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375 Viersco Mag

V

viersco

Private
Minuteman
Dec 18, 2003
69
1
67
Nebraska
www.viersco.com
This has been in the works for quite a while and with some interest from a few private arms companies I decieded to dust off my drawings and run with it. I got the brass in a few weeks ago, thanks to Bruce Bertram for doing a great job on it.
The brass is totally custom made to my specs, Bruce had to make new tooling to form the pieces. It is a massive case, similar to a 408 cheytac only fatter.
375VM-338_Lapua-compare.jpg


338 Lapua looks kinda small

IMG00018-20101203-1813.jpg


The bullets shown are the GS Custom 414gn, MK1 is shown below, MK2 is seated in the caseing. I have been using the MK1's for initial velocity tests. MK2's will be used for actuall accuracy testing.

VM4.jpg


This is the test platform.

I will update more on this project.

Dave
 
Re: 375 Viersco Mag

This is very nice. It kind of reminds me of a monster PPC with the fatter cartrige and the long neck. Nice on the design though. I am very interested in ELR accuracy testing. Nice stuff Dave, very nice. Now hopefully this won't become a dick measuring contest like on the other topic with the MK2 from GS.
 
Re: 375 Viersco Mag

Will be interesting to see if you hit anything without any optics!!
grin.gif
Been waiting to hear about this and looking forward to the range report.
 
Re: 375 Viersco Mag

Here is a little more on the current state of the project.

First off here is a little about the test rifle:
Action Lawton 8000 Reciever (Modified for larger case)
Bolt Viersco custom
Jewell trigger
XLR Industries modular stock
32" 8 twist Lawton barrel
Shark Bite 4 port muzzle brake
8-32x56 Nightforce optics

This was an extra barrel I had on the shelf so it was used for initial tests and load development. I have 3 other barrels that will be used for the final results.

35" 11.5 twist 8 groove Benchmark
34" 10 twist Lilja
36" 8 twist Lawton
----------------------------------------------

The first tests were to find what powder and how much, with a case this big and bore size it would have to be the slow burn types. I tested, US869, H-BMG50 and WC872

The first test was with a 414gn GS MK1 bullet seated to touch
the lands. 155gns of each powder listed. Vel was very close
for the three types. No targets were shot for any of the speed and pressure tests. The temp was 10 deg. Velocity was close to the 2900fps area. No pressure signs on the case.
I bumped the load up to 160gns, still no pressure and velocity increased to 3100fps, some signs of firm bolt lift.
I tested a few of the 350gn Predator solids with 165gns of powder, 3350fps was the top load with a stiff bolt.
It was clear that the barrel is too short for the amount of powder in the case. My best guess is a 35" barrel will be more suitable for this case capacity and bore size. My original projections was to get around 3200fps with the 400gn bullets. Couple that with a bullet that has a BC of 1.25 or more and it will be a very long range rifle.
This is primarily being designed for a hard target long distance rifle, special ops, ect. 3000+ yards.

<span style="color: #FF0000">Special Thanks to Kyle at XLR Industries for the stock.
Bruce Bertram at Bertram Bullet Co.in Australia for the brass work.
Anthony at GS Custom Bullets</span>
 
Re: 375 Viersco Mag

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: ranger1183</div><div class="ubbcode-body">what's the price and availability of brass and dies? </div></div>

I make the custom dies for all my wildcats and all of the 408 based cases.
I only ordered a small supply of brass until I see if I need to make any changes. Once the design is final I will order brass once a year, Bruce said he would keep some on hand there for other orders. If the case is picked up by a defense contractor, then there would be a vast supply of brass available.
Current brass pricing reflects the R&D costs i have incurred and materials.
6.25 ea.
 
Re: 375 Viersco Mag

Dave, can you tell us the reasons for such a long case neck? i know it goves you more options in terms of projectiles, but is there any other reason?
 
Re: 375 Viersco Mag

Dave,
Great case design. Really like the longer neck, and I assume the shoulder angle is around 30 degrees.
Question:
Will this platform be about 20# or more in order for recoil to be manageable?
What size die body will this case require ?
 
Re: 375 Viersco Mag

Dave

Love the loooog neck. Excellent job getting those super long pills out of the powder column.

JeffVN
 
Re: 375 Viersco Mag

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Bluejazz</div><div class="ubbcode-body">Dave,
Great case design. Really like the longer neck, and I assume the shoulder angle is around 30 degrees.
Question:
Will this platform be about 20# or more in order for recoil to be manageable?
What size die body will this case require ? </div></div>

The recoil on the test rifle is not much different than my 375 Snipetac hunting rifle. I would assume this rifle is in the 18-20# class, scoped.

Dies are either 1.250" or 1.500" bodies

A loaded case with the 414gn bullet is just shy of 5" long.

Dave
 
Re: 375 Viersco Mag

Dave,

It sure looks great
grin.gif
Congratulations on getting to where you are now.
Is that a .40 moa rail on the rifle? How high are the rings to clear the tube on the XLR stock?

Cheers,

Master Diver
 
Re: 375 Viersco Mag

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: groper</div><div class="ubbcode-body">Dave, can you tell us the reasons for such a long case neck? i know it goves you more options in terms of projectiles, but is there any other reason? </div></div>

The long neck serves several purposes,
You only need one chamber reamer with a standard throat. You can set up the rifle to shoot the looong High BC bullets
and dont need to have a special throat cut. You can have another barrel set up for more traditional bullets but with
the same throat. The long bullet seated to just touch the lands will have the boattail just into the shoulder/neck juntion. A long neck also helps on throat wear. A long neck will support the long bullets, keep them in line during heavy abuse. Short or standard necks with the long bullet can get tweaked out of line if handled roughly. There is nothing wrong with the standard neck and long bullets for those who are shooting on a bench or very carefull handleing them, but in the military field sometimes going gets rough and we need stable reliable ammo.
 
Re: 375 Viersco Mag

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Master Diver</div><div class="ubbcode-body">Dave,

It sure looks great
grin.gif
Congratulations on getting to where you are now.
Is that a .40 moa rail on the rifle? How high are the rings to clear the tube on the XLR stock?

Cheers,

Master Diver </div></div>

Yes its a 40moa rail, it needs a 30moa as i am using my 8-32 nightforce for testing. Sight in point will just be very far down range, aprox 700 yards.

I have the Badger "High" rings on this, with the 56mm objective i had to mill a small slot on the hand gaurd to give a little clearence for the scope. Normally the Extra High rings would of been needed. A 50mm objective would clear easy. There is a lot of adjustment in the cheek on the stock to make up for the high rings. When i start making my own bases i will just cut them .100 taller vs the Lawton base.
 
Re: 375 Viersco Mag

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Later</div><div class="ubbcode-body">Glad to see this finally become public. It has been a long time in the making
smile.gif
</div></div>

Yes it has and prolly will be much longer to get all of the barrels tested with various bullets.
I will be running the 355 GS Custom in the 10 twist Lilja barrel, along with the 350SMK and the Predator 350, Rocky Mountain 370gn.

The 11.5 barrel will see 350SMK's Jamison 350's, Predator 350's

The 8 twist is set for the 414gn GS Custom, 424gn GS HV bullet, Rocky Mountain 420-450gn jacketed bullets.

I will be ordering a Rock Creek Barrel in 8 twist, 7R rifling 36" with a double contour to lighten the weight some. I will also see if it can be fluted.

Dave
 
Re: 375 Viersco Mag

Thanks,
Making the base taller makes sence one would the be able to use HIGH ringa ja?
Have you thought about the SN9 10-42x80 scope by USO - it should be very sutable for +3000m

Cheers,

Master Diver
 
Re: 375 Viersco Mag

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

Love the loooog neck. Excellent job getting those super long pills out of the powder column.

JeffVN </div></div>

Jeff,
Right now i am running aprox 95% case capacity, powder levels are at the shoulder to the bottom of the neck depending on the bullet weight. I need to get some of the VV 24n29 for testing.
 
Re: 375 Viersco Mag

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Master Diver</div><div class="ubbcode-body">Thanks,
Making the base taller makes sence one would the be able to use HIGH ringa ja?
Have you thought about the SN9 10-42x80 scope by USO - it should be very sutable for +3000m

Cheers,

Master Diver </div></div>

I will leave the big scopes up to the dudes shooting this rig. I will have to do some traveling just to get to test past a mile. I can set up to test 2 miles here but have to get a road closed so they dont drive through the middle of the test range, LOL.

I will have to do some calculations, but i think with the current set up I can get past 3000 yards.

Taller base lets you use shorter rings. Scope objective will come into play. I am going to talk with Kyle and see about slightly changing the hand gaurd so it has a relief cut under the objective. There is plenty room for it as i did it on mine. I milled a 5/8 wide slot the length of the objective. I did not cut all the way through the hand gaurd so no strength was lost.
 
Re: 375 Viersco Mag

Point taken regarding the scopes.
I will not be needing a low mount with little clerance since I will have rails on the tube and a RND 202 top mounted bipod. BUt for the average 56mm scope mount and a conventional bipod it might be good to modify the XLR a bit.

Cheers,

Master Diver
 
Re: 375 Viersco Mag

There was some daylight between the objective and the handguard before i did the mods. I like a little more clearance incase there are any vibrations.

The McRee stock can use lower rings due to the forend difference, but high rings work better so you can get the adjustable cheek plates up high enough to clear the bolt body.

The XLR stock is much lighter vs a McRee.
 
Re: 375 Viersco Mag

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Viersco</div><div class="ubbcode-body">The McRee stock can use lower rings due to the forend difference, but high rings work better so you can get the adjustable cheek plates up high enough to clear the bolt body.</div></div>

But if one has the McRee folding stock this does not matter
wink.gif
grin.gif


The XLR stock sounds like a good solution for a "light" hunting version in the 20 lbs range
grin.gif


The Spuhr sniper mount 1.46" version sounds like just the scope mount for this system.


Cheers,

Master Diver
 
Re: 375 Viersco Mag

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Viersco</div><div class="ubbcode-body">It is a massive case, similar to a 408 cheytac only fatter.</div></div>
what's the end result of case capacity comparison between the 375 Viersco Mag and the 375 cheytac?
 
Re: 375 Viersco Mag

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: ranger1183</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Viersco</div><div class="ubbcode-body">It is a massive case, similar to a 408 cheytac only fatter.</div></div>
what's the end result of case capacity comparison between the 375 Viersco Mag and the 375 cheytac? </div></div>

The 375 Snipetac and the 414gn bullet was using 148gns of US869. In the VM case
i am using 160gns. I dont have a water compairison just yet.
 
Re: 375 Viersco Mag

There is also a guy here in Australia that is working on a heavy long range bullet for the 375VM and i have a 40" 8 twist on order from Rock and my action is int he air so when the barrel arrives i will be able to test them and have past 2 miles available aswell so i should hopefuly be able to contribute a lot with balistics when this all comes together. the thanks has to be given to Dave for his forward thinking as this round is realy going to change ELR even if the 10 twist barrels and conventional projectiles are used. George at Rockey Mountain is also working on a 420gr projectile for this case and will try a 450 aswell so there should be a few more ELR projectiles soon and that also meens that if you have a 375 Snipe Tac and the barrel is getting a bit sad you can just screw a faster twist like an 8 on it and then take advantage of these newer projectiles that are designed for the 375VM and use them slightly slower.

So this case has realy dont a lot for the design and manufacturing of super high BC projectiles in 375 that will allow other calibres to streach their ranges aswell.

Can you please let me know Dave when the dies are ready to send?

Another think i have spoken to dave about is the possibility off rebating the rims to fit the CheyTac boltface but there is a majot problem as a factory offering i see if we just compare say Lawton 8000 and 8500 actions both are available in CheyTac boltface but only the 8000 is available in VM boltface. the lugs ont he 8500 are shorter and have less strength and also the barrel tennon is smaler on the 8500 we had a customer wanting to try and get a 375VM on his 8500 action and the action is to small and would not be safe for this bigger cartrige.

So the problem could be that if the boltface was rebated people might think any action that the CheyTac could be used in this case could be but that is not the case but if you had a Lawton 8000 it would be safe to use with the rebated rims. So it might just be best to get someone to just buy another bolt and leave the rim as is because i have also been asked if this will be safe in a 3 lug Barnard action and i dont know about that one so all i say is the only action i know of that is safe is the Lawton 8000 are there any other actions that you would believe are safe enough Dave?

Thanks for all of your work Dave and hopefuly the testing i will be able to do will help progress this cartrige for you.
 
Re: 375 Viersco Mag

What is the bolt face required for this cartridge?

Also, is the 375 Snipetac and the 375 cheytac pretty much the same thing?
 
Re: 375 Viersco Mag

IS it a .635 bolt face or larger? <div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Viersco</div><div class="ubbcode-body">Here is a little more on the current state of the project.

First off here is a little about the test rifle:
Action Lawton 8000 Reciever (Modified for larger case)
Bolt Viersco custom
Jewell trigger
XLR Industries modular stock
32" 8 twist Lawton barrel
Shark Bite 4 port muzzle brake
8-32x56 Nightforce optics

This was an extra barrel I had on the shelf so it was used for initial tests and load development. I have 3 other barrels that will be used for the final results.

35" 11.5 twist 8 groove Benchmark
34" 10 twist Lilja
36" 8 twist Lawton
----------------------------------------------

The first tests were to find what powder and how much, with a case this big and bore size it would have to be the slow burn types. I tested, US869, H-BMG50 and WC872

The first test was with a 414gn GS MK1 bullet seated to touch
the lands. 155gns of each powder listed. Vel was very close
for the three types. No targets were shot for any of the speed and pressure tests. The temp was 10 deg. Velocity was close to the 2900fps area. No pressure signs on the case.
I bumped the load up to 160gns, still no pressure and velocity increased to 3100fps, some signs of firm bolt lift.
I tested a few of the 350gn Predator solids with 165gns of powder, 3350fps was the top load with a stiff bolt.
It was clear that the barrel is too short for the amount of powder in the case. My best guess is a 35" barrel will be more suitable for this case capacity and bore size. My original projections was to get around 3200fps with the 400gn bullets. Couple that with a bullet that has a BC of 1.25 or more and it will be a very long range rifle.
This is primarily being designed for a hard target long distance rifle, special ops, ect. 3000+ yards.

<span style="color: #FF0000">Special Thanks to Kyle at XLR Industries for the stock.
Bruce Bertram at Bertram Bullet Co.in Australia for the brass work.
Anthony at GS Custom Bullets</span>
</div></div>
 
Re: 375 Viersco Mag

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.
 
Re: 375 Viersco Mag

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: ranger1183</div><div class="ubbcode-body">What is the bolt face required for this cartridge?

Also, is the 375 Snipetac and the 375 cheytac pretty much the same thing? </div></div>

The Snipetac is an improved case design, will add aprox 100fps vs the cheytac.

dave
 
Re: 375 Viersco Mag

<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
 
Re: 375 Viersco Mag

I did a bit of short range testing today for accuracy with the
Lawton 8 twist barrel, 32".

I ran some of the MK1 bullets, 414gn GS customs for initial sight in. I was using 155gns of US869 powder, fed 215 primers.
Velocity 3075 MV
With the 40moa base and the Nightforce 8-32 scope at 100yds i had to use the top hash mark in the R1 retical to get a sight in, aprox 20" high if using the center cross hair. The barrel is still in the break in period but i am shooting 3 shot groups between cleanings.
After sight in i loaded up the same load only i changed to the MK 2 bullet design, 414gn GS custom. The loaded case measured 4.865" bullet seated just off the lands.
Temp was 15deg with light wind from 12 O'clock. 3 shot 100yd group measured .268
tomorrow weather permiting i will set up the 1150yd target and get a 5 shot group and a few pics.
Recoil with this load is very mild concidering the size of the case and bullet weight.

Here is a drop chart for my area.

Calculated Table
Range Drop Drop Windage Windage

(yd) (in) (MOA) (in) (MOA) (ft/s) (none)

0 -2.5 *** 0.0 *** 3052.8 2.858
100 -0.0 -0.0 0.0 0.0 2971.1 2.782
200 -1.4 -0.7 0.0 0.0 2891.0 2.707
300 -7.0 -2.2 0.0 0.0 2812.4 2.633
400 -17.0 -4.1 0.0 0.0 2735.4 2.561
500 -31.7 -6.0 0.0 0.0 2659.8 2.490
600 -51.2 -8.2 0.0 0.0 2585.5 2.421
700 -76.0 -10.4 0.0 0.0 2512.5 2.352
800 -106.2 -12.7 0.0 0.0 2440.8 2.285
900 -142.3 -15.1 0.0 0.0 2370.2 2.219
1000 -184.6 -17.6 0.0 0.0 2300.8 2.154
1100 -233.4 -20.3 0.0 0.0 2232.6 2.090
1200 -289.3 -23.0 0.0 0.0 2165.5 2.028
1300 -352.5 -25.9 0.0 0.0 2099.6 1.966
1400 -423.6 -28.9 0.0 0.0 2034.7 1.905
1500 -503.1 -32.0 0.0 0.0 1971.1 1.845
1600 -591.6 -35.3 0.0 0.0 1908.6 1.787
1700 -689.6 -38.7 0.0 0.0 1847.3 1.730
1800 -797.9 -42.3 0.0 0.0 1787.4 1.673
1900 -917.0 -46.1 0.0 0.0 1728.7 1.619
2000 -1047.7 -50.0 0.0 0.0 1671.4 1.565
2100 -1191.0 -54.2 0.0 0.0 1615.6 1.513
2200 -1347.5 -58.5 0.0 0.0 1561.3 1.462
2300 -1518.4 -63.0 0.0 0.0 1508.6 1.413
2400 -1704.5 -67.8 0.0 0.0 1457.7 1.365
2500 -1907.1 -72.8 0.0 0.0 1408.6 1.319
2600 -2127.3 -78.1 0.0 0.0 1361.4 1.275
2700 -2366.3 -83.7 0.0 0.0 1316.3 1.232
2800 -2625.4 -89.5 0.0 0.0 1273.3 1.192
2900 -2906.1 -95.7 0.0 0.0 1232.8 1.154
3000 -3209.8 -102.2 0.0 0.0 1194.6 1.118
 
Re: 375 Viersco Mag

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Viersco</div><div class="ubbcode-body"> Recoil with this load is very mild concidering the size of the case and bullet weight.
</div></div>

Hi Dave,

I notice you are using the CheyTac type muzzle brake and you say the recoil is very mild.
I find this is quite interesting as I would have thought a much bigger brake with more baffle area would have been required, something along the lines of your "shark bite" brakes with 4 or possibly 5 baffles.

Keep up the good work.

I wrote you a personal email a few weeks ago on hotmail (Tony) as I am following very closely your development work with this cartridge.
I am in cahoots with Wild Bill on this new round of yours and am seriously contemplating having one made up on a Lawton 8000 action by the same gunsmith who is building my 338SnipeTac.
Hell, Wild Bill's 40" inch barrel is gonna be something else.
 
Re: 375 Viersco Mag

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: stac338</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Viersco</div><div class="ubbcode-body"> Recoil with this load is very mild concidering the size of the case and bullet weight.
</div></div>

Hi Dave,

I notice you are using the CheyTac type muzzle brake and you say the recoil is very mild.
I find this is quite interesting as I would have thought a much bigger brake with more baffle area would have been required, something along the lines of your "shark bite" brakes with 4 or possibly 5 baffles.

Keep up the good work.



I wrote you a personal email a few weeks ago on hotmail (Tony) as I am following very closely your development work with this cartridge.
I am in cahoots with Wild Bill on this new round of yours and am seriously contemplating having one made up on a Lawton 8000 action by the same gunsmith who is building my 338SnipeTac.
Hell, Wild Bill's 40" inch barrel is gonna be something else.
</div></div>

That is not a cheytac brake, its a large 4 port Shark Bite.

Dave
 
Re: 375 Viersco Mag

Hi Dave
Your cutting edge! Can't wait to see how this pans out. Now I know why you are so busy
Doug (the 375 lapua Improved guy)
 
Re: 375 Viersco Mag

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: dyoung</div><div class="ubbcode-body">Hi Dave
Your cutting edge! Can't wait to see how this pans out. Now I know why you are so busy
Doug (the 375 lapua Improved guy) </div></div>

I started on your rifle yesterday, Ye Haw!

No i am just trying to get caught up with customers rifles. I have had this project going for about a year now and testing bullets for several companies. I am going to do the final test today at 1150yds, just got done setting up the targets. Its a nice day,
overcast, 17deg, light wind from 6:45.

Dave
 
Re: 375 Viersco Mag

<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: stac338</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Viersco</div><div class="ubbcode-body"> Recoil with this load is very mild concidering the size of the case and bullet weight.
</div></div>

Hi Dave,

I notice you are using the CheyTac type muzzle brake and you say the recoil is very mild.
I find this is quite interesting as I would have thought a much bigger brake with more baffle area would have been required, something along the lines of your "shark bite" brakes with 4 or possibly 5 baffles.

Keep up the good work.



I wrote you a personal email a few weeks ago on hotmail (Tony) as I am following very closely your development work with this cartridge.
I am in cahoots with Wild Bill on this new round of yours and am seriously contemplating having one made up on a Lawton 8000 action by the same gunsmith who is building my 338SnipeTac.
Hell, Wild Bill's 40" inch barrel is gonna be something else.
</div></div>

That is not a cheytac brake, its a large 4 port Shark Bite.

Dave</div></div>

Dave,

Sorry about that. I withdraw my earlier comment. I screwed up big time. I did read your burst but got mixed up when I looked at the outfit above from XLR Industries photo and that is where I mistook the muzzle brake.
No more late nights for me.
 
Re: 375 Viersco Mag

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Viersco</div><div class="ubbcode-body">Its a nice day,
overcast, 17deg, light wind from 6:45.

Dave </div></div>

Ah.. brings back fond memories. Those temperate Nebraska winter days.

Dave,

Most of the country has no idea that in the midwest you work outside til it's 20 below and they think a "nice day' is 60 deg with sunshine. Everyone should do time in Nebraska. Makes you appreciate what you have.
wink.gif
Montana winters are pansy be comparison. (Well, at least where I live. Out east is basically northwest Nebraska...)

John
 
Re: 375 Viersco Mag

Well i just got back from some distance testing.

535yds first sight in test to check drop chart.
6.5moa was added per my computer program.
I fired 3 shots using US869 (153gns)...for some reason today they developed hang fires. Vel was way down from yesterday.
Group at 535 was low. US869 will be a warmer day load.

Loaded up some BMG50, 153gns and fired a 3 shot group at the same target same hold. 3 shots fell 1.75" low of center.
Group size was a decent 2". Drop chart was very close to computer preditions, added 1/4moa.
The BMG-50 powder from yesterdays 100yd test was not as accurate as the US869 so i am wondering what the results will
be at distance.

Reloaded the fired cases and moved to 1150yds. The wind has came up from 3 o'clock, aprox 8 mph and ligh snow is falling.
Getting difficult to see the target. I brought the scope up to 23 moa and fired 3 shots to check sighting. I have to drive out to the target as i cant see any holes.
At target there is one hole on paper and two just left in the snow, aprox 5" i would guess. I measured and need to add
2 moa up and with the wind change 1 1/4 moa to the right.

I checked the chrono from the 3 shots.
2961 was average, ES 6. Drop chart is set for 3000fps.

I went back and loaded up 5 cases, I annealed the necks as they have not been done for at least 3 firings (using the same 8 cases). 153 H-BMG50 414gn MK2 bullets, seated .015 from the lands (I have not played with seating changes). Target now is fuzzy and loosing light from the snow. I have not cleaned the rifle for the entire round of tests today. The barrel has a lot of copper fouling, but i wanted to get the 5 shot group done before its totally dark.
Like before the velocity average was 2968 and ES 7. There has been no hang fires with this powder. Group at 1150yds has went straight vertical, all are perfectly on center only the spread was aprox 2moa. Either anneling the necks had some effect or the fouling was getting so bad the accuracy went to heck. Rifle is now resting with Wipe out in the bore.
I checked the chrono and the speeds were all within a few feet per second so i am not sure what caused the vertical strings.
Tuesday the weather is supose to clear up so i will try another test with a clean bore using the exact loads and scope setting.

Once this test is complete i will install the 35" 11.5 twist barrel and shoot some 350SMK bullets.

Dave
 
Re: 375 Viersco Mag

I was privledged enough to be able to take an up close and personal look at the 375 Viersco Magnum cartridge recently. As a former owner of a 408 Cheytac rifle (serial number CT003), I can honestly say that this new round is a real game changer. That small cartridge you're seeing at the bottom of the picture is a .308.

375_Viersco_Mag-600x398.jpg


The 375 VM made my 408 Cheytac brass look <span style="font-weight: bold"><span style="font-style: italic">skinny</span></span> in comparison. And there is nothing small about the .408 Cheytac. In fact, here is a target from 6 years ago that was shot with my Cheytac using LRBT 416 grain .408 solids at 200 yards. All those sunflowers you're looking at are a testament to the power of the .408.

Copy-of-408-CHEYTAC-Target-1-571x600.jpg


<span style="font-weight: bold"><span style="font-style: italic">But the 375 Viersco Magnum is simply a huge step ahead of the Cheytac!</span></span> I mean that is one fat bastard with an amazing spear of a bullet loaded.
 
Re: 375 Viersco Mag

Jimmy, here are a couple of loads for the 375/408 standard Cheytac 30 in. Lawton 8 twist barrel,350 SMK, 153 gr. US869 Rem. 9 1/2 M primers 3207 fps.

30 in. Bartlein 6.5 twist, 152 gr. US 869 400 gr. solid, 3068 fps. I have no idea how fast the VM will push similar bullets but when the data is available it can be compared to these loads.
 
Re: 375 Viersco Mag

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Jimmy M40a2</div><div class="ubbcode-body">What is the velocity difference between using your case and the 375/408 case. </div></div>

Its hard to compare the two rounds as they are very different. Would be like comparing the 30-06 and a 300 win mag. The Cheytac is a great round and is pretty much topped out for speed around 3100fps. The VM requires a longer barrel due to the case capacity, this is where it is hard to compare. A 32" barrel on the VM will push a 350gn bullet close to 3400fps. Increase it to 35 or 36 and you could see 3500.
You wont gain much in vel with a longer barrel on the cheytac due to the powder has been burnt in 30"
32" barrel is too short for the VM to get the full potencial. Brass is a big difference also, the cheytac case will not hold up too long under these full loads, the VM brass is much heavier designed and under the same presures they will last much longer, like Lapua brass does vs any other brand. During the tests i have been doing on the VM i am using the same 8 cases, i have loaded them now at least 6 times so far and there are no signs of failure, primer pockets are as tight as when they were new. Cheytac brass can loosen the pockets after one or two full loadings. So in saying the VM of course will be aprox 3 to 400fps faster than the cheytac. Cheytac uses around 135gns of powder, VM 160gns.
I will have more info once testing starts on the longer barrels and slower twists.

Dave
 
Re: 375 Viersco Mag

Great info. I really dig this case. What was the velocity in the snipetac case for the 414?
 
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