.615 Ferran Express

[Bigbore.729]

So, working with the 12 gauge fh has given me a huge amount of knowledge on cartridge design. I have noticed some pitfalls with the 12 ga fh since I started loading it.

1- sectional density- The giant slug has a lot of energy, but poor penetration due to a large frontal area.

2- Brass availability- the brass is really expensive $10 a pop and takes months to get. If you use 50bmg brass you have to use a lathe to add a thread on rim.

3- Ease of loading- this brass is fantastically made, but it's lathe turned and VERY thick. That means FL sizing is impossible. Also, getting a die has proven to be difficult

So, with all that said, I got to thinking. What I propose sounds kinda crazy, but that's why I like it.

So, with 50 bmg as the parent case, I want to neck up to .615" (20 gauge) this offers a much better SD that the .729" pill. The first loadings will use standard 50 bmg load data. For the action, I want to use a single shot 50 bmg action ($850) with a custom barrel. This way, you can use 50 bmg brass without having to add a rim. Also
FL resizing is now possible with a 50 bmg press. I can also get a repeater action instead of the single shot down the line. Velocities will be a bit higher than 12 ga fh too as I can load it quite a bit hotter due to the strength of the action. Another great benefit is I would no longer need to mix powder as the 50 bmg primer is sufficient for ignition!

A few problems I will have are

1- I have to get the cartridge approved by the ATF as it's over .50"

2- getting a die that will size the brass

What do you guys think? I've never made a wildcat cartridge before, but I feel I have the knowledge to do so now. I believe this would make an amazing safari/stopping cartridge. I'm pretty confident I can get muzzle energy to the 10k+ ft-lb realm as they were doing that with 12 ga fh with the rimmed 50 bmg brass.

Also, a lot of you guys are very smart, and helped me out tremendously with my 12 ga fh, so help and suggestions from y'all would be fantastic.

[Bigbore.729]

Sent a letter to the ATF Firearms Ammunition and Technology Division". We will see how it goes.

[Bigbore.729]

Had a thought while sleeping just now. Instead of .615" which I'd have to have custom made, I'm going to use the commonly available .620" solids that the 600 NE uses. This means it'll be a lot easier tonload for.

[Rp-]

If you get around to making these then let me know. I'd be interested in one for my cartridge collection.

Sent from my LGLS991 using Tapatalk

[Bigbore.729]

Got these 900 gr solids ordered so I can fashion a dummy round.

[Bigbore.729]

The more I think about it, the more I'm thinking I need to shorten the case. If I didn't, I could use dacron to fill the big void from down loading, but I don't want to do that. I want a good, safe load density. The problem will be reforming the neck and shoulder after I trim the case down say about an inch. If I could get this cartridge to do 12,000 ft-lbs at the muzzle with a max load, I think that'll be best. Then my question is what and how much powder do I use to achieve that? That's where quick load will come into play. I should be able to upload case dimensions and get very close predictions to pressure, muzzle velocity, and powder brand with what charge will give me the best results. Need a cheap laptop

[Bigbore.729]

Today I was on a mission and it was successful. Today I successfully expanded the neck of the .50 bmg to .619" (gives me .001" of neck tension)

Here is how I blew the neck out. I got a bolt from the bolt bin that had a shank that was exactly .619". This gives me .001" of neck tension which is awesome. I cut the head off the bolt, and then took it to the machine shop to have one of the guys put a taper to it. He also drilled a hole straight through to prevent air from preventing movement. He also threaded it so I could get it back out. I then heated it up red hot and quenched it in water to harden it. I then polished it the best I could. So, after hours I grabbed a thick grease like lubricant and placed it on my new mandrel and the inside of the mouth. I then used the machine shops arbor press to press the mandrel in. To my surprise, the case went up a caliber extremely easy. I thought for sure the neck would crack. I the secured the case, and used a on the fly slap hammer to pull the mandrel out. It formed perfectly. It was exactly. 619" at the mouth. Not too bad for the most ghetto on the fly expander set in the world! tomorrow or Saturday I'll have a dummy round made. This is coming together nicely.

[Bigbore.729]

.620 FE prototype V1

[RED BEAR]

Well all i can say is this is more than my old shoulders want to shoot. I really used to like big bores but shoulders can't take it anymore. Not to mention i couldn't afford to do something like this . But good luck with atf. Let us know how it goes.

[lar45]

You might checkout the 600 Overkill, 600 OK,
https://americanhuntingrifles.com/600-overkill/
It wouldn't be your own design, but sounds like the performance you are looking for. It would be cheaper to build and shoot in a more packable package.

There is also the 550 Magnum or Express that use a blowout 460 Wheatherby. They can be built on either the big Enfield or the standard Mauser98 action.

[Bigbore.729]

600 OK is very close you are correct. This should in theory produce 1000+ ft-lbs more muzzle energy than the 600 ok. Also, I want my families name on a cartridge. Plus, this is going to be really fun

[lar45]

Plus, this is going to be really fun

I hear that

[Bigbore.729]

I also have an idea that piggy backs off this. I want this same .620" 900 gr projectile but in a smaller action like the cz (much like the 600 Ok) but cut way down so it remains subsonic. A 900 gr pill doing 1050 fps is similar to a 308 in muzzle energy. You put a giant can on that and you're talking really fun stuff.

[Bigbore.729]

This took some doing, but I got the V1 prototype drew up in Quickdesign. Very steep learning curve, especially since I've never used CAD. Got it done though and it's ready to be uploaded to Quickload when it gets here!

[45workhorse]

[lar45]

Looks great. I absolutely love Quickload. I still have my first copy that came on a floppy disk.

[Bigbore.729]

Better pics of the drawings. I have the V1-V3 done

[Bigbore.729]

Winner winner chicken dinner. Pressure looks great, velocity is where I want, muzzle energy is out of this world! Starting load would be reduced by 10%. Looks like this is everything I wanted.

[Bigbore.729]

Have a more efficient maximum load! Here is some more data to go along with it.

[Engineer1911]

When will a handgun, TC style or revolver, be available?