It will not be good for terminal ballistics either. Let me have the maximum col and the case length then we can do a bullet with the best possible BC and terminal ballistics for the application. GSC does single feed as well as magazine feed for a number of cartridges and it just depends on how the user wants to apply the bullet and cartridge.

Gerard,

For the MRC PH .408 Chey-Tac I would like to keep COaL limited to 3.980"
for magazine feeding of a custom .408 "Battlefield Domination and Varminting" HV.

Maximum brass length is 3.040".

That leaves 0.940" for nose projection.

Box inside length is 4.070",
so with brass trimmed to minimum 3.030" + 0.940" of nose projection, loaded minimum COaL will be 3.970" inside a 4.070" box length,
there would be a whopping 0.100" to spare for "adjustments" to box or bullets.

Or to make it fit the more common +3.8" CZ box,
nose projection would be limited to the common/standard 0.750"
and then one could play with seating out on the bands for the MRC PH +4.0" box length.
I like that idea too.

Still could be well over 300 grains, eh?
Whatever works at plus 300 grains of bullet weight.
.408 groove,
.400 bore
1:13" twist, right?

We'll do that, one or the other, after I get the rest of my "custom sized" .411/317grHV order from GSC-USA.
After the first 100 bullets GSC-USA ran out of the copper stock needed for that size, so I reckon for .408 size too?
Anywho, I have to pace myself.
Weather is promising rangetime for the 400 Whelen-B soon, and gunsmith is promising a finished .408 CT soon.

BTW, for anyone interested in the .408 Chey-Tac brass made by Captech International, formerly Jamison Int., VLLC,
you can get it from Captech or from Chey-Tac USA.
With max brass 3.040" and trim-to length of 3.030", the new brass is all between 3.030" to 3.035" long from factory.

After FL sizing it with die screwed all the way down to shell holder and pushing the shoulder back
and then chamfering the case mouth and priming it, it is all still between 3.030" to 3.035".

Then after firing it, with a 45Kpsi test load, it is all still between 3.030" to 3.035",
and the shoulder has moved back out to where it should be.
Two fired cases on left below, FN and HV to the right, loaded with shoulder pushed back before fire-forming:



Happily, the primers are flush after fire-forming, indent perfectly centered,
and I am going to back off the FL sizing die on initial new brass sizing.

I may only need to trim a few thou to square case mouths after first fire-forming a big bunch of it.
Got it made in the shade with this proprietary wildcat.

Gerard,
Nevermind the .750" nose length, I do not want to encourage that.
I just remembered how short and tight the .408 Chey-Tac throat is, and seating the bands out will not be much of an option.



I think that putting about the same nose length as on the .411/317gr HV onto the shaft of the existing .408/370gr HV will do the trick.

Shortening of the nose length on the .408/370-grain HV from about 28.5mm to 21.5mm:
That would project 0.846" from case length max of 3.040", producing COaL = 3.886".
Then with trimming brass to minimum, the existing throat might tolerate seating one band out of case mouth.
Then COaL would be 3.030" + 0.846" + 0.100" = 3.976". Perfect.



I will be able to use something like that in both the MRC PH .408 Chey-Tac and the "400 Bald Eagle."
The latter is a .408/.338 Lapua Magnum with 2.700" case length
in a 3.6" (Winchester M70) or 3.8" box (CZ 550 Magnum or Dakota M76),
and I can throat the 400 Bald Eagle anyway I want:

Hmmmm... A 404-338 Lapua has a 3.38" COAL.
That would take a lot of work to fit and feed from M98 or 06 length actions but a fun thought.

quote:

Originally posted by boom stick:
Hmmmm... A 404-338 Lapua has a 3.38" COAL.
That would take a lot of work to fit and feed from M98 or 06 length actions but a fun thought.

Boom stick,
I have already done that as a .423/.338 Lapua Magnum and found that the case capacity with Lapua brass was
nearly identical to the standard 404 Jeffery with Norma brass.
A lot of effort, true, to duplicate the 404 Jeffery balistics in a 3.4" box instead of a 3.6" box,
and you lose one round of ammo in the box to boot.

So I cut off the 24" barrel to 23" (actually THE GUNSMITH did), and rechambered it to "404 RIP"
which is short for "404/.416 Rigby Improved Plus."
This has a 20-degree shoulder instead of the Rigby 45-degree shoulder,
and that little change in fact does increase the case capacity a tiny amount,
when the shoulder is at the same location as on the .416 Rigby.
So it is like a .423/.338 Lapua Magnum LONG:



Some actual load data that plotted very close to a nice straight line, and there were no pressure signs, nothing to indicate
that the one "projected" load would not give +2900 fps with the GSC 320-grain HV, from the 23" barrel:

quote:

Originally posted by boom stick:
Hmmmm... A 404-338 Lapua has a 3.38" COAL.
That would take a lot of work to fit and feed from M98 or 06 length actions but a fun thought.

Only if you use those stupid short nosed bullets traditionally used in the 10.75x68 and 404 Jeff.

If you want to use 'modern' high BC bullets then you'll want to use a 3.570"-3.6" COAL. I'm using 3.580" with my 3.615" internal length magazines (Wiebe' 4MJ bottom metal); 3-down plus a 4th in the tube should be sufficient.

Gerard,
Summarizing:
This is a dummy with 3.035" brass length and 3.980" C.O.L., that fits nicely in the +4.0" box (4.070") of the MRC PH action:



I loaded the above with .416 Barrett dies and .408 Chey-Tac brass, with a .416 Barnes TSX, before I had proper dies and bullets.

BTW, the GSC FN fed well from the right side of the box before any feed work. Left side feeding needs work.
All spitzers and round noses feed well out to 3.980" length.
C.O.L. for the dummy with 3.035" brass and .408/385gr GSC FN is 3.900".