M14 Forum

Hauptgefreiter

I need some help with determining an accurate load for an M1A and M1 Garand with the 150 grain Hornady FMJBT and Hornady AMAX 168s:

My questions are:

1) Are there any benefits for accuracy in going over 2550 ft/sec? With other words, might a rifle be more accurate at 2800 ft/sec rather than at 2550 ft/sec, or does a muzzle velocity of 2600 ft/sec do the trick up to 600 yards and any higher velocity is just a waste of powder and unnecessary harm to the rifle?

More concretely, what would be the most accurate load judging by the data below:

2) M1 Garand, 150 gn Hor FMJBT bullet, FC brass, Win primer, OAL =3.300:
46 gn IMR4895, 2698 ft/sec, 6.5 MOA (8 rounds, 100 yrds)
47 gn IMR4895, 2689 ft/sec, 4 MOA (8 rounds, 100 yrds)
48 gn IMR4895, 2682 ft/sec, 3 MOA (8 rounds, 100 yrds)
49 gn IMR4895, 2807 ft/sec, 4.5 MOA (8 rounds, 100 yrds)
50 gn IMR4895, 2861 ft/sec, 4 MOA (8 rounds, 100 yrds)
51 gn IMR4895, 2904 ft/sec, 2 MOA (8 rounds, 100 yrds)

3) M1A, 150 gn Hor FMJBT bullets, FC brass, Win primer, OAL = 2.810:
40 gn IMR4895, 2576 ft/sec, 3.5 MOA (10 rounds, 100 yrds)
41 gn IMR4895, 2539 ft/sec, 4 MOA (10 rounds, 100 yrds)
42 gn IMR4895, 2693 ft/sec, 3.5 MOA (10 rounds, 100 yrds)
43 gn IMR4895, 2667 ft/sec, 3 MOA (10 rounds, 100 yrds)
44 gn IMR 4895, 2759 ft/sec, 3 MOA (10 rounds, 100 yrds)

4) M1A, 168 gn Hor AMAX bullets, FC brass, Win primer, OAL = 2820:

40 gn IMR4895, 2531 ft/sec, 3 MOA (10 rounds, 100 yrds)
40.5 gn IMR4895, 2560 ft/sec, 6 MOA (10 rounds, 100 yrds)
41 gn IMR4895, 2673 ft/sec, 3 MOA (10 rounds, 100 yrds)
41.5 gn IMR4895, 2660 ft/sec, 3.5 MOA (10 rounds, 100 yrds)
42 gn IMR4895, 2748 ft/sec, 3.5 MOA (10 rounds, 100 yrds)

nf1e@snet.net

Just looking at the data provided, it would appear that a barrel change would be in order for both test rifles. 2moa should be easily attainable with at least one or two, and probably more of your loadings.8 and 10 round groups are an excellent test. One last thought , was this benched, or offhand?
Semper Fi
Art

MFD

I have found that increased velocity does not necessarily equal better accuracy. However based on your data, the Garand shot best with the most velocity and that may well be the range of velocity it takes to deliver good accuracy. A 2" group, 8 rnds at 100yds with that bullet is not that bad for an issue Garand. As mentioned, would think you would have gotten equivalent accuracy with the M1A and even better with the use of the 168's. If available you may see increased accuracy with the M1A and your load using the 168's at extended ranges, 200yds plus, but just a guess for sometimes the bullet has not "settled down" at 100yds. Just a thought.
Both rifles are "brass eaters" and I am not a fan of Federal brass due to softness in the primer pocket and a switch to LC mil brass may give you better results. Perhaps a change in primers may reflect an improvment as well. You spent a lot of time developing your loads and at the range, but as a friendly reminder, make one change at a time and test for results of that single change. For the M1A further suggestion would be to obtain some commerical match grade ammo and see how it does. As I am sure you have, do a complete cleaning of the bores on both rifles and upon returning to the range, fire two or three fouling shots prior to doing the accuracy test. Out of curiosity, are your velocity numbers an average?? How much spread in velocity readings are you seeing, more than single digits?? Even at 100yds if you are seeing velocity spreads in the 30-60fps range, can make a difference in bullet impact and even moreso at extended ranges. Just a thought.

D308FAM

When in doubt...and IF possible....I like to test my weapons with known-to-be-good-quality factory match ammuntion so I have some kind of "baseline" to decide if any other loadings either are or are not likely to really be "better" given some known "best case" accuracy scenario in a particular specimen of firearm due only to its mechanical capability.
There IS good USA made quality match factory ammo available in both 308 Winchester and also 30-06 so this approach is something you can consider trying.
I would probably track down a box of Federal Gold Medal Match ammo for both the 308 Winchester and also the 30-06 and fire about half the box of each such that I had about 8-10 called shots across a chronograph and see what kind of group that ammo produced and then consider using that group as the likely "smallest size possible" group to compare your own handloads against. Not just the group size but also the chronograph results on the factory match loads chronograph data should be something to consider in your ongoing decisions about reloads. Some projectiles just seem to "group well" at certain muzzle velocities in certain types of firearms and it's sometimes worth checking out that approximate muzzle velocity range if accuracy/precision is a high priority consideration.
Clean the firearms barrel before starting any new ammo test and also inbetween "levels" of ammo and certainly IF the gunpowder changes as you are testing new loadings. I have joined others in noticing that shooting different types of gunpowder in otherwise similar handloads in the same firearm back-to-back without cleaning the barrel between them can easily "open up" groups of the second powder in the string for reasons I've never seen any scientific reason to quote but none-the-less it can happen and you don't want to get misled by this kind of thing IF the second load really is the "hummer" you are looking for (many have tried one gunpowder for the 200 and 300 yard lines in NRA High Power and switched to another gunpowder for the 600 yard line part of the match without cleaning inbetween the two powders and had the first several shots of the 600 yard string land far from where the rest of the remaining 600 "for record" shots ended up landing after the barrel "settled down").
I hope you find this to be of use or at least to be interesting.

Hauptgefreiter

Thank you for all your replies and input. The M1 is from January 1941 and has standard iron sights. Plus I am not the best shooter. The velocities are averages. The MOA values are mostly due to my shooting, prone rapid fire and sling supported.

I just have the dilemma that I generally feel like I am doing better with a hotter load at around 2700-2800 ft/sec than with a 2550 ft/sec load. However, a 51 gn load seems awefully hot for an M1 Garand, so I just wanted to get some feedback from people with more experience in reloading than me...

I guess I need to get some match ammo and some benchrest support to really see what works best in that M1.


Thanks! I appreciate every opinion!

Haupt

PhillipM

At Jim Owen's highpower class we evaluated loads slung up prone with a bag under our support hand. He said a roll of paper towels would work just the same although I don't think it would be tall enough for me.

I've been reloading for decades, but high power shooting competitively for two. I have found it just takes a run of the mill reload at short ranges of 200 and 300 yards to clean the target if the other two triangles of the accuracy triad, the shooter, and the rifle, are up to the task. 600 yards is another matter; that's where you need tuned ammo.

FWIW I scored my best in my service grade garand with a Nosler 155grain custom competition fired over a 46.5 grain charge of 4895. The sights are cranked up a bit and the action works so slow you are aware of the bolt and op rod spring events, ie, it goes clippity clop instead of one big bang! It shot like a laser beam the next match with my 1903 with a 97-2x in prone.

One thing I tried that didn't work for me was lighter bullets in the 125-135 range. I was in search of a low recoil round but low charge weights resulted in increasingly large groups. I got good accuracy when loaded with 51 - 52 grains but by then the recoil was right up there with a 168 so why bother.

RAMMAC

In general most rifles will have two or more "accuracy nodes"; meaning that you can usually come with two powder charge weights (using the same bullet weight and seating depth) that will provide the tightest groups possible. One node will be at lower velocity than the other. In my experience I have noticed that the low velocity accuracy node is usually at a point where the case is filled to about 93% of it's available volume with the powder you are using. The high speed node seems to be at a point where the case is filled to just over 100%.

The low speed is fine for short and medium ranges (0 - 299 yds and 300 - 600 yds). After 600 yards, the high speed accuracy node performs more consistently.

The problem with pushing high speeds is that the rifle wears more quickly and the bore fouls quicker. Both of which will degrade the rifle's accuracy potential over time.

I'm not a Garand shooter so I won't make any recommendations there but for the M1A, with a 22" barrel, 2550 fps with a 168gr bullet is usually a very accurate load. If the rifle and shooter are working well you should be able to hold 1 - 2 MOA at 100 yards from the prone. I wouldn't even worry about hitting 2600 fps unless I were trying to shoot past 600 yards (with the 168gr bullet).

tankerG

I emailed Accurate Powder several years ago asking for reload data for my .308 Tanker, and their chief ballistician responded to me with suggestions. I liked the fact that this busy man took time out to respond to me personally. I'd say don't count Accurate powders out of consideration.