 Viersco Mag

I have been testing the projectiles in 338 against 3 other solids at the same time and there has been some promising results but there is a small issue that hopefuly will be finalised with the next batch of projectiles. I have fired 5 different variations and one realy showed promise but there is a small thingthat requires a mod and we have talked about that hopefuly it will work out as i have a 375VM going together right now and realy would love to be using them if they come out on top. the BC is a lot higher than any other projectile that will stabalise in a 10 twist 338 i can tell you that but hopefuly this will all become fixed and the tweek will make the bullet a succsess. I am objective in my testing and have no affiliation to Nick besides him asking me to test his projectiles for him and report the true results and they are doccumented with pictures of the groups at ranges and the data obtained. I will not publish the data as it is for Nick but the concept is showing some promise.
 
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