410 slugs with brass hulls

[Jackmerius]

Hi everyone, I’m finally getting around to a project I’ve been putting off for way too long. Im doing a “410 from hell” style project with a rifle barreled shotgun and brass hulls from RMC. I’ve already chosen the Speer DeepCurl 210gr bullet which is a pinch less than 1/2 oz. Velocity I’d like to achieve is about 1,800 fps or better.

Now, on MidwayUSA there is a 5 year old review of this bullet left by a man simply known as James who stated he is doing this very same thing. I’m hoping by chance he may be on this forum and I can pick his brain and experience for load data and barrel grove diameter choice.

I’ve been collecting bits of info around the net so I believe I have a starting point, but I would like to hear more experiences from those of you who have pursued something like this before.

I’m sure a lot of you are familiar with Ed Hubels work on high power loads in numerous shotgun gauges, especially the infamous 12 gauge from hell, so I do believe this project is achievable and could even be suitable for hunting. Please don’t rip me a new one... I’m only interested in hearing real, helpful information from those who have experience. And for those who are going to ask why I’d want to do this, the answer is because I can, and I want to.

[T. O'Heir]

"...I want to..." That's all the reason you need.
"...1,800 fps or better..." I believe that'll be optimistic, but Federal 1/4 ounce(~ 218 grains) slug loads run 1780 FPS.
Biggest issue, I suspect, will be finding a barrel that isn't stupidly expensive. You'd need a .41 Mag barrel. The Mag and .410 using the same diameters.
Try an E-Mail to Mag Tech. They make the brass shells.
Missouri Bullets makes a 225 grain cast bullet. And Graf's lists a few 215's. Closer to 1/4 ounce. Don't think it'd make much difference though. I'd just load for a 1/4 ounce slug. You'll probably need a spacer like oat meal or the like in the case too. Do a net search for BP cartridge loading.

[Jackmerius]

Thanks for the reply O’Heir, yes I agree this is an optimistic project. And possibly expensive. I’m looking at Pac Nor barrels right now, they can make .408 and .411 grove diameter barrels, although they cost a good amount. The bullet I mentioned above is .411. I don’t really like the idea of using the .408 barrel because of the modest pressure of the 410 specs, however I’ve read better accuracy can be had with a barrel of slightly smaller grove diameter than the bullet diameter.

I’ve seen where people are using a lot of slower burning powder to get the velocity gains without spiking the pressure. Also seeing a series of gas seal, cushion wads, and card wads to further help keep pressure spikes down.

[Unclenick]

An ounce is 437.5 grains, so you are right that this is close to ½ ounce rather than ¼ ounce, just to be sure we're all on the same page.

Bore vs. bullet diameter is a topic on another thread. A lot of Sierra MatchKings seem to run about half a thousandth over nominal groove diameter. Palma barrels for long range shooting are often a thousandth and a half under standard groove diameter, making them very snug for the bullet. But that's sort of the range I see.

A question important to velocity is, what barrel length are you planning on?

[Josh Smith]

I think I'm going to follow this one.

Regards,
Josh

[Jackmerius]

Unclenick, thanks for the input. I’ll have to slug the barrel once I get one and see where it lies. I suppose I could go with a .408 barrel and size the .411 bullets down to various sizes for experimentation... that would give me more bullet choices as you can’t generally make chosen bullet bigger.

As for barrel length, I’m probably looking at 20 inches as I don’t want this to be too unwieldy in the field. I know that’s a short runway, but I’d like to keep it practical for carrying through woods and brush. Do you have any leads on load data for me?

I don’t know for sure that Ed Hubel has done any work with the 410 specifically, but I might run this by him to pick his brain. I believe he at least knows people who have done this, if he hasn’t done it himself.

[Jackmerius]

There is an old post on shotgunworld if I’m not mistaken where a guy used 44gr of IMR 4198 with a 210gr pistol bullet in plastic cases. He did say pressure was a little high but it produced 2,177 fps. He went on to say that he will reduce the load to 41gr. He used a .411 grove barrel but his thread stopped before reporting any accuracy information.

[Unclenick]

Well, QuickLOAD thinks that load would be producing pressures of about 28,000 psi, assuming a 3" shell. 410 shotgun 3" pressure MAPs are 13,000 and 13,500 in SAAMI's book. What is unknown are details about how loose the fit of the bullet is in the shell and how much gas bypass occurred. A rifle powder like 4198 isn't going to burn well at those shotshell pressures.

I used QuickDESIGN to modify a 41 Rem Mag case out to the length of a 2.5 inch shell.



I ran QuickLOAD's powder comparing tool to find powders that would not exceed 13,500 psi, gave it a 20" barrel and got 1508 fps from Lil'Gun as the fastest load that could be made up in that cartridge shape without going over that pressure. I then extended the case and multiplied the case capacity to 3" and got about 100 fps more using somewhat slower powders, but they are not powders that would burn well at that pressure, so I don't think you'll get a good load that way and would have some risk of bulging or ringing the bore with them over time.

So, the question is, can you get a barrel and chamber thick enough to deal with more like 45-70 pressures?

[Jackmerius]

Wow, thank you for taking the time to do that! At this point I don’t want to go over pressure and I don’t believe my intended donor gun could handle it, although a stronger weapon system isn’t off the table. I’d be interested to see what’s possible with 45-70 pressures.

While I have you, and I don’t intend to take up much of your time... I really appreciate your help... another popular powder for 1/2gr loads is H110 and according to Hogdon load data, it can produce same velocity as lil’ gun with significantly less pressure. Would you mind checking that powder for me?

[Unclenick]

The software checked all the powders in the database and ranked them by velocity. 296/H110, two different lots having been tested for the database entries, gave 1526 and 1522 fps at 13,500 psi. Lil'Gun gave 1596 fps at that pressure.

Keep in mind, this is a computer model and not actual testing, it gives an indication of what to expect.

[Jackmerius]

Well thanks again for the info. I do understand that it’s only a computer model and I’ll have to be careful working loads up. Perhaps this project can be built on a frame strong enough to handle a much more powerful cartridge and I could experiment with higher pressures. Maybe even have some loads tested for pressure.

[hounddawg]

Pac Nor makes a .411 (.410) barrel

http://pac-nor.com/barrels/

essentially what you are making is a 40-70/65 Sharps shooting a 200 gn bullet

[Jackmerius]

Hounddawg, that’s an interesting cartridge I haven’t heard of. Seems to be an old black powder cartridge that has a decent following today. I see people loading what I believe to be modern rifles with smokeless powder and getting a 300gr bullet to 2025fps with H4895! Any idea what pressures they’re running? I have a feeling that’s way out of my 410 pressure league!

Yes, I am looking at Pac Nor for my barrel. I believe I will go with a .408 grove diameter because it will allow me to size a wide selection of .411 bullets down to a size which produces acceptable accuracy. I’ll slug the barrel to get an accurate size and maybe try a bullet of sizer of .0005-.001 over grove diameter to see what accuracy looks like.

If anyone has any ideas on this, please chime in! While I am a reloader, I’m not a wildcatter! I’d love to hear any input from all you experienced loaders out there, and I want to do this as safely as possible while achieving higher performance from your typical 410 slug.

[Unclenick]

If you're not married to the idea of using shotshells, then Houndawg's suggestion is a good one, assuming you haven't bought bullets yet. I say that because the groove diameters of the seven different 40-70's vary from 0.403" (40-70 Ballard) to 0.417" (40-70 Maynard), but none fall right on 0.410". 40-70 Winchester has the most case capacity.

All those rounds should handle 45-70 Trapdoor Springfield pressures (22,000 psi or so) in guns normally chambered in them. The Cowboy Action Shooters have revived a lot of these formerly-obsolete rounds, though there are no SAAMI standards for the 40-70's as they preceded standardization but have not regained enough popularity to interest large-scale ammunition makers. The CIP, however, has standards for the 40-65 (about 30,000 psi) and the slightly bottlenecked 40-82 Winchester (about 24,000 psi), which is why I think you will be fine with Trapdoor pressures in the 40-70's and can probably go higher.

I'll add what I think is a better suggestion: If you just want a straight cartridge in the 410 shell size range, go to the 405 Winchester, the most powerful rimmed straight wall cartridge ever made. It is old (1904), but has been revived with enough modern popularity to garner a SAAMI standard (while absent from the 1992 SAAMI standard, appears in the 2015 SAAMI standard). It has a 2.583" case and a 0.412" groove diameter, which could shoot a .410 jacketed bullet if you wanted it to (if not quite as accurately as a 0.411-0.412" jacketed bullet). It has a 46,000 psi MAP, so it will contain all the pressure you need to hit your velocity range (it will do over 2,200 fps with a 300-grain bullet). It should be very happy with wide meplat flat nose hard cast bullets, which are terrifically effective on game, and which you could get a mold for or buy. You could even get a .404" bullet and paper-patch it if that interests you. The 405 Winchester (aka 405 WCF) simply gives you more options than the other choices we've discussed.

[2wheelwander]

I've read of guys using .444 Marlin cases for exactly this. I hesitate to post because .444 brass isn't exactly always readily available. I buy it when I can for my Marlin.

[Jackmerius]

Well, I know there are much better cartridges out there for that I’m wanting to do... but one of the reasons for doing this with the 410 shotgun is to make a higher powered option for shotgun only hunting land. The public land I have nearby is archery, shotgun and muzzleloader only. Yes, I could just use my bow, but an accurate shotgun can serve me better at extended range. Yes, I could use a muzzleloader, but I like faster follow up shots. And finally... yes I could use a 12 gauge with rifled barrel, but my suppressor only goes up to .45 caliber.

This rifled 410 could be built on a Winchester or marlin lever action with a threaded muzzle for suppression. Other platforms include various bolt actions, pump actions, and a couple very interesting Saiga and AR-15 style 410 shotguns. Anyone with the will and the funds could hit their shotgun only hunting property with a semi automatic weapon as versatile as the AR-15, using his choice of optics and suppressors. Thermal vision could be used at night on hogs, in any state which allows such things.

I’ve seen much appeal in the 410 for these very reasons, and I hope to create something that people can learn from and copy with their own personal twists.

As with any custom firearm, you start with the cartridge, then you build the weapon based on that. If the 410 can be pushed to higher performance without going over pressure, that would open up a unique niche in the firearms and hunting community.

A question about powder burn rate and pressure... the slower burning powders which “could” give higher velocities in 410, but won’t burn well at the low pressure, how does someone like myself find this information? Can those powders be made to burn better with different types of primers?

[hounddawg]

I know several manufacturers make lever action 410's and the same ones make lever actions chambered in 45 LC and .444 Marlin. You might give a call to Henry or Marlin 's custom shop if they have one. If you have some competent gun smiths that can do custom builds they should be able to arrange a marriage using either the Pac Nor barrel or modding a Marlin or Henry barrel that has a bore that you can live with

BTW I think what you are trying to do makes a lot of sense

edit two- seems this guy has the same idea but he is using a 20 gauge

https://www.outdoorlife.com/blogs/ga...chrifle#page-2

[Jackmerius]

Good link hounddawg, I definitely like what he’s doing there!

I’ve been tossing this around today after my previous post... American Tactical makes the Omni Hybrid in 410 2 1/2 chamber with proprietary mags, bolt, and gas system... pretty much the whole upper receiver. (AR-15 platform) Neat thing about the lower receiver is it will accept and run any mil-spec upper... it’s a standard lower receiver! In this platform, we would be safe running standard pressure slugs through a custom rifled barrel in place of the factory barrel.

With my thoughts going down that road, we can obviously use the AR platform with high pressure loads. Since a standard lower receiver can be used to feed 2 1/2” shells, proven by the Omni Hybrid and the 410 mags already available, I don’t see why couldn’t hot rod a 410 brass shell and use a custom upper receiver and bolt design to get a high performance shotgun running say 35,000 psi. That is, unless primer integrity becomes an issue.

One issue with this idea is how to determine the gas port location on the barrel. A .458 SOCOM runs a max pressure of 35,000 PSI so I imagine I could copy the gas port location from a 458 SOCOM with a similar barrel length, and run an adjustable gas block to help fine tune the gas system.

Thoughts anyone?

[hounddawg]

on that link I would love to see the slug he is running. I calculated the numbers in the article and somehow he is getting .5 BC-1 with that slug to get that little of a drop at 200. A far cry from the punkin ball I put in the side of a neighbors junk car then got my butt switched afterward for shooting it. I guess I disturbed the vermin that called it a home

edit looking at it from a ballistics viewpoint I think that sabot would have to be long and hollow. The diameter is .6 yet it weighs less than half what a 600 Nitro bullet weighs. That is the only way he could get that little drop I think. What would be the twist rate on a shotgun slug barrel ? How long of a sabot would it stabilize?

[Jackmerius]

In that article somewhere near the bottom it has a link to his website. It looks like he’s selling rifled shotguns for a very pretty penny! I see one with a 1-24 twist. His ammo does look very nice. Plastic shells with a pointed billed sticking out the front.

Says he’s using 50gr of “high octane” powder. This is what I’m looking for with my 410 project... lots of powder but slower burn rate.

I went over to Ed Hubels thread on the shotguns from hell and asked him for leads about the 410. At this point, my plan is to use a factory American Tactical Omni Hybrid and have a rifled barrel made for it. I’ve got the rifle mostly torn down, just waiting on a 1 1/8 crows foot to get the barrel but off. Then I’ll talk to some smiths and see if they would turn a Pac Nor barrel for me.

[Jackmerius]

Here’s an update, I bought QL to play around with my cartridge and load parameters and here’s what I got. Note, I’m not a pro at this so please help out if you see a mistake.

I decided to use standard AR15 parts to modify since the platform can handle way more pressure than I’ll most likely need. Goal is now to use the 210gr Speer DeepCurl and get it to 2,000fps from an 18” barrel. This should get into the power range of a 30-30. I’ll have a smith shorten and bore out the bolt to make it appropriate for the 410 rim, and have him set the barrel deeper into the barrel extension to correct for headspace. I may have to build a custom ejector that will preload the spring while holding the ejector deeper into the bolt as the front cavity of the bolt won’t be nearly as deep as a stock bolt. Anyway, more on that later... we have load data to work out.

First, I determined my COAL since it is limited by what can fit in the magazine. Then I measured the bullet length and noted both the cannelure-to-tip, and cannelure-to-base. This allowed me to determine the length of the empty shell, and then use the program to estimate the useable volume after bullet is seated.

I also put in .408 grove bore and .409 bullet diameter, which are both just starting points. I’ll have to get more accurate measurements from the barrel when it comes in and consider what the bullet diameter should be. Anyway, probably a good starting point.

Lil’ Gun is still the powder of choice, keeping the lowest pressure compared to other powders (26,871psi/30.5gr Lil’ Gun) while pushing the bullet to 2,000fps from an 18” barrel. I figured if the load I mentioned in post #7 generates roughly 28,000 psi and his primers held up, I should be able to generate that much pressure without primer issues.

I’d like to upload some pictures to show my QL data so you all can provide more input on the parameters since it’s new to me. And I’d like to show progress with the cartridge. What is a good image hosting site?

[ammo.crafter]

I've been using .444 Marlin brass (fire formed with COW) and it works perfectly in my .410. Looks cool as well.

The .444 brass is stout and should last quite some time.

[Jackmerius]

Ammo.crafter, how long are your cases? What kind of powder and bullets are you using? How do you think shotgun primers will hold up under the pressure I’m looking at? Do you have any other ideas or comments for me?