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SAAMI accepts 400 Legend (which uses 6.8 SPC bolt)

11K views 55 replies 21 participants last post by  earlytom  
#1 ·
Winchester Ammunition had a low-key introduction for the 400 Legend a couple of weeks ago at SHOT. It uses a 0.422" diameter bolt like the 6.8 SPC, but case is wider ( 0.44" vs 0.4207"). It also only runs at 45,000 psi and the case length is 1.65". The lower chamber pressure is likely due to the rebated rim. The back-force of a cartridge is related to max case diameter, not rim diameter.


 
#55 ·
Does the world need another 6mm wildcat??? Following the big covid/Biden price increases and shortages I dug out my 6mm×45s which except for knowing we're in the back of a vault somewhere had not seen in years. Also was having more health issues including spine and remembered I had a bunch of 6mm cast gas check boolits somewhere. Found three plastic screw top cans filled with 87 grain boolits just needing gas checks and sized/lubed. Instead I coated them in one of the new "high speed/low drag" boolit coatings commonly get up to 2,700 fps in my 7.62×51 battle rifles then used a swage die to seat the checks like they are "glued and nailed" plus unifomed them as precise as a jacketed bullet then fell back in love with my super efficient low powder consuming poodle shooters lobbing light cast boolits instead of the 500 and 550 grain boolits normally run in 458 SOCOMs.

While dug them out found a pair of 6mm wildcats had almost forgot but didn't want to run throat burning ultra velocity powder hogs. Then discovered I could buy 24 Nosler projectiles and brass cheap no matter how expensive everything else reloading cost. Every week was getting emails about deals on something 24 Nosler including primed cases when finding small rifle primers was difficult much less paying $100 per $1,000 for CCI military primers and after almost a year of buying 24 Nosler cosmetic blem bullets and brass then found some deals in loaded ammo discovered I had 2,400 rounds of factory ammo, almost 10,000 cases of which about 2,500 were primed plus about 20,000 projectiles and didn't own a single 24 Nosler barrel much less a rifle. Have three barrels to build when feel good enough to get back in my shop then once I run some of the commercial across chronograph after breaking them in will be going into load development.

This last panic/shortage was odd as entire time was able to buy 40 Smith pistol ammo cheap. It's dropped even more and one vendor has 50 round boxes for $13.99 and 1,000 round cans of loose name brand ammo (they do a lot of LEO trade in and some boxes were so mangled they said just dumped them in cans. Been paying $299 for 1,000 round cans and $179 for 500 round cans of FMJs which is cheaper than could reload them a year ago.There were other rounds that are falling in popularity I loaded up on but now 5.56 is reasonable again and 6.8 is down to 80¢ per round for S&B and American Gunner which when drops to 70¢ going to start buying again slowly as watch to see how far down it goes.
 
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#53 ·
Am really interested in the 400 for lobbing subsonic cast. Think brass is going to be more reasonable, easier to find than 458 SOCOM once the hunters start jumping aboard. Having an assortment of bullet molds from 300 to 400 grains made would be easy and likely less abusive on my aging spine than the 500, 550 and 600 grain cast am using in 458 and still drop hogs with authority.
 
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#48 ·
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#39 ·
With deer season rapidly approaching, nothing but crickets for the 400 Legend. Is the 400L DOA?
 
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#32 ·
R Spomer and others on youtube are incorrect. The 400L isn't based on the 38-55/30-30/30Rem/10mm/6.8spc/221val case family. The only thing the 400L case shares with those cartridges is the rim diameter.

Rather, this round is based on the 6.5 (and 7.35) Carcano/220Russian/7.62x39/220ppc/5.45x39/9x39/Grendell/ARC case family. Head and body diameters bear this out. The 400L has the rim rebated to .422" from the origional .447" of those cases.

This combination gives a few advantages. The added body taper compared to the 400AR and similar earlier 30Rem/spc/etc based .40 wildcats greatly aids feeding. A 40 cal rifle round based on the 30rem/spc/etc case is basically straight.

The .422" rim of the 400L allows the use of the stronger spc/val bolt in place of a x39 or Grendell AR bolt. As stated earlier, bolt thrust is controlled by case head diameter, rather than rim diameter. The .422" rim diameter just allows more support for the locking lugs at the bolt face. Of course, in a bolt gun or an AR308 based rifle wouldn't benefit from the rebated rim.

I've been pondering a carcano based 1.6" long .400 wildcat with a 30rem/10mm .422" diameter rim for a few years for those very reasons. Never had the time to build it however. Too many other projects. A few folks have used the carcano/Grendell case for .40 cal wildcats already. This is the first I've seen with the .422" rim.
 
#36 ·
Rather, this round is based on the 6.5 (and 7.35) Carcano/220Russian/7.62x39/220ppc/5.45x39/9x39/Grendell/ARC case family. Head and body diameters bear this out. The 400L has the rim rebated to .422" from the origional .447" of those cases.

This combination gives a few advantages. The added body taper compared to the 400AR and similar earlier 30Rem/spc/etc based .40 wildcats greatly aids feeding. A 40 cal rifle round based on the 30rem/spc/etc case is basically straight.
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?
 
#30 ·
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.
 
#33 ·
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.
That'll likely be the best thing for AR15 wildcat tinkerers to come from this 400L introduction.
 
#25 ·
The case is slightly shorter than a 6.8. For the TAC6 we trim to 1.57ish and then resize (and final trim/chamfer/debur). So I don't see why you couldn't.

I think in one of the oth threads the pressure was listed at 45k or something.

I probably need to merge the threads.
 
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#22 ·
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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