Using .444 MARLIN Brass in a 410?

I've seen that some people use .444 MARLIN brass in a 410 shotgun. 410 hulls are next to impossible to find. What needs to be done to the .444 MARLIN brass to make it usable in a 410? Thanks in advance.

watching with interest.
the .303 british can also be blown out to use....Im led to believe the opposite is how the .410 came about in first place,straight walled case,pack in cordite sticks THEN size down to .303 brit projectile seated and sent off for the troops to use.
do search for everlasting .410 shells

I had to peen the rims out on a few 444 cases for my H&R Pardner, they fell under the extractor. I drilled a hole in a piece of 1/4 in. steel to fit the body and peened out the rim. Only had a dozen so it wasn't to bad. If it closes and doesn't fall under the extractor just use as is.

The rim of a 303 Brit. is too thick for one of my 410's. It would need to be thinned from the front. I found a box of 9.3 X 74 cases cheap, they work well but are usually expensive and scarce.

Ballistic Products has 410 cases occasionally, keep an eye out. I had trouble stocking up several years ago and it is worse now. I loaded plastic hulls with a glued in over shot card till I found a loader at a flea market. I still load a few that way, doesn't matter on a single shot or a double.

I have a little single shot that the 444 Marlins just drop right in. I did get a reloading die set to resize. Here is an article about it https://www.grantcunningham.com/2014...10-shotshells/ and https://www.shotgunworld.com/threads...or-410.523374/
Biggest thing is powder. Harbor freight has a punch set that you can make wads and overshot cards https://www.harborfreight.com/9-piec...-set-3838.html
By the way, you may be tempted to buy the Brass reloading manual from Ballistics Products, don't No info on the 410

Or this punch set. No more Wack! Wack!

https://www.harborfreight.com/6-piec...set-67030.html

I have been trying 444 brass for my Bond derreinger. Was discussing this with a friend one day. Suddenly, mind went crazy because I just realized that also meant you can chamber a 444 Marlin round in the Bond also. Amazing we have not seen some idiot on Tik Tok or U tube showing us how he did it!!!! Scary thought GW

I have used 444 cases for 15 years or so and they work well in two of the three 410s I have without any mods. The rim diameter is a bit small for the one. I have also used blown out 303 brass but the rim needs thinned for two of the 410s. Also I have had about 20% neck splits when trying to blow out the 303 with or without annealing. As I have a lathe, I have made 410 cases from 300 win mag that easily hold 3/4oz of shot. That is quite a bit of work but once you have the case it should last forever.

I also make wad punches that fit in my drill press and spin cut them from material like the cardboard from soda pop cases.

I rarely need to resize 444 cases but if I do I use a 45acp sizer die. Some 45dies are large enough at the threads on top that the brass will go through, some aren't.

I have Not tried 444, but, been doing 303 Brit. for a very long time.. I have decided to stick to generic 410 wads...easier!
1/2ozz of shot and hot glue or wax, depending on how rough gonna get handled.. Working great for me. Much easier than trying to Crimp hulls...especially Paper!!! Yes, I did thin the Rims..