7.62x51 starting loads

N

Nate762

Inactive
Hi all, first post here and I just joined,

I have questions about a starting load for 7.62x51 cases, aguila headstamp. Rifle is a DPMS GII AP4 with 7.62 chamber, 1-10 twist. Bullets are Hornady 168 Amax and Hornady 168 match.

The powders I have to try are H4895 and IMR 4064. I just picked up the revised LEE manual. Powders listed for Amax are neither powder I have. The old Lee manual I have doesn't list Amax, but 168 jacketed starts at I believe around 39 grains for h4895. The new manual states 40 grains starting. Hodgedon is different still and largely lists only for Sierra matchkings.

I keep finding different starting loads for basically the same bullets. I was under the impression that loads will likely top out for me between 40 and 41 grains of h4895. A friend at work loads 40 grains max for his M1a with matchkings. I know I don't have to worry about an operating rod like him but he saw pressure signs in primers above 40 grains. I'm aware our rifles are different and each will behave differently.

Jist of what I'm asking is, what can I use as a safe, useful starting loads that will operate my gas system?

Thanks,. Nate
 
Also, I plan on picking up a Hornady 10th edition manual as well to try and find more data as I believe they have a service weapon section.
 
I cannot speak for Aguila brass. I know a cases water capacity determines how spacious the brass is for its acceptance of gunpowder. 7.62x51 has less case volume and I down load the brass by 1 gr and it is necessary with LC ar any other NATO brass. Other than that I would start low at .308 data and work to the mid range. Should be close to 7.62 x51 that way. Good luck and be safe.
 
Most of my 30 cal rifles respond the best beteeen 41.6 and 43 gr of powder. Lots of variables to precision handloading. Barrel length plays a significant role in final velocities. Test, document, and pay close attention to your primers for excessive pressure signs when loading above 43 gr. Good luck. I enjoy loading and testing just as much as shooting.
 
I'm aware of the case capacity difference. Are you saying that you start the loads 1 grain less than the starting load listed for 308? I'm sure that's fine with h4895 as there are reduced loads for it but what about IMR 4064? Or any other powders?

Also, does anyone have any experience with these two powders and 168 Amax bullets? I'm not finding any load listings for the combination.
 
As long as you are over 80% case fill you should be fine with IMR4064.

Use the data for a similar 168gr match bullet. Yes there are differences, but essentially they are all boat tail match bullets. I try to avoid going from boat tail to flat base because flat bases don't compress as easily in the bore (they have that solid plane of gilding metal to compress).

Jimro
 
The LEE manuals are simply compilations of other(often obsolete) data and shouldn't be your primary source. Get the Hornady (and hopefully another source such as Lyman)before doing any loading. I've have excellent results with IMR 4064 in .308 accuracy loads using 155 BTHP but it doesn't meter as well as the ball powders.
Loading data WILL vary due to different bores, powder lots, and bullet lots. You need to understand that the data given produced the pressure/velocity shown IN THE SPECIFIC CASE, BORE, AND CONDITIONS at the time of the collection. That's why we start low and work up within the parameters of OUR specific equipment.
 
Nate762,

.308/7.62 cases have the same exterior dimensions, but after 300 Win Mag, they have more capacity variation by brand than anything else currently on the marked. I've had cases that weight as little as 150 grains to as much as 186 grains, and have heard of some 190 grain cases from South Africa. The alloys aren't all the same, but you can correctly guess from those numbers that internal capacity varies a good bit and I have no idea where Aguila fall in that range. You best bet is to measure them and report the result back to us. I can tell you the heaviest case I've had needed about 2.5 grains less powder to reach the same peak pressure as the lightest case I've seen using 168 grain bullets.

This is easy to do. You take a fired case that still has the primer in and that has not been resized yet. You pick one that is average weight and length. Weigh it dry. Fill it with water level with the mouth (no meniscus), tapping it a little as it fills to dislodge any air bubbles. Add water or use the twisted corner of a tissue to get the water level with the mouth. Make sure there are no drops on the outside. Weigh it again.

Subtract the dry weight from the wet weight. Tell us the difference and what the length of the case was and we can tell you what other brass it seems closest to and what the starting load should be.

If this is all too much and you just want to do a conventional load workup, I can tell you the Hornady book uses the same starting loads for both bullets in 7.62×51, but they are very light loads and may not function your weapon until you work up further.

These starting loads are:

34.8 grains H4895
36.1 grains IMR4064

The maximums are for their own Hornady/Frontier case which is fairly roomy, IIRC, so I won't give you those. I'll just suggest about 0.8 grains is the largest load increment I would use for stepping the loads up from the starting level.
 
Thanks all, but if you will note Im not using Lee manuals exclusively. I use hodgedon, Lee, Lyman and online sources to compare and contrast loads. I did just pick up a Hornady yesterday and they are in contrast to others still.

Hornady max loads are almost the same as the starting loads of others. I will start with the 2400fps loads listed for Hornady and go up as fore mentioned, I'm not sure if it will cycle my gun any lower that that.

I load for .380, 9x19, .38/357, .44 mag, 454 casull, 45 colt, .223, .243, 25-06, 45/70 and 45/120 sharps. I would load for .40 as well but I'm not allowed to run reloads through my issued duty weapon. I haven't run across quite so much varying loading info except now that I have a .308 autoloader. I guess that solidifies the fact that it's a versatile round and eats all different powders.

I've only been reloading for 15 years, which is just a drop in the bucket compared to other people. I was at a friend's house shooting one day and ran out of 45 Colt. I already collected my brass since I was a kid because it seemed like such a waste to leave the shiny stuff laying around. He said okay let's load some up. I didn't realize he reloaded and we made some darned accurate rounds for cheap. I was hooked. I already was shooting muzzleloaders in competition so I knew how reloading worked aside from the major differences in smokeless vs black powder. I do load BP in that Sharps I listed.

I look forward to reading more on the forum. I find experience in addition to sound and careful practice to be the best approach.
 
Nate. Sounds like you are good to go. I'll tell you how I do a pressure check with unknown components. I charge one primed case with the starting load and one with the next charge increment and so on all the way to the warmest load I've found for it, but I only seat a bullet in the starting load. I put a small Neoprene stopper in each of the other cases and take a Lee Hand Tool and the seating die and appropriate shell holder and bullets to the range with me.

At the range, I fire the starting load, and assuming it shows low pressure, I seat the bullet in the next charge and fire that one and keep going until I see a pressure sign or make it to the top. I am careful the powder has fallen back over the flash hole for each shot, as that produces the maximum pressure I will see out of it. And it does matter. I've seen .30-06 National Match ammo go from a rounded primer with the powder over the bullet to a flat one with the powder over the primer.

I always use a chronograph doing this as one pressure sign is failure of the velocity to increase or perhaps to even to go down with a charge increment. I look to see the velocities plot a fairly straight line up as I shoot. Plotting velocity on a piece of graph paper as you shoot can be helpful for this.
 
Unclenick,

That's a great idea. I happen to have a Lee handheld press and I could always order a Lee loader (great for range) for it. Appears 4064 may fill the case more which is what I want. I would use varget but I can't find any around me. It's like it's completely disappeared. None at LGS, including Cabela's or field and stream in Columbus, OH.

One store nearby is getting out of reloading and they have most powders going for $20 a pound! I picked up more universal yesterday as I use the crap out of that for .38 and 9mm. They have plenty of 4064, and h4895 in stock.
 
IMR 4064 is a great powder for this cartridge. Federal uses it in their Gold Medial Match .308 ammunition, though I believe they buy lots with extra blending for an even more consistent burn rate than what we get off the shelf as their charge of it is the same today as it was 20 years ago. I know they get a flash suppressant added for the military sniper ammo they make. With the 168 grain Sierra MatchKing bullet they use 43.5 grains which is about half a percent more than the powder space, so it is slightly compressed. Being compressed locks the powder in place so vibration from transport doesn't settle it further.

If you go on line and read Lee's instructions for the Lee Loader's, they don't use a press of any kind. They are complete reloading tools and need only a plastic head mallet plus bullets, powder and primers to work. If you just wanted to use one case for all the tests and dispense the powder at the range, that would make sense. But you'll recall the Lee hand press works with standard press dies, so your seating die is all you need. I you set the seating die up on the hand press and use it at home for seating the first bullet instead of using the seating die in your bench press, then you won't even have to change the setup to go to the range with it.

If you have one, the Redding Competition Seating Die is so good at aligning the case and bullet that I don't find the results with it in the hand press are appreciably different than using it on my Co-ax press.
 
One of my best loads for 7.62x51 is 41.5gr imr4064 behind a 168amax in lake city brass. Its a very mild load but shoots great in everything ive run it in. I believe starting load is 41grains according to my hornady manual.
 
Nate:
Also, I plan on picking up a Hornady 10th edition manual as well to try and find more data as I believe they have a service weapon section.
Click to expand...

Here is the service rifle load data for 30-06 Springfield and .308 Winchester (7.62 x 51). This is Hornady 9th Edition Servioce Rifle load data. Something else worth a read and some consideration if you are loading service rifle for the M1A for example is this read from Zediker. Note where he gets into the powders with a focus on powder and port pressure.

Ron
 
(if you go on line and read Lee's instructions for the Lee Loader's, they don't use a press )

Yes, I have several Lee loaders for various calibers. They are my shtf reloading must have items. I find them pretty handy but in retrospect, I see it wouldn't do my rifle much good as they neck size only.

I even bought a set of powder dippers a while back. They are usually pretty close to the charge weight they specify by volume. I use them a lot and trickle any difference onto beam scale. I don't have a powder thrower as I prefer to weigh my charges but I may get one soon because I don't need my pistol rounds to be that exact and running 100+ loads at a time gets old weighing them all
 
My guess for accuracy you will land between 41.5 and 42.5 gr 4064. 42-42.5 shoot extremely well in many 308s with 168. Start from the bottom and work up but 42 is almost magic. Shoots well in both of mine and many others.
 
I have a 50+ year old semi auto .308 (Winchester Model 100) that I handload for. Several different factory loads showed pressure signs and I don't want to damage the rifle. I'm using LC Brass and a 165 Speer BTSP with IMR 4064. Its a very mild load using 42gr of 4064 has no pressure signs and it suprisingly accurate. My Speer manual has a start of 41 and a max of 45.

OP I'd start in the 40gr range and slowly work up till you find your max.

1stMar that weird I just noticed your post and you said 42gr is "magical" in a lot of .308's with a 168 I am using a 165 though. I'd say your onto something because my .308 was made in 1962 and that load does 3 shots @ 100 yards sub-moa the last several times I've shot it.
 
Also reloading 7.62 for .308

New poster here. Really apprecaiate all the previous posters in this thread and the great insight they provide.

I Just came into some mixed 7.62 brass and want to reload for my .308 bolt action Stevens. My previous reloads used .308 LC 72 Match cases. Using Unclenick's procedure above, I have checked the capacity of the 7.62 cases from the several different manufacturers that I have, and they all are larger than the LC cases (55.5gr) I previously loaded.

7.62 Headstamps water weight grains
RIMI A 56.0
RIMI B 56.6
*7.62* 57.3
AFF 55.5

When using mixed brass, would it be safe to work up a load using the smallest capacity case, and then load them all to the same charge (powder weight?). I'm thinking yes, but I would suffer some decrease in performance (pressure and velocity, accuracy?).

Is that decrease in performance important/significant? If my 7.62 case is 3.6% larger than my LC case capacity, if same is applied against velocity, that's a loss of about 100fps. Is that right?

Your thoughts greatly appreciated.
 
Welcome to the forum.

Yes, the loads developed in the tight cases are safe in the looser ones. A load developed in the 55.5 grain case water overflow capacity (CWOC) case will likely shoot about 40 fps slower in the 57.3 grain CWOC case.

QuickLOAD shows that for a peak pressure match, your 55.5 grain CWOC cases need about 1.0 to 1.1 grains less powder than the 57.3 grain CWOC cases do. This assumes same bullet and same seating depth. When the peak pressure matches, the smaller capacity cases will deliver about 20 fps less velocity because, even though the peak pressure matches, the smaller quantity of powder will produce lower muzzle pressure, and that faster pressure drop in the barrel will produce a little less final velocity due to lower late-barrel acceleration.

Re-reading this old thread, I realize I missed mentioning that a Lee Loader, which resizes only a case's neck, is really not suitable for loading for semi-automatic rifles. It can cause feed failures and increases the chance of slamfires if you don't bring the whole case down to size.
 
Thank you. I'd be happy with that. Convesely, if I wanted to attain the same pressures in the 57.x CWOC cases, I'd have to up the powder 1.0 - 1.1 gr. ???

re: case sizing. so when comparing apples to apples we probably need to compare case volumes on those cases that we've actually fired in subject weapon. Or is that variance with other chambers so small that it is insignificant (with regard to bolt action versus semi auto) ?
 
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