Heavier '06 bullet loads for the Garand

[condor bravo]

I seem to have an excessive quantity of 190 and 200 gr .30 caliber Sierra bullets that I would like to cut down on by loading some for '06 Garand ammunition. My usual loadings for 150, 168 and 180 grain Sierras are 45 gr 4895 and 4064 and have tried a few clips with the same powder charge using the 190. Some primer flattening, not excessive, is noticed with the 190s and the loading manuals indicate that the 45 gr powder charges are OK for both the 190s and 200s. So I guess the only question is, does the port pressure remain essentially the same with the heavier bullet loadings and not subject the op-rod to additional strain? Velocities from the loading manuals for the heavier bullets and 45 grains are suitable.

 

[Unclenick]

Port pressure remains the same, but the gas impulse does not. Because the bullet is moving more slowly it takes longer to move from the gas port to the muzzle, so the gas port is exposed to the pressure longer, allowing it to dump more gas into the gas cylinder. For that reason you want a lower load level than you use with lighter bullets.

I strongly recommend you get a vented gas plug or a hollow one from Garand Gear for shooting the heavier bullets so you don't have to wimp them down too far.

 

[condor bravo]

Thanks, will take that advise. I figured that something else would enter into the equation.

 

[Slamfire]

The NRA had loading data for those heavier bullets, and you really have to cut the loads. I have tried 190's with a vented gas cylinder lock and the recoil was still nasty and it was hard on the gun. Accuracy was not as good as I got with 168's or 175's.

Let me recommend that you shoot those heavy bullets up in a nice 30-06 bolt gun.

 

[condor bravo]

Well yes I do have several bolt .30 calibers that I have been using the heavier bullets with, '06s to some of the belted mags. The NRA Garand loading data for the heavier bullets would be beneficial.

 

[condor bravo]

Slamfire and Unclenick:
I think I found the NRA article (by John Clarke) that Slamfire is referring to. It covers both 190 and 200 gr Sierras. For the 200s, 43 grains 4895 and, I think a grain or two more with 4064, are shown with Federal brass. For the 190s, 45 and 46 grains are shown with Remington brass, so should reduce that by a grain or so with Federals (although have used 45 gr with Federals). With the above loads velocities might be considered to be getting a little wimpy. Good article. Recently obtained another good supply of once fired '06 Federals. However was the last batch that my source from Prescott, AZ had.

 

[Unclenick]

Both TAR (March, 1986 issue) and Handloader published Clarke's workups. We require permission to put up copyrighted material here, but someone at the CMP forum created a link to a copy in post #2 of this thread.

 

[condor bravo]

Hmmm: not sure I follow the meaning of the reference to the link creation to post #2 of the CMP forum thread (which brings up the article). Does the posting of the article, by the CMP forum or someone else, to the internet constitute a copyright infringement? I was actually a little surprised to find it there.

 

[T. O'Heir]

Funny how the very mention of anything heavier than a 180 will cause huge arguements and start riots, but M-1 specific data exists.
Used a box or so of factory 220 Silvertips long ago. Did friggin' astounding things to a ground hog. No damage whatsoever to my rifle either.

 

[condor bravo]

I'm pretty much with T O'Heir on this heavy bullet subject and my theory is that the Garand is certainly rugged enough to withstand the pounding with the heavier bullets, providing the port pressure is kept with tolerable limits. To continue with the 190s and into the 200s, I will be reducing the powder charge to 43gr 4895/4064 which should, I guess, reduce gas volume at the port (per Unclenick's information re: increased gas volume at the port with heavier, slower moving bullet) and perhaps exercise some control over port pressure. At the moment will not be replacing the gas plugs for three Garands. All comments on this heavy bullet or related subject are invited. Note to those questioning the admonishment not to use factory '06 rounds with the Garand (especially with heavier bullets), this is because they could be loaded with slow burning powder like 4350 which maintains higher port pressure longer in getting the heavier bullets out of the barrel and perhaps strain the operating rod.