303 British to 410 shotshell

[cwtebay]

Well...I couldn't resist a Henry 410. It is actually a quite practical addition as there is a weapons restricted area that I enjoy hunting elk from horseback on.

Proposal - annealed 303 British brass, sized up in this progression in expansion with the following dies:

32 WS, 348 Winchester, 35 WCF, 38-55, 38 WCF, 405 WCF, and 44 WCF.

Load with primer / powder / cards/ shot and use normally. Final product should be fireformed for final product.

Please point out the logic in my proposal.

Thank you.

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[skeettx]

Can be done but 444 Marlin is much easier
Mike

[cwtebay]

Can be done but 444 Marlin is much easier
Mike

Ahhh.... should have mentioned - I have a bajillion pieces of 303 British brass.
And I am wishing to:
A) make 100 pieces for reloading for a long time.
B) conserve primers

I already have 300 or so from MagTech brass and am just thinking down the road. I have owned it


Oh - and C) kinda want to do this project!
I'm thinking about making a progressive ball type neck expander for this project should I ever wish to repeat it.
(And sort of D) I end up spending quite a little time up at night looking for projects to occupy my mind this time of year)

[Outpost75]

The rims on .303 brass may require thinning. Mag tech all brass or military surplus, M35 cases work fine, as do 9.3x74R fire-formed, though still may need to thin rims on the latter. I use Buffalo Arms .45 wads in my metal - cased .410s.

[cwtebay]

The rims on .303 brass may require thinning. Mag tech all brass or military surplus, M35
cases work fine, as do 9.3x74R fire-formed, though still may need to thin rims on the look latter.

Excellent point, these do not seem to. They lock up tightly on a closed action.

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[Jedman]

I have heard many times of people making usable brass 410 cases from 303 British but to me it doesn’t make much sense ? As mentioned if you ( need ) brass cases 444 Marlin or 9.3 x 74 R is much better and less work.

I have done a lot of projects shooting many different projectiles from 410’s and understand that using a brass case gives you a larger inside diameter than using plastic shotshell hulls but 303 Brit is about .020 undersized at the case head and short once expanded or fire formed but will work.

Jedman

[TyGuy]

I have been dabbling with this as well. Made some .444s into nice blanks and thought I would play with the .303 also. I have a couple that I have annealed and fire formed but they aren’t exactly a smooth transition up the sides. They still have a bit of a waist to them. I’ll try them again when I have more free time.

[Harter66]

I Coke bottled mine out to 40 cal annealed half the case . 5-6 gr Unique cardboard 45 cal wads and meat tray wads 1/2oz of shot , over shot card . Shoot .

It probably won't form out all the way but the next full punch load will .
Use pistol primers to better track pressure vs rifle .
A RB may be used as long as it's less than choke dia . The real examples on hand are .386 but the 45/410 w/o the screw on choke was fine with a .451 .

[trapper9260]

I had fire form some 9.3 x 74 R for 3" shells it was easy to do and now will later work on find some to use for 2 1/2" . I was told I could use 30-30 cases , I just do not want to use them because of the rifle I have for the 30-30 .

[toot]

that is just a rely lot of work. must be an easier way!?

[MOA]

I use 9.3x74R. Easy peze. Just fire form with a slight annealing. Base, rim dia. an rim thickness better suited.




















But, all that being said...if I had a bizzilion 303 cases and no 9.3 is be doing just what your doing too. 9.3 are pricy at any time..now it just crazy time. Almost makes you want to go out and get a nice ads in 410 huh.

[Milsurp Junkie]

I would be willing to buy some from you. I also have 20 blown out 303 british rounds that you can have. I dont have a 410, and there presence is making me consider getting one!

[brass410]

I've never mechanicaly formed from 303 brit always just fireformed with a piece of mask tape wrapped around at base to centre it in the bore,but I much prefer the 9.3 x 74r they just look sooo much nicer in the shell holder on the stock of my little 410 shottie.

[MOA]

i've never mechanicaly formed from 303 brit always just fireformed with a piece of mask tape wrapped around at base to centre it in the bore,but i much prefer the 9.3 x 74r they just look sooo much nicer in the shell holder on the stock of my little 410 shottie.

:-d

[elmacgyver0]

Anything wrong with Magtech all brass shotshell hulls?

[rbuck351]

If you have a bunch of 303s, they can be turned into decent 1/2 oz 410 shells but it is a bunch of work. I started with berdan cases which made it even more work.

I started by boring the berdan primer out to fit a 209 primer. Then anneal clear to the rim. Be careful not to over anneal or under anneal the necks or they will split when expanding.

I use an old Lyman 45acp sizer that will size a 410 case full length and has a top hole of 9/16 fine thread. I made two tapered expander pins from 9/16" x 2 1/2"bolts that fit the die making it an "M" die. #1 .300 tip tapering to .398 over 1.7" #2 .370 to.408 over .460. with the .408 continuing for 1.300". These tapered pins in side the 45acp sizer allow expansion without bending or collapsing the case.

When expanding, the second pin will stop when it gets to the thicker walls of the bottom of the case. You can now use a plastic 410 wad to fire form as it will seal when it gets to the thicker part of the case. I trim the petals off the plastic wads to add enough room for 1/2 oz shot. These will have a waist below the thicker part of the case until fire formed. If you anneal the case to the web, it will expand nicely on the first firing.
Once fired they will hold 5/8 oz shot and work fine. However the 444 cases are good to go in most 410s without any work, same with the 303 cases. Some will need a bit taken off the base. And I would really like to get a few 9.3 x 74 cases.

[rbuck351]

Yeah, there is something wrong with Magtech hulls. They are $38.99 for 25. Berdan 303s were free and 444 Marlin cost me some other range pick up brass.

[MOA]

I just lucked out. I've a No.1 in 9.3 so I did have some on hand but they were not cheap, so dedicating some to .410 was painful. Then someone I forget who was having a closeout on Norma 9.3x74R for 15 dollars for a box of 25. I bought 3, wish I had got 5 or 6. Oh well, I'm set. True, true the 9.3 is the way to go.

[TNsailorman]

Where oh where are you able to find 410 MagTech hulls anywhere at any price. I haven't been able to find any and I have tried several times this year already.

[Mk42gunner]

I did not have very good luck blowing out .303 British to .410. From all the different posts about it, it seems simple, but it didn't work that way for me.

The only .410 I had when I was doing this was my Grandpa's Iver Johnson Champion, with 2½" chamber, so I did not try the 9.3 brass.

I annealed the brass (not far enough down) and loaded a moderate charge of powder and shot, with a wad between the powder and shot and over the shot. When I fired the cases, the front half was well expanded, I needed a rod to extract and eject.

I still had a severe wasp waist in the .303 brass. Maybe it would work with a second firing, but no more than I shoot a shotgun, I figured to just buy a box once every couple of years.

.444 Marlin brass didn't work much better, for me. It did look better, but still expanded enough to stick in the chamber where the shot charge was sitting.

The chamber doesn't look or feel rough, so I don't know what is wrong with my technique.

Robert