Question: Making a New Caliber

[beechbum444]

Question to yall on the forum about making a new caliber....What is the process????? I have the idea in mind so where do I start?? How do I have a reamer made? How do I get specs for it to be made? Who is a good company to have a one off barrel made? These are just a few questions that I can think of......If you have any suggestions or even more comments, please do not hesitate, any direction is appreciated...…….

Thanks for looking

[dbosman]

If you do a web search you'll find several reamer manufacturers. Depending on what you're working on, you may be able to use a couple of off the shelf rental reamers to get close to what you design.
There are any number of barrel makers, all of whom are backed up.
Before you spend money, though, do a search for the caliber and your parent case.
If you're talking a new rim size diameter, you'll be looking to have a bolt made or opened up.

[nun2kute]

I wish I could help, but I'm in the same boat. Still looking for a 40 cal rifle blank. (AR type) I have been meaning to go talk to the Machinist I had open up the upper for my 458 about it, hoped he might give me some direction. I thought that if I could make a dummy round, Hornady could make the reloading dies. I just haven't pursued that project much yet.

[NyFirefighter357]

Read the "Ladybug" thread.

http://castboolits.gunloads.com/show...The-22-ladybug

Two companion threads also.

http://castboolits.gunloads.com/show...m-25ACP-Trials

http://castboolits.gunloads.com/show...-rifle-Wildcat

[dh2]

I would start with Pacific tool and Machine I get wildcat reamers from them, they will make reamers to order.
What are you after there may be a wild cat to fit the bill all ready out there

[beechbum444]

762 x 39 expanded out to 40 caliber in a marlin 336 action....the 400 AR uses 765 carcano brass for the taper to feed from a straight magazine.....and Id rather use 762 as a parent case. It would basically be a 401 wsl I think and hope a 35 rem bolt would work and the guides might work with very little fidgeting...If the 35 rem bolt would not work, Id have to go with a win 94 action with a 357 mag bolt but the COAL would fix the feeding issues (hopefully) ……...Any Thoughts Out There

[adcoch1]

Any reason to stick with a x39 case? You could easily do a 40-30 with a 30-30 case as the parent. The expanding of a x39 case would take some work and a common bolt head size in a levergun may be difficult. A reamer can be had from a few different companies, and barrel blanks can also be found, or possibly just use a 40 or 10mm ar barrel. Once you have the gun built and some cases expanded and fireformed, hornady or p,t&g can make dies. Or you could ream out a 10mm die for neck sizing. Lot's of ideas.

[NoZombies]

If you can't do most of the work yourself, find a gunsmith you like, who likes the idea of the project. PTG makes nice reamers, but I've made most of my own because of cheapness/laziness. For one off jobs a "spoon" or "D" reamer can do fine, and honestly, I usually get at least as good a finish using the "D"-type reamers as I do with commercial or home-made fluted reamers.

[beechbum444]

you are right about the 40-30 round....It just seems that 762x39 brass is everywhere....I first wanted to do a 40-50 SS and then a 445 super mag with shortened 303 brass and use 303 brass for the 40-50ss....trimmed a little.....a 35 rem dia is .460 and oal is 2.5 and the 762 rim diameter is .447 and I think I can get a 2.2-2.3 oal im just curious how much wiggle room there is between ammo manufacture and bolt/ extractor manufacture …...a 357 rim dia is .440 butttt. then Id have to go with a winny action but I would think its easier to go with a smaller bolt head size......just thought a Russian designed round designed to go into an ak retro fitted to go into a pre 1900 designed lever gun would be really cool and it could launch a 250-290 gr lead boolit close to 2000 fps

[crankycalico]

Side tracking:

How would you go about lengthening an existing cartridge? I have always gotten an itch to stretch out a 38 smith and Wesson to the same case length as a 38 special, and run at 38 special +p pressure

[sharps4590]

New caliber or new cartridge?

[rockrat]

clymer has made reamers for me before when I came up with ideas for different cartridges (30-357max and 44/284 and 38-72 with 405 win. rim). Manson reamers also does custom work.

nun2kute--- You might be able to send an AR15 barrel to JES and have him bore it to 40 cal.

How about taking a 35 rem case and opening it to 40 cal, as an alternative. Don't think you are going to get a 280-290gr boolit going 2000fps using the X39 case, but I might be wrong. Using the 35 rem case might be an easier proposition.

Check out Green Mountain barrels for your 40 cal. I think they have them

[country gent]

Start out by drawing up what you want. scale it up 5 or 6 to 1 ( 6" on paper = 1" actual size). This shows you idea much better and also body tapers and such stand out more. This drawing will firm up the design and give you something to work from. This drawing will see a lot of use. Next I bore a sizing die in the lathe to the drawing and start forming some cases, not a lot but a few for dummy rounds and to have the forming process down to where it works. Sometimes a slight change in body taper, shoulder angle or shoulder set back makes a big difference in how a case forms. This is the time before the reamer has been ground. I load 3-5 dummy rounds with the desired bullet and Overall length. These are hands on of the new cartridge, and can be used to check magazines dimensions and theory to a point. Now talk to your reamer grinder ( I use Dave Manson normally) and work with him, Send him a copy of the drawing and 2-3 or the dummy rounds. He now has your thoughts and work on hand including samples he can measure. Trust me here his measuring equipment is probably years ahead of yours, and he can measure it in the way that works for him.
He may call with small changes he wants to aid extraction or case life or to ease grinding the reamer. Once the reamer is ground then its build the rifle and final dies. ( Some Air hardening stocks shrink slightly when hardened and tempered allowing the die to be cut with the reamer). On cases that are necked up with little other changes a tapered expander may work to make the test cases, sometimes other dies can be found to make the dummy rounds 1 for body taper, another for shoulder locations angle and one for neck size.

This can be a slow process and a lot of planning between each step is good.

[Chev. William]

You might check what "Lothar Walther" lists in the Bore/Groove Diameters you are looking for.
Chev. William

[cwlongshot]

I wish I could help, but I'm in the same boat. Still looking for a 40 cal rifle blank. (AR type) I have been meaning to go talk to the Machinist I had open up the upper for my 458 about it, hoped he might give me some direction. I thought that if I could make a dummy round, Hornady could make the reloading dies. I just haven't pursued that project much yet.

Have you seen the 400AR? I am also a big 40cal Fan!

https://400ar.wordpress.com/

https://www.bing.com/search?q=400AR&...8e6105ef65baf0

CW

[beechbum444]

I've seen the 400 ar I like it but I think that I can get a bigger .41 caliber boolit in a 762x39 case and I don't need the taper for a box magazine and the carcano brass is not so common

[country gent]

Taper isn't just for box magazines. The body tapers also aids in ease of extraction. as the case is pulled out the chamber is getting bigger. A true straight wall case fire formed tight to chamber will drag the full length

[nun2kute]

CW ... that link to wordpress was an awesome read. Gets me closer, but it and you'all also kinda lets me know I need to do a lot more research and learning. "The more I learn, the Less I know". I was thinking along the lines of 10X51 er' 40-06, AR 10 size. Now I don't know.

[john.k]

There is no need for a reamer to cut a near straight taper chamber with little or no shoulder .................it is easily cut with a small boring bar.,and lapped when to size...A reamer will add at least a $100 to the build.....A D reamer is a good idea,but the chamber must be 90% roughed out,or need only a small metal removal.....Reloading dies can also be made with a D reamer.

[357Mag]

Beechbum -

Howdy !

I formed some sample cases of a new .411" cal wildcat based off .35 Remington, which was the brainchild of a Michigan deer shooter.

While .35 Rem ( Remington brand brass ) has a nominal ID of .400" from the shoulder/body juncture down to .125" the case web....
he wanted to use .405Win left over bullets, and also go w/ a 1.800" case max oal, for legality.

I used a small assortment of ( LEE ) expander mandrels, to mildly expand the cut-off .35 Rem cases to .41" cal ID.

The shooter had hoped to run a .405Win reamer in "short", to cut the chamber for the .35Rem-based wildcat brass.
Math showed that this would not be tenable, and the project thereafter was idled.

It does appear that use of the .405 Win reamer run-in short could be a viable approach, were one able to instead use
7 X 64 Brenneke as the parent case ( IMHO ).

I believe an AR format was being considered, and of course.... case' major diameters are always a central question.

I shot a .224" cal wildcat based on .35 Remington in a single shot bolt action rifle. I used the stock .308 bolt face,
and it had an M-16 style extractor installed. I never had any problems w/ case/cartridge feed or extraction.

For barrels, you might check w/ MMC, PAC-NOR, Criterion....... there's a variety out there I should think.


With regards,
357Mag