This Site





Slugs & Buckshot


This message boar is now closed.

Goto ......
  • We can't provide valuations.
  • You are entirely responsible for the legality of Guns/Ammo mentioned in these pages within your locality
    (e.g. in the UK, Slug and Ball (Buckshot) loaded ammo is classed as 'Section 1' (Firearm) ammo and shotgun barrels must exceed 24").
  • This site has NO responsibility for any reloading data submitted by contributors. Reloading is YOUR responsibility
  • For 'Wants' and 'Sales', Please indicate which part of the world you are in (Country,State,County maybe).
  • Old Ads and requests will be removed after a period of time when this page gets too big, though useful or interesting info will be retained.
    If we delete an ad. and you want it retained, please send it again

The .410 for Self Defence by Marshall Williams

The June issue of Guns Magazine lists a buckshot load in an article by C. Rodney James.
In a 3" hull (Remington by the looks of it) he loaded 6 #OO buckshot in a plastic shot cup (wad) over 16 gr. of Alliant 2400. He says the load is from the NRA Reloaders handbook and is intended for 3/4 oz of shot. No mention is made of which primer or shot cup.

I'm playing with Speer .38 HBWC's run through a swage die with a homemade punch to make a very deep hollow base. Some success- I'm on my third base punch and just bought another 23/64" drill bit ( they're cheap, available and they fit the die perfectly) to grind down. If I get the bugs worked out I'll send it to "info".

For what its worth, I've been using standard loads of H110 (IMR4227 wasn't burning cleanly) intended for 1/2 oz of shot. They're likely a little warm but SEEM safe in my gun. I can't recommend them because I haven't had them pressure tested.

Dear 4-10's men,

I am still looking for in all over the Internet and I can't find yet a reloading company to produce a .410 slug mold (Lyman, Lee, RCBS, Saeco etc.).
Can I reload round balls .396(10,06mm.) in .410 shotshells instead of .410 slug?
I think this choice is better than nothing.I'm waiting for your opinion.
Thanks!!! Kostas Tzoutzos.

No! .395 balls are too tight Try .375 ball, loaded over 12 gr. of 2400, and enough card wads for wad column height.....roll crimp....and try...you are at your own risk for trying any unpublished load, or exceeding this level of powder....every gun can be different, but this one has worked in many styles of 410s that I own.....write me back D. Scott.

Dear Sir or Madam, I would like to ask you where I can find a .410 slug casting tool. (There are some companies that have casting tools for gauge 12 but none for .410).
Please, would you sent me any information on this issue?
Yours faithfully, Kostas Tzoutzos.

Several years ago I bought two little flat five round boxes of 000 or "triple ought" .410 buckshot shells manufactured by Winchester. I have never seen these shells listed in Winchester’s catalog, although I may have missed it.

The cases are typical red one-piece plastic Winchester AA-type, the head stamp is the typical "WW" on one side on the head and "410" on the opposite side. Each case is prominently marked around it periphery "Winchester" over "000 BUCK." The shells are roll crimped without an over-shot wad, so the foremost buckshot is exposed.  I did not disassemble the shells to see what was inside.

The boxes are plain white with black lettering and bear no big red "W" logo. The only mention of Winchester is on the back side at the bottom where it says, "Ammunition Manufactured by Winchester." The front carries the information that the shells "Will fire in any .410 GA. [sic] shotgun chambered for 2 in. Or 3 in. 410 ga [sic] shotgun shells. It will also fire in pistols chambered for .45 Colt/.410 GA."

These shells were intended to be used in modern copies of the Remington over and under derringer in caliber .45 Colt. One of my cohorts bought one of the big derringers and similar buckshot shells for self-defense and was quite proud of his armament.

I have no derringer but I fired two of them from my Remington 870 Skeet gun with its 25 inch barrel over my chronograph. The chrono read out said 1272 feet per second for one shell and 1252 for the other at a range of 15 feet. The first pellet to cross the light sensor trips the eye, so the velocity is only for that pellet, not an average for all three. However, since the first pellet was pushed to prominence by the other two, I am sure they were not far behind.

Assuming the 000 buck are .360 diameter and weigh 70 grains each, that first pellet had 247 ft lbs of energy, comparable to a .38 special revolver bullet. With two more close behind, the total energy at five yards is nearly 740 foot pounds. The two-shot 25 yard pattern showed five holes in about five inches and a sixth hole a couple of inches away. Thus, out of a long barrel, each shell would have about as much effect as three .38 special pistol bullets.

I live in West Virginia where buckshot may not be used for deer hunting (.410 slugs may be used). Nevertheless, any deer which caught this load in its vitals should be venison.  For the cannibals out there, any man who caught this load in his vitals also would be meat.

Velocity from the 3 inch barrel of one of the big derringers would be substantially lower, but I have no information on what it might be.

Marshall Williams

I don't know if this would be opening a can of worms or not, given the present lamentable firearm situation in the U.K., so I won't go into a great deal of detail...
It is possible to substitute 4 .375 (3/8ths inch) roundballs, or three .395 cast roundballs from a LEE mold for the normal 11/16ths ounce shot charge. Weight of 3 of the larger balls, (that will just roll thru the chokes of the guns we have tried), weigh within a few grains of the 11/16ths oz. shot charge, with variation due to alloy. (Pure lead is heavier at aprox. 92 gr. per ball. Wheelweight lead casts a harder less easily deformed ball a few grains lighter. Being that "slugs" weigh from 90gr. for the Amer. "Foster-type", to 114gr. for the fine Brennekes, you have three times the mass, albeit at aprox. 1,100 fps rather than 1,700 to 1,800 fps (advertised vel.(?))
Most of the guns tried with these loads pattern "usably" at 20 to 25 yds. The lighter factory slug loads will shed vel. fast, and realistically, are not useable at longer ranges than this except on small game, where almost no .gun will shoot them with sufficient accurascy anyway....
Around where I live in the inland Pacific N.W. USA 30 miles from the Canadian border, we have had blackbear and cougar in our yard, and it is nice, if you are carrying a tiny-bored scatter-piece, to be able to have the means at hand to deal with something larger than a grouse.
I have been working on a Rossi .44 mag. rifle, slimming the stocks and making a poacher-stock cut-out in the buttstock so as to get it to balance well despite the shortened barrel, as well as fitting a .410 barrel to it. (Hopefully with screw-in choke tubes, if I can get the tooling.) This will compare favorably with a decent quality Rook rifle when done. The Rossi's are a good value. Some two barrel sets in .22LR/.410 can be had on sale for $99 U.S. The small-frame ones are much nicer to handle and wrap your hand around than the NEF that has a universally large frame, that I will not buy another NEF. (The large frame is kind of like installing a Ford COurier engine in a 50 cwt truck chassis. Over-heavy and unwieldy.)
Dave Orchard

An 11/16ths oz. factory load pulled and weighed on a Dillon elctronic scale weighs 302.3 gr.

A .395 roundball of pure lead is 92gr.(Say 90gr. for wheel weight alloy...) 3x90gr.+270 gr. combined weight for three .395 cast balls. A .22Short bullet weighs 29 gr., so the three .395's plus a .22Short bullet would weigh just shy of 11/16ths oz., so three .395's are well UNDER 11/16ths. oz. weight.

A felt "wonder-wad" between the 1st and 2nd balls into the case may cushion the two most likely to be deformed a bit and cause "flyers". (The above are just thoughts on a subj. that intrigues me and a few others and I don't have press. results from H.P.White Labratory or anything like that, so you are on your own...

And remember, "funny" things can happen between the time you drop the hammer and your charge exits the barrel!)
Dave Orchard

If any of you would like to make .395 dia. round lead "fishing sinkers" of wheel weights, I reccommend the LEE mold in this dia. If you cannot get LEE products in the UK, I will try to ship you one for "cost +". (My cost is aprox. $10 U.S.) Kind of a "hands across the water" thing, to make your "piscatorial pursuits" more versitile. E-mail me off page and we can figure out how to give it a try if you cannot get the right tool over there. Dave Orchard

THINGS NOT TO TRY .. Amongst them is "waxing a load" by pouring molten wax into your shot chage after opening the crimp.
You hear the ignorant/unimaginative say "It works just as well a a slug load and is cheaper."
What will happen is that you very well may deaden your powder charge, and you WILL create a solid mass that will want to swage your choke from the inside of your bore onto the outside of it, possibly deforming the muzzles and breaking the solder joint of your nice SxS's barrels and rib, and turning your nice tight choke into at best a malformed "skeet 1" or cyl. bore.
Your pressure is bound to go up as well, as you have added the weight of the wax poured into the shot charge, as well as creating a bore obstruction.
Dave O.

.... About the buckshot. If you mean opening the crimp and replacing the factory shot with buckshot- NO. If you mean reloading fired hulls- maybe. I've seen loads on the net and, if you like, I'll try to find them for you. These would be loads developed by someone like you and me. No pressure tests and no powder company sanction. You would be on your own as far as safety. I haven't tried them.
If you just need a few, .410 buckshot is on the market. I don't think they're defense loads for bear though.

Take care, Bob

Anyone interested in the .410 as HOME PROTECTION WEAPON or LIGHT COMBAT SHOTGUN ? I've collecting many different shells in the USA , would be interested in hearing about your related shotgun and ammunition.




    BRENNEKE 3"(2 7/8")- 1/4 OZ BRENNEKE SLUG

*SELLIER&BELLOT AND REXIO- www.cheaperthandirt.com
*ALL OTHERS- www.ammobank.com


See the article on the .410 for Self Defence by Marshall Williams.


Click here for Dougs .410 Slugs Forum

June 2007 Update:-
Doug may not be in major Slug production these days, please contact him to confirm...

Check out MCB's Excellent 410 slug information here


June 2007.

18 Sept 2003

I have been engaged in exporting firearms for many years, with most shipments to Japan. A few years ago I received a request to quote a single shot .410 slug gun to a customer in Japan. After some effort, I quoted a Thompson-Center Contender carbine with a rifled stainless steel (blued) barrel with rifle sights, drilled and tapped for a scope. The barrel length was dictated by legal minimum overall length at about 23 inches. No such barrel exists, so I proceeded to have one built.

When it came time to rifle the barrel I asked the customer what slug he planned to use. The answer was that he did not know - what would I suggest? I suggested the usual factory loads, but the customer wanted something better and asked if I could find brass cartridge cases and slugs for reloading. I soon discovered that such things did not exist, so I set about designing my own. My design for a case was a semi-rimmed brass case with a large rifle primer (shotgun primers are rare in Japan). The outside shape was based upon a .410 chamber reamer from Clymer and the inside was cylindrical and sized to fit a normal .410 shot cup wad. I had both 3 inch and 2.5 inch cases made.

For the slug I designed a round nosed, waisted slug with a hollow base to fit into a normal .410 shot cup wad and had a mold made to my drawings. My target was 1/2 ounce, but the result was about 240 grains when finally cast, depending upon the alloy.

Using an old NEF single shot .410 shotgun with the choke cut off, I tested the concept using shot loads and shot a few slugs for effect. Using published .410 reloading recipes for a start, I found that over 1600 fps resulted in extensive damage to the shot cup. The slugs were unstable in the smoothbore, but I understand that performance in the rifled barrel is fine. A great deal more work could be done with this cartridge, but you can see that the 240 grain slug at 1600 fps is quite powerful for a .410.

I also made some 28 gauge slug guns, and they are easier because .54 caliber black powder sabot slugs are a readily available perfect fit. The 28 gauge brass cartridge cases were made much like the .410 cases and seem to work well. I never actually tested the 28 gauge slug loads, but they promise to be a really powerful load.
Jerry Crossett

14 July 2003

I was wondering why the 410 cartridge is loaded with say 1/2 ounce of pellets but if loaded with a slug the slug weight is only 1/5th ounce? Is it because of the hollow point or are the wads/shot cups so different.
Anyone know? Mike L

This responds to your inquiry on the 4-10 site in which you ask why the common 1/5 oz, 87.5 grain, .410 slug is so much lighter than the lightest common shot charge which is 1/2 oz. or 218 grains.
I have no first hand information, but I believe it is a carryover from when shotgun shells were loaded with round balls instead of the hollow base Foster-style slugs now common. These often were called "punkin' balls" (pumpkin balls) in the US. I start by pointing out that if you look at the other gauges, the same thing is true, slugs weigh less than shot charges, although it is not nearly as pronounced. For example, the traditional 20 gauge slugs weigh 5/8 oz while shot loads range upwards from 7/8 oz. and tradditional 12 gauge slugs weigh 7/8 oz. although the common shot loads start at 1 oz. and 1 1/8 oz.
The wisdom of the punkin ball era was that a ball had to be smaller than the smallest choke it might have to pass through. A 12 gauge gun has a bore diameter of approximately .729 inches, and the tightest common choke, full choke constricts that down to .689 inches. However, some guns are noticeably smaller than the standard, notably guns made in Italy and Germany. Therefore the round ball had to be smaller even than .689 inches in diameter to avoid the danger of bulging the barrel or otherwise damaging the choke in a gun.
I have a 1940-era list of the size of punkin balls sold commercially for reloading. According to that list, the 12 gauge ball should be .640 inches in diameter which corresponds to the 7/8 oz. weight of a 12 gauge shollow base slug. A round ball weighing 1/5 oz. or 87.5 grains would have a diameter of .387 inches, about right to pass through a full choke .410. As noted, I have no first hand information. I believe the real answer to your question probably has been lost in the mists of time, but this theory fits the facts well enough. M. Williams.

11 July 2003

I recently wrote to Lee (www.leeprecision.com) (they are famous for dies, reloading tools) I asked them if they would be able to make a .410 slug mould. The response was yes! Now, they are already producing some pistol bullets that are great shapes, look at their site. I think that their wadcutter design would be great! One would only need to order a die that was hollow based, and .375 diameter or so. They can do this for around $175.00 US funds. There moulds are really good, I own 8 of them, as I load for many things. I have, unfortunately, already ordered a swager for my slugs from CH DIES. It has been several months wait, but I await the dies, and they are about the same costs. Since most of my slugs from Liberty (see mention) have a harder alloy, a casting mould would open the possibilty of using many more alloys than a swager set-up could use.This would be a good source for outside US "4-tenners" to consider. Lee has been extraodinary in service to me. Doug

27 May 2003

I wanted to comment on the 410 slugs available from Liberty shooting supplies. These are top quality, perfect slugs. I have ordered, and shot them.These people are very friendly, and are eager to serve you. The slug is best loaded over cardwads, and I have had the best luck with winchester AA, and remington hulls (2 1/2"). There is no reason to try and load a 3" hull. The power and accuracy in a 2 1/2" is good enough. The real trick out there is to find a roll crimper for a .410....There are none that I can find except the UK option. I have written to them on numerous times, and have had no response. Perhaps they don't know that most of us here in the US want to know cost in US dollars, and if it can be FEDEX"d to us. I had a real nice friend that is a machinist make me one. I am really amazed at how I can duplicate a factory round...I also wanted to comment that the Liberty slug is a lot larger than a factory slug (length and weight). This is nice for the factory slug has always been somewhat whimpy. I am going to order some new hulls from ballistic products to see what they do (roll crimp, accuracy) when they have never been fired. The absolute best place for 410 info is certainly this Website! (Thanks.)
I also welcome any 410 correspondence to my e-mail <removed> I have a load worked up for the slug, but it has not been scientifically tested...Doug in Washington State / USA
(Also see letter below re Liberty slugs)

9 Aug 2002

Dear 4-10's men,

I am still looking for in all over the Internet and I can't find yet a reloading company to produce a .410 slug mold(Lyman, Lee, RCBS, Saeco etc.).
Can I reload round balls .396(10,06mm.) in .410 shotshells instead of .410 slug?
I think this choice is better than nothing.I'm waiting for your opinion.
Thanks!!! Kostas Tzoutzos

Dear Sir or Madam, I would like to ask you where I can find a .410 slug casting tool. (There are some companies that have casting tools for gauge 12 but none for .410).
Please, would you sent me any information on this issue?
Yours faithfully, Kostas Tzoutzos.

I am trying to locate moulds or swaging equipment for the 410 rifle slug. Is there a source where I may purchase the slugs and reload myself. Thanks Tom

Checkout Corbin Mfg. & Supply, Inc on our suppliers page for swages.

We would be very grateful for information on moulds (molds) for .410 slugs, thanks

Over here in Northern Ireland it is very hard to come by rifles for fox hunting. There now appears to be an upsurge in the use of .410 with solid slugs for fox hunting.
I have seen pump action .410 fitted with telescopic sight and was told it was very effective. Could any one let me know any details on fitting sights to .410 or have they ever used them for foxing.

I've put scopes or had scopes installed on a few.  The Win 9410 is drilled and tapped so that was easy.  On an older Winchester 94 in .30-30 I just
used a heavy piece of aluminum angle to make a mount for testing handloads.  It attaches the same way a shotgun side mount base does and I tapped the top for a scope base with a flat bottom.  It looks bad but it worked and didn't require the gun to be drilled.

For a Mossberg 500 pump I redrilled a cheap Tasco side mount intended for the 12 gauge model.  This put the centerline of the scope to the right of the bore centerline.  I'm left handed so this wasn't a problem for me.  The good thing is that the mount is high enough to use the normal bead.  I
haven't tried "see through" type mounts intended for rifles on a shotgun so I can't say if they're convenient or not.

A neighbor cut the choke from an old house brand single barrel.  I took the barrel to a gun shop and tried different bases until found one that closely matched the radius of the barrel.  I sent the barrel out to have it drilled, tapped and the muzzle crowned.  By the way, the mount worked fine but the gun didn't shoot well.  Some .410's will shoot 2" cloverleafs and 50 yards and a few only give 8"-12" "patterns".  I have found that the .410 foster type slugs tend to lose stability beyond 50 yards.  If you get a gun with a tight choke- try it before you have it removed.  Some .410's shoot slugs just fine with full chokes.

Later I found a web site that lists Williams sight bases numbers and the diameter of the barrels/ receivers they were made to fit.  Its at www.members.tripod.com/PFBT.html   Its toward the bottom of the page under various home gunsmithing information.   You can measure the diameter or radius of your gun's receiver, get a base to match and have it drilled and
tapped.  If Williams bases are not available there are retailers that list rifles and which base number fits.  Another manufacturer's base for the
same rifle should have the same radius.  If you have trouble with the list, I have a MS Word file with just the scope base information I can send you as an attachment.  I formatted it for faster lookup.  I've given it the several people and there have been no reported errors...but...

Low power scopes work fine for the ranges involved.  If you can get used to a Red Dot type scope, they are very fast in use.  I have also seen mounts that clamp or screw on to barrel's rib but haven't used one.

Take care,

Dear Sean, I think you will have the best luck with Brenneke slugs in your .410.
Also, the range of slugs is short, so consider iron sights. If you do mount a scope, do not go over 2 1/2x. 1 1/2x would probably be better.
The Rossi single shot has too high a comb on the stock, but is just about perfect with a scope mounted. You might try loading three .395 roundballs. These will sometimes go into 2" at 20 yds., and may have good results much further away. (If you need a mold to make these and cannot get one locally, I will send you one. They are quite reasonably priced from LEE.)
Don't you love this 4-10/uk site?
I most always feel like I am at an AA meeting. ("My name is Dave, and-and-and I shoot a .410!" (big chorus) "Hello Dave, we shoot .410's too!")


In "Complete Reloading Guide" by John E. and Robert J. Traister, (published by Stoeger, 1996) there is a.410 slug load that uses a 238 grain Lyman slug. (Possibly a missprint see *)
The data shows velocities up to 1565 fps. While the primer is no longer made they, and the hull, can still be found.
My problem is that the mold number is not given. I've tried both Lyman and Stoeger for more information with no success. Does anyone know what "slug" was used?
The rest of the data seems to have been supplied by others, so it is likely it was published elsewhere. "Cartridges of the World" 3rd edition (1972) lists the primer as still in production, so the load would have been from around that time.
Thanks Bob

The data for the 238 grain .410 slug originated with Lyman, the gunsight and bullet mould company. It appears in my Lyman’s Reloading Handbook, 44th. edition, copyright 1967, however, I think the data was developed some years before, probably mid-50s, and merely reprinted in later handbooks.

The slug was cast in Lyman’s .410 slug mould which has been obsolete since about 1968, if not before. Although Lyman's Handbook lists its mold numbers for all rifle and pistol designs for which they gave data, no mould number are listed for any of the shotgun slug molds. I used many Lyman molds for casting pistol bullets and was generally familiar with their catalog and services in the 60s, however, I do not recall that Lyman used mold numbers for shotgun slug moulds.

At one time, Lyman made both slug moulds and dies to swage the rifling grooves on them in 12, 16, 20 gauges and .410 bore. However, tests conducted by the staff of The American Rifleman magazine showed that the swaging rifling grooves on the soft lead hollo base slugs did little to improve accuracy and the dies were discontinued.

The .410 slug mould was never popular and I imagine that it would be extremely difficult to find a used one.
Please note that the Lyman data called for pure lead for all slugs except the .410, but recommended Lyman #2 alloy for the .410. Lyman #2 alloy consists of 90% lead, 5% tin, and 5% antimony. Its hardness approaches that of linotype. Based on other reading, I suspect this was related to a problem specific to the .410.

Marshall Williams, ALOOF

I looked again at the question related to the heavy .410 slug load, and a couple of bits of trivia popped into my mind.
One would need to have been reloading since about 1965 to know what a Remington 69 primer is. Until sometime in the early to mid-60s, Remington and Remington-owned subsidiary Peters shotgun shells used a shotgun primer that was smaller in diameter than the Winchester standard 209. Remington designated the smaller primer 57. The 209 proved more popular with reloaders because both Winchester-Western shell and Federal shells used it, and during the mid-60s, Remington phased out the 57 size in favor of the standard 209 size. However, Remington designated this size the 97. These primers were used only in R-P paper and "S-P" (steel-plastic) cases with fiber or composition base wads. The SP case used in the heavy slug load is of this type.

Although the size 57 and 69 primers had disappeared from other cases by about 1970, I believe the last shells to use the smaller size were Remington 10 gauge magnum shells made with SP cases into the early 1980s and using a combination of fiber base wad covered with a black plastic disk. R-P 10 gauge magnums with a one-piece yellow base wad use the standard size primer. It is possible to resize the 57 primer pocket to take a 209 primer by first forcing a fired 209 primer into it, depriming the fired primer and then loading a standard size primer.

The 69 primer is a specialty version of the 57. The significant difference between the two sizes was the length of the battery cup. The 69 used a battery cup that was noticeably shorter than the battery cup used on the 57. The 69 primer was used is applications where one needed to make the most of the space available inside the shell. The shorter version allowed about 2 grains weight of additional powder. The most common use of the 69 was in the .410 and 28 as they had the least space, but it also could be found in the 12 gauge magnum and 10 gauge magnum shells in the heaviest loads.

Occasionally Remington primer may be seen with an asterisk after the number, 57* or 97*. I no longer recall the significance of the star.

One final thing about the heavy .410 slug load, a 238 grain slug at 1565 fps would develop 1294 ft. lbs of energy at the muzzle.

Marshall Williams

*To Liberty Shooting Supplies

I note from www.4-10.co.uk that you offer a .410 slug and I am hoping you can clear up a mystery for me. Some info on the 4-10 website says your mold is a Lyman and your website says that your slug weighs 140 grains cast of pure lead and is .372 in diameter.

The mystery concerns Lyman data for their .410 slug. Starting in the mid-60s, I cast many thousands of bullets from a variety of Lyman moulds, and I well remember the larger 12 gauge and 20 gauge moulds, but I have never seen a Lyman mould for a .410 slug. I know they exist because my old Lyman Reloading Handbook, copyright 1967, contains data for reloading them.
However, their data say the slug weighs 238 grains.

If yours is the original mould and your slugs weigh just 140 grains cast of pure lead, then almost certainly 238 was a typo about fifty years ago which, through reprinting in many subsequent manuals without any fact checking, has become part of shooting folklore.

One other matter, Although my old Lyman Handbook contains mould numbers for all rifle and handgun bullets, it shows no numbers for shotgun slug moulds, only gauge.

So I have two questions:
1. Is your slug cast in the old original Lyman .410 slug mould?
2. Is there a Lyman number or any other identifying markings on the mould blocks?

Marshall Williams,

You may very well have found one of the few errors in the catalogs over the years. this is one that customers bring up from time to time. Just for comparison purposes, in that weight range of 238grs.. 45 maxi ball is 245gr.; .530" RB is 210gr.
Our mold is an original obsolete Lyman marked 410 Ga. it was a special find, not too many made. As you may know from your research, this bullet/mold is scarce. To answer your other question, the only other identifying marks on the mold are 146, which identify the 2 halfs. Thank you for your interest in our product, Patrick & Victoria
Liberty Shooting Supplies

Liberty Shooting supplies .410 slugs page

Does anyone have a clue what kind of trajectory you can get from a 410 slug from 3" shell? Dave Chandler in North Carolina

Ballistic products Inc. ( www.ballisticproducts.com) sells a "light game slug". It uses a .36 cal (.375") muzzle loading pistol ball carried in a wad that looks like the Gualandi ( www.gualandi.it/eng/pallae.htm) wad and slug.
The data they supply uses US powders and is anemic by any standards. The powders on the list also require a card wad that was not included with my order. The price is $3.99 for 25. I wasn't too happy with them.
The other is a company called Liberty Shooting Supplies at Patrick & Victoria Gilbert: PO Box 357: Hillsboro OR 97123-0357.
They have a web site but I can't seem to find it ( its here (editor) www.libertyshootingsupplies.com) . A www.dogpile.com search for cast bullets should turn it up. The .410 slug is under Muzzle Loading bullets. Theirs is a .372"/ 140gr. foster type slug. They sell for $15.00 for 50 and shipping would be $4.65 to Ohio. In response to my email they said the mold is a Lyman. Liberty has no data but say it is in one of the old Lyman shotshell manuals. #4 is current so I'd guess #1 or #2- out of print naturally. If you happen to come across one of those please let me know. By the way Liberty doesn't accept charge cards. I'm going to order some and if they work, probably have a mold made- assuming I can find data. Corbin ( www.corbins.com) will make dies to swage almost anything. There is a shotgun slug page on their site. Corbin is very good but the prices make them more of a commercial solution.

Dynamit Nobel ( www.dnrws.com) makes a 2 7/8" (73mm) slug.
The velocity/ energy table at their web site is incorrect. The .410 is in a table with other gauges and I think the velocities are for one of the other gauges. If you work out the slug weight and muzzle vel. their energy calculation is way off. Barnaul Ammunition ( www.barnaulammunition.com) makes 3 different 70mm (2 3/4") slugs.
They are steel cased and the site only gives muzzle velocity. I can help you with general ballistic calculations.
The following sites are still active and have links to freeware/ shareware ballistic programs. I use Ballistics for Windows (good program but it won't calculate ballistic coefficients) and WinBallistics (it will calculate all BC's but won't graph very low BC's- such as roundballs and shotgun slugs).
My versions are rather old so the programs have likely changed.