What's the methodology for working up a load for the M1 Garand?

[Mr. Farknocker]

I recently got myself an HRA M1 Garand and have been reading up about using factory ammo and reloading. I've decided to go the route of working up my own loads with IMR4895 and IMR4064 without an aftermarket gas plug and am wondering how you are supposed to do this. There's a ton of data out there about what load people use for a given bullet and what is recommended but unless there's some objectively verifiable means of ascertaining that the amount of pressure being generated is within the safe limits of my rifle, I am uncomfortable with simply relying on someone else's opinion.

When working up a load for the Garand, is the goal to find the powder charge at which point the gun fails to cycle properly for a given bullet and then work up from there until the action functions reliably and thereafter fine tune for accuracy or is it something else? If this is the case, at what point do you stop increasing the charge in your quest to find an accurate load?

I've been reloading my brass with Noslers' 168 gr. Custom Competitions HPBT bullets. If my memory serves me correct, my Nosler reloading manual indicates that the starting load is 48 gr. with a maximum load of 53 gr. (sorry, I don't have the manual in front of me as of this writing). I started off with 46 grains of IMR 4895, however, and have actually been working backwards down to 43 grains in 1/2 grain increments in hopes of finding out the minimum charge to cycle the action properly. The rifle cycles properly with all of the reloads and I'm beginning to wonder how much further down on the powder charge I'll have to go to determine the point at which the action will not cycle the ammunition properly.

Am I on the right track or am I way off base on what I'm supposed to be doing? Any guidance on determining the proper load for my Garand would be helpful? Is bullet speed and the use of a chrony the only reliable way to determine the proper charge for a given bullet/powder combination?

 

[rcmodel]

The newer Hornady reloading manuals have good service rifle tested data for 5.56 NATO, 7.62 NATO, and 30-06.

That's probably a good place to start.


IMO: 100% function and acceptable accuracy is much more important then Max velocity.
You can do that with a 100 or 200 yard range, a bench, & sandbags.

The sights are adjustable to make up for velocity / trajectory differences.

Without a chronograph.
Chronographs do not give you any indication of gas-port or chamber pressure readings!!

rc

 

[cfullgraf]

As rcmodel said, the new Hornady manual is a good place to start as they have a section on Garand friendly loads.

IMR4895 is one of the few powders acceptable for use in the Garand. With suitable loads with the Garand safe powders, an adjustable gas plug is not needed. H4895 is my main powder for the M1 but IMR4895 is an alternate if I cannot find H4895.

I load for my Garands to be a bit slower than military ammunition. While I do use a chronograph, it is not necessary. Virtually all 30-06 service rifle load data for Garands was tested in a Garand so the velocity obtained in your rifle will approximate the data's velocity.

In my opinion, Garands are fine old rifles that can be enjoyed for years but there is no need to hot rod the ammunition loaded for it. If you want a hot rodded 30-06, get a modern bolt rifle.

Enjoy your HRA Garand.

 

[rg1]

Garands have specific load data which is less than modern bolt action 30-06 data. Nosler says 44-48 grains of IMR 4895 with 165-168 grain bullets. Hornady in their Garand section says 39.6-47.1 of IMR 4895 for their 168 grain bullets. You should be in the 46 up to 47 grains max for 168 grain bullets. The data you mentioned is for bolt rifles and is too high for the M1 Garand. No need to load less than 44 grains to start working up. There's plenty of info available at sites such as the CMP forum. This info provided by the NRA is widely used as a guide. http://masterpostemple.bravepages.com/M1load.htm
Hodgdon's 2013 Annual Manual has an article comparing H 4895 with IMR 4895. In the article a load of 40 grains of IMR 4895 which is a very light load only showed around 2300 fps while a popular load with 168 gr. bullets at 46 grains showed 2600 fps. They used Sierra 168 gr. bullets with Win cases and Fed 210M primers. I'd start out by dropping 2 grains below suggested loads and work up to standard Garand data and not try reducing until it won't cycle. I wouldn't start below 45 grains of IMR 4895 with 147-150 grain bullets and not below 44 with 168 grain bullets.

 

[ArchAngelCD]

From what I've read it's really not the pressure itself that will cause damage to your Op-rod, it's the slower powders still building pressure when the bullet passes the gas port that does. You need to choose a powder in the correct burn rate range and the 2 you chose are safe.

Just a note: IMR4895 and H4895 are just about perfect since IMR4895 was the original powder used for Garand ammo but AA2495 is almost a clone to 4895 and AA2530 (the Camp Perry Powder) is the ball powder equivalent to 4895. I'm mentioning this because powders are hard to find so you have options if you need them.

 

[Grumulkin]

Besides not using too slow powders, one should also not use too heavy bullets; i.e., keep bullet weight less than 180 grains.

 

[USSR]

I've been reloading my brass with Noslers' 168 gr. Custom Competitions HPBT bullets. If my memory serves me correct, my Nosler reloading manual indicates that the starting load is 48 gr. with a maximum load of 53 gr. (sorry, I don't have the manual in front of me as of this writing). I started off with 46 grains of IMR 4895, however, and have actually been working backwards down to 43 grains in 1/2 grain increments in hopes of finding out the minimum charge to cycle the action properly. The rifle cycles properly with all of the reloads and I'm beginning to wonder how much further down on the powder charge I'll have to go to determine the point at which the action will not cycle the ammunition properly.

Am I on the right track or am I way off base on what I'm supposed to be doing? Any guidance on determining the proper load for my Garand would be helpful? Is bullet speed and the use of a chrony the only reliable way to determine the proper charge for a given bullet/powder combination?

You're going the wrong way, Farknocker. Ya want to start low and work forwards (up) with charge weights. That being said, the reloading manual data that you referenced (48 gr. with a maximum load of 53 gr.) is not suitable for the M1 Garand's gas system. Your original load of 46.0g of IMR4895 is good. Personally, I use 47.0gr with a 168gr bullet. The Garand is not a precision rifle, so just load 46.0gr to 47.0gr and go have fun.

Don

 

[NeuseRvrRat]

IMR 4064 is another popular choice for garand-safe loads

i recently started loading for a garand and i started with 46.0 gr of 4064 under a 150 FMJ M2 ball pulldown. i got 2400 fps. i was expecting a little more velocity. should i bump up the charge and get a little closer to 2700 fps or should i be content where i'm at?

 

[rg1]

I'd bump up your charge of 4064 to get to around 2650 fps watching for pressure signs of course and searching for the best accuracy. 2400 is slow for the 150 gr. FMJ-FB bullet in a Garand.

 

[USSR]

To put this in perspective: The charge weight of 1965 LC M72 Match ammo is 46.5gr of IMR4895 with a 174gr FMJBT bullet. Being match ammo, it is not a hot load (2650 - 2700fps). Now we are talking about lighter bullets (147gr - 168gr), so using less powder than the USGI match ammo makes little sense. Also, regarding IMR4064, since it is a slightly slower powder, you can argue using just a little more makes sense. Just MHO.

Don

 

[NeuseRvrRat]

i also had some instances where the spent case was ejected but it failed to pick up the next round. happened once or twice per clip. i did some reading and chalked it up to insufficient greasing. greased all the sliding and bearing surfaces and the next day it only failed to pick up the next round once. seems now that my load is light and i'm short-stroking.

 

[Slamfire]

I have been shooting a 168 with 47.0 grs IMR 4895 for decades, and since 2000 when CCI introduced its #34 Mil Spec primer, been shooting that load with that primer. Mil spec primers, such as the Tula 7.62 and CCI #34 are the appropriate primer to use. Commercial primers are more sensitive and increase the probability of a slamfire. IMR 4895 was the propellant used in most if not all National Match ammunition. There is no reason to rediscover the wheel. These loads can be cut to 45 grains without any function problems, I consider 47.0 a max load in a Garand.

Since my velocities with this powder charge with a heavier bullet is less than or equal to the desired velocity of military match ammunition, I have no concerns about pressure issues in my Garand.

[SIZE="3"][B]
M1 Garand  Douglas Barrel 1:10 twist [/B]			
								
174 FMJBT White Box 1968 NM M72, Headstamp LC67 match, box velocity 2640 fps 	
								
14 Nov 2011 T =  74 °F						
								
Ave Vel =	2592							
Std Dev =	28							
ES =	103	 						
High =	2647							
Low =	2544	 						
N =	10							
								
								
								
								
174 FMJBT 47.0 IMR 4895  Lot L7889 thrown LC62NM CCI #34 OAL 3.30  		
								
14 Nov 2011 T =  74 °F						
								
Ave Vel =	2632							
Std Dev =	20							
ES =	60	 						
High =	2671							
Low =	2611	 						
N =	10							
								
								
174 FMJBT 47.0 IMR 4895  Lot L7889 thrown LC62NM Tula 7.62 lot 1-10 primers OAL 3.30  
								
14 Nov 2011 T =  74 °F						
								
Ave Vel =	2582							
Std Dev =	15							
ES =	49	 						
High =	2602							
Low =	2553	 						
N =	10							
	excellent group						
			[/SIZE]

 

[NeuseRvrRat]

i would've used 4895, but it's impossible to find now (as i'm sure you know)

 

[Hondo 60]

The methodology of working up a load is the same for all calibers.

1. Start with a RECENT reloading manual.
Powders get reformulated, and testing equipment is updated, so sometimes charge weights are changed.

2. Begin with the lowest charge weight.

3. Make up say, 5 rounds.

4. Increase charge by a small number. Say, 2 or 3 tenths of a grain. Make another 5 rds.

5. Stay at or below the maximum. There's a very good reason it's the max.

6. Shoot your rounds, changing targets between charges.

7. See if you like any of weights, if not, change powder & start over.

Anyway, that's my method.