7.62 Lake City Brass and IMR 4064

[TheClasonater]

Just came across som LC brass and intend to work up loads for a couple 308 m77 bolt guns with Speer 150 grn hot cors and IMR 4064. I've never loaded LC brass but am gearing up start with 556 as well. I have a swager coming in the mail to head of those questions.

Now for the conundrum. The manuals I have start data around 43 grns with IMR 4064. And of course, I go reading the forums and red flags and sirens start going off every where that even starting loads could be over pressure. I have no problems starting below minimums, but how low should I go. There is only so much powder and so many bullets right now if you catch my drift. I do have some blc2 on hand but would rather save it for other loads.

 

[eyeshot]

I think I read that the military brass is thicker than the commercial and in turn holds 1-2 grains less powder.

I don't understand how this would relate to pressure so I just bought commercial to reload with until I grasp the situation.

 

[Random 8]

I've been running 44 gr with the same 150 Hot core in PRVI NATO contract 7.62 brass and SB primer. I don't remember my COL, but I'd describe it as "standard" based on printed references. It is a relatively mild .308 load, and very accurate in my wifes rifle. It chronoed in the 2700 ballpark. I've also used the same load in LC and WCC brass with no pressure signs. Accuracy is outstanding. If you'll be using Win, LRM or NATO primers, I'd back that off a grain or 2 to start with.

I've found IMR 4064 to perform well a bit below listed start loads, so don't be afraid to start low and at least make up a 3 shot sample to get a feel for what your pressure curve is doing. You may find a remarkably accurate target load. My .308 and 30-06 basically shoot .300 Savage loads, and they kill plenty deer.

 

[lightman]

My pet load is in LC Match brass and I think you will be perfectly safe starting at 43 grains.

 

[Charlie98]

Rule of thumb with true military brass is to reduce 1grn for starting. Many of the loads you will see with brass like LC is 'service rifle' data... loads designed for gas operated service rifles like the M1a and target shooting, using non-hunting bullets. I have had issues in my .308 Savage bolt gun using loads I developed for my M1a, but using a hunting bullet (in this case swapping a 168grn SMK for a 165grn SP... they immediately showed pressure signs,including sticky bolt lift. So... again, reduce 1grn from minimum, and if possible, use data developed using that specific bullet if possible.

 

[Howa 9700]

One of the guns I'm loading for is a 308, but as I'm starting out, I was short of both primers and brass. Solved that problem when Midway was running a special on LC pull down brass with primers. Picked up a 500 piece box.

Immediately ran into same conundrum as to what to do about loading for the LC brass and magnum primer. Not knowing who to trust, I did some looking on my own. One of my tests was to take prepped and ready to load brass......both Lake City and new Starline.....ran both through the sizing die, then drilled out the primer pocket so I could dump powder in the case with a bullet inserted. Figured that would give me an good indication of what a "full case" of powder would be. Then seated a bullet to the depth I planned to use. Did this by bullet as internal volume is unique to the bullet and seating depth. Then same case with seated bullet was filled with powder to the base of the web.....where primer pocket would end. Dumped that out and weighed it.

Anyway, found the volume of the LC brass was less, but not by much. The most it changed for the powders I was using was 0.9 grains. Some only 0.2 grains.

So based on that. I went to starting load, reduced it one grain for LC brass, and another full grain for the CCI 34 magnum primer. Of those I've shot, had no issues with pressure. Have several more ladders loaded and ready to shoot.

Edited to delete reference to 243. Measured a full case of imr 4064 in 308 and it was 43.0 grains in LC brass with 150 gr hornady interlock. Beyond that, I would begin compressing the powder.

 

[Charlie98]

Anyway, found the volume of the LC brass was less, but not by much. The most it changed for the powders I was using was 0.9 grains. Some only 0.2 grains.

The standard of case volume measurement is with water, not powder. The issue with using powder, and particularly Lincoln Logs like IMR4064 (for those of you who are old enough to know what Lincoln Logs are... ) is the volume of the powder can change depending on a number of factors, including charge drop, vibration, and settling. It is not a good standard.

 

[AJC1]

A starting load is exactly that. It's a place where all variables are considered a place to begin. If your not comfortable exceeding book max the going below book min is equivalent. Build a short ladder to test pressure and get some initial speeds if you have a chronograph. Start at minimum ang go up 1% or .4 grains until you see pressure, reach your desired speed or achieve listed max. Should be less than 10 shots.

 

[TheClasonater]

Thanks for the replies gents. Lots of great info here. I think I will start with the book min. These are for deer rifles so I'm not looking for sooper dooper velocities. I'm not sketched out by laddering up to find pressure signs.

If your not comfortable exceeding book max the going below book min is equivalent.

This was my next question. If the manuals state never never never go below min, and if there is such a perceived danger, why wouldn't any of them mention this? They mention service rifle addendums, but not using the question of capacity as the only variable.

I guess I shouldn't speak for all manuals, but still...

 

[Howa 9700]

The standard of case volume measurement is with water, not powder. The issue with using powder, and particularly Lincoln Logs like IMR4064 (for those of you who are old enough to know what Lincoln Logs are... ) is the volume of the powder can change depending on a number of factors, including charge drop, vibration, and settling. It is not a good standard.

I get that part and especially using those 4064 Lincoln logs.....which they nearly are. But for my 308 test, I was not using those. It was finer grained stuff. One of them was N-140.

But what I wanted to know was at what weight of powder from my lot of that powder would I get to a 100% case fill. That was with the bullet I am using seated to the depth I had selected. Water, or any other medium would not give me that, not to mention all the variables that surface when using water or any other liquid medium.

 

[Howa 9700]

BTW, on the issue of less volume inside a LC case vs other types of brass, have given it some thought as to where the difference could be. The thickness of the metal in the body or neck does not seem likely to account for much of a change in internal volume. So best guess would be at the head and thickness of the web. Not sure why it would be beefed up there, but that seems to be the most likely place to find it.

 

[7mmsavage]

I regularly shoot 42 gr of IMR4064 with Hornady 150 gr bullets out of an M1a. I started with only LC brass, but don’t change the load when I use commercial 308 brass.

According to the Hornady manual it’s hot, but by all the other info I’ve found it’s middle of the road. Feels more like the latter to me. No sign of over pressure, accurate, and slower than some factory ammo I’ve tried.

Your bolt gun shouldn’t have any issue with the load you’re making.

 

[The Glockodile]

From somewhere online...

Sides (is what they call this the "Web?") should be thicker, too.

 

[Random 8]

I think the reason most manuals don't specifically caution against below start loads is that it is a very complicated subject, and by default, they must keep things safe and simple. H110 is a well known "don't reduce!". H4895 and some of the pistol/rifle powders popular with cast bullet shooting are well-known OKAY to reduce powders. In my personal experience, IMR 4064 fits into the latter category, BL-C2 does not, at least in very cold weather. I would be leery of reducing any spherical powder below start loads in a rifle case. That's a whole nother topic I won't get into here at risk of derailing the thread.

 

[entropy]

BTW, on the issue of less volume inside a LC case vs other types of brass, have given it some thought as to where the difference could be. The thickness of the metal in the body or neck does not seem likely to account for much of a change in internal volume. So best guess would be at the head and thickness of the web. Not sure why it would be beefed up there, but that seems to be the most likely place to find it.

Because NATO 7.62mm brass is designed to be fired through belt fed MG's, which put a lot more strain on a case, particularly in feeding and extraction.

 

[TheClasonater]

In my personal experience, IMR 4064 fits into the latter category, BL-C2 does not, at least in very cold weather. I would be leery of reducing any spherical powder below start loads in a rifle case.

I think this is relevant, because how many hunters will develop loads in warmer weather? Particularly with more ARs out there. I don't hunt with ARs and haven't really studied the platform, but that could pose an issue.... maybe?? And particularly in areas where even hunting conditions could change from subzero to 50.

I think a 10 shot ladder as mentioned a few posts above just to find pressures might be the ticket here for these two rifles as a prelim.

Now, to really dig into it, should I segregate this brass by numbers on the headstamp? (Years of production im assuming?) Or sort by the weight of the case?

 

[Charlie98]

Ball powders, like BL-C(2) and H335, are typically more sensitive to temperature, and particularly very cold temps... that's why most data suggests Magnum primers. Extruded powders are typically not as sensitive (IMR4895, for example) and there are powders formulated to not be temp sensitive at all (Hodgdon's 'Extreme' line, H4895, for example.) If you are really hunting or shooting in extreme differences in temperatures... you should load a 'warm' and 'cold' load, or find a powder that works well in your handload, with a minimum of variation at temperature extremes.

I regularly shoot in the NV desert. I have documented differences in velocities of some of my handloads, and factory or surplus ammunitions... from 60F to 118F, factory 150grn .308 ammos had a difference anywhere from 50fps to 150fps (out of a 16" barrel.) Most was in the area of 75fps... but that could make a ballistic difference at longer ranges.

If you are OCD... sure, separate your brass by headstamp. I do, but that's mostly to segregate my brass into more manageable lots... plus the OCD thing. If you really want to split it down, weighing the cases and discarding the outliers will give you a chance of having more consistent brass volume... but , really, the only way is to measure each case with water volume. FWIW, surplus brass is not that good of brass to be wasting time on that... if you are really striving for the best handloads you can possibly produce, you need to start with more consistent brass.

 

[TheClasonater]

118??? Yikes!!! Ya, that'd be a temp swing alright. I do have some ocd, but for this project I'm just looking for a consistent hunting load out to 300/400 yards, and have the choice between either mixed commercial or mixed LC. I now have more of the LC.

I was thinking mixed LC would give me a little more consistency because of mil specs but didn't know if that would make a difference. Only in the question of powder capacity. Would I even need to sort them in your estimation?

 

[Random 8]

The reason I mention BLC and cold weather, was that I had an interesting (bad) experience there. Load was from Hornady Garand data, which was below their regular 30-06 start loads, and fired in sub-zero Temps. I got an audible hang fire and a bent operating rod. Something very strange was happening with my pressure curve and the delayed ignition. This is one of the risks of under-loading. Generally it just shows up as erratic velocity and poor precision, but in severe cases it can lead to a delayed ignition which replicates a detonation.

 

[Charlie98]

I was thinking mixed LC would give me a little more consistency because of mil specs but didn't know if that would make a difference. Only in the question of powder capacity. Would I even need to sort them in your estimation?

You are correct... you are better using mixed LC because it would likely be more consistent as a single headstamp. Commercial brass can be all over the map as far as weights. If you wanted to get frisky, depending on how much brass you intend to use for your hunting loads, you could spend an hour or so weighing X amount of cases and culling out the most consistent for your hunting brass.

 

[Airborne Falcon]

Threads like this are exactly why I feel it is so worthwhile contributing financially to this forum.

Any reloader, regardless of experience level, should benefit from threads like these. These are informative, insightful and entertaining.

 

[MikeInOr]

Just came across som LC brass and intend to work up loads for a couple 308 m77 bolt guns with Speer 150 grn hot cors and IMR 4064. I've never loaded LC brass but am gearing up start with 556 as well. I have a swager coming in the mail to head of those questions.

Now for the conundrum. The manuals I have start data around 43 grns with IMR 4064. And of course, I go reading the forums and red flags and sirens start going off every where that even starting loads could be over pressure. I have no problems starting below minimums, but how low should I go. There is only so much powder and so many bullets right now if you catch my drift. I do have some blc2 on hand but would rather save it for other loads.

I have been loading LakeCity military 7.62x51 brass with 4064 for 25+ years. I am sure I started at the minimum load but I am well into the mid range charge for commercial .308 brass. Yes the military LC 7.62x51 brass is thicker than .308 commercial brass so it has less case volume. From experience I know that the starting 4064 load listed for .308 commercial is just fine for LC military 7.62x51. I would not recommend going under the listed starting load for commercial .308. 4064 is a somewhat fast burning powder so you probably wouldn't have issues with a lite load but I wouldn't go there myself.

P.S. I sort by weight my LC 7.62x51 brass (I have a bunch of it) for my bolt action target Remington 700. For my HK-91 I do not sort the LC brass but I don't mix LC with commercial brass.

 

[TheClasonater]

Threads like this are exactly why I feel it is so worthwhile contributing financially to this forum.

Any reloader, regardless of experience level, should benefit from threads like these. These are informative, insightful and entertaining.

Man... I'm actually honored by this. This is why I ask here instead of other forums. You all actually wanna help, instead of swinging it around if you know what I mean.

Now the next conundrum.... I started resizing some brass tonight. I will use comparator measurements so disclaimer, this is an example. These aren't the exact measurements, just a representation. I measured pieces of brass fired in the rifle. I came up with 3.630-3.631. The brass I aimed to resize averages At 3.635. I wanted to resize to 3.626-3.627 for a 3-4 thou resize and shoulder bump. So, right around a 9-10 thou change.

I use RCBS 2 die sets... thats all I really use, but heres what happened. Started with 1 tester piece, went 3.635 to 3.634 to 3.635 and then over corrected to 3.625. Started with another and the same, then another and the same, then another then the same. Backed it off, and started getting brass in the 3.630 to 3.627 range. I tested these in the rifle and they went, some tough and some easy,, so I went with it. I have never experienced this before, and I started seeing red at the press and I just went with it.

I have never experienced this. When I size commercial brass, I usually average a consistent size. Because this is thicker brass, does it have more tension coming out of the sizing die than commercial brass?

 

[Blue68f100]

You need to lube the nicks to prevent pulling them. Annealing will also help even things out.

 

[Keyfer 55]

I have found imr 4895 as good . But 4064
is my goto powder for a 308.