bulk ordered ammo for m1a, accidentally ordered .308, big deal? yes? no? why?


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PowerJoker6.0
January 5, 2011, 07:51 PM
i ordered 200 rounds of (what i thought was) 145gr 7.62 Prvi Partizan from aim surplus the other day and unfortunately i spaced out and didnt read that it was 308 instead of 7.62 NATO. they are both in the same category and i guess i pay the price for not paying attention to detail. yet again. i had intended on using it in my M1A its the only 7.62 rifle i own, i have read here that you do not want to shoot 308 through your M1A. i guess my question is, how big of a deal is it to shoot these through my rifle? some clarification of WHY and WHAT could be affected? if its a bad call ill get rid of it but im not going to pay to ship it back, too much hassle for $70 worth of ammo, i can sell it to a friend. thanks for the replies and sorry if its a common/stupid question

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plodder
January 5, 2011, 07:56 PM
PowerJoker: I was just getting ready to throw out a question of allowable "jump" space as I attempt to reload my first 30-06 for my Garand. I'll just tune in to this thread because no doubt, there will be a myriad of answers and opinions offered that will shed some light on my ultimate question.

Cal-gun Fan
January 5, 2011, 08:01 PM
I thought the M1a WAS .308?

Dionysusigma
January 5, 2011, 08:06 PM
For a Springfield M1A, accidentally ordering .308 instead of 7.62x51 is like accidentally putting 89 octane instead of 87 octane in your car.

In other words, it will be fine. :)

BrocLuno
January 5, 2011, 08:12 PM
It better shoot civilian and Mil-Spec ammo, or why bother?

NCsmitty
January 5, 2011, 08:15 PM
Isn't the SA M1A stamped 308?


NCsmitty

W L Johnson
January 5, 2011, 09:16 PM
Other than a slight head space difference, 308 and 7.62x51 (7.62 NATO) are the same. If the head space is good on the gun, and a new M1A should have good head space, then fire away.

PS: the parts desc for the M1A barrel on Springfield's parts list says 308.

UKWildcats
January 5, 2011, 09:40 PM
I would worry for the following

7.62 x 51 Brass is thicker -- Handles extraction better but has less powder space. On the extraction issue the thinner 308 brass could fail resulting in base seperation.

308 Ammo I believe can produce a higher chamber pressure -- could cause Op-Rod failure which could be solved by getting an adjustable Gas Plug.

A better place to ask the question in the m14 firing line website.

UK

W L Johnson
January 5, 2011, 10:51 PM
308 Ammo I believe can produce a higher chamber pressure
Pressure in PSI is the same.
You may find info on the internet saying 7.62x51 is 50,000 PSI vs 308's 62,000 PSI, it's wrong. 7.62x51 is 50,000 in CUP (copper units of pressure), people keep changing CUP to PSI without converting. When 7.62x51 pressure was tested they used the crush copper method as oppose to the piezo method used to test 308 thus the two different units. Just like inches vs centimeters

Good read on the subject
http://home.comcast.net/~ehorton/The%20Truth%20About%20308%20Win%20and%20762%20NATO.pdf

Roughneck08
January 6, 2011, 01:46 AM
They are almost the same there are multiple threads on this subject. The 7.62 has a thicker case, also they have a tiny difference in OAL. I shoot Winchester soft point 150 grain out of my M1A scout. Accurate and no issues at all. Shoot it up.

madcratebuilder
January 6, 2011, 05:51 AM
Other than a slight head space difference, 308 and 7.62x51 (7.62 NATO) are the same. If the head space is good on the gun, and a new M1A should have good head space, then fire away.

PS: the parts desc for the M1A barrel on Springfield's parts list says 308.
This is the correct answer. You should be fine with a new M1A, I just checked the head space on two new M1A's for guys and both were well with in spec for either ammo. If you know someone with head space gauges it wouldn't hurt to check it.

LemmyCaution
January 6, 2011, 12:00 PM
PowerJoker-

You're talking about this (http://www.aimsurplus.com/product.aspx?item=AP308FMJ145&name=Prvi+Partizan+.308+FMJ+145grn+20rd+Box&groupid=164)?

PPU makes NATO spec 7.62x51 ammunition. I'd not be surprised if what you ordered was exactly that and just has ".308 Winchester" printed on the box. PPU's 145gr FMJ should be exactly the same, whether labeled 7.62x51 or .308WIN.

nathan
January 6, 2011, 03:24 PM
They should be fine. Enjoy. Just check for signs of overpressure , primer backing off on spent casings.

ball3006
January 6, 2011, 06:27 PM
I have been shooting both out of my rifles for 45 years with zero problems.....chris3

PowerJoker6.0
January 6, 2011, 08:49 PM
yes lemmy that is what i bought. i guess it'll be fine then! gonna throw some rounds downrange asap. thanks so much guys, this forum rocks

LemmyCaution
January 7, 2011, 09:18 AM
PJ-

Most folks report that PPU shoots well. Let us know how it goes.

Also, the PPU is boxer primed and reloadable, at a very reasonable cost. About the only reloadable 7.62x51 I've seen that is less expensive is the Turkish MKE sold under the American Tactical brand name. I've got a couple hundred of those I'm burning through right now.

Double Vision
January 7, 2011, 09:43 AM
I was concerned about this too but as long as you're getting quality ammo it shouldn't be an issue.

PowerJoker6.0
January 8, 2011, 08:40 PM
nice, i was pretty upset at myself for awhile there haha. the reason i bought the PPU instead of the german stuff is b/c i read here on thr that the ppu was a bit higher quality

kmcintosh78
January 8, 2011, 10:43 PM
This has been brought up since dirt was invented.
I have shot both 308 and 7.62 in my SAI Standard M1A with no issues and so has just about every other M1A/M14 person out there.
You will be fine.
The 308 may shot better then 7.62. Most ammo ID'ed as 7.62 is military surplus.

1KPerDay
January 9, 2011, 12:57 AM
You're fine... you don't want to shoot heavy bullet weights in the M1A but the 150ish grain stuff is golden. If you call Springfield they'll tell you both .308 and 7.62 are fine in the M1A.

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