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SAAMI accepts 400 Legend (which uses 6.8 SPC bolt)

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11K views 55 replies 21 participants last post by  earlytom  
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I'm thinking it's probably available bullets is the reason for the low pressure spec.

I hope it could be done. Probably be a PITA. Have to be in stages I'd guess. It's beyond my knowledge or skill currently, but I sure like the idea of a ARC capacity cartridge able to take SPC pressure and maybe squeeze more speed from it than the ARC.
 
Well it seems it may be close for forming a 6mm cat. The once or twice fired case might be 1.67, and the TAC 6 is 1.57, while the ARC 6 is 1.47.

What shoulder angle? Just curious would it still feed at say 1.37? How short would it actually be after forming? How much bolt thrust would be reasonable? Max pressure?
 
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it will depend on popularity. In essence its turning 6.8 brass into a .40/10mm straight wall cartridge. All 3 cartridges come from .30 Remington brass. I tried once to cut the shoulder of 6.8 brass to make 10mm brass, but the wall is thicker. You would need to ream it out slightly to seat a bullet.
Nativeman I think the 400L is a new case. It’s a rebated case with the SPC bolt head size of .422 so it has more capacity from the larger body size. That’s why I am thinking it might be possible to neck it down to a 6mm. We might get to 6 ARC capacity with a stronger bolt and higher pressure. H would be the guy to say if such a cat would work.
 
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Its case only slightly shorter than the 6.8 SPC, 1.65 inches vs 1.687 so it could possibly make a good candidate for another 6mm wildcat, or will it be a smidge to short?
 
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Here's what a Savage is supposed to look like. They don't have one 400 Legend on their web site. I can't find one in the wild.

Image
 
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I know it, sure seems like it. Haven't seen any ammo yet.. Anybody seen 400 Legend anything? Rifles,ammo, dies?
 
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The base of the case is only 1 thousandth of an inch smaller than the Grendel/ARC case, so that is possible. The odd thing is the 45,000 psi max pressure vs the 52,0000 for the Grendel/ARC. It makes me wonder if there were bullet issues or if the pressure was held down for a particular rifle design. Possibly a lever action?
IMO likely for lever action. Should be GTG at useful bottleneck pressures.
 
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I'm intrigued by the idea as well. But, I'd have some concerns with the rebated rim. I know some calibers, such as the .22 Nosler, struggle with extraction in the AR platform due to having a rebated rim. Obviously Winchester must have got it figured out for the 400L. But, the 400L is essentially a straight walled cartridge, so I'm guessing because it doesn't have a shoulder, extraction is easier. But, by necking it down and introducing a shoulder, a 6mm wildcat might pose some problems for extraction with the rebated rim.
Valid concern. Though the 22 N is rebated down to a 223. Thinking the SPC bolt would work.
 
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I am intrigued by the 400L case. More capacity and stronger bolts. I'm thinking 6mm is a good candidate.
 
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