Author Topic: 38-40 improved? (Read 825 times)

45LCshoooter · « **on:** July 08, 2005, 08:21:03 PM »

Does such a thing exist? I am guessing the profile of the 400 Corbon would do nicely (I have not seen that one but imagine it like a larger 357 SIG) but how tricky would the chambering be? Would a smith be willing to run a 400 Corbon reamer to 38-40 depth? If that is workable, I would see no problem neck sizing brass on a 400 Corbon die if it is adjusted right. If full-length sizing is needed, the rest could be done in a 45 Colt die. Would this offer a considerable improvement?

Mikey · « **Reply #1 on:** July 09, 2005, 01:56:50 AM »

45LCshooter - don't go there. I would not ruin a 38-40 in any condition to chamber it for the 400 Cor-Bon. The cor-bon cartridge is rimless - it is a take-off of the 45 acp. The neck on the cor-bon is too long to rechamber any 38-40. The cor-bon is not a cartridge that has found any wild acceptance in the shooting world or major manufacturers. Sig turned it down as an upgrade on their 357 Sig due to the case design and pressures involved. Basically, the 400 is nothing more than the old Clarke 38-45 target cartridge opened up to 40 caliber. The 400 gets its bark from shooting lightweight bullets but doesn't do well enough with the heavier weight bullets the 38-40 shoots to compare.

The 38-40 is a better cartridge than the cor-bon and in modern revolvers and lever guns it will turn out better perfromance than the cor-bon cartridge will. My old Lyman Manual shows that for a 20" Winchester 92, 180 gn jacketed slugs in the 38-40 would chrono at 1980'/sec under 24.6 gn of 2400. The 172 gn and 170 gn castings from Lyman do a hair better. The factory duplication load with the 172 gn cast is 6.8 of Unique for 1190'/sec. The 38-40 gives superior performance with reloads than the 400 cor-bon.

Let's not compare current CASS loadings in the 38-40, which are mild for competition and use in older firearms with the ballistics of the 400. I wouldn't own a 400 but I would appreciate a good condition 38-40. HTH. Mikey.

Nobade · « **Reply #2 on:** July 09, 2005, 05:17:40 AM »

You might want to check out what Gary Reeder is doing with bottlenecked revolver rounds. I know he's got a 41 mag necked to 357, not sure if he's got any 40 cal ones but it might pay to give him a call. He's on the web at www.reedercustomguns.com

45LCshoooter · « **Reply #3 on:** July 12, 2005, 07:04:50 PM »

Whoa! I never suggested that the Corbon itself was an improvement over the 38-40: case capacities alone would dictate otherwise. And I dropped my subscription to Guns & Ammo because they print Bob fokker's arrogant schemes to keep grand old cartridges down (interestingly enough, he vandalizes the 38-40 this month: he demands pressures be kept low yet compresses dacron filler in another photo - a definite no-no among express shooters).

No, I was impressed by the shoulder profile only, looking at using the die (and reamer profile, though it would have to be ran deeper than the reamer is made for) of the existing corbon to form a shoulder on 45 Colt brass or .454 and trimmed if the Colt is too short.

This may all be frivolous anyway, as the case isn't necked very far down to begin with, not gaining usable case capacity. I just wanted to knock the idea around.

I shoot 45's but my father has a couple of .40's. I wanted to give him a Ruger in 38-40 for woods use knowing it can be a heavy hitter. I would be reloading for him and might even form brass from 45 Colt if it is not too short. I really like using the same caliber in various guns for the advantage of bulk buying and for economy in bullet moulds. Thought I would enjoy setting Dad up with a .40 battery, but it is not quite as common as .45.

Nobate: funny, I was just on the reader site earlier tonight. I may contact him.

stuffit · « **Reply #4 on:** July 12, 2005, 08:49:52 PM »

Interesting thread. Back around 1968 I acquired a Colt New Service in .38-40 for the express purpose of trying out some loads that I found in an article in one of the gun magazines (either Skeeter Skelton or Jeff Cooper, I'm not sure which) using the Boser bullet. (I've lost the article and sure wish I could find the info again). Anyway, the interesting thing was that after firing in the New Service, the brass has a slightly different contour, the nickel cases here unfired and the brass cases "reformed":

At the time, I went to just "neck sizing" this brass to try to maintain the shape for purposes of case capacity and brass life. Some of the loads were close to .41 mag territory. I had no chronograph back then, but I'd try them again if I could find the article.
:wink:
stuffit

Lone Star · « **Reply #5 on:** July 13, 2005, 02:54:59 AM »

The "radical" change in shape between the unfired and fired cases is quite normal for many rounds besides the .38-40. It happens with the .44-40, the .32-20, the .25-20, and even the .30-30 (although few shooters ever notice the latter). My old M94/.30-30 moved the shoulder forward almost 1/8" when firing factory ammo. The chambers for these cartridges are often cut with a longer body and shorter neck than the virgin brass.

This characteristic is one reason that the old, thin .38-40 and .44-40 brass was prone to case separation; resizing the cases back to factory dimensions and firing in the long chambers reduced the case wall thickness enough to cause the separations in only a few reloadings. Smart reloaders do what the poster above did - neck size so as not to set the shoulder back.

Mikey · « **Reply #6 on:** July 13, 2005, 02:57:55 AM »

45LCshooter: Sorry if I appeared a bit 'over-wrought' (lol) but I just couldn't see doing that sort of thing to a 38-40. The 38-40 you got for your Dad sounds like just the ticket. As stuffit said, some of the loads for the 38-40 approach the 41 magnum levels.

I used the bore size and ballistics of the 38-40 as a basis for my wildcat years ago and was verrrry happy to see that my notion worked and that I had developed a viable cartridge for hunting medium sized game with a 1911 platform. I have this 'thing' with cor-bon for the way the screwed up a prefectly good cartridge design nd then tried to hype the thing as the best there is. Ah well.

Stuffit: those changes you noticed in your fired case shoulders may be due to the cartridge backing out a bit or some sharp shoulders in your chambers. You said you were using an older Colt New Service - it may have some generous chambers that cause that. A number of years ago there was an article on handloading the 38-40 - Rick Jamison I believe - not so much said about top end loads as it related to problems with forming brass (and crushing it, too) and full-length sizing versus neck sizing due to should angle changes after firing. I think I recall that he had similar results from revolvers with upper end loads but not with rifles or carbines. HTH. Mikey.