Ammunition and Handloading
Factory made ammunition is available from Cor-Bon in a variety of bullet weights and types: 115 gr (7.5 g) Glaser Safety Slugs; 155 gr (10.0 g) DPX; 135 gr (8.7 g) Pow'RBall; 130, 150, and 165 gr (10.7 g) tradition JHPs; and 165 gr (10.7 g) Performance Match; and is sold by major mail order retailers.
Many shooters, however, handload their own ammunition to save money. Fired .45 ACP cases can be resized and trimmed to handload .400 Corbon cartridges. New brass cases are manufactured by Starline Brass and are readily available directly from them and major mail order retailers such as MidwayUSA. According to Starline Brass, "The primer pocket was changed from large pistol primer to small pistol/rifle primer in 12/00. Test results concluded no adverse effect from switching to small primer pocket. Cor-Bon is now recommending Win. small pistol works best and if using small rifle Remington 7½ works the best."
Lee Precision, Inc. offers a .400 Corbon 3-Die set. Redding Reloading, according to their catalog, offers custom made 3-die sets for the .400 Corbon. Lubricating of the bottleneck case can be avoided when starting with .400 Corbon cases by using a carbide .45 ACP sizing die before using the .400 Corbon sizing die. Using a 5-stage progressive reloading press makes this less of a chore.
Setback of the bullet in the case—which can cause excessive pressure—can be avoided by using a tight roll crimp and, if necessary, Corbin's Hand Cannelure Tool for jacketed bullets. Since the cartridge headspaces on the shoulder rather than the case mouth, a tight crimp will not cause headspace problems.
Information on handloads for the .400 Corbon can be found online, 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 with a 5" barrel still make the IPSC Major Power Factor, even without stressing the caliber's upper limits.
Corbon said that they gave the 400 Corbon to the market and have no patents on this cartridge whatsoever. Eventually, someone with several thousand dollars may even have SAAMI set a standard for it.
Read more about this topic: .400 Corbon