[davemccarthy707]

Originally Posted by jpattersonnh

Dave, If you notice, Ed Hoffer disagreed w/ him. Ed's a pretty smart guy. What is the issue w/ caution w/ these old rifles? You do what you want w/ your rifles, but for someone not familiar don't you think caution is best?


Here is an article you may find interesting. CUP Versus PSI

He is disagreeing with him because he is Canadian. Nothing more or less. I guess he doesn't know who CIL was. They were the 3M of Canada. However us Canadians can't build or design firearms. Except maybe, I dunno the M1 Garand.

[jpattersonnh]

Aside from the Ross, Canadians build great guns. That was not the point though, was it? The Firearm is a M93 or 95 Mauser. Dave, I completely understand your point, I truly do. My Dad was an engineer, He worked for Companies like Combustion Engineering and Grumman aero space. He designed part of the LEM. He thought me at an early age about pressure, and what variables can cause failure, such as pressure spikes. OK, we know 90% of Nato spec 7.62x51 has a thicker case. It also uses a similar burning powders. Sammi spec ammo can use either ball or stick powder that produce an average pressure, but can have higher spikes. Take most ball powders and develop a load in the winter, shoot that same load in 90 degree weather and see what happens. Powders like H335 or BLC(2) are great, but the loads need to be tailored for the ambiant air temperature. Loads I develop in the Summer w/ them do not perform the same in winter, loads developed in Winter may have serious pressure signs in Summer. Cartridges w/ stick powder tend to be less sensitive. It is MHO that caution is better in the case of 7.62x51 vs .308. That is all. I'm not sure where the thought of just because he is Canadian, that is why his info is questioned comes from. I also own 2 Canadian made guns. A No4mk1/3 Longbranch and a Cooey 12ga travel gun. Both are excellent. Information has been so muddled over the years that there is not one person that can show anything diffinative. The 7x57 was a low pressure round, the 7.62x51 is a little higher, .308 is slightly higher again w/ a similar weight bullet. The difference in velosity, although only 100fps w/ a 150gr shows this between 149gr nato and 150gr commercail. Volume of Water is less in 7.62 brass compared w/ commercail. So a case w/ more capasity and using a fast burning (cheaper) ball powder is more inclined to have a higher pressure peak since volume needs to be equal so to speak, relitive to burn rate.

[danf_fl]

I procured 100 rounds of 7.62X51 ammo that was slated for use in competition. 170 gr and 140 gr.
I plan to keep the 140 for the Mauser and shoot the 170 through the CETME Model C.

Thanks for the information. The information provided by all parties is of great benefit to me.

[smarquez]

For what it's worth, I shot probably 400 rounds through a 95 Mauser in 7.62. I used PMC, Federal that came in a white box all sold as 7.62. I think the old PMC boxes said "Ball". I haven't had it's headspace checked so I don't know if I have caused any damage. Now, I did try some Wolf ammo in a steel case that had to be hot. I only took 2 shots and had the cases stick, could barely lift the bolt and had primers backing out. I will load my own since I have all the brass now.