View Single Post
Old March 12, 2013, 07:16 AM   #29
AK103K
Senior Member
 
Join Date: May 1, 2001
Location: PA -- In the shadow of the Shade
Posts: 7,597
Quote:
The GI spec on 150gr ball ammo is 2750fps +/- 40fps. NOT 2900fps!
Yup, youre right. I was discussing the .308 vs 7.62 thing in another thread, and had referenced the 30-06 in it, and in a hurry, grabbed the wrong number. My Lake City manual from July 1969 lists .30 M2 ball at 2740 +/- 30 for a 153 grain bullet @50000psi.

That said, the reason the 30-06 was in the discussion I was referring to, was the "pressure" thing that always gets beat to death with the .308/7.62. I think it the same vein, there is relevance here.

SAAMI lists pressure for the 30-06 at 60000psi (sound familiar) and, as I showed above, my LC manual lists it at 50000psi. Now, curiously, SAAMI lists the .308 at 62000psi, and LC the 7.62 at 50000psi. It looks like there is some confusion here when stating what the definition of psi "is". I wonder if Bill Clinton isnt involved here.

As I had pointed out in the other thread this was being discussed in, I had a conversation with Speer a few years back on another caliber and issue, and they told me that a bullet of equal or similar weight, driven at the same or similar pressures, should give the same basic velocity.

That appears to be holding out here, in both cases, and I found this looking into it a little deeper, and this fella seems to have the same thought, and seems to have done a little more in depth research ....

http://how-i-did-it.org/762vs308/chamber.html (30-06 is referenced here as well)

Now, after all that. If what Speer is saying is correct, and if in fact, GI 30-06 and commercial 30-06 of similar weights are really very similar pressure wise once you get the indicator correct, I really dont see a problem here.

Now, if you dont buy into all of that, and are just going to base it on velocity alone, I seriously doubt that they would design the M1's operating range with a margin of error in that was as narrow as 100fps, give or take.

Whatdaya think? Am I out there, or maybe not?
__________________
“The enemy is anybody who's going to get you killed, no matter which side he is on.”
― Joseph Heller, Catch-22

Zeitgeist - The Movie
AK103K is offline  
 
Page generated in 0.04827 seconds with 7 queries