Wow! CIP for 505 is 39,160 PSI.
I was just thinking classic weights/pressures/velocities with modern powders and about extraction. With the Gibbs CIP PSI on the CT case that would probably give traditional 416 Rigby velocity. One of the reasons I first liked the 416 Rigby was because of the low pressure.

I thought about designing my own bullet for the 400 UnderKill (.408 Chey Tac Sporter), but soon realized GSC had already done just what I need:

408370HV148: Hollow point, monometal copper.
408385SP144: Target bullet, solid copper.
408385FN108: FN solid, monometal copper.

One shot of HV in the chamber and a magazine full of FN loads.
That will work with either a MRC M1999 PH action or a CZ 550 Magnum.

HV nose length is 1.040", bullet length is 1.88".
.408 Chey Tac brass length is 3.040" max.
MRC PH box length is 4.005"-plus.

Maybe I could even make a jig or die to file the HV bullet nose to shorten it by .05", so it will load into the mag box of the PH action.
Or just trim the .408 Chey Tac brass short enough to allow HV loading into the magazine.

A chicken in every pot, and a 400 UnderKill in every home.

The .408/370-grain HV (BC = .650 at 2800 fps, length = 1.88") ought to look like this generic HV if rescaled/reproportioned:



And here we have the 408/385-grain SP (BC = .856 at 3000 fps, length = 1.99"), represented by a generic SP, not to scale for .408-caliber:







http://www.gsgroup.co.za/sp.html

http://www.gscustom.co.za/

Maybe the FN solid is no longer offered
due to poor sales in .408 caliber?

Then file and polish 15 grains off the nose of the 385-grain SP,
to make a short enough "FN" to feed from the box?
Another "Bastard File Bullet Werkes."
Or just turn the 370-grain HV backwards and call it an FN solid?

CheyTac USA, LLC produces dies for the 408 in either 1.25" or 1.5" diameter. They sent the 1.5" on my request, parts are accumulating:





While we are at it, take a look at an early version of the .408 CheyTac brass made by Jamison.
Here is the dummy cartridge that Marc Jamison himself bestowed upon me when I visited him in Sturgis, about 2005.
On the top is that dummy with a bullet that might be an early version of the Jamison .408-caliber/305-grain bullet, in the prototype brass.
On the bottom is the current version of the .408 Cheyenne Tactical made by Jamison, now Captech International.
A straight edge was used to line-up-even the bases of the two pieces of brass, so yes, the prototype brass is shorter than the current spec of 3.040" max length,
and the base-to-shoulder length is greater for the current make of .408 CheyTac brass also:



Prototype headstamp on the left, current headstamp on the right:

Good news. GSC can still supply the .408/385-gr FN solid.

Have you looked into CEB MTH 408 bullets? They usually have long and short projection on their high BC line.

quote:

Originally posted by boom stick:
Have you looked into CEB MTH 408 bullets? They usually have long and short projection on their high BC line.

Yes I have, and they will work only as single loaders for either a 400 Underkill (4.050" box) or 400 Bateleur (3.800" box).
The COL with those two MTH bullets in the .408 CheyTac is 4.354", +0.040" or -0.100", same for both 390-grainer and 415-grainer.

The GSC FN and the GSC HV will work through the magazine of both, though I might have to short-seat the HV by only -0.040".
Max COL with the HV is 3.040" + 1.040" nose projection = 4.080"
The GSC SP, though only having 1.080" nose projection, will be a single-shooter like the CEB.
Also the GSC bullets are 370 grains (HV) and 385 grains (FN and SP).
Just right for Underkill and Bateleur.

In fact, all 3 GSC bullets will work through the magazine of a 400 Bateleur (2.7" case maximum length) with a +3.8" box length.

I need to get some custom-made 305-grain "Battle Field Domination" bullets made, since Lost River is gone.
Maybe Captech/Jamison will resume offering their copper solid of that weight.
A .408-caliber monometal hollow point of 305 to 355 grains is on my wish list.

This PH stock arrived from MRC. It weighs 2-pounds-10-ounces.
Surprisingly slim, graceful, light for the huge action it fits.
The grain through the grip ain't half bad.
In fact, it is better than half good.
With such a slender grip, a steel rod in the grip WOOD BE A GOOD IDEA!!!
Aluminum pillars, full glass bedding ... I'll try not to let it get too heavy.

A piece of steel allthread placed through the grip cap, then covered with a decorative steel grip cap would be nice.

A deep hole drill all the way from the butt to the rear pillar is also a possibility.
Then filled with epoxy and steel allthread through the grip area.
Hole could be enlarged rearward for mercury tube(s):

If the barrel is so heavy as to require weight in the butt to balance, I might finally find a use for one or two of those 10-ounce mercury tubes ...
since the stock weight is so surprisingly light.

Well, I never got that bored.
But I am sure I will be eventually.
The 400 Underkill has been re-christened the "400 Goodkill."
I am waiting for JGS to deliver the reamer,
then I shall have all the bits and pieces to turn over to Sir Rusty McGee, Gunsmith and Knight of the Realm, to create the 400 Goodkill.
This is a sporting weight .408 Chey-Tac on an MRC PH action (stainless) with a 1.350"-shanked, fluted, No. 7 sporter, stainless Dan Lilja barrel,
and rifle No. 2 (always gotta have a backup) will be a CZ 550 Magnum action (chrome-moly) with a 1.200"-shanked, plain No. 6 sporter contour, stainless McGowen barrel.
McGowen and McGee.

Here is the Dan Lilja barrel:



I will post the McGowen barrel pic for comparison soon ...

What is the ideal quarry for this rig/cart combo?
We need to reintroduce saber tooth tigers and cave bears for exotic retro hunting

quote:

Originally posted by boom stick:
What is the ideal quarry for this rig/cart combo?
We need to reintroduce saber tooth tigers and cave bears for exotic retro hunting

boom stick,
I was thinking for when great white sharks grow legs and walk on land.
Or post apocalypse if you stumble upon a cache of .408 bullets, brass, or ammo, you won't want to let them go to waste ...

1.200"-shanked No. 6 sporter plain barrel from McGowen vs. 1.350"-shanked No. 7 sporter fluted barrel from Lilja:
Which is heavier?

I think this is an awesome over 600 yard elk gun for hiking in rough terrain.

Surprising weight check on the .408 barrels:

The Dan Lilja No. 7 contour, fluted, with 1.350" diameter shank and 28" length (where the diameter is 0.820", 0.850" at 26" length) weighs 4.50 pounds.
The McGowen No. 6 Douglas contour (no fluting) with 1.205" diameter shank and cut to 26" length (where the diameter is 0.740") weighs 5.00 pounds.

Advanced Riflemen: I believe the .408-caliber McGowen barrel can be turned down to .660" diameter at 25"-length muzzle with cylindrical knoxform of 3" length.
We might thus get the weight down, and use it on a CZ 550 Magnum action with a "CZ Kevlar" (B&C Medalist) stock.
Only Rusty McGee knows for sure.

quote:

boom stick,
I was thinking for when great white sharks grow legs and walk on land.
Or post apocalypse if yo

Well, keep up the good work. All you need to do is pass 2850fps with 350 grain bullets (meat on the table for your cartridge), and convince some of us that it will be fun to carry in the African sun. Personally, it sounds like a great 300-400 yard eland gun, and things don't get much better than that.

350-grainer at + 2850 fps.

416Tanzan's favorite, .416/350gr TTSX ...
I now have an arbor press and CH4D bullet sizing dies:
.412
.411 (on back order)
.410
.408
.407
Plus the CH4D Canneluring Tool, which arrived with the 4 bullet sizing dies, off the shelf.
Will have to wait a while on the .411" sizer ...

Ought to be able to make that bullet fit the .408/.400 barrel.
Well enough for hunting elk or eland.

Some .408/370-gr GSC HV are on order too.

The heavy sporting .408 CT:
PH action = 3 lbs 14 oz
walnut stock = 2 lbs 10 oz
Lilja barrel before cut, thread, chamber = 4 lbs 8 oz
Total = 11 lbs 0 oz.

Some of the weight comimg off the barrel goes back into the stock as epoxy bedding and grip bolt.

11 pounds before scope and rings.
Maybe as low as 10.75 pounds.
That is about as heavy as one of the early Ruger .416 Rigby RSM rifles.

I'm thinking the McGowen 5-pound barrel could be turned down a bunch and used on a CZ 550 Magnum action
with a B&C-CZ "Kevlar" stock to get under 10 pounds: Maybe 9.5 to 9.75 pounds.
Fingers crossed.

Ordered .408CT reamer from JGS on 5 April 2013.
Supposed to take 6 months. Meanwhile work on other projects continues
... Ho hum.

Good news!

GS Custom Bullets LLC of Edwardsburg, MI, USA is turning out bullets.


Incoming .408-caliber bullets:
370-grain HV
385-grain FN
385-grain SP

Waiting on a JGS reamer ...

GSC has kindly got the program dusted off for the .408/385-grain FN (Sectional Density = .3304).
This drawing should be fairly close to the proportions of the .408/385gr FN (though it is actually of a .458/500gr FN with SD = .3405):



The .408/385gr FN bullet has not been a big seller in the past, but with the growing popularity of the .408 Chey-Tac Sporter, there will be increased demand.
It can be used to fit the magazine box beneath the long and pointy load on top.
Either a CZ 550 Magnum or an MRC PH will do.
Undoubtedly the coming proliferation of .408 Chey-Tac Sporters will soon result in many new choices for smaller game too, including short and pointy varmint bullets, etc.

Similar "trio" here, the .395/340gr FN is in the middle (SD = .311):



Just guesstimating for now, the .408/385gr FN might be about 1.44" long. Will measure eventually.
All the details on all the bullets at GSC are not listed on the web yet.

http://www.gscustomusa.com/

http://www.gscustom.co.za/

A Ruger 1 in Chey-Tac could be quite interesting and not too long overall with the action type.
Ruger-Tac No. 1 rifle. 28" barrel 10 lbs?

quote:

Originally posted by boom stick:
A Ruger 1 in Chey-Tac could be quite interesting and not too long overall with the action type.
Ruger-Tac No. 1 rifle. 28" barrel 10 lbs?

Excellent idea.
If the rimmed .577NE works in the Ruger No.1, then the rimless version of the same case ought to also, with a little custom extractor/ejector and safety button work.
You have put another bee in my bonnet, thank you boom stick.

On 500A2 Ruger No. 1 below, barrel is 29" to the end of the removable muzzle brake, 27" without brake.
It could be changed into a .510/.408 Chey-Tac by use of the .408 Chey-Tac reamer with proper pilot and neck&throat reamer.



But ... I would not want to drill holes over the chamber for the pins and screws of a Ruger quarter-rib.
Maybe a band-mounted picatinny rail would work, and forget the iron sights like on the 500A2 Ruger No.1,
which is very accurate in 500A2,
or rather, a longer throated version of it, aka 510JAB:

Quite welcome sir.
Problem is making it accurate.
load out as far as you like.

Ruger No. 1's can be very accurate.
The minimum throat of the standard .408 Chey-Tac makes the COL of the cartridge mainly dependent on how long and pointy the bullet is,
not much play in seating depth.
But yes, no magazine length restrictions on a Ruger No. 1.

Might be able to get the rifle weight down a bit by using the Ruger No. 1 instead of a CZ 550 Magnum for a .408 Chey-Tac Sporter.
Certainly would not need to have that McGowen barrel slimmed any for a Ruger No. 1. The extra half pound will be appreciated there.
No ugly muzzle brake needed for a 400 Underkill.

The august authority, COTW 13th Edition, says of the .408 CheyTac:
"The cartridge works well with 25- to 29-inch barrels using a 1:13" rifling twist."
It also quotes these ballistics for the proprietary factory loads:
305-grainer at 3500 fps
419-grainer at 3000 fps
But the barrel length for those ballistics is not specified.

If COTW says it, it must be true, or close enough.
Thus I can get that fat McGowen .408 barrel just shortened to 25" and install it on a Ruger No. 1.
That will be sporty enough.

The McGowen barrel has 4" of straight cylindrical shank and tapers gradually after that.

I reckon a qualified gunsmith could put dovetail cuts on the barrel about 4" and 7" from the breech,
then insert a couple of raised flats and machine them level, or with a 20-minute tilt,
or a couple of barrel bands with flats on top,
and attach a picatinny rail to those flats with heavy screws,
then solder everything,
or use JB Weld.
Maybe just drill and tap some screw holes in the barrel beyond the chamber area of the rifle, would be better afterall.

I need to get a lighter-contoured .408 barrel than McGowen's No.6 Douglas Sporter rendition,
in order to make a CZ 550 Magnum sporty.
I will also tell them to leave it 28" long next time, so the gunsmith can cut it to 26", as I thought I told them this time ...

The No.6 McGowen cut to 25" will be perfect on a Ruger-Tac No.1,
thanks again to boom stick for that idea.
Why didn't I think of that?
A straight, 1.2" diameter cylinder 30" long with .408 rifling would also be "Ruger-tactical."
But I might need some wheels on the bipod then.
Wheels are not sporty on a rifle, no matter what kind of hubcaps.

Might want to pre test some powder loads on a program to see what ones will be good with that 25" barrel but I think a 28" on a Ruger 1 would be great. At 25" and .409" diameter you can still burn a lot of powder in that tube and maybe less barrel whip. A Ruger 1 can make the 408 CT look quite sporting and a 1.5 mile sniper rifle on the down low. Loading out long can give you some good advantage in performance too if you can burn enough of the powder. Glad you seem to be making "1" more

boom stick,
I did a preliminary powder rundown on page 2 of this thread, for 26" barrel and .408/305-grainer.
I am therefore already stocked up on Hodgdon's Retumbo Extreme.
It should be impossible to blow up the rifle with Retumbo and 305-grainers.
Might be possible to get into trouble with 419-grinners, however.

Does anyone make an aluminum tank break? Thought that could be useful for a "Sporting" CheyTac. A screw on one hard anodized that would weigh almost nothing but have a big impact on shooting this 2,500 meter 10 pound beast.

quote:

Originally posted by boom stick:
Does anyone make an aluminum tank break? Thought that could be useful for a "Sporting" CheyTac. A screw on one hard anodized that would weigh almost nothing but have a big impact on shooting this 2,500 meter 10 pound beast.

Ah, so! Another great idea.
Gas-cutting erosion of the aluminum would only make the brake more effective with each shot, until it fell apart.
But that would probably take a long time, probably have a good enough effective life. Might out-live me.
That would be a fun thing to get Rusty to homebuild,
as long as the threads matched that of something like a Vais.

A tank style would work better made from aluminum would it not? Maybe too tacti-cool and not "sporting" looking? A good hard anodize should make it last and if you can make a CNC program for it the unit cost could just be a few bucks. With all that gas and short ish barrel this will come in handy big time.

Like this but aluminum.

Egad! AR-50 trash!
No, that would be heavier in "aluminium" than an equally effective steel brake, the latter being much more aesthetic.
First we'll try it with no brake.
This is a "400 Underkill" afterall.
A whimpy 10-pound .408 CheyTac needs no stinking muzzle brake.

I think there can be a good Goldilocks aluminum brake. Maybe something like the one from AHR or this one.

Big fishgills on the sides won't make the aluminum brake fly or swim, because the bullet still has to exit a hole down the middle
that can't be any bigger than about 50-thou greater than bullet diameter.

It would gas cut there, and it might not cut evenly so the exit hole might be an accuracy problem sooner than later.

Better stick with slim steel brake, on second thought, or no brake ... on a light kicker like a 400 Underkill.

Barrel extender for a Ruger No.1:



Vais Brake's do not increase noise, do they?
The .408 CheyTac burns enough powder to make the brake effective with light or heavy bullets.

Hi RIP, something you may be interested to know.

http://www.gsgroup.co.za/faqcoating.html

Gerard,
You are right. I have not kept up with the GSC coating technology. This is news to me. I think you been holdin' back, not revealing when you made the switch from moly to something else?
When I first started ordering GSC bullets they sure looked like a dull gray moly coat.
Last ones I got had a spectral shine to them, as if from heat treating or color case hardening ...

Have you actually made a change in the coating sometime since 2001, or has it always been the same stuff, maybe differently applied?

"BULLET COATING" (by GSC)

There is a misconception that GS Custom Bullets are coated with moly (MoS2 - Molybdenum Disulfide)

This is not correct. GSC bullets are coated with complex coating that consists of three metals, none of which is moly. ..."

Gina has cashed my check, and it did not bounce, four-o-eights incoming!

We are constantly developing and testing new concepts. For example, our coating process has gone through several formats since 1997 and each was at least as good as the previous one, some were better. The coating we use now is probably the biggest coating improvement we have made so far. The last testing we did in 2010 was with a 270 rifle and, for the same pressure levels, speed increased by about 80fps with no downside at all. All GSC bullets made in the US has had this coating and, since 2010 the SA factory has been using it as well.

quote:

Originally posted by Gerard:
We are constantly developing and testing new concepts. For example, our coating process has gone through several formats since 1997 and each was at least as good as the previous one, some were better. The coating we use now is probably the biggest coating improvement we have made so far. The last testing we did in 2010 was with a 270 rifle and, for the same pressure levels, speed increased by about 80fps with no downside at all. All GSC bullets made in the us has had this coating and, since 2010 the SA factory has been using it as well.

glad to know this. I hope to test the 450 GSC HV tomorrow. I'll do some pressure testing but I couldn't find any H322 available. So only H4895 for now. H335 will be used on the CEB 350 grains since I can get more in the case, but I want to find H322 before I decide on African loads.

Gerard,
Thanks. That is sufficiently explanatory and yet proprietarily vague enough.

416Tanzan,
How about posting a picture of those .510/450-grain HV bullets of latest vintage from GSC?
And you are readying for pressure tests? Please do tell how you are doing that, either here or on the 500 AR Nyati thread, you know which one.
If you cannot find H322 Extreme, then Benchmark Extreme is worth a try, if that can be found.


I'll go find a picture of the 2009-2010 vintage .510/450-grain HV for comparison.
IIRC, there have been some design changes ...

On the extreme left, old model .510/450gr GSC HV next to a .510/570gr GSC FN: