Comparing Hornady manual loads for 308 vs. 7.62 Nato

Kayser · March 31, 2012, 09:14 PM

So, I have a ton of 150 gr BT-FMJ bullets that I use to reload 308. I noticed that the Hornady manual doesn't list loads for these bullets for 7.62 Nato. The closest thing list for both calibers is the 155 gr a-max (using imr4895)

308: 37.7 - 46.4
7.62: 37.6 - 43.4

They seem to favor a lower maximum pressure for the 7.62.

The bullet I care about, 150 gr BT-FMJ is listed with the same load numbers as the 155gr a-max in 308. Therefore, does it seem to make sense that I could swap this same bullet in for the 155 in the 7.62 load? I would of course start at the min and work up.

dacaur · March 31, 2012, 10:24 PM

7.62 is loaded to lower pressure than .308, which is why you should not shoot .308 ammo out of a 7.62 marked bbl....

Yes, what you are asking would be fine to do.

steve4102 · April 1, 2012, 10:07 AM

The 308 Win and the 7.62 Nato are loaded to virtually the same pressures. The 308 has a Max pressure of 62K psi while the 7.62 Nato is loaded to 50K CUP. 50K CUP equates to approximately 62K psi.

The Hornady data you speak of is specific to the M1A. I believe the reduced powder charge is due to the rifle and not the Nato chamber.

UncleNick might stop by and set us straight the the pressure difference (if any) between the 308 and the 7.62 rounds.

Until then check this out.
Federal 7.62 ammo specs, 168gr bullet--2650fps.
http://www.midwayusa.com/product/953...open-tip-match

Federal 308 Ammo specs, 168gr bullet--2650fps.
http://www.midwayusa.com/product/953...oint-boat-tail

Only way these two can have identical velocity is if they are loaded to same or similar pressures.
Also Lyman 48 lists load data as the same for Nato and 308.

What rifle are you loading for?

Kayser · April 1, 2012, 12:19 PM

No rifle, yet

I'm mulling an M1A. It's attractive because I'm fully equipped for 308 reloading.

Second question : is it kosher to use 308 brass for 7.62x51? I know that factory 7.62 is supposed to have thicker case walls, but I dunno if that makes a difference for loading purposes.

Edit : Actually, while I'm here, what's the deal with Springfield's specs for their M1As? They list it as "7.62x51mm NATO (.308WIN)". That seems kind of bizarre, as they are not the same caliber. Do they have some kind of Wylde-chamber-for-7.62 thing going on?

dacaur · April 1, 2012, 12:58 PM

Its fine, but you dont want to use a load you developed in a .308 case in a 7.62 case since it has thicker walls which equal less internal volume, making for higher pressures with the same amount of powder.... if you work up your loads in a 7.62 case, you are fine to load the same load in a .308 case, but not the other way around...

They actualy are the same caliber as far as the chamber is concerned. The .308 win was released as the commercial version of the 7.62x51 nato.

oldpapps · April 1, 2012, 03:29 PM

My 'for what it is worth' view.

Load for the weapon. A change in components require a safety evaluation. This may be nothing more than testing the new primer type, to a full work up with a new/different powder.

7.62 NATO brass is functionally the same as .308 Win brass. Some say the military brass is thicker/heaver. I have not found that to be always true. Segregate your brass and load in set lots. Always keep records, it will make later loading processes simpler.

Loading for the M1A is no more difficult than any other weapon. Being an auto-loader, I advise you full length size.

I load a wimp loading for my Remington 600 in .308 Win. The rifle is very light and kicks a lot (over 17 foot pounds of free recoil, ouch). I have found that this same wimp load is very, very accurate out of my M1A. But it is a wimp loading, 43.0 grains of 748 under a 150 grain FMJ, over a CCI LR primer, in military brass. From the Rem 600 with 18 1/2 inch barrel and 1 in 10 twist - 2468 FPS. Same load from the Spfd M1A with 22 inch barrel and a 1 in 11 twist - 2677 FPS.
(These load are safe in my weapons with my component. All ways defer to know loading data from know sources and error on the side of safety.)

My wimp load is not that wimpy after all.

It comes down to you should load for the weapon, keep the loads within the power/velocity/energy range needed/desired.

Enjoy,

OSOK

kraigwy · April 3, 2012, 08:13 AM

Quote:

is it kosher to use 308 brass for 7.62x51

Yes its safe to use 308 brass in a M1A.

Hornady and others show different loads for gas vs bolt guns, in 223, 308, and '06.

Reason being these guns (for a lesser entent the 223) are desighted for 149-175 grn bullets and mideum buring powder 4895/4064, etc.

Its not because of the pressure per se, but when the pressure is where, its hard on the gas system, not the action. The actions of the M1A/M1s will take it.

When reloading forget the 7.62 NATO vs 308 Winchester crap. I've been shooting both in my M1A since I got it in 1977 and I don't mean I've shoot it a little bit, I've shot the crap out of it while shooting for the Guard, Went through several barrels but the gun itself is still sound and still shoots.

If you walk up and down the line at a high power match where people are shoooting service rifles you'll find Winchester Brass is the most popular.

tango1niner · April 4, 2012, 04:10 PM

my ancient lyman reloading manual states when loading for the .308 and using military brass reduce max loads by 2 grains.

dacaur · April 4, 2012, 06:28 PM

In print all I have ever read is that you must use lighter loads with military brass and you should not shoot .308 through a bbl marked 7.62....

Of course, on the Internet there are many people who say differently, many anonymous people.....

Who do you think is more careful about what they say, someone who could easily be held liable for it due to it being there in print, or some anonymous person on the internet? (who likley doesnt use max loads anyway....)

"some anonymous person on the internet told me its OK" isnt a good excuse when you have a broken gun and/or personal injuries.....

There is a reason you wont see anyone say its OK in print, dont forget that...

PED18 · April 9, 2012, 01:21 AM

Military 7.62 NATO brass cases are thicker to allow for operation in machine guns. As a result, space available for powder is somewhat smaller. If you use military cases, reduce the maximum load by 2 grains.

In what kind of rifle are these reloads are to be used?

March 31, 2012, 09:14 PM	#1
Kayser Senior Member Join Date: May 29, 2002 Location: Illinois :( Posts: 550	Comparing Hornady manual loads for 308 vs. 7.62 Nato So, I have a ton of 150 gr BT-FMJ bullets that I use to reload 308. I noticed that the Hornady manual doesn't list loads for these bullets for 7.62 Nato. The closest thing list for both calibers is the 155 gr a-max (using imr4895) 308: 37.7 - 46.4 7.62: 37.6 - 43.4 They seem to favor a lower maximum pressure for the 7.62. The bullet I care about, 150 gr BT-FMJ is listed with the same load numbers as the 155gr a-max in 308. Therefore, does it seem to make sense that I could swap this same bullet in for the 155 in the 7.62 load? I would of course start at the min and work up. __________________ ----------------- Box Of Truth Afficionado!

April 1, 2012, 12:19 PM	#4
Kayser Senior Member Join Date: May 29, 2002 Location: Illinois :( Posts: 550	No rifle, yet I'm mulling an M1A. It's attractive because I'm fully equipped for 308 reloading. Second question : is it kosher to use 308 brass for 7.62x51? I know that factory 7.62 is supposed to have thicker case walls, but I dunno if that makes a difference for loading purposes. Edit : Actually, while I'm here, what's the deal with Springfield's specs for their M1As? They list it as "7.62x51mm NATO (.308WIN)". That seems kind of bizarre, as they are not the same caliber. Do they have some kind of Wylde-chamber-for-7.62 thing going on? __________________ ----------------- Box Of Truth Afficionado! Last edited by Kayser; April 1, 2012 at 12:59 PM.

March 31, 2012, 10:24 PM	#2
dacaur Senior Member Join Date: March 16, 2010 Posts: 733	7.62 is loaded to lower pressure than .308, which is why you should not shoot .308 ammo out of a 7.62 marked bbl.... Yes, what you are asking would be fine to do.

April 1, 2012, 10:07 AM	#3
steve4102 Senior Member Join Date: December 23, 2005 Location: Minnesota Posts: 2,955	The 308 Win and the 7.62 Nato are loaded to virtually the same pressures. The 308 has a Max pressure of 62K psi while the 7.62 Nato is loaded to 50K CUP. 50K CUP equates to approximately 62K psi. The Hornady data you speak of is specific to the M1A. I believe the reduced powder charge is due to the rifle and not the Nato chamber. UncleNick might stop by and set us straight the the pressure difference (if any) between the 308 and the 7.62 rounds. Until then check this out. Federal 7.62 ammo specs, 168gr bullet--2650fps. http://www.midwayusa.com/product/953...open-tip-match Federal 308 Ammo specs, 168gr bullet--2650fps. http://www.midwayusa.com/product/953...oint-boat-tail Only way these two can have identical velocity is if they are loaded to same or similar pressures. Also Lyman 48 lists load data as the same for Nato and 308. What rifle are you loading for?

April 1, 2012, 12:58 PM	#5
dacaur Senior Member Join Date: March 16, 2010 Posts: 733	Its fine, but you dont want to use a load you developed in a .308 case in a 7.62 case since it has thicker walls which equal less internal volume, making for higher pressures with the same amount of powder.... if you work up your loads in a 7.62 case, you are fine to load the same load in a .308 case, but not the other way around... They actualy are the same caliber as far as the chamber is concerned. The .308 win was released as the commercial version of the 7.62x51 nato.

April 1, 2012, 03:29 PM	#6
oldpapps Senior Member Join Date: September 22, 2011 Location: Middle America Posts: 518	My 'for what it is worth' view. Load for the weapon. A change in components require a safety evaluation. This may be nothing more than testing the new primer type, to a full work up with a new/different powder. 7.62 NATO brass is functionally the same as .308 Win brass. Some say the military brass is thicker/heaver. I have not found that to be always true. Segregate your brass and load in set lots. Always keep records, it will make later loading processes simpler. Loading for the M1A is no more difficult than any other weapon. Being an auto-loader, I advise you full length size. I load a wimp loading for my Remington 600 in .308 Win. The rifle is very light and kicks a lot (over 17 foot pounds of free recoil, ouch). I have found that this same wimp load is very, very accurate out of my M1A. But it is a wimp loading, 43.0 grains of 748 under a 150 grain FMJ, over a CCI LR primer, in military brass. From the Rem 600 with 18 1/2 inch barrel and 1 in 10 twist - 2468 FPS. Same load from the Spfd M1A with 22 inch barrel and a 1 in 11 twist - 2677 FPS. (These load are safe in my weapons with my component. All ways defer to know loading data from know sources and error on the side of safety.) My wimp load is not that wimpy after all. It comes down to you should load for the weapon, keep the loads within the power/velocity/energy range needed/desired. Enjoy, OSOK

April 4, 2012, 04:10 PM	#8
tango1niner Senior Member Join Date: March 5, 2009 Location: NY Posts: 317	my ancient lyman reloading manual states when loading for the .308 and using military brass reduce max loads by 2 grains.

April 4, 2012, 06:28 PM	#9
dacaur Senior Member Join Date: March 16, 2010 Posts: 733	In print all I have ever read is that you must use lighter loads with military brass and you should not shoot .308 through a bbl marked 7.62.... Of course, on the Internet there are many people who say differently, many anonymous people..... Who do you think is more careful about what they say, someone who could easily be held liable for it due to it being there in print, or some anonymous person on the internet? (who likley doesnt use max loads anyway....) "some anonymous person on the internet told me its OK" isnt a good excuse when you have a broken gun and/or personal injuries..... There is a reason you wont see anyone say its OK in print, dont forget that...

April 9, 2012, 01:21 AM	#10
PED18 Junior Member Join Date: April 9, 2012 Posts: 1	Military 7.62 NATO brass cases are thicker to allow for operation in machine guns. As a result, space available for powder is somewhat smaller. If you use military cases, reduce the maximum load by 2 grains. In what kind of rifle are these reloads are to be used?