400 corbon completed

H

Harry Bonar

New member
Shooters:
I'd never dreamed of a 400 corbon but Doc' bought me a reamer, a Kart 40 S&W bbl and 200 Starline cases!
To fit to a 1911 package you must, before fitting the bbl short chamber it. My lathe three jaw runs out only .001TIR, so I went in very slow cutting the hood - then on in till I only had about .050 to go and finished fitting bbl.
Fit bbl and then finished chamber and loaded some brass with 10 gr. of AA #5 with a 155 gr, Gold-Dot.
Shot great with an 18 # recoil spring but I installed a buffer anyway (although I don't like them for serious combat work) and it really goes "BOOM" - unlike any report I've ever heard and virtually cut bullet holes.
Now, if I want to return to 45ACP all I do is change out the bbl.
Have any of you guys built one of these and do you have any load data?
Harry B.
 
I just bought my barrel instead. Found one from a company called accurate arms that fits my Glock 21. no machining. Shoots wonderfully.

I have shot 165 XTP's with unique underneath, and I have some 180gr LSWC also under unique. I will consult my load book and get the correct figures for you.

You can get load data from www.corbon.com. Under the "products" heading, select "load data."
 
At the last OC gun show I picked up a new, Fire Dragon, ported, 400 Cor-Bon barrel for my Sig P220. I just got the Redding dies that includes a sizing die to make 45 ACP brass into Cor-Bon 400. Anyone had any negative experiences doing that? I ordered some new Starlines also to try both. Met a shooter from Oceanside ca. who says he uses those same dies, sizes 45 acp for his P220, and competes in IPSC with it. He loads 135 gr bullets. Recoil is a bit "sharper" than .45 but not a problem. He really likes the Cor-Bon. I'm anxious to get give it a try. I've never owned a ported gun so I can also get a handle on that.
 
My SA 1911A1 GI has a .400 Cor-bon barrel. Was having quire a few failures to eject till I had a smith fit a new bushing on the barrel. I am shooting a 155 grain plated round nose over 8.3 grains of Unique. I foumd that the round nose bullets provide way better feeding than any kind of flat ot hollow point.
 
Any and all bottlenecked cartridges can be difficult feeders in the 1911. The reduced diameter at the front does not offer the support in the magazine that a straight wall does.
This can lead to the first and second rounds out of an 8rd mag, nosediving into the feedramp.
They are a rather fun diversion, but not indicated for 'serious' work.
 
Misfire: The downside to forming .45ACP cases for .400 Cor-Bon would be a case failure. Starline makes their .400 Cor-Bon cases from .45ACP +p cases. .45ACP cases are fine for less-than-nuclear loads, though. Just pay particular attention to feedramp setback. Don't use fast powders with heavy bullets. (I use AA#7, exclusively, for .400 Cor-Bon reloading.) For hot loads, I also use Magnum LP primers. If I were using newer .400 Cor-Bon cases with the small primer pocket, I'd probably use small rifle primers for hot loads.
 
400 corbon

Dear Shooters:
I have learned more about chambering and headspace in semi-auto pistols.
I've noticed that if you make the head fit perfectly on your bbl. that you want the case just about .005 below the hood! Why?
I don't know, but they are far more accurate if the headspace is a little long. I have an idea - cases in semi-autos are notorious fort varying in length and if a case is too tight the bbl locks up on the case instead of the case hood. It must just take a thou. or two to do this.
I think you want contact with the hood and lugs - not with ANY interference with cases!
Do any of you have any insight on this - I can learn something!
Harry B.
 
Harry,
Many years before the 400 Corbon round came out I had a customer that was experimenting with a round called the 40 Centaur (the spelling on that may be wrong). It had a much longer neck then the 400 Corbon so it created some feeding difficulties, but after a little tuning of the extractor, mags and slide stop the gun ran fine.
As for load data I don't recall what he was loading but I'll see if I can find out.

As for headspacing a 1911 pattern gun most people have the misconception you headspace off the hood of the barrel. This is incorrect, headspace is controled by chamber depth as you have found out.
I've found that most 1911 pattern guns shoot best with .005 to .007 in headspace.
A lot of the old bullseye shooters believed that to long of a chamber created eractic ignition which in turn created inaccuracy problems. Most wanted the chambers in their barrels kept to the minimum specs when it came to headspace.
Good luck in your endeavors with the 400 Corbon, it's a good round especially if one wants a 40 & 45 caliber gun using the same slide and frame.
Regards
Bob Hunter
www.huntercustoms.com
 
400 corbon

Dear Bob:
In the past (and present) I've always tried to be so precice in setting headspace but in semi-auto's you're right on! I fit a Hi-Power bbl (Bar-Sto) precicely and it didn't shoot - took a few thou' off the lug and right on!
I guess you can ALWAYS learn something - thanks for the info.
Harry B.
 
kinda data ('cause I don't want you trying what I tried)

In my actual gun: Starline case, CCI300, 135g Rainier TCJ-FP, OAL 1.180", 10.0g WAP (DON'T USE 10.0g), av = 1281fps @80F

Suggest reducing load by at least .5g; can substitute Silhouette.

I also tried some loads I interpolated (means "pulled from nether region") using the same bullet (I had a zillion on hand for 40 S&W practice loads) and Universal Clays.
Fired indoors at a six-lane NG Armory; never found the cases (musta stuck in the ceiling?).

Here's some data from Handloader #192: 135g JHP, 11.5g HS6 / 9.0g Universal Clays / 11.0g WAP / 12.7g W540; 150-155g JHP, CCI350, 14.0g AA7 / 10.5g WAP / 12.0g N105 / 8.2g WSF; 165g JHP, CCI350, 11.2g N105 / 10.0g AA5 / 8.2g WSF.

All loads were in Starline cases, and all loads are maximum (but pressure-tested).

Me? I'd carefully reduce charges and chrono-map my way up.
 
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