243 Mendoza

[mod70]

Does anyone know about or have a picture of the 243 Mendoza cartridge? Thanks! John Roberts

 

[243Mendoza]

Does anyone know about or have a picture of the 243 Mendoza cartridge? Thanks! John Roberts

John,
THe Mendoza is a 243 with a 6BR neck length and shoulder angle. Hopefully I have successfully loaded an image file. The cartridge shown has been run through a 6BR die but not yet fireformed.

 

[mod70]

Steve, That's what I thought, looks a lot like the 6 super X.
Thanks! John Roberts

 

[Cheechako]

Steve, That's what I thought, looks a lot like the 6 super X.
Thanks! John Roberts

John

You are correct. It is exactly like the 6mm Super X and many other wildcats going all the way back to the first one, the 240 Page from 1952. Yes, I know, neither the 243W nor 308W existed in 1952 but Warren Page got his hands on some of the experimental brass that would become the 308W, shoved the shoulder back to 30 degrees and the rest is history. Had Winchester taken his advice, that is how the 243W would have looked but then all the wildcatters would have been cheated out of designing and making their own over the next 55 years.

Ray

 

[rcw3]

Ray

I would be careful saying it is "exactly like" the 6mm Super X. I had no idea what the body dimensions of the 243 Mendoza were when I made up the 6mm Super X,in fact I didn't even know the 243 Mendoza existed then), and I made up the 6mm Super X using 243 Win brass and a 6XC sizing die. While the cases look somewhat alike, I am not sure they are interchangeable or that you should try to chamber one in the other.

Robert Whitley

 

[mod70]

Robert, What I don't understand is why these improved case designs have not taken off. I like ever aspect of them myself.
John Roberts

 

[Cheechako]

Robert

You are exactly right. I should have said very similar in shape and dimensions and ballistically alike.

Like most wildcats that work, most of the 6mm Super X types were developed by different shooters, without knowledge that others were doing the same.

Ray

 

[rcw3]

Robert, What I don't understand is why these improved case designs have not taken off. I like ever aspect of them myself.
John Roberts

John

I don't know why such a design did not take off either. The 6BR certainly took off. The 6XC is basicly a stretch body 6BR and the 6mm Super X is basicly a super stretch body version of the 6BR. The neck length of the 6XC and the 6mm Super X are very close, but a little shorter than the neck length of the 6BR.

Robert Whitley
www.6mmAR.com

 

[dsbw]

This seems to be a very interesting cartridge, especially if you are having problems acquiring brass for 6.5 x 47 etc. How do one form the brass for the Mendoza, what about reamers/dies etc?

 

[Cheechako]

It is indeed a mystery as to why the cartridge never became popular in any of it's names. Because, you see, it goes all the way back to 1952 or 1953 when Warren Page made the first one,240 Page) using a prototype case that would become the 7.62x51 and the 308 Winchester. It's probably because Winchester came out with the 243 Winchester and it has been so popular that it's hard to dethrone. Now, with the 6.5 x 47 LAPUA brass being available, it's not likely to overcome a double hit. JMHO

Ray

 

[243Mendoza]

This seems to be a very interesting cartridge, especially if you are having problems acquiring brass for 6.5 x 47 etc. How do one form the brass for the Mendoza, what about reamers/dies etc?

I used a 6BR sizer and sized until the brass chambered. Rick Beginski chambered my barrel and made my sizing die.

45.7gr of H4831SC will shoot the 115gr DTAC 3130fps. Will shoot .25"-.33" 5-shot 100yd groups. Will shoot 1/4-1/2 moa groups at 600yds