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milkman
02-05-2013, 09:43 AM
I just got some 9.3x74R brass to make 410 3" shotshells. The brass has a long taper and a very slight bottleneck. From an online post I found, I loaded them with 8g Herco with some packed newspaper as a powder wad, under a full case of cream of wheat.

My problem is incomplete forming. The last case looked like an old coke bottle. The neck was expanded to chamber diameter for about 1/2 an inch, the rest of the case hadn't changed much. I am assuming ( yeah, I know ) that the small bottleneck isn't causing enough resistance for pressure to build sufficient to expand the entire case. Would any other media work better, would pouring some melted paraffin on the COW work to raise pressure?

Milkman

wool1
02-05-2013, 09:53 AM
I've used a bit of bullet lube with some success before on other cases I've fire formed.

mongoosesnipe
02-05-2013, 10:43 AM
You could try a faster powder

elk hunter
02-05-2013, 10:48 AM
I think it will be difficult to safely get enough pressure to fire-form the 9.3 cases to a 410 chamber as they are much thicker and made to operate at much higher pressure than the 410.

Willbird
02-05-2013, 10:48 AM
Annealing the case further back might be required, some of that ammo they leave the annealing "color" on the case and it extends about as far back as where your case expanded on the 9.3x72r cases I have. For use as shotgun shells you do not have to worry as much about over annealing the brass because it will not be holding a bullet with neck tension ?

http://i.imgur.com/Hpiun.jpg

Bill

milkman
02-05-2013, 12:41 PM
Thanks for the replies, I did think about using a faster powder, but didn't know what kind of pressure I would end up with. I guess experimentation would tell me. The first two cases I tried did much better than the last one. Almost complete fire forming on the first try, then, a load of shot finished things up. I think I will try a plug of boolit lube first, and if that doesn't work will anneal and try a faster powder.

Once fireformed, they load easily and shoot as well as crimped plastic. I have been using a heavy paper over shot card and the groups have looked pretty good at 20 to 30 yds.

Milkman

Willbird
02-05-2013, 01:03 PM
Somewhere I have a 410 case a guy gave me he made from a belted magnum ctg case, he turned the belt off. It will hold a lot of shot :-).

woody1
02-05-2013, 01:04 PM
milkman,
I've got some 9.3's I reformed to 410. When I've got one like you show, I usually just load it and shoot it with a regular 410 shotload. Does that make any sense? Throw in around 14 grains of 2400, a wad, shot and top with an overshot wad and use it. I've also found that they do not fully expand toward the base so I put a wrap of beagle tape around the base above the extractor groove. The tape also helps keep 'em centered in the chamber during fireforming. HTH Regards, Woody

milkman
02-05-2013, 02:33 PM
Woody1
Great info. just what I was looking for. I will give that a try shortly.
Milkman

milkman
02-05-2013, 03:03 PM
Woody1
Do you find you can use shot cups with brass shells? If you cut wads, what size punch do you use and what do you use for wad material?

milkman
02-05-2013, 06:22 PM
This has turned out to be a 2 step process. First firing with COW and then a shot cup and shot. The picture is 4 shots at a measured 20 yd. about 3/4 oz of home made 7 1/2 shot with an over shot card wad.60476

woody1
02-05-2013, 06:42 PM
I usually use shotcups with regular 410 plastics and homemade wads with brass but have used shotcups in brass also. When I use shotcups in brass I still use a homecut wad under it for a better seal. I use a 7/16" hollow punch and cut out of everything including milk jugs and the tray that comes under a poppa murphy's pizza.

fredj338
02-05-2013, 08:45 PM
When I fireform w/o a bullet, I seal the neck w/ wax. Then work the charge up until you get 99% fillout. I do this w/ 300RUM cases for my 404jeffery also did it to make 458Lott cases from 375H&H. I like 2400 or 4227, but many pistol powders will work.