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I have a 1943 vintage SA M1 I just got from the CMP. It came with an uncut op rod and I added a Shuster plug. What are the specs on ammo I can safely use? Is it just bullet grain and bullet speed or a combination of the two.
EX) Just got a box of Winchester Super X. 150gr 2920 speed and 2839 energy. Bullet weight is fine but othe specs seem high. What kind of parameters can I use> Thanks for your help in advance.
Ed
I only use the American Eagle 150gr round that specifically states it is for the M1 Garand on the box. They are kind if hard to find, but better safe than sorry.
If you have an adjustable gas cylinder lock screw...called a Schuster adjustable gas plug, you can use any ammo you like because you can allow excess gasses to escape. You simply vent them and adjust the Shuster to your current ammo. A real pain in the butt though, because you have to do that every time you change any spec on your ammo.
You can use ANY ammo you wish.
Is that also the case with the uncut op rod and thanks for the responses
The uncut op rod could crack any time with any ammo. Or, it could function on for decades. I'd use a shooter op rod on a shooter rifle. I had a LL M1 SA 328219 and it had round firing pin, uncut op rod...and I didn't shoot it. I shot the other rifle. The one with common or replaceable parts. Others here will disagree.Quote:
Originally Posted by Interlake
I go with Browningautorifle. I have a Shuster plug fitted to my Garand. I use Prvi Partizan which is a bit hot and used to eject the cases a good 15 feet or more. The Shuster changed that to about 3 ft. When using my hand loads with 168 grn HPBT I don't need to change the setting unless it is very cold.
In short, the Shuster plug is the best thing since sliced bread.
How do you define Garand Friendly ammo if not written on the box?
Will just a 150 gr bullet do or are the other considerations.
One of the biggest issue is the speed of the powder burn. Modern ammo burns quicker than the original load, more quickly in fact than the Garand action can respond. What that speed is, I don't know. The technique with the adjustable plugs is to open the set screw way up* until the action won't cycle and then slowly close it again, 1/4 turn at a time, until it just cycles.
Bob
* The Schuster comes opened up already.
Exactly, so it doesn't matter what you're using after that. The pressures will be low enough.Quote:
Originally Posted by Bob Womack
"...specs on ammo..." The Rifle was designed and tested to use .30 M1 ammo not .30 M2. .30 M1 was loaded to duplicate the M1906 service ammo. It used a 174.5 grain bullet at 2800 FPS and was loaded to give more range in MG's. However, it was found it had too much range for the U.S. National Guard ranges so the Ordnance Board ordered a lighter bullet load. That was a 152 grain bullet at 2640 FPS. In 1940 the velocity was increased to 2800 FPS to match the ballistics of .30 AP and its 168 grain bullet.
Undocumented internet rumour has it that the M1 Rifle op rod can be damaged by using heavier than 180 grain ammo. Never seen nor heard of any such damage that was not totally hearsay on an internet forum in over 40 years. (I have personally fired 220's out of my rifle with no fuss. Wasn't a steady diet of 'em. They did truly astounding things to a ground hog.). Watch for the glib reactions here.
There is absolutely no documented ballistics lab testing that's ever been done proving anything one way or the other. And the whole thing has been argued about ever since.
However, the ammo used during W.W. II was called .30 M2. It used a 152 grain bullet at 2800 FPS with IMR4895 powder at 50,000 PSI.
JC took one of 'em to 120,000 PSI when the left locking lug cracked. He then fired a further 5,000 rounds of standard Service ammo, that'd be .30 M1, with no more damage of any kind.
Have a look here.
Ammunition for the M1 Garand
That appears to lay it all out. So with my uncut op rod and Shuster plug, I should be safe to use any non-high power loads. Thank you for everyones input.
According to Hatcher's Notebook the M2 was designed to replicate the M1906 round for all the reasons that Sunray described. The .30 M1 was the result of WW1 experience where the range of the M1903 and machine guns was not as far as advertised. The heavier bullets in the French Balle D and British MK VII carried further and were better for defilade fire. Testing at the end of the war with Swiss bullets from GP-11 showed that a heavier bullet was needed to get more range. To keep pressure the same, the velocity was reduced to 2,640 fps with the 172 grain bullet (all velocities were measured at 78' from the muzzle). The M2 was 2,800 fps, 100 fps faster than the M1906's 2,700 fps from the beginning. AP was 2,775 fps so pretty close to M2.
There is an interesting article on M1 Garand Ammunition and the Ported Gas Plug While not a ballistics lab, is shows a nice picture of how the port pressure is affected by different ammo types. The only op rod damage I have personal experience with is the tab at the rear wearing and the rod coming off the track when fired. Not sure why this happened, it was a CMP gun and only fired M2 ammo.
I stick with ammo that either says M1 Garand safe or make my own with powders in the burn range of IMR 4895 (my favorite is IMR 4064 but it meters like logs) and 150-175 grain bullets.
Dave
"...safe to use any non-high power loads..." Pretty much. No Hornady Superformance ammunition that used to called "Light Magnum" despite Hornady saying it's OK in semi-autos. Otherwise any 150 to 180 grain ammo will do.
"...my favorite is IMR4064..." Yep. It's far more accurate than either 4895.
"...the port pressure..." I think that's an internet invention too. When JC loaded to 125,000 PSI, there was no mention of port pressure. He was debunking critics, who were mostly advocates of the Johnson, who were saying the M1 wasn't strong enough.
Matching ballistics was likely more about logistics than anything else. There was no such thing as .30 M2 until 1940 anyway.
I don't think the Schuster plug is anything but marketing myself. Been shooting my Rifle without one for nearly 50 years now with no fuss.
There's yet another statement that shows no actual knowledge of the M1 operation and certainly no knowledge of the Shuster or other venting gas cylinder lock screws. That statement is wrong.Quote:
Originally Posted by Sunray
Yes, that will work just fine but I would take BAR's advice and just get another op-rod to shoot with if you could afford to do so because of the uncut rods are prone to crack and are less common and are usually put on corrected rifles that predate the revision to cut them.jmoQuote:
Originally Posted by Interlake
Most people are not going to use 180+ gr bullets and slow powders so the various types of pressure reducing gas plugs are pretty useless for the average M1 owner. Before these gas plugs existed people were shooting whatever ammo they had. A M1 is a pretty durable rifle and when properly maintained would take a steady diet of heavy bullets and loads to damage it. Most 150 gr off the shelf ammo puts less energy into the op rod than the heaviest M2 ammo.Quote:
Originally Posted by browningautorifle
Before the internet exploded with stories of M1s supposedly destroying op rods with sporting ammo we shot whatever came to hand. I know that to be fact. I never even heard of a part breaking. When the vented gas plugs came out I tried one and it eased up the ejection of cases and softened up the action without stoppages. That was forty years ago for me, parts are older now and have had more time to fatigue.Quote:
Originally Posted by bml
The OP asked about using a Shuster and a steady diet of the hottest ammo still won't do damage. Your brass will be closer after as well.