Shooting .30-06 in an M1 Garand

[Bart B.]

Originally Posted by HiBC

I can't answer your questions,Bart. I'm not Po and I never met him.

I'm willing to learn if there is something we need to know.

Master Po's data isn't based on factual velocity and pressure measurements like military ammo is.

[JohnKSa]

Superformance works by stretching the pressure curve. The peak pressure (what ruptures things) is kept under safe limits, but the propellant is designed to make the pressure peak last longer. That allows higher velocities without higher pressures.

https://www.hornady.com/support/supe...rated-firearms

"Superformance propellants provide a longer duration/application of peak pressure in the pressure time curve that occurs within the barrel (see Fig. 1 pressure curve). In other words, both Superformance and standard propellants provide an equally powerful “push” applied to the base of the bullet, but with Superformance propellants, the “push” is applied for a longer period of time."

Seems like exactly the kind of thing that would be very bad for a Garand since the longer the pressures stay high, the more likely you are to get pressures at the port that are higher than the design was intended to withstand.

"Due to the longer duration of peak pressure produced by Superformance™, the post peak/declining port pressure at common carbine and mid-length gas port locations is still higher than that produced by standard propellant. "

Seems pretty conclusive. But then they throw this in to confuse things a bit.

"However, there is very little difference in port pressure between Superformance™ and standard propellants at the rifle length port location."

And the pressure curve plots provided actually suggest that the pressure in the barrel past about the 15" mark could actually be lower with Superformance than with standard propellants.

At any rate, it's certainly "safe" in a Garand. It won't blow anything up since the peak pressure isn't any higher. Will there be too much pressure at the port for the op rod? The blurb suggests that there won't be. But I would still contact Hornady before I ran any Superformance through my Garand.

[Bart B.]

Hornady's pressure curves are not even close to what real ones are. Real ones peak about 5% to10% into the time lines. Not midpoint as Hornady shows.

[Jim Watson]

You got real pressure curves? I have been trying to get a look at an instrumented pressure curve of black versus smokeless but have only been shown pencil sketches.

[HiBC]

Master Po's data isn't based on factual velocity and pressure measurements like military ammo is.

Bart,given your background,very few people have had the resources you have had.
Rest assured,I'm here to learn from you,rather than argue with you.

I appreciate your contributions.

When I received my Garand, I was aware of the port pressure issue,so I set about finding some appropriate load data.

I found Master Po's page. On the page it says "Provided by the NRA" Maybe I'm wrong,but I connect that to a long history of DCM,CMP,and the NRA sanctioning of competition providing quite a pool of experience anout what works in a Garand.

I enjoy shooting my Garand. I don't shoot competition. The longest convenient range I have access to is 300 yds,unless I go to some ranch land I can access.

My needs are met by ammo that does not beat up the gun,is reliable,and acceptably accurate.

For myself,at the "stakes" I shoot my Garand,there is no trophy on the line.

In your case,trimming 1/2 MOA off the groups or gaining 70 fps are significant to winning.

In my case,a CMP rack Garand n decent shape levels the playing field.Its not all about focusing on the rifle or the ammo,

Of course,your primary asset was shooting skill. But in your league,to be competitive,the best in rifle and ammunition might be assumed. At least,there aren't any excuses.You shoot with the Big Boys or you don't.

For most Garand owners Its more on learning to shoot it to its potential.

I stock H-4895 in my teloading room for other purposes. I stock Nosler 168 gr Custom Comps for other purposes. I buy WW virgin 30-06 brass for other purposes.

I stock the CCI mil spec large rifle primer for other purposes.

With what I already have,I can load 46 to 47 gr of H-4895 behnd a 168 gr Nosler CC and have pretty good ammo that meets my needs.

Frankly,I did not devote time to learning if RE-15 or Varget or 4064,etc would serve "better" Same with 155 gr MK's or 175 g rMK's,etc.I found "good enough" to meet my needs. If shooting my Garand was my life and passion,then relentless improvement would be the order of the day.

But its casual recreation.

If I had reason ,or opportunity,to shoot 600 yds +,I'd probably switch to 175 gr MK's.

If there is any good reason to switch my load,especially for the good of the rifle,I'd be happy to know about it. Thanks

[Bart B.]

Originally Posted by Jim Watson

You got real pressure curves? I have been trying to get a look at an instrumented pressure curve of black versus smokeless but have only been shown pencil sketches.

Here's some smokeless examples ....

http://closefocusresearch.com/calcul...ty-gun-systems

And some black powder ones ....

https://www.google.com/search?q=blac...0ifYA55bbw-7M:

[Jim Watson]

"Keep in mind that the results rendered by the methods below are based purely on Math and Physics."

"This is a graph of a simulation of the 5.56 mm NATO round, being fired from a 20-inch (510 mm) barrel."

[Bart B.]

Originally Posted by Jim Watson

"Keep in mind that the results rendered by the methods below are based purely on Math and Physics."

"This is a graph of a simulation of the 5.56 mm NATO round, being fired from a 20-inch (510 mm) barrel."

So are those using crushed copper disks and piezoelectric transducers based on physics and math.

The graph link isn't working, please try again...... thanks.

[tangolima]

Originally Posted by Bart B.

Hornady's pressure curves are not even close to what real ones are. Real ones peak about 5% to10% into the time lines. Not midpoint as Hornady shows.

The Hornady curve is not scaled. It is just to show the difference between this powder and the rest. A qualitative comparison.

-TL

Sent from my SM-N960U using Tapatalk

[Jim Watson]

Texas Mac's black vs nitro was interesting, too bad he didn't use the same bullet for both.

[Red Devil]

Originally Posted by 44 AMP

...If the GI spec says a 150gr bullet at 2750+/- and the commercial ammo says its a 150gr at 2900fps (or higher??) do you think its the same pressure as the GI load??...

The problem w/ this is: The original 2740 fps M2 Velocity Spec was recorded 78' from the muzzle.

...which give an actual muzzle velocity of 2800 fps. Pretty std. for a 150 gr. 30-06 round.

And modern manuals reflect that.


The M1 Garand was also designed to handle the M1 174.5 gr. ammo, and both the M1 and M2 ammo were M1903 Springfield bolt action ammo before they were M1 Garand ammo.

If you stay w/ simple ammo like Remington green box and slow powders, the M1 Garand will be fine.

GarandGear.com's charts are also a good check.




Red