Sizing down to 410 musket

KotKotofeich

KotKotofeich

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I have a shotgun cane that's simply labelled 410. By the obvious length of the loading guide it needs 2" shells. But 410 cut down to 2" still would not chamber. Thinking it may be in 410 musket I sized the 410 hulls down to 303 by running them first through a 450bushmaster die (barely any sizing though there was some resistance) then through a 303brittish - significant size down, hull is sized off center... The hull would then chamber.

Can someone suggest some interim dies to use to avoid the off center skew on the hull? Something in between 450 and 303?
 
You could make up some 303 British blanks and fireform them as said above, although I'm not sure how strong the action is. May want to keep it to something like 5gr titegroup and fill the rest with cornmeal.

or you could just take 303 British cases, trim the to 51mm and expand them to 410. Then run brass cases. The base will also be the correct size using 303 British cases.

Its not hard to expand cases and keep them on center. I bump 300 weather by mag brass to .446" when making 43 express brass

I use one of these and just whip up any size I need as I go on the lathe. I've also been lazy and turned some town while trying to be quick

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Ganderite said:
Fire form?
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Fire form the 410 hulls after they are lopsidedly sized down? Will that fix the off-center shape?

Evanguy said:
You could make up some 303 British blanks and fireform them as said above, although I'm not sure how strong the action is. May want to keep it to something like 5gr titegroup and fill the rest with cornmeal.

or you could just take 303 British cases, trim the to 51mm and expand them to 410. Then run brass cases. The base will also be the correct size using 303 British cases.
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Was hoping not to wreck 303 cases :) But, yes that's an option I suppose. Would much rather use 410 hulls - plentiful.
 
Fair enough, and to the first point yes, they are likely to straighten out and be more so on center after firing, if they are way off center try making up blanks. It doesn't take much to move the plastic around
 
I've used the Lee factory carbide crimp die (44mag & 45acp) with the innards removed. It becomes a straight wall carbide sizer similar to any other but with nothing above the sizing ring and so will allow any length of brass to go through.

I've also used a 30'06 sizer to taper the last inch+ of brass cases that didn't want to seat fully in tight (euro) chambers.
 
450 bushmaster 12.70 mm

45 acp 12mm

303br 11.68

44mag 11.6

So while 44 is overkill, 45acp may be a good one to use in the middle. Thanks, I thought it was the same as 450.

Just checked and 45 win mag is 12.1mm so can also use that... Exactly what I was looking for to make the sizing in smaller stages.
 
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FWIW, I fireformed some PPU 303 brass donated by potashminer. No splits, worked like a charm. I use them in an original Ishapore conversion "410" musket. I also have one of these conversions with a rechambered barrel to accept regular 410 ammo.
 
fred0000 said:
Why not start with cut 303 britt cases instead

Edit: I see it's been suggested, how about 45lc cases
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45lc is too short
kjohn said:
FWIW, I fireformed some PPU 303 brass donated by potashminer. No splits, worked like a charm. I use them in an original Ishapore conversion "410" musket. I also have one of these conversions with a rechambered barrel to accept regular 410 ammo.
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yes, 303 is the alternative, after all that's what was used to make 410 musket in the first place. Will do that if I can't make the 410 hulls work.
 
Have an 444 Marlin brass? These are almost exactly right for a 410, the rim may need to be thinned but they may fit as is. They are 2.25in, can easily be trimmed down to 2in.

Would be cheaper to fire form 303 Brit brass though, the single shot Lee Enfield 410s were originally just straight wall 303 Brit cases loaded with shot.
 
For anyone following this, I've run into a problem with the primers being too hard (added) on my 410 hulls ... Granted I only had magnum primers available... Are there shotgun primers that are soft like, say, pistol primers?

Meanwhile I attempted using a 303 case cut to 2 inches today ... and found that even regular LR primers do not ignite. I used LP primers and they worked fine... That's why I'm asking about shotgun primers equivalent to LP...

Frankly this is getting annoying so I'm considering running a 410 reamer through it. Will probably start with 2" at first and see how cut down shells work before I ream to a full 2.5"

Thoughts?
 
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