[wombat12]

The MAS 7.5 has a working pressure of 49.000 the units of pressure, not 40,000. I have no idea where this figure came from.

The Book Of Rifles, Smith and Smith, copyright 1948, lists the M1929C at 40,000 PSI. That's the earliest reference I am aware of. I always assumed that the 40,00PSI was in deference to the M1907/15 M34 conversions which were designed for the 8mm Lebel, rated at 38,000 PSI. What is your source for the 49.000 PSI number?

 

[wombat12]

I defer to Kelt- in my experience the final authority on all things French (although I've not asked him about his favorite Bordeaux)!
Still not sure I'd be comfortable feeding a Berthier a steady diet of 50,000+ PSI ammo, even with a new bolt and barrel.

 

[wombat12]

Just so this is clear in my head, are we saying that the M1929C was loaded to 50,750Psi or that is the maximum pressure for the 7.5x54? The reason I ask is that reloaders routinely improve on the performance of the cartridge with no signs of excess pressure in the MAS36. Is this due to better powders or being done by increasing pressure to 7.62 NATO levels?

I really appreciate all who have added info here. It has been an education and has dispelled some long held beliefs.

 

[wombat12]

Another example of the 40,000 psi misnomer. They did testing on several Century 7.62x51 NATO conversions. I'd like some discussion of their findings.

http://www.jpfo.org/filegen-a-m/masrifle.htm

 

[wombat12]

I read this years ago. Toth went under,I under stand.I tried the solution,annd it was a flop.

Any theories on why the conversion doesn't work? Measured some brass I had handy:

7.5x54 Syrian surplus, unfired. Measured 9/16 up from base (amount Century cut barrels). Measured .4724"

.308 Privi Match, once fired (in a Savage10 FP). Measured .4665 at base.

The difference in chamber size doesn't appear to explain why the Century conversions don't work.

Gunsmith, you might be able to make a few bucks converting Century 49/56s to .308/284 Winchester . Shouldn't take much in the way of mag work and would still hold 9 rounds (plus one in chamber). Only question would be if there is enough metal left after cutting barrel 9/16".

 

[wombat12]

Gunsmith, Thanks for all the ihfo. Just shows that even being old and "well read" doesn't mean that you can't learn!