400 Corbon info??
Dick DiVittorio
I am considering building up an Open class IPSC pistol in .400 Corbon.
Does any one have any loading data for this round?
I am interested in the pressures and fps figures.
Thanks for the info.
Dick
Peter Jordan
In article <5f83kg$r...@xring.cs.umd.edu>,
Dick DiVittorio <di...@magicnet.net> wrote:
#I am considering building up an Open class IPSC pistol in .400 Corbon.
#Does any one have any loading data for this round?
#I am interested in the pressures and fps figures.
#
The 45/400 Corbon combo actually gives more versatility than
the 40s&w/ 357Sig combo. I say this because you can shoot supersonic rounds
with the 40s&w and the 357Sig. But with the 45, you can shoot really large
subsonic bullets that produce excellent momentum for maximum knock down power
(with the flexibility of using a silencer); or you can shoot lighter
supersonic rounds in the new 400 Corbon format, to give maximum knock down
power at the other end of the spectrum, using very high energy and lighter
bullets. You have a bullet range of 135 grains to 300 grains!
As of January 1997, Starline beefed up the 400 Corbon brass, even though it
wasn't really necessary; the brass weighs about 10 grains more now -- aprox
94.5 grains, compared to the older brass weighing in at around 84 grains.
The bottle-necked case of the 400 Corbon, in conjunction with the new modern
400 Corbon barrel standard, can handle full power Corbon factory loads (using
powder unavailable to reloaders), with pressures up to 26,500 psi. One of
Corbon's goals was simply to match 10mm specs with the 135 grain bullet,
not necessarily to supercharge it beyond those specs. In this way the
45 Auto can be used without making major changes; just drop in a barrel.
In fact, the standard .45 has two SAAMI standards: 21000 psi for standard
loads, and 25000 psi for .45+ loads. The top full-power factory 400 Corbon
loads just slightly exceed the .45+ standard. It should be noted that most
of the starting 400 Corbon loads still make the IPSC Major Power Factor, even
without stressing its upper limits.
Corbon markets a 135 grain 40/10mm bullet that is pushed to 1450 fps
according to the ammo box --- not bad for a low pressure 45 huh? It's
somewhat like having a 45 and a 10mm in one gun. You will probably be hearing
a lot more about this round now that barrel makers, brass companies, and die
set companies are beginning to ship in volume.
Interesting note: Glock will be coming out with a 400 Corbon pistol as well
as a 357 Sig. I heard it from a Glock rep.
I don't know which pistol the following chronograph info came from. My
guess is a 5" 1911 barrel with a Glock 21 4.6" barrel not far behind in
velocity:
135 JHP 1450 fps 630 ft/lbs 197 power factor
155 Bonded HP 1330 fps 608 ft/lbs 206 power factor
165 JHP 1300 fps 581 ft/lbs 214 power factor
Note: These are the bullet weights recommended by Corbon, although I
have heard of others experimenting with heavier bullets very successfully.
Some have even experimented with using very hard lead bullets, but
Corbon recommends using only jacketed bullets.
"The performance level of this new cartridge rivals the time
honored 357 Magnum or the hottest loads in the 10mm." That's a Corbon quote.
----------
RELOADING:
I received some 400 Corbon reloading data in the mail from Corbon.
I'm posting it here but I take NO responsibility for typos or inaccurate data.
Use at your own risk. Call Corbon to get an official copy for yourself
(800-626-7266).
One interesting thing to note is that even the starting loads are close
to, or exceed, the IPSC Major Power Factor of 175. The Power Factor for
the Enhanced Service Pistol Division of IDPA is only 125.
TEST gun: Les Baer - Premier II 5" barrel, Brass: Starline, Primer: CCI primer
135 JHP Starting Maximum
------- grains velocity P.F. grains velocity P.F.
------- -------- -------- ----- ------- -------- -----
Winchester WAP 10.0 1260 170 11.0 1400 189
Winchester WSF 8.5 1200 9.8 1325
Winchester 540 12.0 1300 176 12.7 1400 189
Hodgdon HS-6 11.5 1240 12.5 1350
Hodgdon Universal Clays 8.2 1260 9.0 1400
Vihtavuori N-340 8.5 1300 9.7 1400
150/155 JHP Starting Maximum
------- grains velocity *P.F. grains velocity *P.F.
------- -------- -------- ----- ------- -------- -----
Winchester WAP 9.8 1225 184 10.5 1310 197
Winchester WSF 7.8 1150 8.2 125
Accurate Arms AA #7 13.0 1250 187 14.0 1300 195
Vihtavuori N-105 11.2 1150 12.0 1250
*Power factors in this section are based on the lighter 150 grain bullet.
165 JHP Starting Maximum
------- grains velocity P.F. grains velocity P.F.
------- -------- -------- ----- ------- -------- -----
Winchester WSF 7.6 1050 173 8.2 1150 190
Vihtavuori N-105 10.5 1125 186 11.2 1250 206
Accurate Arms AA #5 9.0 1025 10.0 1200
Corbon states that they use powders that are NOT available in canisters
for reloading. So their factory loads have slightly higher velocities:
Corbon 135 gr jhp 1450 fps 630 ft/lbs 195 P.F.
Corbon 155 gr jhp 1330 fps 608 ft/lbs 206 P.F.
Corbon 165 gr jhp 1300 fps 581 ft/lbs 214 P.F.
The Following Quotes are from the Corbon brochure:
"Because the 400 Corbon headspaces off the shoulder, it is important
to maintain a distance from the base to shoulder midpoint (datum line),
of min .717", max .725". This dimension should be monitored carefully
throughout the forming or sizing process. We suggest that a tight
bullet crimp be used. A roll crimp gives a much more effective hold
than a taper crimp and is highly recommended. It is usually not necessary
to bell out the case mouth for bullet seating. Excessive belling of the
case mouth may make it difficult to maintain a strong tension on the
bullet when crimping. Overall length of finished cartridge should be
no longer than 1.225".
If you're not into the above method of measuring the base to shoulder
midpoint, the overall brass length should stay within the range of .895 to
.900 in length. The brass usually shrinks a bit during firing; one person
stated that he fired the 400 Corbon brass nine times without needing to trim
the brass, which is the high end of the maximum brass life.
A little extra work is required since the 400 Corbon is bottlenecked. You
must first do a quick light spray lube of the brass, before starting the
reloading process. And at the end of the process, you must wipe off the lube,
or as an alternative, tumble dry the brass for about 10 minutes. The bright
side of lubing is that my Dillon press runs smoother and the Over-All-Length
of the cartridges have much tighter specs -- only about a 2/1000 deviation,
instead of the normal 5/1000 to 8/1000 deviation when using unlubed cases.
For bottlenecked cases, you have to always check for trim length as well as
lube the brass before reloading; this is generally blasphemy for straight-
walled pistol reloaders, but a true art form for the initiated. Gun
companies who don't like reloaded ammo in their guns, should flock to the new
400 Corbon and 357 Sig calibers since there is a better chance that not as
many pistol shooters will reload bottlenecked cartridges.
I also recommend expanding the brass as little as possible so the bullet
just barely fits in, and to use a firm roll crimp without smashing
the bullet in the process, and to try and avoid getting lube inside the
case so the bullet won't slip; You only have a little over 1/8" of case
surface to grab the bullet. Make sure you use a bullet that can withstand
supersonic speeds, such as full metal jacketed bullets.
Lastly, I like to do a thumb pressure test (pushing on the primer end with
the thumb while the bullet end is on a hard surface). You want to make sure
the bullet is well seated and does not slip into the case, which could cause
severe over-pressure conditions. Corbon recommends ordering a cannulure tool
from CH Tool & Die (about $45) in order to assure a firm bullet crimp,
although the new improved 400 Corbon brass as of January '97, may
render the cannulure tool unnecessary; time will tell.
"The 400 Corbon is a new cartridge design. While extensive testing has
been done by Corbon Bullet Co., it has not been possible to test these
loads in guns and/or barrels manufactured by all companies. It is
extremely important that you begin with the starting loads and test
these loads in your gun. Estimated chamber pressure for these loads was
obtained by an Oehler Research Model 43 and appropriate test barrels."
Note: A Corbon rep told me that they test all their ammo with actual
production guns, like Glock, etc.
Calling Corbon, 800-626-7266, can give you information of where to buy
die sets, brass, head space gauges, and reamers, as well as give you a
listing of gunsmiths and custom gun manufacturers.