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Making my own cartridge
akfanatik
Member Posts: 580 ✭✭✭
Me and Mr. Gunz have been thinking about making our own rifle cartridge, im not gonna post specs cuz its top secret, where could we get loading dies, would have to be custom made, and also a barrel properly bored??
Comments
Dies will have to be custom made unless you can modify existing dies to make the cases. It's something to look into simply because custom forming dies get pretty pricey. The more complex the cartridge case, the more expensive the dies get.
All of the commercial die makers will be glad to take a lot of your money for custom dies. This includes RCBS (Huntingtons), Redding, and Forster. I'm not sure about Lyman or Lee but you can contact them.
I'm not sure what you mean by a 'barrel properly bored' but if you want to explain that phrase, I'm sure I can help with all sorts of suggestions that will be more appropriate than just telling you 'any custom barrel maker'.
You will also need a custom chamber reamer and a custom die reamer in case the die maker suggests it. I suggest that you get a very accurate drawing made of the cartridge and then discuss it with Dave Kiff:
http://www.pacifictoolandgauge.com/
But you can also call:
Clymer
JGS
Dave Manson
Here's where I'll throw in my words of caution. In the slightly more than 100 years of wildcatting cartridges, there probably isn't an idea that hasn't been done directly or there is something that is the equivalent that already exists thus making the new one unnecessary. I've even seen some ideas that are just plain silly and useless.
But, and this is a big but... if you think this idea is truthfully worth pursuing and spending probably a couple of thousand dollars on, then by all means get after it! But be aware, the cash is big dollars and if you make a mistake in measuring and then have to correct it, it just costs more.
Best.
Troy Newlon for a bushing die blank set www.newlonprecision.com @ about $125
Dan Lilja, Doug Shilen, Pac-Nor and any number of barrel makers @ about $400
IF your barrel is CM, and your die set is SS, than you should have the proper difference in size. If both are SS, than you will need to have the ID of the die hard chromed to a thickness of .0015 (per D. Manson and T. Newlon). If you opt for a CM/CM combo, than you will need to purchase the die reamer @ about $110.
You will also need to have a qualified machinest or gunsmith do the machine work on your barrel and die blanks.
"A barrel properly bored" could be a problem if "proper" means "some odd calibre". You can have about any case shape to fire a 7mm .284" bullet or a .30 cal .308" bullet. But if your secret cartridge involves a .295" bullet, you will have to search far and wide for a barrelmaker who will accomodate you.
Any of the reamer makers will work with you and your drawings. Sample cases or dummy cartridges work well in addition to the prints especially if you seat a bullet to the length that you intend to use them. That way they can grind the leade and throat to the correct dimensions.
These are various types of cartridge drawings:
Here's an example of a JGS reamer primt:
This is a German reamer drawing:
This is a blank reamer drawing ready for dimensions but it's in Excel:
http://benchrest.netfirms.com/PDF/Blank Reamer Print.xls
Chambers in barrels are usually reamed not bored. In your situation, you will have to supply the barrel maker or gunsmith with your reamer so they can cut the chamber.
If you can use existing dies to make the cartridge case you can save some money. If the design is completely new, you have to draw the case, get the reamer made for the chamber and the reamer(s) made to make the dies.
Best.
Most never get the roughing reamer, because they cut so few chambers anyway.
"Most never get the roughing reamer, because they cut so few chambers anyway."
This may be true in the most general of circumstances with low volume gunsmiths but when accuracy is a concern, roughing reamers are ignored.
Most never get the roughing reamer because of the lack of quality and accuracy that the final chamber suffers from since the pilot of the finish reamer cannot reach the the center of the bore thus maintaining concentricity. Greater accuracy is obtained by using the one finish reamer and resharpening as required. The areas of greatest wear are the transition angle at the front the neck and the shoulder angle of course. I have been known to use boring bars to partially cut certain chambers under unusual circumstances but I have specialized longer pilots on the finish reamers. This technique is reserved for very short cartridges such as the PPC/BR chambers.
There are 3 types of reamers:
Rougher
Resize
Finish
While you can make do with the rougher, it is actually more accurate to use a true resize reamer for the cartridge dies.
Best.