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Old November 18, 2012, 01:23 PM   #7
Bart B.
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Join Date: February 15, 2009
Posts: 5,477
Note the chamber pressure stated in post 6 for this thread, "52,000 psi" is the military's (and many commercial companies still do that today) way of stating the pressure measured by the old copper units of pressure system. It is the same as SAAMI specs using the same system for the .223 Rem. which is 52,000 CUP; cheers for SAAMI using the correct pressure unit term. All the different 5.56 NATO live ammo with bullets spec for pressure runs from 50,250 cup to 55,000 cup, but the MIL SPEC documents state it in "psi" terms. Shame, shame, shame on all of them not using correct terms for confusing so many folks!!!!!!

SAAMI also lists peak pressure for the .223 Rem. using an electronic transducer measuring actual physical pressure force on the chamber wall which is 55,000 pounds per square inch; "psi."

Could someone please cite me a MIL SPEC document's web page that states peak pressure for any 5.56 NATO round at 62,000 psi based on peizo, strain gauge or transducer measuring system! I cannot find one anywhere.

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My Toy, it's a waste of time to try everything to duplicate the ballistics of a given cartridge in any rifle you own. Close is good enough. Unless your barrel and firing mechanics have the same dimensional and force specs and your ammo's loaded with the same lot of cases, primers, powder and bullet, then gets assembled to the same dimensions with the same neck tension producing the same release force needed to get the bullet moving. you'll spend a fortune trying.

No match winning and record setting competitor ever tries to duplicate someone elses load ballistics. Their stuff is different. And who knows; your load that's 22 fps slower than your dream load may well be twice as accurate.

Different lots of commercial centerfire match ammo for both rifle and pistol may well shoot equally accurate across them, but no two will have the same muzzle velocity. Even military M118 and M152 7.62 NATO match ammo has a 60 fps spread in acceptable muzzle velocity around 2550 fps measured at 26 yards from the muzzle.

Go figure all this out. Then go do well with whatever you chose.

Last edited by Bart B.; November 18, 2012 at 02:04 PM.
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