By Marshall Williams.
The correct case for the .44 shotgun is essentially the basic .44-40 case. The rim diameter is .525 inches, and the base diameter (diameter just forward of the rim) is .471 inches. These dimensions are almost identical to the .410. The problem is that the .410 case is nearly straight at .471, while the .44-40 case tapers to a diameter of about .457 inches just .9 inches ahead where it has a small shoulder and then a short neck with a diameter of just .443 inches. Thus, a .410 case, even if shortened, should be too fat to go very far into the chamber. Overall length also is a problem. The .44-40 case is about 1.31 inches, while the .410 cases are 2, 2 1/2, and 3 inches long.
I see several possibilities.
One is to have the chamber lengthened to accept a .410 shell, probably just the 2 1/2 inch shell. Based on the few .44 shotguns I have seen, they are identical except for chambering with similar .410s from the same makers and I would expect them to be OK for the conversion. However, without seeing your gun, I cannot offer an opinion. Have a competent gunsmith look at it and give you an opinion. Then, if you go the rechambering route, have the gunsmith fire a proof load in it. If the gun doesn't blow up, then it ought to be safe.
If you are an experienced reloader, I think the best way to go is the way outlined in the "Pre-Historic .410s -- the .44 Shot Cartridges." which will be found under the "ALOOF, etc." heading.
Obtain a supply of .44-40 cases and some of the Speer .44 shot capsules. I cobbled my reloads together using assorted dies, but I strongly recommend that you obtain a set of .44-40 dies as well as a .44 special/magnum sizing die.
The Speer capsule requires a straight case to support the bottom part which serves both as wad and closure for the capsule. Resize your .44-40 cases in the usual way, then use a .44 special or .44 magnum sizing die to push the shoulder back and make the neck long enough to support the bottom of the capsule. For loading data you may use the loading information listed with the Speer capsules for reloading the .44 special shot cartridges. This data should result in chamber pressures well under 10,000 lup and give satisfactory velocity.
I anticipate one problem with using the .44-40 cases. The brass is very thin and the resized section where the shoulder got pushed back will expend when the case is fired. Reloading the case again requires moving back the shoulder again. This works the brass excessively and the cases will soon split in firing.
I also suspect that you can use CCI .44 special/magnum shot shells just as they come. There is a minor conflict between case dimensions. As noted above, the mouth of the .44-40 case should have a diameter of about .443 inches, while the case mouth of the .44 special and magnum measure about .457 inches. The chamber probably is loose enough to accept the slightly larger .44 special/magnum case mouth, but you must check to see.
The way to check for fit is as follows: Remove the barrel from the receiver, push the extractor down into its recess, and drop a CCI shotshell into the chamber. If the CCI .44 shotshell freely drops all the way into the chamber, then you are OK. However, if it has to be pushed in the last little bit, then the case mouth is too big and pressures will rise when such a cartridge is fired in that chamber.
If the chamber of the gun will freely accept them, I see no reason why the CCI .44 special/magnum shotshells could not be used; they are loaded to modest pressures.
The .44 special/magnum has a rim diameter of .514 inches and a straight case diameter of .457 inches. The CCI .44 special/magnum case also will expand noticeably upon firing but should not split. The CCI Blazer aluminum cases use Berdan primers and cannot be reloaded, so one need not worry about excessive resizing. However, they are expensive, about $9 for ten (10) shells.
You also can use the Speer capsules to reload .44 special or magnum cases (Well, that is what they are designed for.) and use standard .44 special/.44 magnum dies. However, before using them, check for fit as described above. They will expand noticeably upon firing but should not split the first time. However, they will require excessive sizing when reloading a second or subsequent time, and they soon will split from the excessive working.
Rechambering may be the cheapest way to go. My guess is that it will cost in the neighborhood of $50-$100. The initial cost is a bit high, but after that you can use easily available .410 shells.
If you already reload either the .44 special or .44 magnum and find that the cases will fit your chamber, then your only additional cost will be Speer capsules and the shortened case life. The Speer shot capsules are about $7 per box of 50.
If you want to use the .44-40 cases, the costs of a set of .44-40 dies, a .44 special/magnum resizing die, .44-40 cases, and Speer shot capsules will add up.