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Old October 12, 2011, 09:08 PM   #1
b money
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1980's data & new powder and a M1 Garand??

I bought a M1 Garand a few months ago and am just now starting to reload for it. With loading data fairly hard to find for the garand(I only know of the hornaday manual having a seperate section, which I dont have) I was wondering if a 1986 issue of american rifleman would be ok to use?

The data is as follows for IMR 4895 and 150grn HPBT
military brass-
48.5grns @ about 2730fps
49.0grns @ about 2800fps
comercial brass-
48.5grns @ about 2650fps
50.0grns @ about 2870fps
Would this be ok to use with modern IMR4895 and 147-150grn FMJ without bending the op-rod? If so how far sould I drop the starting load?

If anyone has a scan of the hornaday Garand data they wouldnt mind sending me I would greatly appreciate it

Thank you
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Old October 12, 2011, 09:18 PM   #2
mehavey
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See Master Po's classic website here:

http://web.archive.org/web/200006200...rpo/M1load.htm

(Note that although NRA-sourced, Master Po is about 1.5 grains too hot for my target tastes)


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Last edited by mehavey; October 12, 2011 at 09:46 PM.
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Old October 12, 2011, 09:36 PM   #3
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B money,

The old loads still work because IMR4895 hasn't changed significantly in all that time. Your op-rod needs to be in good shape.

Note that the Hornady manual loads are way milder than the old loads. I haven't had a chance to talk to their techs about it, but I believe they are falsely premised on the idea a medium load will get you lower gas cylinder pressure than a maximum load. In reality, powders with burn rates appropriate to the Garand will have the gas cylinder pressure peak in the middle range somewhere, about where Hornady's load maximums are. Above that, bullet velocity gain with additional charge starts to outpace muzzle pressure rise. As a result, the time between when the bullet exposes the gas port to the bore pressure and when it exits the muzzle gets shorter faster than pressure is growing. The result is it can't pressurize the gas port as much before the bore pressure drops to near zero.

The main thing is just to find a load that shoots as accurately as your Garand can take advantage of it. 168 and 175 grain bullets with IMR4895 in the 47 grain range, plus or minus a grain, often do well. With 150's, figure 48.5 or so will be close.
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Old October 12, 2011, 11:46 PM   #4
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My standard M1 Garand load is 47grn IMR4895 and a 145-150grn FMJ bullet... I did work up to this load and I suggest you do the same. I'm using Federal commercial brass and WLR primers. The rifle functions well with this load; I don't see any reason to hot-rod the .30-06 cartridge.
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Old October 13, 2011, 12:59 AM   #5
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Yeah I don't think there's any point to push the gun(or me) for no reason. So should I start at 45grns and work up(in both commercial and military brass) from there? Also when I work the loads up do I still look for standard presure signs or(because the max load for IMR4895 is well above 50grns) should I stop at say 49grns? Don't get me wrong I will always be looking for things out of the norm like pressure signs etc. Basically I'm wondering at what point to stop?
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Old October 13, 2011, 05:50 AM   #6
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Locked up, the Garand is one of strongest actions around. It is the Op Rod and the heel of the receiver that take a beating upon opening, and the weak links. So once you see classic pressure signs in the brass, you're way beyond system design. Stick w/ UncleNick's and Charlie's suggestions and you'll be more than pleased.
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Old October 13, 2011, 09:05 AM   #7
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I wouldn't load higher than 48 grains of IMR 4895 with 150 gr. bullets and would only load just a few at 45 grains which is a good start load. From 46 to 48 grains you'll find best accuracy and an optimal load for the Garand. I shoot 47-47.5 grains of IMR 4895 with 5 different 150 grain bullets in my Garands. I use RP 9 1/2 primers in Rem, LC, HXP, and Win cases. Watch cases closely for stretching as Garand chambers can and often are on the long side of spec. Make sure primers are seated flush or below. Have fun and the Garand is definitely a fun gun to shoot.
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Old October 13, 2011, 07:10 PM   #8
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Thanks everyone, just what I wanted to know. Just a theoretical question but what if you had a machine shop make a op-rod out of a block of billet steal. Improving it so it wouldn't have the "weak" uncut point. Plus billet is very strong(assuming the correct grade of steal was used). Would it then be strong enough to shoot factory ammo or using slower burning powder? I only ask because I know the receiver is very strong and the barrel is proofed to either 75000psi or 100000psi I can't remember which but in either case the rifle itself would be more than capable to shoot full power loads.

*Notice* I would not alter my rifle to do this even if it was possible, I'm just interested in engineering etc.
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Old October 13, 2011, 07:58 PM   #9
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This won't answer your question about the op-rod but, you can install an adjustable gas plug. The plug will allow you to use factory loads, without worry of bending the op-rod, or a wider variety of handloaded bullet wts. Brownells has them, Shuster and/or McCann "Adjustable Gas System".

I have the Shuster installed and use my M1 for moose hunting. The Shuster uses a set screw and the McCann uses interchangeable screws for adjustment.

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Old October 13, 2011, 09:19 PM   #10
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If you are worried about operating rod damage and are not competing in an as-issued rules match, the gas ports are the way to go. Not only do they protect the op-rod, but you can pick the port size to drop your particular load's brass nearby.

To protect the rear of the receiver, you want to be sure your op-rod spring is in good shape. I advise against the extra power types, even though I used to use them, because they can encourage slam fires by stripping a round from the clip too vigorously. The springs Orion has made special have mil-spec tension and are a stainless alloy, to boot, so they shouldn't go bad easily, and are what most folks now recommend as new replacements.

The op-rod's tube is what is vulnerable to bending. It is heat treated seamless 1050 steel tubing. You could try to use something else, but you need the right combination of springiness and toughness. You definitely don't want to change its weight, as that could affect cycling function.
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Old October 13, 2011, 09:40 PM   #11
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Yall have given good advice, as cheap as chronographs are now days all reloaders should have one, they will save a lot of guesswork on working up loads for a Garand or anyother rifle or pistol.
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Old October 14, 2011, 10:43 AM   #12
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One more note about scary Garand loads. The gun can take more than a lot of manuals would lead you to expect. If you are shooting surplus M2 ball that is old enough to have IMR 4895 instead of WC852, then you'll find it was loaded to 2800 fps as measured at 78 feet from the muzzle. The M2 bullet is 152 grains +0/-3 grains (150.5 grains average) and its ballistics cost it about 0.833 fps per foot of travel in that velocity range, so these rounds would be at 2865 fps at the muzzle, 2857 10 feet from the muzzle, and 2853 fps 15 feet from the muzzle on average.

Those velocities would be from a tight velocity barrel chamber and bore, and are likely to be lower in your gun (as will the pressure be). But my point is that it takes anywhere from about 49 to 51 grains of canister grade IMR 4895 to get that bullet to that velocity in a tight barrel using LC brass, depending on the lot number and on what primer you use, so you've got some wiggle room. The military used to use a 50 grain charge at one point, so their bulk lot of IMR 4895 at that time must have been close to what canister grade burn rates are today.

My main point is, while I would not encourage you to load hotter than necessary (no point in loading hotter than best accuracy anyway), if your gun's gas system tolerates surplus M2 ball then it tolerates the higher load levels mentioned anyway.
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Old October 14, 2011, 12:37 PM   #13
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Ok thanks for that reassurance UN. As far as what I'm going to load it will sart at 45grns and end at 48-48.5 but I'm sure accuracy will decline way before I get that high.

Also I didn't even think about the properties of the steel changing and especially the weight of the op-rod I was just thinking billet had to be better haha. The car side of brain took over on that one. I don't plan on shooting anything but reloads and M2 ball so I probably won't get an ajustable gas plug(you never know though) I was just wondering if it could be done. But after reading what everyone said I relized their would be no point even if it could be done.
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Old October 14, 2011, 09:38 PM   #14
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The spec values that people quote are very misleading. The military did not publish reloading manuals, the TM’s that people get these numbers were from spec values. What is not understood is that all these velocity and pressure values are traceable to Government acceptance barrels, I assume from Frankfort arsenal.

The 2750 fps +_ 50fps was not tested in Garand barrels but in vendor pressure barrels. Reference cartridges that gave spec values in the Frankfort Arsenal barrel where fired in the vendor barrel and velocities and pressures were “corrected” to the Frankfort Arsenal values. I don’t know the dimensions of that barrel but GI ammunition fired in my barrels is a lot slower, which makes me think the Frankfort Arsenal barrel was of different length.

GI ammunition is not hot, you want to keep your 150 grains velocities in a Garand below 2700 fps.


30-06
M98 26" 1-10 Wilson Barrel


150 gr FMJBT TW 56 Ball
24 Mar 04
T= 70 ° F

Ave Vel = 2680
Std Dev = 31
ES = 78
Low = 2620
High = 2698
N = 6
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Old October 15, 2011, 10:06 AM   #15
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You're overthinking this. 47gr of 4895 under a 150gr bullet. Done.
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Old October 15, 2011, 10:25 AM   #16
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Slamfire,

That's why I pointed out the velocities would be from a tight test barrel. If you look at the SAAMI specs, velocity and pressure barrels all have minimum chambers and specified bore dimensions. The length is standardized to 24" for most chamberings, including .30-06. LC test barrels are the same way, AFAIK, so I assume Frankford's were, too. The tight chamber is used because that represents the worst case for pressure from a given charge. Even so, lower actual velocity in a particular Garand will only tell you the pressure achieved is lower than the test barrel had, but that doesn't change the powder charge quantity, which is what the OP is concerned with not making excessive.

FWIW, did you tip your muzzle up before firing each shot? I once shot a fair number of rounds of LC 65 NM ammo through our club Garands. Tipping up to get the powder over the primer increased velocity about 80 fps and caused visibly increased primer flattening as compared to tipping the muzzle down and getting the powder away from the primer. That aside, with normal horizontal loading, one of the club Garands averaged 2495 fps with that ammo, while another averaged 2611 fps. The box said 2640 fps, but actual records show 2708 was measured in a test barrel (see table below). So, a span of 200 fps from test gun to sloppy Garand seems normal. You see the same thing running QuickLOAD. It'll hit some gun's numbers on the nose, but finding one 200 fps different (usually slower) just isn't all that unusual. Chamber size, throat length, lug setback, bore wear; they all take their toll on velocity in actual guns. They are, obviously, among the reasons there is no one best accuracy load for all guns; only ones that are best on average. You still end up having to test for what yours likes best.

This table is interesting from a couple of standpoints. One is the range of IMR 4895 loads used. It's probably a fair indicator of what lot variance was like for bulk purchases. Another is that FA seemed to try to lock in a load and stick with it for awhile. It may all have been the same batch of powder for '57-'60, I suppose.

Attached Images
File Type: jpg NM ammo load history.jpg (87.2 KB, 388 views)
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Last edited by Unclenick; October 15, 2011 at 10:32 AM.
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