Reloading .308 in 7.62 brass

Good to go. Heed rcmodels advice. Size as normal and you are good. If it has a crimped primer pocket that will need swaged. Show a pic of headstamp.

They are the same.

There's no such thing as a 7.62 sizing die. They're all .308 win

Be aware that military brass can be thicker than commercial brass… which translates to less internal volume, which can give you higher pressures than commercial brass, all else being equal. As someone mentioned, it very likely will have crimped or staked primers, which you will have to swage or cut out before you can prime them.

Charlie98 is correct. In general start with a 10% reduction in powder charge.

ReedTX said:

Hello all,

I have around 180 rounds of brand new Winchester white box 7.62 FMJ that I was given. I know I can shoot this through my .308 safely but I want to know is if I can reload this to .308 loads?

I found this thread https://www.thehighroad.org/index.php?threads/reloading-7-62-brass-for-a-308-question.306424/ and I am still none the wiser.

Does anyone have any experience? I do not want to really pull the bullets and would like to just use it for practice in my bolt gun.

I want to use my .308 Lee full length dies. Is it possible?

Thanks!

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You can shoot it in your .308 rifle and you can resize it in a FL resizing die. the issue is, 7.62 NATO has less case capacity due to thicker brass and so a given volume of powder will develop more pressure than .308 win. per the ideal gas law: PV=NRT. According to the ideal gas law, if a fixed Number of gas molecules (N)are contained in a container with a specific Volume, the Pressure of those gas molecules will increase as the Volume of the container decreases and/or the Temperature of the gas molecules increases. The R is the gas constant btw and can be disregarded here. What is important to understand is that as the volume of a container decreases, the pressure of the gas inside it increases. It's also good to understand that as the temperature of a gas increases, it's pressure also increases if the container volume remains unchanged. Think of a 2L jug of soda pop that is refrigerated versus one that has been sitting in your 100° back seat all day. Which one will open more explosively? The 100° one of course because the temperature of the CO2 is much higher. keep that in mind when you leave your ammo lying out in the sun.

So, as you see here, if the case walls are thicker, the internal volume of the case will be less and; therefore, the pressure of the gas molecules will be higher which is why we like to know what our case volumes are as this increase or decrease in pressure will affect A) our safety and B) our accuracy/consistency.

By coincidence, just today I finally got to shoot some test loads I've been sitting on for awhile. Test was 5 loads LC 7.62 pull down brass, and 5 loads new, never fired 308 Starline brass. Both loads at start level loads with 42 grains of N 140 under 150 Speer Hot Cor bullets seated to same depth. Goal was to see if there was any difference at all between the two. LC brass shot an average of 100 FPS higher than Starline, which to me suggest a bit more pressure. But both loads were mild with low recoil. Wasn't shooting for accuracy, but this is what I got from the LC brass. A deer would have been in big trouble. BTW, that photo should be rotated 90 degrees to the left. Shot string was horizontal, not vertical.

Edited to include: I should also mention, the LC pull down brass also included the CCI 34 Magnum primer they use in LC ammo. So part of velocity gain may be due to the lower volume case, and part to the magnum primer. Rule of thumb I am using is reduce load 1 grain for LC case........and 1 more grain for the LC magnum primer. Based on what I found, that may be over cooking it. Probably need to load them again and use the same primer next time.

In for the knowledge.

If/when I find any reasonably price LRPs, I will be venturing into necked cartridge reloading for the first time. I've worn out two Dillons (a 550 and a 650) loading hundreds of thousands of pistol rounds during my USPSA days, so I do know a little about reloading, just never ventured into rifle calibers.

I have a fair amount of once-fired 7.62x51 brass and this is what I'm going to use. Not going for hyper accurate reloading, nor max loads. I'd like to try getting a bit better accuracy out of my AR10 and RPR (best to date for this old guy is about 1.2" @ 100 yds. w/M80).

I really just want to shoot my rifles and have fun while I still can.

Howa 9700 said:

By coincidence, just today I finally got to shoot some test loads I've been sitting on for awhile. Test was 5 loads LC 7.62 pull down brass, and 5 loads new, never fired 308 Starline brass. Both loads at start level loads with 42 grains of N 140 under 150 Speer Hot Cor bullets seated to same depth. Goal was to see if there was any difference at all between the two. LC brass shot an average of 100 FPS higher than Starline, which to me suggest a bit more pressure. But both loads were mild with low recoil. Wasn't shooting for accuracy, but this is what I got from the LC brass. A deer would have been in big trouble. BTW, that photo should be rotated 90 degrees to the left. Shot string was horizontal, not vertical.

View attachment 1051578

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That's nice. There have been two times when I felt like maybe the LC brass pressure thing was pretty valid. Once with BLC2 loaded into them at a pretty hot load and after that ammo had spent some time in the sun and once (well twice) when my DPMS Recon's hammer broke on 42 grains of Varget and my Armalite's bolt hold back catch broke on the same load. The Recon broke when it was like 0° outside and it could have been bad MIM and brittle fracture. The Armalite might have just broke a piece. So I backed off to 40.8 grains, bought a heavy duty match grade trigger and an AGB for the Recon and replaced the Armalite piece and my groups stayed sub-MOA and no more problems. My velocities are always a little higher than the published velocities still but I have 2 more inches of barrel so I think it's all good. Regardless, I'm hesitant to go anywhere near max with LC brass now.

Ditto what everyone else said. I was just down in the basement loading some Lake City 7.62 brass for my .308s. In doing load work up I always start middle of the range and work my way up. Then check for pressure signs as I shoot. Never have had a problem but don't often get close to max loads.

ReedTX said:

I know I can shoot this through my .308 safely but I want to know is if I can reload this to .308 loads?

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When in doubt, gather more data. Do you have any 308 brass fired from that rifle?

If you do, weigh one of the cases. Right that number down and weigh it again, once you fill it to the rim with water. You now have a weigh in grains of water that fills the internal volume of the case.

At this point you can do the exact same with your Winchester white box, one you fire them.

With this information we could draw a more informed conclusion vs a wild guess.

First, check the volume of your new 7.62X51mm brass against some .308 brass. The new stuff might be the same as the 308. If not and the 7.62 brass has less volume yoh will need to work up a new load to be sure you don't go over pressure. There won't be a big difference and it you are not near the top end of the load range you might not need to cut the charge at all. Then do as usual and find the most accurate load.

You will be fine, especially with a single shot rifle.

I LOVE my RPR for sure. I am on vacation for 3 months at Padre Island, but when I get back to my reloading room, I will dig out some data I have developed. It might save you some time if interested.

what optics are you using on your RPR?.

Dan

To build on some of the comments...

I regularly shoot in the NV desert, near my inlaws. Temperatures can range from the 50-60's, as it was over Christmas, to well into the 100's... my highest recorded shooting temp was 118F. Yes, it was hot... so hot that ejected brass never cooled off, and I had to police up my brass wearing gloves.

Anyway, recorded data from my 16" barreled M1a... with the ambient temp at 60F, and 110F...

110grn Hornady TAP, 2975, 3130fps
150grn RG (Radway Green) surplus, 2550, 2625fps
145grn Prvi white box, 2575, 2640fps

145grn Prvi FMJ, 43.5grn IMR4895, 2450, 2500fps

So you can see, even with factory ammos, ambient temps can make a difference. Once I get over 100F, I keep my ammos under the truck... in the shade... because a green USGI ammo can turns into a pressure cooker in the sun. I was not ready to test ammos left in the sun for velocity...

Carrying this idea forward, powder selection can make a difference... with powders that are not temperature stable... and/or a load near max, worked up in the cool months, taken to a hot range day, well... you can see there might be a difference.

dgod said:

I LOVE my RPR for sure. I am on vacation for 3 months at Padre Island, but when I get back to my reloading room, I will dig out some data I have developed. It might save you some time if interested.

what optics are you using on your RPR?.

Dan

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I mentioned in my post that I have a RPR. I'm not sure who this question is directed at?

ReedTX said:

I think it was you. I don't own one but hope to one day!

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I can't afford the real expensive stuff since landing on early SS/retirement, but I managed to get a Vortex Strike Eagle 5-25 x 56 ffp scope recently. Best scope I've ever owned, which isn't really saying much, but I really like it.

For what it's worth...
Using a chrono, and IMR 4895 (and AA2495) I found that my load in 7.62 nato brass (1960s through 1982 stamps) needed to be reduced by .5 grains (point five grains) to achieve the same FPS and overall behavior as the load I had developed in commercial Winchester and federal 308 brass.

And then there was PMC brass, which also wanted the same load I use in 7.62NATO

brmiller said:

I mentioned in my post that I have a RPR. I'm not sure who this question is directed at?

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I was asking you about your RPR. and about your optics..

dgod said:

I was asking you about your RPR. and about your optics..

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It's just a stock RPR with a Magpul bipod on it. And the above mentioned (post #18) scope. I've only spend a couple of hours with the scope so far, but I have no complaints. My local range is limited to 400 yards, so I'm not trying to do any real fancy long distance shooting.

Ahh, I see it now, Vortex is hard to beat, that’s what I have as well.

Dan

Not sure on annealed. The nato + pretty much guarantees that it has crimped primer which you will have to remove before priming again. Rcbs makes a setup that isn't terrible that does it but a strong press is almost a must to use it. There are better tools out there and some folks even use a drill or countersink bit.

ReedTX said:

Better late than never. Here is a pic of the head stamp. It looks to me like it says WMA 17. On closer inspection of the box, this is not Winchester White Box but is Winchester 'Service Grade'.

I ran it through my .308 die and it seemed to resize and deprime fine. It does look like the brass has been annealed though around the neck, does that sound right?

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Nato stamped means: crimped primer and should have been annealed too, not polished off.

Should be good brass if not shot in a MG.