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Old March 18, 2013, 01:14 PM   #36
Bart B.
Senior Member
Join Date: February 15, 2009
Posts: 6,318
The reason you should not use commerical ammo in a Garand without an adjustable gas plug is becasue the military powder burned faster, creating less pressure, and a shorter explosion. The commercial powder in todays cartriges uses slower burning powder, creating high pressures, and in some instances, the burning of powder almost half way up the barrel. This can cause an ossilation of pressure, that really screws with the op rod gas system. Of course, this is identical round to round, so it does not affect accuracy, but it can seriously damage the op rod.
The arsenals and other military shops have used several makes and types of powders that are identical to canistered stuff civilian ammo makers used for both the .30-06 and 7.62 NATO rounds. To say nothing of the many thousands of rounds of commercial match ammo loaded on the same machines with the same commercially availabe components producing the same peak pressures as military ammo that was used in both M1 and M14/M1A rifles without any problems whatsoever. Especially the popular '50's and '60's Western Cartridge Company .30-06 match ammo with 180-gr. bullets seated in two different OAL's; long for single round loading and standard for clip fed ammo in rapid fire. While some commercial powders are slower than what military ammo uses, their peak pressures in the commercial ammo is no different than it was years earlier with faster powder. SAAMI's specs have not changed. And much commercial .308 Win. ammo's loaded today with the same powder as it was years ago and it's totally safe in 7.62 M1 and M14/M1A rifles. The military marksmanship teams handloaded many thousands of rounds of ammo with commercial powders (cases, bullets and primers, too) using the same charge weights as the arsenals did with the powder they bought from commercial companies. Their rifles did not have adjustable gas plugs. But the gas port in 7.62 NATO Garands was larger than the ones in .30-6 barrels; less port pressure from smaller powder charges.

Most rifle powder's not all consumed by burning until the last kernel's well down the barrel. Don't know if anybody's every measured it; it happens. With the M14's gas port about half the distance back from its muzzle than the M1's gas port is, there is no difference in powder residue in the gas systems of both.

And I have checked, a clip IS NOT considered a magazine, because it is ejected automatically when it is empty, it is fully inserted into the firearm, and it does not contain a spring.
Some clips have springs that hold the rounds in them but do not feed the ammo for loading; original Mauser, M1903 and M14 five-round ones as well as larger capacity ones for the 5.56 NATO rounds and the thousands of commercial ones used in bolt action box magazine repeating match rifles such as the Win. 70 and Rem 40XC having clip guides in their receiver bridges. None of these clips are fully inserted into the firearm's magazine; their bottom's about 1/8th inch clear of the magazine when its charged with live ammo.
US Navy Distinguished Marksman Badge 153
Former US Navy & Palma Rifle Team Member
NRA High Power Master & Long Range High Master
NRA Smallbore Prone Master

Last edited by Bart B.; March 18, 2013 at 01:20 PM.
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