7.62x51 NATO (.308 WCF) in the Springfield M1A

This was the first try with cast boolits in my brand-new M1A, which has had a tad less than 500 jacketed rounds through the tube. It wears the issue iron sights.

For the first 'go', I took a leaf from BobS' Garand book, and went with olde H4831, charge weight 35.0 grains with both designs fired today. This load was the subject of much thought before I chose the charge weight, because it's basically uncharted ground. This is why I'm pleased to be able to post about it, so others don't have to do the same "interpolation" schtick.

The bullet designs were Lyman's 311672 and 311299. 672 is a bore-riding 167-grain job much like a SAECO RG-4 in profile, to my eye at least. 311299 is a reduced-diameter version of 314299, a famous bullet intended for the .303 British and other "fat .30s". My 311299s weigh 210 grains, cast hot and fast, and water-dropped in straight WW alloy, as were the 672s. Lube was the Felix stuff, of course. All bullets were sized at .311". Primers were CCI #34 "military" type. All rounds were fired with a timed one minute interval between shots, with ambient temperature at 59 degrees and NO wind. The barrel never got more than comfortably warm...easy to touch, in other words. Cases are unfired (new) pull-down Lake City 1988.

For the 311672s, I loaded two ten-round batches, one batch with a TINY dacron tuft (because there's not much room in a 7.62 NATO case above 35 grains of bulky powder) and the other batch without dacron.

I fired five rounds of the NO-dacron rounds first. The initial two rounds went through the same hole from 50 yards, PRECISELY on the point of aim/zero for 168 Matchkings at 2600 fps! "OOOooooh", sez I. The next three rounds landed progressively further down the target, and ended in a total group of about 3.5 inches.

Average: 1414fps; extreme spread: 102 fps; standard deviation: 47 fps

Hmmm. So, I switched to the 311672 WITH dacron, and this time the first THREE rounds cut into a single hole on point of aim, followed by one hole an inch out at 4:00 and the fifth an inch out at 10:00, for just over a two-inch group. Now, check out the readings WITH dacron, after the group being barely HALF of the no-dacron group:

Average: 1524 fps; extreme spread: 60 fps; SD: 22 fps

I admit to being surprised here. Over 100 fps higher speed, and about HALF the ES and SD, all for a truly MINISCULE bit of dacron!?!?

I refired both loads on the original target for each, and the groups did not enlarge over the initial five rounds. The chronograph readings also stayed very close to the original results.

Shifting to the 311299 load, the group formed about 1.5" above where the 672s were landing on their targets. 299s did not demonstrate the movement of successive impacts, and the entire ten rounds ended up making a 1.5" group These rounds had NO dacron.

311299, average: 1546 fps; ES: 117 fps; SD: 36.

Notice that with this same charge and a bullet 43 grains heavier than 311672, the velocity was just about the same as the 311672 with dacron..

Pressure with all loads was very mild. The cases were FILTHY, indicating marginal obturation (based on observations with the service-level Matchking loads). The primers are also VERY rounded compared to those same jacketed loads. Ejection was a great deal softer than with the jacketed loads, especially with 311672. The 299s were much snappier than the 672s, but still nowhere near the functioning speed with Matchkings.

It's my conclusion that these carefully-figured loads are operating on very safe ground, pressure-wise, and I can safely work them up without worry.

Here's one of the neat parts: even with some rounds dropping down into the high 1300s for speed, the rifle functioned PERFECTLY, even to the point of locking open on the empty magazine! This is awesome, to me.

On inspecting the rifle afterwards, (only 30 rounds fired, of course) I found no evidence of leading or excessive fouling anywhere. Since the flash suppressor prevents looking sideways at the surface of the bore at the muzzle, I contented myself with a hard look down the barrel and saw no visible leading. The inside of the suppressor can sometimes tell us a tale, but in this case I found it totally clean, without any of the gray wash I've seen in similar places on other rifles.

Am I happy? You bet! I've been looking forward to this day for months, and it went very well indeed. This is one IMPRESSIVE rifle. By the time NCBS 2006 rolls around, I'll be sure to have plenty of good, tested loads for y'all to shoot.

...........Sounds like you're on to something Bruce.

"............By the time NCBS 2006 rolls around, I'll be sure to have plenty of good, tested loads for y'all to shoot."

HA! Wonder what it would cost to get the Rooles Komittee to allow it in a stake or balloon shoot?

...........Buckshot

I had an M1 Garand, didn't care for it much. I ended up trading it for my 22-250. An M1A always interested me, now more than ever. Thanks BruceB

David

Hey, it looks as if you've got the M1A perking. I'll bet if you keep the 35 grain charge and use a heavier boolit the velocity will be even higher. I found this to be true when using a .30-30 and 4831.
Did you have much unburned powder left in the bore? -JDL

JDL, pard;

That is precisely what the next batch consists of, 311284 (222 grains) with the same 35 grain charge of H4831 plus a couple of additional loads at 36 and 37 grains. Also, I loaded 311299 with 36 and 37 grains of the same stuff for trials.

I'm off work on Tuesday and Wednesday, and hope to fire these rounds then. The weather is cold and nasty , but being able to shoot from inside Der 'wagen sure helps that situation a lot.

It seems I have enough different boolit designs in the appropriate weight bracket (150-220, I think is reasonable) to keep experiments running for a long time.

I intend to stay with the slower-burning range of powders for at least a while, and there are many candidates there as well. IMR4831 and 4350 seem obvious, and "45-2.1" has strongly recommended AA3100 for this application, too. If I could get a good accurate load with something in the 180 grain-200-plus bullets at maybe 2000 fps, I'd be pretty well content. All I really want is a load which allows reaching 200 yards or so with a good chance of hitting accurately at that distance.

Of course, "good enough" is never really good enough, and I reckon I'm doomed to experiment until my shooting days are over!

Good functioning is also a requirement, but it sure doesn't look like that'll be a problem, given the results so far.

311284 has to be seated to about 2.722" over-all length to keep the front band out of the rifling origin. 311299 and 311672 can be seated a tad over 2.780" and still chamber freely. Rounds MUST be free-chambering for these semi-autos, without any restrictions due to land contact, etc.

I'll be running tests with 311466 and 311467, 155 and 180 grains, as well. Both are the Loverin design, with feed-friendly shapes and reputations for good accuracy. Then I have 311334, 311314, and a bunch of others that will likely get trial runs. I can see a LOT of shooting ahead.

This project is also the first serious use of my new chronograph, a 'CED Millennium' from Dillon Precision, courtesy of my wife. So far, it's been a real revelation in ease of use and excellent function. Hope that continues!

On today's trip to the range with the M1A, I fired some 311284s (222 grains in my water-dropped WW alloy, .311", Felix lube, Hornady gaschecks), as well as some 311299s, same as on the last occasion.

From 50 yards, off Der Schuetzenwagen's benchrest, I got the following results with H4831 powder and CCI #34 primers:

311284, 35.0 grains, av 1697; es 91, sd 28; 10 rounds scattered to 2.8".

311284, 36.0 grains, av 1770; es 81; sd 32; 10 rounds scattered to 3.1".

I dry-brushed the bore for forty strokes at this point.

311284, 37.0 grains, av 1815; es 168!?!?; sd 54; 5 rds in 1.04" and 4 in 0.40"....the widest shot was called "out" as soon as the hammer fell.


311299, 210 grains: 36.0 H4831: av 1575; es 63; sd 29; 4 in 0.45", fifth round tipping and making the group 1.01"

311299, 37.0 grains, av 1651; es 146; sd 53; 5 in 1.15".

I don't like the wide velocity spreads in some of these, but I'm gonna keep working with this H4831 with more loads and see what sort of history accumulates. Clearly there is some hope in the experience so far. It'll be interesting to see what powders just a tad quicker might do, and I'll try IMR4831 and 4350 soon.

Temps today were much cooler at around 40 degrees, but rifle and ammo aren't affected much since they are inside the van. I did find that even firing every thirty seconds never heated the barrel beyond mildly warm to the touch.

The rifle continues its unbroken record of PERFECT function, at over 500 rounds so far. I like it better and better, every time I take it out!

Got one of those myself. I often wondered about the Pb in the gas cylinder thing. It"s double lugged into the Kevlar stock. I guess I'll have to keep wondering. Great report on the M1A. :)

BruceB,

I buy one gun a year. Keep it up and It will be an M1A.

David

Continuing tests with 4831, but this time with IMR 4831, NOT H4831. Good weather, 45 degrees, some gusts of 20 mph or so.

311284, same specs as before:

37.0 IMR 4831: average 1907 fps; extreme spread 56; standard deviation 17.

50-yard group stringing vertically, 2.8" for 10 rounds. Note that velocity is almost 100 fps higher than with H4831.

311467 Loverin, same as before:

37.0 IMR 4831: av 1860; es 89; sd 30

This was a bit of a puzzle. The first round landed several inches high with the hole clearly indicating a tipping or yawing bullet. The next two came in an inch or so below the first one, nice round holes.The last seven formed a separate group an inch or so lower yet, and all seven snuggled into 0.8". All shots were called good from a very solid rest.

311467, 38.0 IMR 4831: av 1928; es 75; sd 22. Ten rounds formed a loose-but-round "group" of 2.3"....but it looked better than the mess created with 37.0 grains.

When loading this last bunch, I sorta "discovered" some linotype .311" .30 HBC boolits hangin' out on the bench, so, "Why not?" (Sigh) THIS is "why not?"

.30HBC, 35.0 IMR 4831: av 1789; es 88; sd 39, figures taken from only five rounds fired.

Four rounds grouped in a lateral 1.8", and the FIRST round was four inches below those four. Again, all shots called good from the rest.

.30 HBC, 38.0 IMR 4831: av 1912; es 53; sd 18. Ten rounds in 5.5" at 50 yards....yuck.

What I've been doing with this rifle so far is identifying load levels that allow it to function, plus some interested watching for indications of future accuracy loads. I'm pleased as all get-out with the rifle to date, so now I moved into another uncharted zone for my semi-autos by trying a load with IMR 4198.

I KNOW the 4831s are "too slow" for the 7.62 NATO... but they work fine at low pressure, even with wider velocity spreads than I like. I also KNOW that the 4198s are "too fast" for the same cartridge IN A SEMI-AUTO.... but with the way the rifle tolerates low port pressure from 4831, I wanted to make an assessment of 4198 in the same rifle.

311467, 22.0 IMR 4198, dacron fill: av 1838; es 63; sd 19. The group was fully 3" for ten rounds at 50 yards.

The load was carefully chosen by comparing personal previous safe loads with the same powder and similar bullets in the .303 British, .30-40 and .30-06.

Allowing for differences in case capacity and other factors, I came up with 22 grains, and it performed exactly as expected, since my forecast was 1800 +/- for the load fired today. 1800 fps happens to be about where I want my future plinking and target loads to be, too, so the estimate was dead-on for my purposes. The REAL question was how the rifle would function, and ....it doesn't quite digest this load. It ejected all ten cases successfully, but failed to feed the next round on every shot, which naturally means the bolt isn't coming back far enough to pick up the next round. This of course is no fault of the M1A, since I was feeding it ammunition which simply failed to develop enough pressure at the gas port. It MIGHT function properly with 311284, it being forty or so grains heavier, but I think for now I'll drop down the burning-rate ladder a tad and try some 3031 and 4895 loads.

It's fascinating, being able to actually SEE the different burning rates modify the rifle's function. I've been through this with quite a few semi-autos over the years, and it is always an interesting quest.

It was a grand, glorious, beautiful day on the range...and the weather was pretty good, too.

Trying to get some rifles in trim for the Nevada Shoot next month, I took an assortment of goodies to the range today. The battery included the M1A. I zeroed my Ruger 77 in 7.62x39 at 1" high @ 50 yards, followed by Karen's M77 .270 with a similar zero. Both grouped VERY well, under an inch in the final groups.

The M1A came last, as I had about a dozen experimental loads to run. My rifle does NOT like the classic 311284 bullet in any load yet tried, as witness below:

311284 (WW, water-dropped, .311" sizing, felix lube) ALL WITH DACRON

28.0 IMR 3031: 1848 avg; 126 extreme spread; 35 std dev; 3.5"/10 rds/50yd

29.0 3031: 1940 av; 44 es; 14 sd; 3.5"/10 rds/50

30.0 3031: 2002 av; 58 es; 22 sd; 5"(!)/10 rds/50

31.0 3031: 2034 av; 39 es; 13 sd; 3.7"/10rds/50

32.0 3031 2084 av; 78 es; 20 sd; 4.0"/10 rds/50

I was pretty downcast after all this, questioning the rifle, the ammo, and my shooting. However....

311672 (WW, water-dropped, .311", felix lube) ALL WITH DACRON

27.0 3031: 1764 av; 101 es; 37sd; 2.25"/10/50, but with 7 in 1.2"

28.0 3031: 1830 av; 159 es; 52 sd; 2.4"/10/50, but eight in 1.10"

29.0 3031: 1917 av; 140 es; 42 sd; 2.1"/10/50, 8 rounds in 1.2"

30.0 3031: 2000 av; 90 es; 30 sd; 1.5"/10/50, and 9 in 0.90"

31.0 3031: 2046 av; 90 es; 30 sd; 1.4"/10/50, and 9 in 0.80"!

...and for the grand finale, the last group I shot today involved a load which I reduced slightly from an earlier attempt. #311467, the 180-grain Loverin, had shown a few tipping bullets when loaded over 37.0 of OLD H-4831, but still put eight rounds into 0.70" the last time out. I decided to see if reducing the speed might also stop that tipping, and that's exactly what happened:

311467 (WW, water-dropped, .311", felix lube) NO FILLER:

35.0 OLD H-4831: 1694 av; 56 es; 18 sd: TEN ROUNDS IN 0.60" at fifty yards. I have done found my load for the Nevada Shoot, I do believe...

All groups were shot with the issue iron sights. Perfect function was achieved with all listed loads on this expedition, including locking the action open on the last round. Groups were fired starting with all ten rounds in the magazine. (One minute between shots, five minutes between strings) All shooting was done from Der Schuetzenwagen's benchrest with the help of a Cabela's "Ultimate" rest, which does NOT have all those fine-tuning micrometer super whatsits all over it...just a pair of felt-lined cradles for butt and fore-end.

I'm including all the 'bummers' simply as information for anyone looking for data regarding functioning issues for 7.62 NATO rifles in the future.

I LIKE THIS RIFLE. 311672 has started showing some real promise, but my mould for that 'un is a measly 2-cav job, and I have a FOUR-cavity 311467! Gee, I wonder which one gets the nod....?

Bruce,

Hey pardner...that's some damn good shooting with iron sights. Looks like you indeed do have your load. I think it's very cool you're getting a M1A to shoot cast and function and with accuracy.

Joe

.............Heck Bruce, 0.600" at 50 yards for TEN ROUNDS at 1700 fps and the rifle cycles. Yeah, I think I'd stop there and call it good. What the heck else would you do for an encore? Looks like the ole 311284 may have had guidance issues.

.................Buckshot

That 0.60 surprised me, too, since I'm really having trouble seeing iron sights clearly of late.

The targets are a standard pistol "center" folded precisely in half, so that the aiming mark is a black semi-circle with the flat side down. This is placed on a blank piece of paper so there's a clean contrast for silhouetting the sights. I find the flat bottom of the aiming mark gives a more-visible index both for elevation of the front sight, and also for minimizing any tendency toward canting of the rifle. This isn't my invention, as the Canadian Army was using the idea for probably about a hundred years now, and that's where I picked up the concept.

I fired the first three rounds of this group before peeking into the spotting scope, and then wondered where the rounds had all gone. Turned out they were all snuggled into the same biggish hole right at 12 o'clock on the line of the ten-ring...call it two inches high and dead-center for windage. After the preceding scattergun performances, it was mighty nice to see. I immediately went into that inner turmoil state of "DON'T SCREW THIS UP, DUMMY!!!!" which I'm sure everyone will recognize. With seven rounds still in the rifle, it was an exercise in self-control, lemme tell y'all.

Getting home, I quickly ran an inventory for boolits....311467, check. WW, water-dropped, check. .311", check. Felix lube, check. ....and it turns out that I have about 800 bullets of PRECISELY that description READY TO LOAD. What a wonderful state-of-being that is! Those coming to the Nevada Shoot will be able to try this rifle out for themselves, with plenty of ammo on hand. I don't even have to mess with my beloved dacron in this load.

Seems like sometimes, though rarely, things actually do work out.

Bruce,

That group also speaks for your fast and consistent casting method. Good show ole chap.

Joe

................Re: "Just coming together".

I've had a couple instances of this whilst stumbling and bumbleing around without rhyme or reason. Not to say YOU were :-) One was with the SR Mauser in 35 Rem. My one real 35 cal rifle boolit for it is the Saeco # 356, a 200gr FP with GC. Doing load work surp WC846 seemed to be in the right speed realm so I started a bit below what I thought a good statring load would be. Then loaded enough (60 rounds ) incrementaly until the boolit's bum was firmly on, but not compressing the dropped charge.

At first I wouldn't have bet a plugged nickle on a positive outcome. Yet I felt the easiest way to rid myself of the ammo was to unload it through the muzzle. As I shot, it became a bit interesting. Then moreso. I had started too low with this powder. As the case filled, two neat things happened. The velocity increased which is to be expected. But also the velocity variations disappeared and the groups tightened.

As I fired off the last 3 five round groups the velocity tipped over 2300 fps and the rounds ended up snuggleing right down into a scant inch at 50 yards. There we go! Stop right there, plant a couple trees and build a house as I'm home.

The other was the 7.62x39 in another SR Mauser. Ditto pretty much with surp 4895. A full caseload under the Lee C312-155-2R nets 1950 fps and stack'em right in on top of each other. Throw away all the other effluvium in the notebook and cast that load in concrete :-)

..................Buckshot

Quote:

---

Originally Posted by Buckshot

.............Looks like the ole 311284 may have had guidance issues..................Buckshot

---

These range results made me curious about the actual dimensions of the 284s, too.

The mould is an older 'Ideal' -marked single cavity, for which I waited a long time before it came up on Ebay. I prefer the older ones in many cases, because they often cast a bit fatter than current-production moulds.

Checking the dimensions of the actual bullets in the batch fired on the day in question, I find that the nose is .2995" and the bands are right at .311", so I really don't see much in the way of problematic dimensions. I'd rather have the nose more like .301", but....?

However, I can take a hint, as administered by the 311467/H4831 load that shot so beautifully. I now have over 500 rounds loaded with that combo for the entertainment of visitors. I also think the M1A will be my iron-sight "competition" rifle... why not? It's outshooting all of my iron-equipped bolt-actions! In loading all those 500+ rounds, I visually checked every single powder charge, simply because of the long-stick format of the 4831 granules. I found exactly ONE instance wherein the charge did not drop from my Uniflow, but that one occurrence made all the checking worthwhile.

In an effort to avoid this in the future, I plan to do two things...one is to try the load with H4831 SC (short-cut) and the other is to run a series with H 335 or maybe something a bit slower in ball powders. The ball types make for greater confidence when running big batches on the Dillon 550, since they pour like water. H335 does NOT work at all well in my .30-06s, and in the Garand H 335 gave repeated and consistent hangfires. (I'm finding 335 rather useful in my new Interarms .223, giving me 3290 fps from the 20" barrel with 52-grain match HPs, and with good accuracy.)

..................BruceB, do a test if you would, when you have a chance. Take 10 of those 311284's and when they are fully in the lube die apply some extra grunt to see if you can't form a bulge rigth there at the turn of the ogive. Carefull as that old scraper groove in front of the top drive band can allow the nose to lean over. Ask me how I know :-)

Of course you have a fantastic load already, but it would be interesting to see if it made a difference.

Mike'em to see if they come up to 0.300"+ or more. Load'em and shoot'em and see what happens. I had a Lyman 400gr 40 cal mould for my 40-65 and it wouldn't shoot fer beans. The nose was like .398" or some such. I bumped them in the lube press and danged if they didn't do twice as good. I shucked the mould, cause heck if I'm gonna do that all day to a bunch of 40 cal boolits! Got a RCBS 410gr mould, and no problems.

...............Buckshot

Awk! A "Pogo Stick" shooting into 0.60" at fifty yards? Looks like big trouble for the dueling Springfields at this year's NCBS. Multi magna congratulations!

Right now I am regretting braying about the wonderful .60 group, at least in public like this.

What if it was the ONE occasion when ten flyers fluked into the same hole????? What if it NEVER HAPPENS AGAIN????? My sorrow would be boundless.

Gotta have faith...gotta have faith....ommmmm.... ommmmm..... will Hare Krishna meditations and chants help?....ommmmmm.... Naw, fergit it.

Careful loading and careful triggering WILL let the rifle shine. I BELIEVE, pilgrims!! (So there....get thee behind me, Satan!)

The M1A survived the glare of publicity at the Nevada Shoot in pretty good fashion, I'd say. That load which gave me the wonderful 0.60" group was mass-produced for our honored guests to try, and I had close to 500 rounds of the recipe on hand when it all started.

Checking just a few minutes ago, I seem to have something less than 100 rounds remaining, and a LOT of empty brass. What impressed me the most was the utter EASE with which everyone was hitting the gongs, from off-hand, yet! Deputy Al's first shot (from standing) at the 6" round 100-yard gong was dead-center, and I suspect his hit average over about forty rounds was 95% or better, on a variety of steel targets. Others did equally well, and I think Curmudgeon on one occasion emptied all fifteen rounds from the magazine (all that I'd stuffed-in, before giving it to him) without a miss.

The 311467/35.0 H4831 load is JUST marginal for function. While it worked 100% from the benchrest, it would occasionally fail to open the bolt far enough for ejection when fired off-hand. Some unburned powder appeared in the action area, but nothing was left in the bore except some very fine dusty-looking debris in the bottom of the bore. NO leading appeared, even when the rifle was so hot I couldn't hold the HANDGUARD, never mind the barrel!

I took advantage of having my whole outfit set up on the range to test-fire a few new and different loads in the M1A. Since I didn't have my usual grouping targets posted, I just fired for chrono readings and function. H4831 SHORT CUT, loaded on the Dillon 550, ran a wee bit faster than the original H4831, and seemed to function well. A few loads with H335, again loaded on the 550B, also functioned well and gave standard deviations as low as TWO fps and extreme spreads down into the single digits on five-round samples. I'm eager to get these loads out for a full accuracy trial!

Note that 4831 Short Cut metered perfectly in the 550, and I checked every round to make sure! H335, of course, is a slam dunk for easy metering. I intend to get out for some extensive shooting next week, and will post results here.

The longer this rifle stays with me, the better I like it.