Anyone, and mind sharing, what the barrel tenon threads are for a Marlin guide gun or other Marlin lever action chambered for the 45-70 or 450 Marlin?

Thanks,
ASS_CLOWN

I was under the impression that they are the same as for the 336 Series, 12 TPI, square thread, major .780, minor .722. At least that's what my old handout from Trinidad says....

fireball168,

Quote:

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12 TPI, square thread, major .780, minor .722.

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I certainly hope that the Marlin's chambered in 45-70 and 450 Marlin have a heavier barrel tenon that that!

With a tenon of that size, and chambered in 45-70, one is looking at catastrophic barrel tenon failure in the 42000 psi to 55000 psi range depending upon how hard their barrel is (Rc 30 to Rc 40 and based upon von Mises stress analysis). That is down right SCARY!!

If they are using such a scrawny barrel tenon that explains why I have heard/seen blown up Marlin 45-70 lever guns!

Anyway, this was why I was asking the question.

Thanks for your reply.

ASS_CLOWN

Ok, I'll bite.

Ernie Stallman at Badger Barrels, in Bristol Wisconsin, has the contract to make the Browning "High Wall" BPCR barrels, Winchester Super Grade barrels, special run 94/92 octagon barrels, etc.

Miroku(sp?), who is making the High Walls for USRAC, did a pressure test to failure with his barrels on both chamberings for the BPCR's, and videotaped them. The receiver held to what I believe he told me 145,000psi, where it let go, and the barrel made it through, as I recall he said it could be unscrewed by hand from the receiver due to it "unloading".

Pretty interesting that, as I recall, he said the brass went basically liquid at about 80,000, and they had to beat the actions open to give them another pill up to 145k.

If you look at the barrel tenons on those rifles(High Walls), I believe they are only .825 major.

Ernie will talk your ear off about this stuff....

Show me pictures of blown up 1895's.

fireball168,

Thanks for the information. I now understand it, the receiver will blow up long before the barrel because the pressure acting inside the barrel actually produces much larger stresses on the receiver than on the barrel. That alas explains the desire to have pencil thin ultra light barrels on rifles, as they will have lower stress for any given internal pressure.

Out of curiousity, if the brass is gone ~ 90,000 psi or so, how does one achieve 145,000 psi? Wouldn't the gas pressure kinda fall off since the brass is no longer there to seal the breech?

Thanks again for the enlightenment. I did not realize the barrel on my M70 Supergrade was a Badger, nice to know. Helps explain that 0.75 MOA accuracy all of a sudden.

ASS_CLOWN