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Can 7.62x51 brass be loaded to .308 Winchester specs

Shaneo7

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Dec 26, 2023
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I loaded a box of 7.62 brass specifically Lake City 72 Match brass to .308 specs, 168gr Hornady A-Max with 44.0gr Hodgdon BL-C (2) rounds are crimped and intended to be fired in a PA-10 chambered for .308. Load data for .308 Win and .308 Win Service Rifle both have a starting load of 44.0gr and another option for .308 win Starting 43.0gr. The lake city brass is thicker walled around 3gr heavier than Federal .308. With the lower case capacity I've read that rounds should be loaded .5gr lower. I can't find specific load data for 7.62x51 or a clear answer. Would this be expected to be a safe starting point? Should the bullets be pulled and the rounds down loaded? Is .308 Win Service Rifle data the same as 7.62x51?
 
Most military brass is thicker/weights more than commercial 308 Win brass. If you notice that most reloading manuals will specify which brass the reloading data is based on. Changing any one of the components can change the pressures of the loaded rounds. Decreasing capacity will increase pressure which is why common practice is to reduce powder charge.

Do your research because you have to be comfortable when you pull the trigger.
 
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Most military brass is thicker/weights more than commercial 308 Win brass. If you notice that most reloading manuals will specify which brass the reloading data is based on. Changing any one of the components can change the pressures of the loaded rounds. Decreasing capacity will increase pressure which is why common practice is to reduce powder charge.

Do your research because you have to be comfortable when you pull the trigger.
Thank you for your input, this helped a lot. I've been using Hodgdon's online reloading center for everything and I've always just tried to stay on the low side for powder charge. I've never noticed the specified case. All 3 loads specify Winchester .308 case so that answers my my question on whether the service rifle data is 7.62x51, it is not and should be loaded down.
 
I don’t load with BL-C(2), so I’m not sure how far you are from max with those loads, but start at the low end and work up if ever in doubt.

Another thing worth mentioning is if you’re going to continue to use LC brass, know where you’re getting your brass from. Make sure it wasn’t fed through a machine gun, like a M240. You’ll have a hard time resizing it, and even if you get it back to dimensions with a small base die, you might have web deformation inside the case.
 
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I don’t load with BL-C(2), so I’m not sure how far you are from max with those loads, but start at the low end and work up if ever in doubt.

Another thing worth mentioning is if you’re going to continue to use LC brass, know where you’re getting your brass from. Make sure it wasn’t fed through a machine gun, like a M240. You’ll have a hard time resizing it, and even if you get it back to dimensions with a small base die, you might have web deformation inside the case.
Max load data for .308 service rifle specs shows 45.2gr, the 2 for .308 show a max of 46.0 and another max of 47.0gr but all data states they are using .308 Winchester brass. As for the LC brass I'm not sure what it was fired out of, it was purchased at a gun store near me and was already resized, trimmed and chamfered. I don't plan to buy more but they came in a nice box with 100 cases in it and I don't have a whole lot of .308 brass to load otherwise. Thank you for your input I will absolutely do more research on web deformation and check my cases carefully.
 
Max load data for .308 service rifle specs shows 45.2gr, the 2 for .308 show a max of 46.0 and another max of 47.0gr but all data states they are using .308 Winchester brass. As for the LC brass I'm not sure what it was fired out of, it was purchased at a gun store near me and was already resized, trimmed and chamfered. I don't plan to buy more but they came in a nice box with 100 cases in it and I don't have a whole lot of .308 brass to load otherwise. Thank you for your input I will absolutely do more research on web deformation and check my cases carefully.
If the LC brass is marked "LC LR" then it was made for precision weapon systems and fired out of M40s/M24s, M110/Mk11 and similar...if it's not, its machine gun brass. I use tons of LC LR brass but never the machine gun shit.

Dont worry about 308 vs 7.62. Simply work up a load until you see pressure signs then back off a half to one grain or simply stop when you arrive at a load that meets your needs and doesnt exhibit any signs of overpressure.

For reference: 308 Winchester/7.62 NATO SAAMI headspace is 1.630-1.640.

You need to determine where your chamber falls in with the above range (easiest way is to measure case head to shoulder datum on a few fired cases) then set up your sizing die accordingly.

I never buy brass already sized.
 
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Max load data for .308 service rifle specs shows 45.2gr, the 2 for .308 show a max of 46.0 and another max of 47.0gr but all data states they are using .308 Winchester brass. As for the LC brass I'm not sure what it was fired out of, it was purchased at a gun store near me and was already resized, trimmed and chamfered. I don't plan to buy more but they came in a nice box with 100 cases in it and I don't have a whole lot of .308 brass to load otherwise. Thank you for your input I will absolutely do more research on web deformation and check my cases carefully.
Just pull as many as you need to in order to start with a lower charge weight and work up. Don’t pull all of them. Chances are your load is fine, but do your due diligence and check it by working up and looking for pressure signs.
 
If the LC brass is marked "LC LR" then it was made for precision weapon systems and fired out of M40s/M24s, M110/Mk11 and similar...if it's not, its machine gun brass. I use tons of LC LR brass but never the machine gun shit.

Dont worry about 308 vs 7.62. Simply work up a load until you see pressure signs then back off a half to one grain or simply stop when you arrive at a load that meets your needs and doesnt exhibit any signs of overpressure.

For reference: 308 Winchester/7.62 NATO SAAMI headspace is 1.630-1.640.

You need to determine where your chamber falls in with the above range (easiest way is to measure case head to shoulder datum on a few fired cases) then set up your sizing die accordingly.

I never buy brass already sized.
He said it is LC72 Match brass. The old M118 match brass is almost as good as LR brass. I VERY strongly doubt LC72M was run thru anything but a NM M14 or MK2-1.
If you have a bunch of that brass, 1x fired, I would gladly trade you FGMM 1x for it. I have a few hundred LC72M 1x and 2x and am always looking to get more.
 
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If the LC brass is marked "LC LR" then it was made for precision weapon systems and fired out of M40s/M24s, M110/Mk11 and similar...if it's not, its machine gun brass. I use tons of LC LR brass but never the machine gun shit.

Dont worry about 308 vs 7.62. Simply work up a load until you see pressure signs then back off a half to one grain or simply stop when you arrive at a load that meets your needs and doesnt exhibit any signs of overpressure.

For reference: 308 Winchester/7.62 NATO SAAMI headspace is 1.630-1.640.

You need to determine where your chamber falls in with the above range (easiest way is to measure case head to shoulder datum on a few fired cases) then set up your sizing die accordingly.

I never buy brass already sized.
I checked the head stamps, it only has LC 72 Match on it, no LR. They look to be in very good shape but will definitely inspect further. I usually don't buy brass at all. I typically just buy factory ammo, fire it and reload from there. Bought these for $20 in a case of 100. Starting to understand now why they were priced so low. Thanks for the input!
 
He said it is LC72 Match brass. The old M118 match brass is almost as good as LR brass. I VERY strongly doubt LC72M was run thru anything but a NM M14 or MK2-1.
If you have a bunch of that brass, 1x fired, I would gladly trade you FGMM 1x for it. I have a few hundred LC72M 1x and 2x and am always looking to get more.
Thanks for the input, makes me feel a little better about my purchase. They were $20 in a really nice reloading box for 100 cases I only bought 1 box but they had 20 cases there. Unfortunately they no longer have them but will keep an eye out.
 
He said it is LC72 Match brass. The old M118 match brass is almost as good as LR brass. I VERY strongly doubt LC72M was run thru anything but a NM M14 or MK2-1.
So he did. I missed that. Good eye. 👍
 
By the way, drop about 2-4 1/10ths of a grain from commercial loads and you'll be gtg with about any LC 7.62 brass.

I saw some folks running a 44.0gr load of BLC-2 under a 168smk many moons ago in NM M14s. Seemed to be quite accurate on the 600yd line. Watch for temperature sensitivity.
 
Just pull as many as you need to in order to start with a lower charge weight and work up. Don’t pull all of them. Chances are your load is fine, but do your due diligence and check it by working up and looking for pressure signs.
Thanks for your input, this sounds much better than pulling rounds, I think what I'll do is load some of the same brass I have lower and work my way up and watch the pressure signs, that way I may not have to pull any bullets.
By the way, drop about 2-4 1/10ths of a grain from commercial loads and you'll be gtg with about any LC 7.62 brass.

I saw some folks running a 44.0gr load of BLC-2 under a 168smk many moons ago in NM M14s. Seemed to be quite accurate on the 600yd line. Watch for temperature sensitivity.
Thank you for this reply, this was going to be my next question on how far I should drop on my charge. I have read things about BL-C(2) being temperature sensitive. I have about 10 lbs of this powder it works well for most of the rounds I reload, especially .223.
 
He said it is LC72 Match brass. The old M118 match brass is almost as good as LR brass. I VERY strongly doubt LC72M was run thru anything but a NM M14 or MK2-1.
If you have a bunch of that brass, 1x fired, I would gladly trade you FGMM 1x for it. I have a few hundred LC72M 1x and 2x and am always looking to get more.
Yea I didnt read his first post, only the one I quoted...LC Match is the predecessor to the LR stamped stuff IIRC so prob no different than LR for reloading purposes. No reason to think it was ever belt fed through machine guns...

I may or may not have small amounts of the LC Match stuff, most of mine is LC LR 07 and some 19 and other misc years. The 07 stuff is fed to my M40A5, Mk11 and M14 while I have an equal amount of Federal brass that's fed to my Remington 700P. Fed brass and LC LR seem to have a very similar case capacity though id have to measure to be sure.

I checked the head stamps, it only has LC 72 Match on it, no LR. They look to be in very good shape but will definitely inspect further. I usually don't buy brass at all. I typically just buy factory ammo, fire it and reload from there. Bought these for $20 in a case of 100. Starting to understand now why they were priced so low. Thanks for the input!
You're welcome. If you're looking to stock up at reasonable cost, be on the look out in the PX for once fired LC LR in whatever year head stamps (the year doesnt seem to matter insofar as case capacity variation) or Federal 1x fired brass...You can usually find someone selling 100+ pieces at a time...Just make sure it hasnt been sized already or otherwise altered (other than maybe the spent primer removed).
 
LC LR is about 1 gr less capacity than Lapua. Winchester is about 1.5 gr more capacity than Lapua. LC 72 Match will be roughly 2.5 gr less capacity than Winchester brass.

I'd start about 2.5 gr lower charge weight then what Hodgdon calls out for Winchester brass in the LC 72 Match to get similar/same velocity.
Hodgdon Service Rifle data used to be tested in an M1A.

PSA-10, probably has a slightly longer freebore and different lead angle than what was used in M1A Match chamber.
Land / groove ratio and land / groove diameter will also have an influence on how quickly you'll generate pressure.

How long is barrel on the PSA-10 bbl? Hodgdon data is from a 24" bbl, you'll lose about 17 fps / in.
18-20" barrel, you'll probably find best accuracy in the 2550 fps average velocity (+/-25 fps).
Do you have a chronograph?
 
LC LR is about 1 gr less capacity than Lapua. Winchester is about 1.5 gr more capacity than Lapua. LC 72 Match will be roughly 2.5 gr less capacity than Winchester brass.

I'd start about 2.5 gr lower charge weight then what Hodgdon calls out for Winchester brass in the LC 72 Match to get similar/same velocity.
Hodgdon Service Rifle data used to be tested in an M1A.

PSA-10, probably has a slightly longer freebore and different lead angle than what was used in M1A Match chamber.
Land / groove ratio and land / groove diameter will also have an influence on how quickly you'll generate pressure.

How long is barrel on the PSA-10 bbl? Hodgdon data is from a 24" bbl, you'll lose about 17 fps / in.
18-20" barrel, you'll probably find best accuracy in the 2550 fps average velocity (+/-25 fps).
Do you have a chronograph?
I don't have a chronograph yet, I can definitely see how it would be extremely useful for load development and accurate ballistic calculations though, it is on the purchase list. As for the PSA-10 it has a 20in SS bbl. 2.5 grain drop sounds comfortable to me, I was unsure of how far of an initial drop I could make. I'm always in favor of accurate loads over hot loads. IMO if you want a more powerful round buy a higher caliber gun. Thank you for your input!
 
When it comes to .308 load data, if it notes Winchester brass then I always keep my max 2 to 2.5 grains below their listed max when I'm loading LC brass.

Mike
 
When I first started reloading for .308, I remember reading that the rule of thumb for loading LC brass was to drop data 10% and work up.