Subj : Re: M1
To   : Weatherman
From : Moondog
Date : Mon Jun 08 2020 04:20 pm

  Re: Re: M1
  By: Weatherman to Moondog on Sun Jun 07 2020 01:59 am

 > -=> Moondog wrote to Weatherman <=-
 > 
 >  > -=> Gamgee wrote to Dumas Walker <=-
 >  >
 >  >  DW> I think that because I would want one I could shoot without
 >  >  DW> worrying about something happening to it, while I also admire
 >  >  DW> them for the history element.
 >  >
 >  >  Ga> Good points.  Just as an FYI, they do make special ammo just for
 >  >  Ga> an "original" (or partly original such as one from the CMP), which
 >  >  Ga> is slightly less "hot" than current commercial .30-06 ammo.  I
 >  >  Ga> don't think there are any safety issues with an older one if you
 >  >  Ga> are careful to use that type of ammo.
 >  >
 >  > I've read on the interweb that commercial ammo with bullet weights of 150
 >  > grains or less (although Hornady has a 168 grain load that is Garand frie
 >  > is suitable for feeding to your Garand.  I have purchased quite a bit of 
 >  > equivalent ammo from http://www.ammogarand.com and had good results with 
 >  > They are also a good source for bandoleers, en bloc clips, slings and som
 >  > other odds and ends M1.
 >  >
 >  >                               Regards,
 >  >                               -==*>Weatherman<*==-
 > 
 > 
 >  Mo> Bullet weight makes no diffeernce.  It's  the powder charge that
 >  Mo> determines the
 >  Mo>  pressure.  147-150 grain fmj is standard combat bullet, and some
 >  Mo> allied nations produced tons of it at the mil spec "Garand friendly"
 >  Mo> pressure.
 > 
 > I see, so the inertial mass makes no difference in the chamber pressure prof
 > nor does the bearing surface of the heavier weight bullet.  You've an amazin
 > grasp of physics.  Guess all my reloading manuals showing reduced powder loa
 > for heavier weight bullets are no good and should be thrown out the window. 
 > I understand it, the issue is not the actual peak chamber pressure, but rath
 > when it occurs in relation to the bullet's path down the barrel.  I shall
 > recognize you as the all-knowing, omniscient god of all things reloading, ye
 > will still defer to the judgement of those who have owned, shot, and loaded 
 > the revered M1 Garand rifle.
 > 
 >                                         Regards,
 >                                      -==*>Weatherman<*==-
 > 
 > ... 2 + 2 = 5 for extremely large values of 2.
Forgive me for my choice of words.

You are correct in terms of powder speed and initial pressure curve being
critical with an M1 gas system.  Again, my choice of how pressure was applied 
wasn't properly phrased.

The point I started with was relying solely on the bullet's weight to
determine if a round was safe to use was a poor decision, as ammo loaded with
modern (post WWII) powders may be fine in any other rifle than an M1.  The
M1's gas system was designed around using a 147-173 grain proijectile pushed
by a mid range powder such as IMR 4895.  I use powders such as IMR 3031 and BL
C-2 which would be fine in lighter bullets in a .30-06, however they would be
a bit too fast for an M1.  IMR 4895 or IMR 4064 are much better choices.

Even amongst similar speed powders the pressure curve is not equal.  The origi
nal M16 ran like a top when ran with a powder such as IMR 3031, but when
McNamera's whiz kids thought they'd save money by substituting it with a
surplus powder from recycled poweder from tearn down ammo (BLC-2
equivalent)the bolt carrier group would cease to unlock.  Changing the buffer
design resolved it's sensitivity to the pressure curve.

By the way, thank you.  I do appreciate the corection.

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