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
MikeAhhh.... 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.
https://i.postimg.cc/q7c8ZDzD/Screenshot-2022-02-05-05-35-23.png (https://postimg.cc/jW5wDX6y)

https://i.postimg.cc/LsFtDF6Z/Screenshot-2022-02-05-05-34-08.png (https://postimg.cc/NKb2GVXg)

https://i.postimg.cc/FsjHzxgV/20190407-093636.jpg (https://postimg.cc/1f3QYwd8)

https://i.postimg.cc/tgSpNp9X/20190225-144235.jpg (https://postimg.cc/f39Gw43F)

https://i.postimg.cc/tg7b3dPf/20190407-105953.jpg (https://postimg.cc/GB06ryXJ)

https://i.postimg.cc/J4qCSY5v/20190407-111004.jpg (https://postimg.cc/0bb4wf30)

https://i.postimg.cc/Gtx6w9GG/20190407-111141.jpg (https://postimg.cc/GT9XvLMm)

https://i.postimg.cc/3N0Wt5vs/20190407-114629.jpg (https://postimg.cc/dZvq0fn6)

https://i.postimg.cc/0QTZWv4m/20190407-120741.jpg (https://postimg.cc/wykhMCgT)

https://i.postimg.cc/FFPHLK27/20190407-121518.jpg (https://postimg.cc/jC7TVRqb)

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

[cwtebay]

Well, I am going forward with this but had someone trade me for 100 - 444 brass. Perhaps I'll do a bit of both!
Thank you for everyone's help!

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[blackthorn]

Please record and post your successes and failures on your journey as you go forward.

[nhithaca]

Bought some of the Norma 9.3x74r brass years ago to try and blow out for use in an AK style 410 auto loader (will only feed 3" shells from the mag). Ended up getting about 60 cases cheap on a discount table @ LGS. Only tried about 20 of them; just could not get past the wasp waist issue. Should have annealed them I guess.

Also tried the 444 Marlin for use in a 2.5" Judge. Not a good fit! The chambers on the Judge are stepped so only a 45 Colt will chamber, not a 454 and the odd chamber shape is tough on a brass case. They do not want to come out after firing regardless of the powder charge used.

Bought a fair number of the Russian steel 410 shells for use in the above mentioned AK 410 (2.75" long). They shoot and cycle fine but are Berdan primed. Figured out that the little dimple for the primer is formed with a punch and by lining up the correct drill size on the dimple inside the case I could drill out the old primer and use standard shot gun primers. Seems to work OK. Resized the steel cases on a MEC loader or 444 dies with a lot of lube.

Lastly, bought a paper package of British military issue 410 ball loads that as I understand it, were issued for crowd control!!!! Only shot one or two out of a SMLE that was modified specifically for these by boring out the standard 303 barrel to 410 and installing a plug in the mag well. Recoil was quite brisk and the shells did not want to extract well. Cases are Berdan primed and about 2.1" long. Lead ball is exactly 0.410" in diameter and appears to be harder than pure lead. Ended up buying a whole case (original wood box) of these things but have not even opened it yet (collector value?). Don't know what would happen if you shot one through a choked gun. The two I shot seemed to be loaded quite hot.

[Texas Gun]

Where do you all find 303 Brit brass to waste on 410 I have tons of 410 halls and i need 303 brass 😑

[Milsurp Junkie]

As I said, I would be more than happy to trade my blown-out 303 brass, for some that aren't. I have a couple of enfields, and not near enough brass to feed them with. No 410, and i am afraid it is going to cause me to buy one!

[cwtebay]

Where do you all find 303 Brit brass to waste on 410 I have tons of 410 halls and i need 303 brass [emoji58]I helped out a group that has a Lewis gun. They reload no more than 3 total firings for it then they're considered unreliable. I can see why, I have had a couple of split necks from that batch. I ordinarily would offer them up for sale or trade but I don't feel that they would be a fair deal for most. The trade I made was 5:1 for the 444 brass, locally so I can make it right if there's a hang up - just to give you an idea on what I think it's worth.

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[cwtebay]

Bought some of the Norma 9.3x74r brass years ago to try and blow out for use in an AK style 410 auto loader (will only feed 3" shells from the mag). Ended up getting about 60 cases cheap on a discount table @ LGS. Only tried about 20 of them; just could not get past the wasp waist issue. Should have annealed them I guess.

Also tried the 444 Marlin for use in a 2.5" Judge. Not a good fit! The chambers on the Judge are stepped so only a 45 Colt will chamber, not a 454 and the odd chamber shape is tough on a brass case. They do not want to come out after firing regardless of the powder charge used.

Bought a fair number of the Russian steel 410 shells for use in the above mentioned AK 410 (2.75" long). They shoot and cycle fine but are Berdan primed. Figured out that the little dimple for the primer is formed with a punch and by lining up the correct drill size on the dimple inside the case I could drill out the old primer and use standard shot gun primers. Seems to work OK. Resized the steel cases on a MEC loader or 444 dies with a lot of lube.

Lastly, bought a paper package of British military issue 410 ball loads that as I understand it, were issued for crowd control!!!! Only shot one or two out of a SMLE that was modified specifically for these by boring out the standard 303 barrel to 410 and installing a plug in the mag well. Recoil was quite brisk and the shells did not want to extract well. Cases are Berdan primed and about 2.1" long. Lead ball is exactly 0.410" in diameter and appears to be harder than pure lead. Ended up buying a whole case (original wood box) of these things but have not even opened it yet (collector value?). Don't know what would happen if you shot one through a choked gun. The two I shot seemed to be loaded quite hot.I'll bet those would at least control 1 member of the crowd! Wow, those sound a little rough!
That's interesting about your Judge experience with them. I have made quite a few brass shells for my wife's Judge - but only from MagTech so far. Now I'm not so optimistic about this Henry idea that I have.

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[rbuck351]

M42gunner:

What powder,amount and shot weight were you using? I use either 13grs of 296 or 15grs of 2400 with both 1/2oz and 3/4oz . 3/4 oz will only fit in the 444 cases. The 303 cases are fairly thick on the bottom 3/4" of the case and you need to anneal to the web of the case. I don't know why you would have extraction problems with either 303 or 444 cases unless pressure is fairly high.

[Mk42gunner]

rbuck351,
It has been several years and I don't remember for sure off the top of my head. I want to say it was 12 or 13 grains of H2400 with a half ounce of shot. Not real sure, but I did look it up in one of the Lyman shot shell manuals.

Primer was a WW LP, and I think I used a Winchester 410 wad with a playing card overshot wad.

If I can find the box they are in I am sure I wrote it on the box. I'll look tomorrow (no power in the old house).

It was weird the back half of the case looked fine, but where the shot rested was dimpled.

I know others have had good luck using brass cases, I didn't; and no more shotgun shells than I shoot anymore, I just buy a box occasionally.

Robert

[rbuck351]

I'm wondering if you didn't get the wad completely down on the powder. I haven't had real good luck fire forming the front part of the case either. I push the case out with a home made set of "M" type dies to about .408 using a Lyman 45acp sizing die that prevents the case from wadding up. But the ,408 expander will only go down to about 3/4" from the bottom of the case. 15grs of 2400 will fill the case up to where you can seat a cut off cup from a shot cup. The case will just hold 1/2 oz of shot with a thin over shot wad and I have good luck with this. I'm not sure it's worth the effort for me as I only shoot a few rounds a year but I gave a 6 year old grand son a 410 for Christmas and he needs some ammo for it that can be easily loaded by hand. I gave my son a lee hand press and I'm building some pieces for it so he can load brass or plastic shells if he can find powder and primers in Anchorage. Other than possibly having to thin the rims a couple or three thousands they work as they are.

303s are a lot of work and I'm not sure why I even bothered as I have about 150 444 cases. So far I haven't had any problems with brass cases sticking in my 410s but I had a lot of sticking cases when I loaded plastic cases until I started sizing them in a 45acp die.

[garandsrus]

Cwtebay, I tried to send you a PM. Your box is full.

[cwtebay]

Cwtebay, I tried to send you a PM. Your box is full.No, it's actually completely empty.
You can email me at cwtebay@gmail.com

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[Mk42gunner]

I'm wondering if you didn't get the wad completely down on the powder. I haven't had real good luck fire forming the front part of the case either. I push the case out with a home made set of "M" type dies to about .408 using a Lyman 45acp sizing die that prevents the case from wadding up. But the ,408 expander will only go down to about 3/4" from the bottom of the case. 15grs of 2400 will fill the case up to where you can seat a cut off cup from a shot cup. The case will just hold 1/2 oz of shot with a thin over shot wad and I have good luck with this. I'm not sure it's worth the effort for me as I only shoot a few rounds a year but I gave a 6 year old grand son a 410 for Christmas and he needs some ammo for it that can be easily loaded by hand. I gave my son a lee hand press and I'm building some pieces for it so he can load brass or plastic shells if he can find powder and primers in Anchorage. Other than possibly having to thin the rims a couple or three thousands they work as they are.

303s are a lot of work and I'm not sure why I even bothered as I have about 150 444 cases. So far I haven't had any problems with brass cases sticking in my 410s but I had a lot of sticking cases when I loaded plastic cases until I started sizing them in a 45acp die.
I'm reasonably sure I fully seated the overpowder wad. I looked today and didn't find the box of remaining loaded shells???

The whole reason I started reloading .410 those many years ago was that Dad said I was driving him broke buying shells for me. A Lee loader, a bag of shot, wads, 100 primers and a paper sack of Herco soon followed us home.

The .410 loader was stolen from storage many years ago, but the thieves left the 20 gauge one alone.

Robert

[rbuck351]

Yeah 410 have always been expensive compared to 12 or 20 ga. A couple of weeks ago there were two boxes of old Peters 410 2 1/2" shells at an online auction that sold for $250 plus 15% commission. Other than that I haven't seen any 410 for sale anywhere at any price.

[cwlongshot]

I have had 40 on my bench sized up to 38/55 ready for fire forming.

444, had too small a rim for couple of my 410's. Caused many misfires fire forming them.

All but one take 303 as is. Have had some for years. Need more but have been stalled.

All also take the 9.3x74.

BUT of coarse 9.3 is unobtanium for most folks. Either because just cannot find or are cost prohibitive. Im lucky to have two boxes but knowing value I have hesitated to convert.

Even 303's are not commonly found. I bought two hundred and found them to be berdan primed. I should have been smarter to have asked. Seller was unresponsive.

CW

[rbuck351]

I converted my Berdan 303s to 209 primers and then formed them to 410.

[SOFMatchstaff]

I converted my Berdan 303s to 209 primers and then formed them to 410.

What kind of tooling/cutters did you use? One cutter or multiples?

[rbuck351]

First I have a lathe and I use multiple cutters. I started with a small center drill and drill through the primer into the berdan anvil. Then I drill through with the proper size drill for #57 primers as I have 600/700 of those to use before redrilling to 209 size. Next I use an end mill to cut for the primer rim. I really enjoy working on the lathe otherwise this would be more work than it's worth. Anyhow I now have about 150 loaded 303/410 cases loaded with 1/2 oz of #9 shot for final fire forming

[ulav8r]

What is the reason or justification to converting to 209 primers? I have 2 boxes of the 9.3 x 74R that I will use for my one .410.

[rbuck351]

Converting to #57 from berdan makes them easy to reload. It gives me a use for the 500/600 #57 primers I have. Once I have used the #57s it is a simple to drill for 209s. Berdan 303s are cheap, 9.3 x 74R are not cheap assuming you can even find them.

[rockrat]

Saw a box of 410 Federal 3" shells at wally world today for just shy of $20 and 2.5" shells were just shy of $18

[eljefeoz]

Here in Oz, most brass is either unobtanium or made of platinum!
I had a pillowcase of .303B brass, dis a lot of web search etc.
as stated by others, some shotguns will not lock up because of the thick rim. My Rossi .410/.22LR switch barrel will not.
I thin the rim and check for fit in the action, case by case.
Next, run the case into a 9.3x62 FLS die. Thats the biggest I have. Standard LP primer, 11.4 gr of Blu Dot or 15 gr 2205 (w296) OP cork wad cut crom wife’s ex favourite cork coasters usingan evilbay wad punch - 11mm iirc- had a mate machine up a ‘seater plug’ on a stem which screws into Lee universal expander die. Use that to squish down on the OP wad after seating the case in the press. Then 1/2 oz of no6 shot. Next OS wad cut from soft cheese can covers. A dab of Elmers white glue. I did try to run the loaded shell into a .303 seating die to help with the mouth crimp. Sometimes it did and sometimes not.
blue dot gave the best ignition and pattern. The w 296 equivalent gave bloopers and lot of unburnt powder.
I’ve now progressed to using Buck and .38 wc in these cases.
Fair warning, novice shotgun loader. I have a long way to go.

[toot]

I have a MARLIN 410, lever action. made from 1929 to 1932, would I have any problem in using a 303, or a 444 case? feeding & ejecting. I believe that it is chambered for 2 & 3/4 inch hulls.

[15meter]

I have a MARLIN 410, lever action. made from 1929 to 1932, would I have any problem in using a 303, or a 444 case? feeding & ejecting. I believe that it is chambered for 2 & 3/4 inch hulls.

I thought .410 came in 2-1/2 and 3". Was there a 2-3/4" that's now obsolete?

[Texas by God]

I have a MARLIN 410, lever action. made from 1929 to 1932, would I have any problem in using a 303, or a 444 case? feeding & ejecting. I believe that it is chambered for 2 & 3/4 inch hulls.You have what a lever action .410 should be. My friend had one for a few hours at a gun show and sold it for a small profit. Well balanced and lighter than the later introduced models. I looked at a Henry .410 lever action and it also was too heavy for a .410 shotgun.
I believe the old Marlin is 2-1/2" chamber only.

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[racepres]

and the 303 converted comes up short of 2-1/2"... Mine are anyway...but, mine have Not fully formed except about half way to the head..
Sorry... No Experience with a "repeater" in 410... Don't see why it wouldnt work...except that, again, they are Short.

[barnetmill]

Bought ......e.

Lastly, bought a paper package of British military issue 410 ball loads that as I understand it, were issued for crowd control!!!! Only shot one or two out of a SMLE that was modified specifically for these by boring out the standard 303 barrel to 410 and installing a plug in the mag well. Recoil was quite brisk and the shells did not want to extract well. Cases are Berdan primed and about 2.1" long. Lead ball is exactly 0.410" in diameter and appears to be harder than pure lead. Ended up buying a whole case (original wood box) of these things but have not even opened it yet (collector value?). Don't know what would happen if you shot one through a choked gun. The two I shot seemed to be loaded quite hot. I can not say for your gun, but I know of one case where oversized projectiles like of .429 and .452 were fired through a .387 choke and no damage to the choke or gun even from factory .454 casull. .454 casull reloaded with range trash powder in a later video did blow up the gun.

start 4:00 minutes


https://www.youtube.com/watch?v=wAnbDvLIAac&t=257s

[toot]

15meter, my bad. a senior moment. stuck on old 12 gauge.

[toot]

Texas by God, yes you are right.

[indian joe]

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)

sort through your loading dies and find one that will clear the outside of your 410 case and has a 3/8th thread in the top - then get ye a couple of bolts and make an expander with a long slow taper - if you work it right that will get you out to 375 in one pass - have someone run the same thread on a 7/16 bolt and repeat the excercise - gonna need to anneal these before (not too far down the case first time out) then after first pass (further down the case body for the second expand)

I took PMC 30/30 to 375 BB in one pass with this kind of expander die didnt lose a case - didnt need to anneal (sadly we dont see PMC brass anymore it was good stuff)

[BrassMagnet]

I really detest folks that form 303 Brit to 410! I need more 303BR brass!

Here is a thread I did years ago making all brass 3" 410 from 9.3x74R:

https://castboolits.gunloads.com/showthread.php?339427-Weird-way-to-cook-Cream-of-wheat-10-grains-of-Red-Dot!

444 Marlin makes great 2 1/2" 410 all brass hulls. 444 Marlin dies with the stem removed size any 410 case.

Yes, I do have Magtech brass for 410 and 12. Also 444 and 9.3x74R. I still haven't made noticeable progress since I posted this thread. Too much going on out here!

I suspect you can expand 303, 444, 9.3x62R or 9.3x74R to 410 in one firing with the right amount of slow pistol powder. Start small and increase slowly. Since I posted this thread, I have learned a 1/4 square of toilet paper wadded up on the powder and in the case mouth is an improvement to what I did. I also learned that extra wads to put the crimp where you want it can cause case head separations in only two or three loads. These all brass hulls made from rifle brass should be good for a hundred or more loadings! Enjoy and have fun!

[toot]

Brass Magnet. your thread should be made a STICKY!! I just saw it and it is the most informative one on the subject.

[rbuck351]

Although I have a bunch of 303/444marlin brass converted and loaded for 410, I decided to try another longer brass case. I bought a bunch of brass at an auction and some were 300Win that had been sized in a 300H&H die. I sized the cases in a 45acp sizer die until they got hard to size any farther. This left about 3/4" of the base unsized. I turned a mandrel to fit the mouth of the case using a live center in the primer hole and turned the case to .470 leaving the rim untouched. This leaves the rim to thin and my gun has a short firing pin so I drilled a 15/32" hole through a 3" piece of 3/4" cold roll and cut a 20 degree taper on the end. I slide the case in the tube and using a light hammer pound the edge of the rim forward to adjust the head space. I then anneal the neck/shoulder.

Next is fire forming. I prime and use about 5gr of nitro 100 with a patch of cloth about 1/4" square packed on the powder. Then fill to the base of the neck with cream of wheat. Then I push a 98gr .311 boolit in the neck and fire form. They form out nicely and can then be loaded. I load with 15gr of 2400, a 1/2oz plastic wad and 3/4 oz of #9 shot with an over shot wad glued in with silicone.

It's a lot of work but the 9.3x74R cases are very hard to find and very expensive if you do find them. These cases are 2.65 inches long which is long enough to get a full 3/4 oz load. You nee a lathe to make these but it is another option and 300 Win is a lot easier to find,

I could have used 300 H&H cases but they aren't easy to find or cheap either.

Just another option for those with access to a lathe.

[Electrod47]

Bought some Prvi made 9.3x74R a couple weeks ago from Graf's. 49.00 for 50. Used Large pistol primers about 10.5 grains Lil'Gun a card on top of the powder, tried corn meal etc got the wasp waist with huge top. Went ahead and used 3/4 oz of 7.5 shot and swapped to 12.5 grains Alliant 410 powder and finally blew them out to size in my Uplander Coach side by side in 410. Trimmed them a bit then loaded up 10 each with the following.
Powder 410...12.5gr.
Claybuster (red) Wad
5 ea. 00 Buckshot
another card on top and Elmers glue to anchor.
Shot them off OK but I think they are a bit under powered, so after chrono I will probably go to 13.5 grain 410.
All and all it was a lot of work, But, Hey what are you going to these days.

[deltaenterprizes]

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.

This was my experience also!

[poorman]

in stock at bpi
https://www.ballisticproducts.com/MagTech-410-2-1_2-empty-brass-shotshells-for-reloading/productinfo/3924165/

[rockrat]

Been messing with the same thing, forming from 9.3x74r. Have some Norma brass I was trying. Problems galore (didn't want to fireform) until I glanced at the shelf and there was a set of Lee dies for the 416 rem mag. Pulled out the expander, and it was tapered, probably to form from 375 H&H brass. Tried a lubed case and it was fairly easy. Only bad thing, it wouldn't go far enough down to seat a plastic wad, so got on the lathe and made an expander to open the case up farther down the case and fit it to the seating die. Really needs to be polished up more, but works as is. Plastic wad seats with about 20 lbs pressure and loaded some over 13 gr. 296 and 3/4 oz shot with a .030" wad on top and crimped with a 375 H&H seating die. Haven't shot them yet, maybe next week when it warms up a bit.
Next is trying some 444 brass for my Marlin 410

[Barry54]

I really detest folks that form 303 Brit to 410! I need more 303BR brass!

Here is a thread I did years ago making all brass 3" 410 from 9.3x74R:

https://castboolits.gunloads.com/showthread.php?339427-Weird-way-to-cook-Cream-of-wheat-10-grains-of-Red-Dot!

444 Marlin makes great 2 1/2" 410 all brass hulls. 444 Marlin dies with the stem removed size any 410 case.

Yes, I do have Magtech brass for 410 and 12. Also 444 and 9.3x74R. I still haven't made noticeable progress since I posted this thread. Too much going on out here!

I suspect you can expand 303, 444, 9.3x62R or 9.3x74R to 410 in one firing with the right amount of slow pistol powder. Start small and increase slowly. Since I posted this thread, I have learned a 1/4 square of toilet paper wadded up on the powder and in the case mouth is an improvement to what I did. I also learned that extra wads to put the crimp where you want it can cause case head separations in only two or three loads. These all brass hulls made from rifle brass should be good for a hundred or more loadings! Enjoy and have fun!

@brassmagnet
Came into a partial box of 303 ammunition. Was looking for ways to fire form it to 410 and saw your post. I’d hate to be detested.

[cwtebay]

I guess full disclosure, I received about 20 pounds of 303 British brass. I am close to 250 pieces going to 410 so far, plan on forming it all that way. I have a set of dies I purchased at a gun show years ago that works on my Lee Progressive.

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[ascast]

I don't understand your hunting Elk from horseback with a .410? as for full mail box -check both recieved and sent -they both count.

[cwtebay]

I don't understand your hunting Elk from horseback with a .410? as for full mail box -check both recieved and sent -they both count.In weapons restricted areas you can use a shotgun. There is no restriction on hunting or firing from horseback as long as you observe the restrictions for weapon as well as other pertinent game laws.

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[Owen49]

Has anyone tried 9.3 x 72R brass? I've not had any luck finding 9.3 x 74R but found some of the 72R.

[G.O. West]

322789

Fireforming the 303 British case results in a 1/8" longer case than mechanically expanding it. A previously fired case needs to be annealed to avoid split necks. You often need to remove .005" from the case head to reduce rim thickness. If you use a home made plastic shot capsule as described in the link below, you can load any recommended weight of shot.
https://thefiringline.com/forums/showthread.php?t=607960&highlight=303+to+410

[Quinnbrian]

Can be done but 444 Marlin is much easier
Mike

Yes I've used 444 Marlin brass before,with great Results.

[cwlongshot]

Yes I've used 444 Marlin brass before,with great Results.


But know, NOT all guns will properly function with 444 cases. The rim dimentions are not as full as 303 or 9.3 cases.

[lar45]

https://www.youtube.com/watch?v=vwV0WYn52Ik
This how I fireform 30-30 to 375 Win.
It should be doable for 303 to 410 also.

My guess is you are going to load a nice heavy slug loaded in converted brass.
Get close and slip one in behind the shoulder. Should do the job.
What about using a hollow base 458-405. Then size it down to fit your brass and chamber.
The hollow base will expand to seal and maybe give better accuracy and velocity?

The hardest part is getting close. Maybe the Horse will help with that?

We need pictures of your gun and brass forming operation. :)