The discussions this weekend about the various over 40cal. cartridges brings me to a question. If you have three different case designs, with virtually identical case capicities, shooting the same weight bullets, would load data from them interchange laterally? The 416 Taylor(93.6 gr.), 10.75x68(93.8 gr) and the 404 Dakota (96.3 gr.) have similar case capacities. The 404 Dakota can be loaded, according to Dakota, to 2450 f/s. Could the others with similar case capacity be loaded with the same powder charges and bullet weights? If they were all housed in the same actions with identical barrels what would be the reason that one would shoot significantly faster/slower than another???? Modern brass, adequate action, proper barrel dementions, and Modern loading supplies should take the variables out of the equasion, shouldn't it???

Good Question??????

quote:

Originally posted by lb404:
The discussions this weekend about the various over 40cal. cartridges brings me to a question. If you have three different case designs, with virtually identical case capicities, shooting the same weight bullets, would load data from them interchange laterally? The 416 Taylor(93.6 gr.), 10.75x68(93.8 gr) and the 404 Dakota (96.3 gr.) have similar case capacities. The 404 Dakota can be loaded, according to Dakota, to 2450 f/s. Could the others with similar case capacity be loaded with the same powder charges and bullet weights? If they were all housed in the same actions with identical barrels what would be the reason that one would shoot significantly faster/slower than another???? Modern brass, adequate action, proper barrel dementions, and Modern loading supplies should take the variables out of the equasion, shouldn't it???

Good Question??????

Amazing that they are that close.

The 10.75x68mm Mauser does have a smaller base diameter (.492") but is longer (2.67" case length).

.416 Taylor: .511" ahead of the belt but only 2.5" case length.

.404 Dakota: .544" base and about 2.57" length?

The .416 versus .423 caliber bullet differences will make for higher pressure in the .416 for a given bullet weight and same powder charge, even if case capacities are equal, of course.

I would want to assess the cross-section of the 10.75x68mm case head and walls to make sure it is not significantly weaker, and hopefully it is not Bertram brass.

I think the .404 Dakota will be the "efficiency" champ of all of these, purely based on a fatter for length powder column, FWIW. That might be an aid in getting the most out of each grain of powder with least cost in pressure, with the right powder.

That means that the .423 Dakota with about .585" base diameter and about 2.48" brass lenght will really shine.

quote:

If you have three different case designs, with virtually identical case capicities, shooting the same weight bullets, would load data from them interchange laterally?

Yes, assuming the cases are of equal strength.

But of course, you'd have to work up a load for each individual rifle the same way you'd have to do this if each were chamberd for the same round, because all rifles are individuals. As you know, for example, even two "identical" .416 Rigbys might have significantly different maximum load levels .....

So if one wanted to make a short barrelled fairly light weight rifle to stalk big game and one already had a nice custom 9.3x62 would you make a 10.75x68 or the 404 Dakota. Both would be made up in 1935 Chilean contract actions. If the 404 Dakota is chosen I have custom Blackburn bottom metal for that round. If the 10.75x68 is chosen, I already have bottom metal/brass/dies/bullets on hand and would only have to increase the amount of brass I have.
Decision decision decision.
I already have a couple of great stock blanks I got from Adam and a good stock shape to work with.

Please help Dakota out of bankruptcy. Buy some brass and dies for .404 Dakota. Build your own or get a model 97 for about 2000 bucks or a model 76 for 8000 bucks. They will actually build a .404 Dakota on the cheaper rifle. However, this would be perfect for a standard Mauser 98 of Oberndorf pedigree.

I will be doing one on a stainless Ruger M77 MkII as soon as I finish the .45/404 Dakota RIPoff.

Now I am going to get nasty:

The 10.75x68mm Mauser has the most minimal shoulder of any factory cartridge I know of. It is the favored weapon of Yoda Ray.

quote:

Originally posted by RIP:
I think the .404 Dakota will be the "efficiency" champ of all of these, purely based on a fatter for length powder column, FWIW. That might be an aid in getting the most out of each grain of powder with least cost in pressure, with the right powder.

close, but the 416 AR is the small 40 champ!!

LOL

cheaper bullets, 9% larger case (due to casehead), and a "slightly" higher SD, within 1# of recoil and FPS ....

and 40 cent cases!!!

jeffe

What are the AR cases made from?

from the 375 RUM cases

quote:

Originally posted by jeffeosso:


close, but the 416 AR is the small 40 champ!!

LOL

cheaper bullets, 9% larger case (due to casehead), and a "slightly" higher SD, within 1# of recoil and FPS ....

and 40 cent cases!!!

jeffe

Shameless! LOL

If the AR cases are off the RUM case, and the 404 D is off the Jeffery case, then they are essentially the same. Is the 9%increase due to a longer body or What?

LB,
the 404 has a .540 base, the rum (and therefore AR) have a .550 base (nominal and remotely propritary). Then we take into account that the AR is "improved" over the RUM (its .540 at the shoulder) and you wind up with a 308 vs 30/30, as they are both called 7.62x51 .. but the 30/30 is the 7.62x51R, and has hugely less capacity... to "fix" that, the 30/30 ackley, then the 307, were created.

further, the AR has a higher shoulder/shorter neck, which also adds capacity

jeffe

Thanks for the clarification.

It's been fun watching the AR rounds develope.....I sent a couple bucks to help out and have got it all back in just watching.

These standard action rounds are as good as it gets.....I'm impressed.....

quote:

Originally posted by vapodog:
It's been fun watching the AR rounds develope.....I sent a couple bucks to help out and have got it all back in just watching.

These standard action rounds are as good as it gets.....I'm impressed.....

Thank you Sir, both for the contribution and the kind words. Stuff like this, besides cool rifles to shoot, make the work even more worthwhile.


stay tuned for brass!!

jeffe