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Discussion Starter · #1 ·
I am considering purchase of a model 94 in 450 Marlin but have a question regarding frame strength. I own two 94 Big Bores in 375 Winchester. I know that cartridge operated at a factory spec of 52,000 psi and Winchester significantly strengthened the area near the locking. The case has an effective head diameter of .422 inches with a rim diameter of .506 inches. The 450 Marlin operates at a lower, 43,500 psi (if my memory is correct) but is a larger case with an effective diameter (exclusive of the belt) of 0.5121 inches while both the belt and base of the cartridge are 0.532 inches. Even with the lower pressure, the 450 Marlin exerts greater force on the bolt than the 375 Winchester (using the diameter of the effective head diameter rather than the maximum diameter, as the larger parts of the case such as the belt and rim only tend to spread out the force over a larger area). So why is it that the model 94s in 450 Marlin did not need the Big Bore frame modifications while the 375 Winchester did? Has Winchester (Miroku) used a higher strength alloy or has Winchester ultimately determined that the added frame strength was not required after all, or is the 450 Marlin a bit much for the 94 platform?
 

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Your assumption on bolt force and diameters isn't what is going on to decree the gun maker wrong. Your premise is invalid.
 

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Discussion Starter · #3 ·
Well nuts. Forums such as this one can be a tremendous source of information or a tremendous source of frustration.

It was not my intent to "decree the gun maker wrong." I was hoping to find someone who knew the answer as to why the 450 Marlin could be used with a standard model 1894 frame and the 375 Winchester required the heavier Big Bore frame.

As for my premise regarding cartridge diameter and back thrust force on the bolt, it is correct to first order. It assumes the cartridge is a right circular cylinder with zero cartridge wall thickness. This ignores cartridge web thickness and ignores the contour of the brass on the bottom inside of the cartridge. Without actually measuring these, it is impossible to know what they are and their impact on back thrust on the bolt. Also, we do not have the time pressure history to calculate the temporal characteristics of the impulse delivered to the bolt. Without such details, to first order, we model the system as a right circular cylinder at constant pressure and calculate the static force on the bolt as pressure times area. Doing that calculation, the 450 Marlin seems to deliver a greater force to the bolt than the 375 Winchester.

Now, with that out of the way, the question remains, and I am hoping someone with knowledge of firearms design or materials science has some insight to share. Why can the standard frame 1894 be chambered for 450 Marlin but the 375 Winchester cartridge required the stronger Big Bore frame? Is this a materials issue (different steel being used for the new production 1894s)? Is this a safety margin issue (was the Big Bore simply over designed)? Is there some other explanation?

As mentioned in the original post, I love the 1894 platform. I am seriously looking at the purchase of an 1894 in 450 Marlin. No one is attempting to malign the manufacturer.
 

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MrAckerM, Your Forces are correct.

I don't know why the Miroku actions are not reinforced. But you do raise a good question, maybe someone can give a good opinion.

My experience has been with the Marlin 336 in 375.

My guess is either better material or the Japanesse designer figured things closer to the limit.
 

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If I remember correctly, Winchester made the 450 marlin chambered rifles on the standard frame. That was before Miroku began making the 94. The reason that Winchester made the 375 on the bigbore frame was a matter of advertising, to make it look bigger and stronger. Did the 375 need a Big Bore frame? I don't think so, Marlin uses the standard frame 336 with good results.
 

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The .375 was introduced around 1978, at a time when Winchester was using “sintered metal” for the frame. I do not know for certain if this “mystery metal” was as strong as the forged steel used prior to 1964 or after ~1982, but I suspect it was not. This could explain Winchester’s decision to leave extra metal in the BigBore receiver.

You can’t really compare the 336 and M94 receiver strength because the former has a ‘better’ engineered frame with three sides taking the thrust, not just two sides as in the M94.

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I think you hit it right on Mr Day. Sintered metal was the factor.

The larger looking 375 receiver has nice lines, and loks better to me.


See Mr ackerm, some one on here always has the answer to your quesstion.
 

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Welcome to the board !

FWIW, I never experienced a bit of difficulty with the .450 Winchester Model 94 Timber I had; so if you want a .45 cal Winchester 94, then don't over think it - just buy it & never look back. :p

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Firearms makers DON'T usually produce products that aren't thoroughly tested as to pressure limits and SAAMI limits...asking the general public for specific information on engineering information is just asking for trouble, all you get is hear-say krap. If you want that kind of information go to the source..THE GUN MAKER.

Wiki has a very complete tome on bolt thrust that gives the various ways bolt thrust is/can be calculated...no rocket science here.

I have a Marlin 336 switch barrel(356 Win, 444 and 458 American) that can handle all the pressure of the 450 M and a 450 M BLR I can exceed SAAMI specs for the 450 M cartridge because the receiver can handle magnum pressures of ≈62 Kpsi...I DON'T ADVOCATE GOING BEYOND SAAMI specs either for the case OR the receiver at ANY time.

I also have bolt and SS guns for 45-70 and 458 American which has, basically, the same case capacity (≈75 gr H2O) as the 450 M and I SILL only load for the individual receivers pressure limits. but I can DEFINITELY exceed load manual pressure/velo limits for ALL the cartridges with respect to the individual receivers.

Good Hunting
 
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