Garand loads

[gunney 67]

what's a good load for the Garand (147gr. fmj) to eliminate excessive pressures at the op-rod, but still reliably cycle the action?

[Unclenick]

The Hornady manual has a whole separate section of loads for the Garand, though they are far milder than those published in the American Rifleman in the late 80's. They are getting more concerned about the age and strength of the op-rods these days. It is very conservative, but if your gun is old, it won't hurt. Hornady also makes one of the better FMJ bullets (150 grain). I've had some very bad ones in the past that had trouble staying in 3" at 100 yards even from a match accurized rifle that shot match ammo to well under 1 moa.

Hornady's manual uses 43.2 grains of H4895 to start, and 46.4 grains maximum. That is very light. My book shows I used that powder with 47.6 grains under that bullet weight and that it was still very mild. H4895 burns a little faster than IMR4895, and that results in somewhat lower gas port pressure for a given peak pressure the load is adjusted to.

The other thing you can do with the Garand is get one of the ported gas cylinder plugs that vents excess pressure. You can start with it wide open (or largest hole, if it has fixed steps rather than continuous adjust; both types are available) and just keep tweaking it tighter until the op-rod just does its job and the brass isn't being thrown a mile away.

[kraigwy]

A tad bit off topic. I dont shoot the 147s but I have a lot of pulled 173s. The Army list 50 grns of 4895 for the 173 grn military match bullet. In compairing my reloads to the M72 30 cal match, I found that 47 grns of 4895, M72 brass, Fed primers, equal the Army's 50 grn load, both in velocity and impact in my M1.

I would recommend you start by adjusting your load to match the army's specs, then tweek it tell the accuracy suites you.

[Unclenick]

I'd read in several places that the last order the DCM placed for M72 used 46.5 grains of IMR4895 (but with a military (magnum) primer, which likely accounts for that half grain charge's worth of performance difference you see with the Federal primer). I pulled 20 rounds of M72 several years ago and found that 46.5 grain charge was about right (forgotten the year headstamp). The only place I've seen a 50 grain load for M72 mentioned is in TM 43-0001-27, but I notice they list the exact same load and same pressure for M2 ball with its lighter 152 grain bullet, changing only the MV by 100 fps. So I think the M72 load listing is either a typo or it and the pressure are upper limits that are not not necessarily reached by most batches of non-cannister grade IMR4895 in reaching the desired velocity in a test barrel.

[cobra81]

You want to keep muzzle velocity below 2750 fps to avoid damaging your op rod. I shoot a lot of the pulled 147gr. FMJ's, with 47.6 grs. of H4895. That gives me 2600-2700 fps over the chrono, with CCI 200 primers in LC brass.
Good accuracy, cycles the action every time, and never any signs of overpressure.

[hodaka]

I got a CMP HRA Garand this year. I have been experimenting a bit and have settled on IMR 4064 as my most accurate power. I shoot 168's with 47 grains and 155's with 48 grains. I've also been shooting the 155's with 47.5 gr. of RG-4895. This is good, but not quite as good as the 4064.These loads have been very consistant in velocity.

[AlaskaMike]

Has anyone used 3031 for Garand loads? Seems like it would do pretty well.

My normal load seems about the same as most of the others listed here: pulled M2 bullets over 47.0 grains of IMR-4895 in mil cases.

Mike

[Unclenick]

Cobra81,

Actually it is the gas port pressure that determines how hard the op-rod runs, and that varies with the powder type. 9,000 psi is the port pressure M72 produces with a tight match barrel and chamber when the powder is loaded to the full 2640 fps, which takes about 47.2 grains of IMR4895 according to the model for that powder in QuickLOAD. I use that number as an upper limit for all my Garand loads, since op-rods are getting harder to find. But the light 147 grain bullet lessens that pressure considerably when driven to 2700 fps. It doesn't offer as much of Newton's equal and opposite reaction force to build pressure against.

For example, if I drive a 147 grain FMJ BT bullet seated to 3.150" at 2700 fps with IMR4895, the port pressure for the same model is about 8,600 psi. If I drive it to 2700 fps with IMR4064, that drops to 8430 psi. If I get to 2700 fps with IMR3031, the port pressure drops to 8,330 psi. If I drive the bullet to 2700 fps with IMR4198 (and yes, that can be done well within SAAMI chamber pressure maximum) it drops to 7,120 psi. And even if I bang that up against SAAMI maximum pressure (producing 2900 fps in QuickLOAD), the port pressure is still a very safe 7,600 psi because that powder made all its gas early and couldn't keep pressure up through the expansion ratio (not that I am recommending you work up to maximum in your older gun, but this is just to illustrate the point.)

So, anyway, there is no simple velocity limit that can be applied unless you also specify a bullet and powder choice.


Alaska Mike,

There used to be more IMR3031 used. The March-April 1985 issue of Handloader had a Jon Clark article on match loads for the Garand, and he listed IMR3031 loads for bullets ranging from the 150 grain Sierra MatchKing to the 190 grain SMK's (neither the 155 gr. SMK nor the 175 gr. SMK had been introduced to the public at that time).They were:

SMK,      charge,        MV measured
150, 48 grians,          2785 fps
168, 44.5 - 46.5 grains, 2599 - 2697 fps
180, 44.0 - 45.0 grains, 2592 - 2632 fps
190, 43.0 - 45.0 grains, 2387 - 2562 fps

The article also lists velocities for the different case capacities available at the time, though some of those designs, most notably the Winchester, have changed since it was written. As and example:

168 grain SMK, 47.5 grains IMR4895, Federal 210M (then called BR210) primers.

Case, MV measured
RP,   2674 fps
FC,   2681 fps
WW,   2694 fps
LCM,  2697 fps

RP=Remington-Peters, FC=Federal Cartridge Co., WW=Winchester-Western, LCM=Lake City Match.

The test rifle was a match M1C built by Springfield Armory, so the barrel and chamber were tighter than average for Garands, and the op-rod would have been brand new. The chronograph was an Oehler 33, so the readings should have been reasonably accurate. If I had more time, I'd check the case fill % for the 3031 loads, but have to go do some work.

Given that the Garand op-rods are now aging, I would be judicious about working up to those loads, but in a new rifle they should work out.

Nick