I am fireforming 303 British into 410 shotgun. I usually use 10 grains of Unique which works well. I have run out of Unique but I have a pound of Winchester 540 and my Powder Burn Rate chart shows that 540 is a bit slower but fairly close to Unique. My question is: Would the Winchester 540 be a reasonable choice to finish up fireforming these 303 British cases?
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Question about powder for fireforming
- Thread starter G.O. West
- Start date
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I would think so, but I don't know the method you are using, so I don't know if you are shooting a bullet or a pile of Cream of Wheat or what, exactly. I can tell you that with a 150-grain bullet, QuickLOAD thinks you would need about 12 grains of the 540 to match the peak pressure of 10 grains of Unique. The spherical will be a little less ignition-friendly, so you want something that keeps it back over the flash hole.
I would think so, but I don't know the method you are using, so I don't know if you are shooting a bullet or a pile of Cream of Wheat or what, exactly. I can tell you that with a 150-grain bullet, QuickLOAD thinks you would need about 12 grains of the 540 to match the peak pressure of 10 grains of Unique. The spherical will be a little less ignition-friendly, so you want something that keeps it back over the flash hole.
FrankenMauser
New member
It will probably get the job done, but this is one of those things where I buy the proper brass.
Magtech .410 brass hulls are in stock several places right now.
You'll have more capacity, a more appropriate primer, proper dimensions, better wad fit, less CoW on the bench, and more time to shoot instead of fire-forming a case that is really only considered suitable by people because the base diameter is "close".
(I don't consider an intentional extra ten-thou clearance to be "close" in a firearm chamber. Nor do I care for the oversized rim on .303 B. It causes issues in some shotguns.)
I use the Magtech brass cases for .410, as well as cutting them to 1.75" for a sloppy .44 Shot (.44 XL) chamber.
Don't forget a shell holder if you want to use a press or priming tool for priming/decapping. I believe RCBS #35 is the usual recommendation, and #43 is often suggested if playing with plastic hulls.
I do have both shell holders, but don't use them. I decap and reprime with punches.
Magtech .410 brass hulls are in stock several places right now.
You'll have more capacity, a more appropriate primer, proper dimensions, better wad fit, less CoW on the bench, and more time to shoot instead of fire-forming a case that is really only considered suitable by people because the base diameter is "close".
(I don't consider an intentional extra ten-thou clearance to be "close" in a firearm chamber. Nor do I care for the oversized rim on .303 B. It causes issues in some shotguns.)
I use the Magtech brass cases for .410, as well as cutting them to 1.75" for a sloppy .44 Shot (.44 XL) chamber.
Don't forget a shell holder if you want to use a press or priming tool for priming/decapping. I believe RCBS #35 is the usual recommendation, and #43 is often suggested if playing with plastic hulls.
I do have both shell holders, but don't use them. I decap and reprime with punches.
FrankenMauser, you are right, but... some guys enjoy fabricating ammo just about as much as they do shooting it. Where I live we don't shoot much in the winter, but I'll load up 500 of these brass 410's to shoot this summer.
Where I live Magtech brass costs $2.40 (Canadian) each, plus shipping. That equals $1200.00 for 500. I could buy another shotgun for that. As for 303 Brit. cases, I have already accumulated 750 from the range that didn't cost me a cent. When I lock the carriage and use the cross feed on my lathe it takes 15 seconds per case to turn the 303 rim to the proper thickness. After fireforming I use a special expander plug to increase the bottom half of the case to the proper dia. The result is SAAMI 410 specs except for the solid web base, which does not matter. (Except for the web, there is no extra ten-thou clearance for the full body of the case.) This case is strong, and thicker closer to the head than the Magtech.
Because of my home made polyethylene (HDPE) shot capsules, case capacity is more than adequate even for the largest recommended loads of shot. These modified 303 cases easily accept large pistol primers just the same as Magtech brass does. My cardboard overpower wads work just fine and cost nothing. I am happy with the 1150 ft/sec I get, plus excellent patterns that consistently nail clay pigeons at 35 yards. After 150 firings, there is zero lead fouling because the shot does not touch the bore.
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Ecc 11:4 He that observeth the wind shall not sow; and he that regardeth the clouds shall not reap.
Where I live Magtech brass costs $2.40 (Canadian) each, plus shipping. That equals $1200.00 for 500. I could buy another shotgun for that. As for 303 Brit. cases, I have already accumulated 750 from the range that didn't cost me a cent. When I lock the carriage and use the cross feed on my lathe it takes 15 seconds per case to turn the 303 rim to the proper thickness. After fireforming I use a special expander plug to increase the bottom half of the case to the proper dia. The result is SAAMI 410 specs except for the solid web base, which does not matter. (Except for the web, there is no extra ten-thou clearance for the full body of the case.) This case is strong, and thicker closer to the head than the Magtech.
Because of my home made polyethylene (HDPE) shot capsules, case capacity is more than adequate even for the largest recommended loads of shot. These modified 303 cases easily accept large pistol primers just the same as Magtech brass does. My cardboard overpower wads work just fine and cost nothing. I am happy with the 1150 ft/sec I get, plus excellent patterns that consistently nail clay pigeons at 35 yards. After 150 firings, there is zero lead fouling because the shot does not touch the bore.
------------------------------------
Ecc 11:4 He that observeth the wind shall not sow; and he that regardeth the clouds shall not reap.
jetinteriorguy
New member
Ingenious.FrankenMauser, you are right, but... some guys enjoy fabricating ammo just about as much as they do shooting it. Where I live we don't shoot much in the winter, but I'll load up 500 of these brass 410's to shoot this summer.
Where I live Magtech brass costs $2.40 (Canadian) each, plus shipping. That equals $1200.00 for 500. I could buy another shotgun for that. As for 303 Brit. cases, I have already accumulated 750 from the range that didn't cost me a cent. When I lock the carriage and use the cross feed on my lathe it takes 15 seconds per case to turn the 303 rim to the proper thickness. After fireforming I use a special expander plug to increase the bottom half of the case to the proper dia. The result is SAAMI 410 specs except for the solid web base, which does not matter. (Except for the web, there is no extra ten-thou clearance for the full body of the case.) This case is strong, and thicker closer to the head than the Magtech.
Because of my home made polyethylene (HDPE) shot capsules, case capacity is more than adequate even for the largest recommended loads of shot. These modified 303 cases easily accept large pistol primers just the same as Magtech brass does. My cardboard overpower wads work just fine and cost nothing. I am happy with the 1150 ft/sec I get, plus excellent patterns that consistently nail clay pigeons at 35 yards. After 150 firings, there is zero lead fouling because the shot does not touch the bore.
------------------------------------
Ecc 11:4 He that observeth the wind shall not sow; and he that regardeth the clouds shall not reap.
QuickLOAD thinks you would need about 12 grains of the 540 to match the peak pressure of 10 grains of Unique.
QuickLOAD is correct on this one. The fireformed results with 540 are identical to what I was getting before with Unique powder. Thank you Unclenick for that information.
45 basic is the wrong size . Expanding the .223 case to straight wall is how I first made the .357 Bandit round , which became the 350 Legend . My line of straight wall Bandit cartridges started about 30 years ago and are all made from bottle neck cases . .357 - .500 . So it is no unheard of .