408 Cheytac Brass

[Brent]

My brothers friend gave him a new 408 Cheytac case from a hundred he got from Warren. Got to run and do some measuring now. I'm using the RCBS Casemaster to measure wall thickness and will check water capacity too. I'll have all the "dim's" when I'm done. Got to run, let me know if your interested in the findings. My brother is already talking about necking it to .510" in a Ruger #1 and using the 750 A-Max.

Later
Brent

 

[texas]

OF COURSE WE WANT TO KNOW

Also how it works out. Maybe some other actions besides a custom one nothing agaist single shots.

Know some people that can reload them almost as fast as one can cycle a bolt action.

Pack'n big iron and shoot'n hot lead

 

[Brent]

Here's what I found,

0.014".....Neck Wall Thickness
0.012".....Shoulder Wall Thickness
0.050".....Base Wall Thickness
0.430".....Outside Diameter of Neck
0.600".....Outside Diameter Below Shoulder
0.633".....Outside Diameter Near Base
3.330".....Overall Case Length
2.675".....Case Length From Base to top of Shoulder
2.450".....Case Length From Base to bottom of Shoulder
0.240".....Case Web Thickness

Total Case Volume,
165.3gr Water Capacity

For comparison ONLY,
175.3gr of H110 Powder

355.7gr.....Case with Primer
521.0gr.....Case with Primer and Water
531.0gr.....Case with Primer and H110 Powder

This is a VERY awesome cartridge indeed!!
Put a 419gr .940 BC bullet on top and this is a tough combination to beat if it's in a long barrel. I want to see what it will do in a 40" tube!

The 50 caliber version looks pretty awesome too if the velocities are up at 3000fps with a 750gr A-Max too. The energy at 2000yds is just HUGE and it's just as flat too.

I'm not sure what part was thickened over the 505 Gibbs to make it stronger as I've never examined the 505 Gibbs case personaly, but it looks plenty strong. I wonder if the brass from Mast Tech. is harder than Normas 416 Wby or Rigby stuff?

Dimentions seem to mimmick that of the 416 Rigby pretty close giving a little edge to the Rigby in thickness at the web,lower shoulder and necks. They are very close except for size, the Rigby looks like a 338RUM next to it though.

The shoulder seems to be a little shallow at about a 20° angle, but for the auto loader which it might be used for it would feed better this way, for me it would get a 30-40° shoulder angle if it were of an improved desighn.

Warren definitly has a winning cartridge here. And when better powders become available it will just get better and better.

 

[gkgeske]

Interesting feedback on the brass. Thanks.
There is a possibility of this cartridge being used on an action that may not handle it. I will give some numbers in order to help with informed decisions.

The Ruger uses a 1" barrel tenon on the #1 and the M77. I dont know about the 'Magnum' action. Anyway, here's chamber diameter expansion in thousands of an inch at 50 and 60 thou. PSI for a 1" tenon.

cartridge head. 50000 60000
.535(regular mag) 1.9 2.34
.580(.416 Rigby) 2.4 2.8
.633(Cheytac) 2.9 3.5

The 3.5 figure would be reduced to 2.9 if an 1.125" tenon were used and to 2.3 if a 1.5" tenon were used. And then there is lug strength to be considered...

 

[Brent]

Gwahir,
What is a barrel tenon, the thread length?
And what are the figures representing you gave?

Bowen chambers the 505 Gibbs in the Ruger Magnum action also, they had one at Great Northern Guns in Anchorage for a while. I seen a 600 Nitro in a bolt action there today, the bolt face was opened up large enough so that the casehead would fit and the top margin was completely milled off except for a small amount opposite the claw to hold the casehead. It may have been that way to load straight into the bolt from the top also. Not sure what action it was.

 

[gkgeske]

Hello, Brent.

The barrel tenon is the portion of the barrel that threads into the receiver. The greater it's diameter, the greater the amount of steel used to contain the pressure and the less the chamber diameter will expand and contract when the rifle is fired. The chart didn't come out very well. Let me redo it:
------------------expansion at--expansion at
Cartridge head-----50000 PSI-----60000 PSI
diameter
.535 (Magnum)------1.9 thou.-----2.34 thou.
.580 (.416 Rigby)--2.4 thou.-----2.8 thou.
.633 (Cheytac)-----2.9 thou.-----3.5 thou.

 

[wmorris]

Brent.
It has been a few years since I was in Anchorage and had time to go to Great Nothern Guns. Is it still in the same location? Do they still have as many guns as always? Just wondering. I may try and make it back up there this summer if air fares stay down.... Thanks....

 

[Brent]

Wayne,
they're still in the same place and they have many new rifles all the time, matter of fact a $40,000. double rifle laying on the counter last week looked sweeeet.

Gwahir,
Dare I ask the formula to figure that out?

Thanks........