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Has anyone here ever fireformed 9.3 X 74R brass into 3" .410 shells? If so, specifically, did the rim thickness cause an issue with chambering in a .410? Also, how much increase in case capacity would be expected over current 3" plastic .410 hulls?

I've found a little information about this on the 'net, but not much, mostly just that it can be done.

For anyone living below 39°43′20″ N, I find the use of Cream of Wheat abhorrent for fire forming. Any self respecting resident living below 39°43′20″ N should use grits or corn meal (both dry, not wet) instead of the finely ground paste additive known as Cream of Wheat. Gil

I'm thinking I'll go to the river, park my boat, and shoot the grits over the river. I'd rather fish eat the swelled up grits than ants. I can see it now .....

I'm doing this 48 times. During this time a game warden pulls up. What are you shooting? Grits. Blank expression on GW's face. What? Yeah, shooting grits out of rifle cases to make them into shotgun cases. Silence. Is this how you bait up your carp hole? Blank expression on MY face.

One hundred and twenty years ago, a .40-85 primed empty was the answer --

The simple thing is buy a bag of cases and stick one in the gun.

Not wanting to start a squabble, but I looked at a couple of sources and both listed the dimensions of the 410 as larger than the 9.3 at every important dimension. The 410 is shown as .470 base, .535 rim. .060 rim thickness and 3 inch length. The 9.3x74R is shown as .469 base, .525 rim, .055 rim thickness and 2.94 inch length. The rifle rim is about .01 smaller than the 410 and .005 thinner. The base is .001 less. There should be no case work left except forming. I also found a quote of 82.3 grains of water for the 9.3 capacity but this is meaningless unless you know the fill point quoted. Add to that the fact that the case volume will go up a lot after forming and get a little longer to near the 3" mark.

I am making a rough guess that the 410 cas has an ID close to .410. Measuring a wad should give this number(I don't have any).

The 9.3 is .469 base and probably has around .015 walls for most of it's length. Net ID would be roughly .440. Also close to what I measured on the Magtech. 9.3 is very slightly shorter, but basewad in 410 likely cancels this out. From this, the volume difference should be right at 15% more than the 410, according to my rough calcs. If you really want to stretch it, use punched wads and an overshot wad glued in and you can really get more capacity. The overshot you will use will give you quite a boost. Given the fact that the 410 is star crimped and the brass case can be fully loaded, I suspect the difference will be closer to 25%. Or, as we say, a 28 gauge load. (Most 28 gauges weigh less than the same 410).

The big unknown is the pressure. That's a small bore and the guns run at pressures above most shotguns. Start raising shot charges by big jumps and trying to keep velocity reasonable could put you into rifle pressures.

Stan,
You would be surprised how much you can do with a drill press or even a 1/2" "drill motor" in a vise and a file until you get a lathe. A lathe is a necessity of life, even if you don't hand load. Anyway, with only .005" difference, manufacturing tolerances in the rims vs. the chamber/headspace may allow 9.3 cases to fit (cases have to be the same or smaller and the chamber has to be the same or larger than the listed standards).
Mike

Hey Stan,
In case you were curious, I measured some new Nosler brass, rim diameter .524", rim thickness .054", head diameter .464", length 2.93".

I had a similar thought as what you're thinking, but other little projects, happen. If you aren't in a rush, monitor the Nosler website, it seems they just had a sale that puts the cost of their brass, at about what you're considering with the Privi brand. I never loaded any, but I recall figuring out that a 41 mag seating die would put enough of a crimp to hold an overshot card. I was going to try filling the bullet seating cup with epoxy, so it would be more or less flat.

I may have read it wrong, but you mentioned opening up the primer pockets? Why not just use large rifle primers? Anyway, best of luck with the project.

Stan, realizing that you have a streak of McGyver/DIY, Rocky Mountain Cartridge sells minimum orders of 20 brass shells ranging in .25" increases of length, 2" to 3" from $85 to $94. They have machined primer pockets for shotgun primers. They are precision made, one at a time, to .410 specs. Gil

Stan, I wonder if a lighter, or heavier load will both keep convergence at the same speed? Is it the speed or weight of payload that causes the issue, or a combination? It might be fine with a lighter load, going fast, or a heavier load, going slower. You might have discovered slow and heavy is the same as lighter and fast. More likely they used 1/2 ounce loads to set convergence than the harder to find 3/4 ounce loads. If you would just learn how to pump one of my 42 pigeon grades convergence would not be a problem. But with doubles you do have it working, your sweet spot, stay there. Your seems to be about 1200 fps.

Yes, we both enjoy using a .410 for Dove. It is also my default Sporting Clays gun which gives me a lot more shooting chances than just Dove. For me I don’t think an extra 1/16 ounce shot will gain me more than 3-5 yards, if that. But I also am trying to stretch it out to begin with. You know I am happy using a full choked .410, out to a measured 30-33 yards for Dove. Sporting Clays you can take longer shots because there is no worry about not cleanly killing the bird. All hits, that make a chip or better are scored the same.

Knowing your exact distance is key. I’ve seen a lot of shooters, who pride themselves with their 50-60 yard shots, which measure 40 yards at most. Worse are those who measure to where the Dove is recovered, not where it was shot. The real math gets bigger the longer the shot. If I can keep leads in the 5-6’ range I can do well, stretch them out just a couple more feet and I don’t. The .410 patterns just whimpers out for hunting.

I agree this is an interesting problem. Guess first step is fire forming a bunch of shells. Be aware that if only the upper part is annealed the lower half will not fire form well. So you might end up with a bit of internal taper which will create a wad sealing issue. Might be inconsequential as the wad sealing in the taper should continue to seal as the shell and bore gets larger. It might even make all wads usable but I would stick to the larger diameter wads. You testing will tell you in that if the wads seals well, there will be little variance in speed and pressure because you have no blow-by. If you do get blow-by, a card over the powder may be needed under the wad.

Stan, you sure your farm does not need a bag of brass spacers? Let Joe pay for this. Tell him Corn Pop said so.

If I had to fire from a lot of brass I would like to have a gun built as stout as possible. Perhaps one of the .303 rifles converted to .410. Ease of loading and strong extractor, plus it was designed for a real rifle cartridge. Or even one of the Marlin bolt action .410. Don’t know if you might have extraction issues but would not like to damage my regular .410.

liverwort,
303 would work ok for 2 1/2" shells, but they are looking for 3".
Mike

My brass hulls from RMC measure .025" wall thickness. Unfired Cheddies, .035. Below are some of my fired hulls ready for tumbling in walnut hull media. There is a slight difference in diameter full length. Towards the head, the last .4" is about .0005' larger in OD because of the gun's chamber's form--a Yildiz TK36 single shot .410. I shoot a mix of plastic and brass hulls depending on whatever I grab out of my pocket. Patterning shows an increase of holes inside the 10" ring at 40 yards with the brass compared to plastic, all other things equal. Maybe just anecdotal but my barrel man has noticed in the drinking and betting turkey shoots into paper, he has noticed that a chamber length matching the open hull length of the standard shell used at shoots performs better than those overly long or shorter than the beginning of the forcing cone. He believes an exact match gives a smoother, non-disruptive transition from chamber to forcing cones. I've been using this brass for 8 wild turkey seasons. The RMC reloading kit is to the right of the shells. Top to bottom, deprimer, primer, primer seating block, deprimer block and a collar that fits over the hull for ease of powder and shot pour. I seal the shot behind an OSC Duco cemented into the hull. Gil

Thanks, Jon. Some good info there, tho' he does not mention having to thin case rims, with the rifle brass.


Yep. Sounds like a job for a Baikal. You can't hurt those things.


That is very interesting. I have wondered about that for much of my shotgunning life, but never heard an informed opinion on it. Those card shooters have forgotten more about making even, tight patterns than most of us will ever know.

Preach on brother, while I tap my foot.

Was blessed yesterday to receive a box of fired 9.3 X 74R brass in the mail, from a generous member here. Lo, and behold, they chambered in two of my .410 doubles! All the concern about thinning the rims were for naught. Onward we go. Next step, fireforming. I assume I should I use an OS card between the powder and grits?

I suggest annealing the cases first.

A small wad of crumpled toilet paper should suffice between the powder and the grits.

What Parabola said, plus another 1/4 sheet of TP on top of the grits, so you don't have to sweep them up.
Mike

In fire forming I used a top layer of wax. It comes in sheets that are about 2mm thick. Just press the loaded shell into the wax and the case cut a perfect plug. It only needs to keep the contents in place.

https://www.grafs.com/retail/catalog/product/productId/76364

https://castboolits.gunloads.com/sh...sh-to-410-shotshell/page3&highlight=

Stan,
If there is an American Legion, DAV, VFW, Marine Corps League, etc in your area, one or more of these could organize special assisted disabled veterans hunts or special youth hunts, for Deer during the season or Hogs during the off season. This would help you with your problem and since these organizations are usually classified as 501.c.3 or similar, any cost to you, including the fair market value of the use of your land could be accounted for on your taxes. They can insure appropriate assistance for the disabled veteran hunters and parental supervision for the youth hunters. They can also prepare "hold harmless agreements" agreeable to your insurance company to protect your and their interest. If desired, you, the organization, an outside agency or individual could advertise processing services or provide concessions, such as breakfast and/or lunch items as well as portable toilets and waste removal services. If you do or allow something like this I suspect you would receive positive "feedback" from the community.
Mike