Help with my G.R.I Ishapore

[vintage hunter]

Er........ I think you have misread the thread Seaspriter and VH!

Nope. Seen right off it was a .303. I was merely commenting on the 7.62/308 pressure difference myth.

An EMPTY 7.62 NATO case should rattle around in your chamber like a arm in a wizzards sleeve

Not quite.

[Seaspriter]

I don't think an empty 7.62 will even chamber in a .303" rifle somehow. It will foul.......

It will -- just checked -- don't try it!

Your "gunsmith" was probably referring to the only "Ishapore" he is familiar with... The model 2A and 2A1, which are manufactured to fire .308. Your rifle, unless stamped otherwise, was manufactured to fire .303

And this is where the gunsmith created more confusion.

That's a common misconception caused by some published data for 7.62 NATO pressures being established using test equipment giving pressure readings in Copper Units instead of P.S.I. People tend to believe C.U.P. is equivalent to P.S.I. When tested on the same equipment the max pressures of the 2 are nearly identical. Max Pressure limit for the 7.62 NATO is 60,191 P.S.I., which is the same as the C.I.L. limit for commercial .308. In the U.S. the SAAMI limit for .308 is set at 62,00 P.S.I.

I just did triple checking and this too is correct, but 98% of the postings between the NATO and 308 round perpetuate the confusion. No wonder it takes a team of experts to sort out the confusion about ammo. That's one of the reasons modern weapons have the type of ammo stamped on the barrel in big figures.

Thanks mates for all the good corrections.

[Peter Laidler]

And yet MORE ambiguities..... Seaspriter, thread 12, line 1. 'It will..., just checked....... '. Do you mean it (the 7.62mmcase in a .303" chamber?) WILL...., will what? Fit or foul.

I say that so far as I am concerned, .308winchester is totally different to 7.62mm NATO. Based on this scenario.

I was the range conducting Officer a few years ago when one of the shooters wanted to range test and zero his privately owned rifle brought some commercial .308 ammo to the range. No problem. He set about shooting during a break and successfully zeroed his target rifle using our issue RG 7.62mm NATO ball. Leaving a few unopened of factory .308 Winchester at the ammo point.

Not wanting to take this back I told a few of the firing point supervisors to load up a few Bren and L1A1 rifle magazines and shoot it off in a small £1 a go range sweepstake. The commercial .308 was too long to fit into the magazines. It is different

1900hrs: Someone PM'd me to suggest that highlighting the ambiguities in the thread could be construed as a bit of nit-picking. It could......, but it's not. If something can go wropng, it WILL. And if someone can hang on to an ambiguity as a form of defence....., guess what........

[browningautorifle]

The commercial .308 was too long to fit into the magazines.

I'd be really curious as to exactly what this ammo was. I'd never try to second guess you Peter, but I've used this stuff back and forth for years...with FNs and others. I'd like to have seen the ammo. Something was slightly amiss...as in bullet profile or type...

[WarPig1976]

In my Hornady manual the case dimensions for .308win/7.62 are identical the powder charges are not. I'm using Lake City 7.62+51mm surplus brass in a brand new Remington 700 SPS with .308 winchester stamped on the barrel with no issues.
Yes, something was amiss.

[Peter Laidler]

The bullets were longer and as such, they were too long to fit into the L1 rifle and L4 Bren magazines. These were in red/black new boxes. Strangely, I kept one round just to show the ammo techs - but then thought better of it.

I dare say that the round might have fitted into another type of mag and fired in our Brens/L1A1';s of it'd been hand loaded. But that's my only experience with factory W.308"

[cupking]

Thank you for all your input folks......It was just like Peter and SpikeDD said.... What I found out from the "gunsmith" was that the "senior"- "gunsmith" in passing saw Ishapour on the receiver and said , "make sure you tell owner never use .308 ammo in this rifle " . I questioned them how they head spaced the rifle... then asked for my money back . Is it safe to say RFI didn't make a 7.62 x 51 rifle till the 1960's ?? I happen to have a .308 (7.62 x51 ) . I'll be more selective having the rest of the inheritance checked out...

[scoobsean]

The bullets were longer and as such, they were too long to fit into the L1 rifle and L4 Bren magazines. These were in red/black new boxes. Strangely, I kept one round just to show the ammo techs - but then thought better of it.

I dare say that the round might have fitted into another type of mag and fired in our Brens/L1A1';s of it'd been hand loaded. But that's my only experience with factory W.308"

I have fired both in my Bren and they fitted into the mag fine. Maybe it was a dodgy batch?

[Bindi2]

As a reloader of 308 using projectiles from 110gn to 215gn in three different rifles and wanting to fill the case with powder not projectile I have different length throats cut for the longer heavier projectiles ( range rifle) so I can seat them out or just to the bottom of the neck. There fore I can not close the bolt on the short cut throat with the heavy projectiles. As I don't use mags the COAL is of no concern.

[Seaspriter]

WILL...., will what? Fit or foul.

It will foul terribly -- like jam and be hard to extract. Don't even try.

The commercial .308 was too long to fit into the magazines. It is different

If you ever want to get confused, read all the conflicting info on this issue. As one authority said: "I've yet to find a 7.62x51mm cartridge that fails to fit a .308 case length gauge, and I've checked every single one that crosses my path. Interestingly, the cartridge dimensions themselves for 7.62x51mm are identical to .308 Winchester. All that extra (chamber) space is just to improve reliability of feeding and prevent headspace issues in firearms that love to slam the case into the chamber with enormous force; e.g. machineguns. However, there are anecdotal accounts on the web that over-long rounds have been encountered. that extra headspace is forgiving to cartridges that might be slightly oversized. Ammo that might never have an issue for a military using 7.62x51mm arms could prevent a bolt from going into battery on a .308 chamber. In a bolt-action rifle, this could cause headspace problems or overpressure if the bolt is forced closed. In a semi-auto, it could cause a slamfire."

Apparently the necking and shoulders are sometimes different -- some sources say yes, others say no. Go figure. Some chambers may be different, some may not. Go figure.

Fulton Armoury's Walt Kuleck and Clint McKee (they make some of the best new weapons in this round) say: "They are the same, 'cause nobody makes 7.62MM ammo that isn't to the .308 "headspace" dimension spec. So 7.62MM ammo fits nicely into .308 chambers, as a rule. Most of the time it's a distinction without a difference. .... Many military gas guns (e.g., M14 Rifles & M60 Machine guns) run wildly long headspace. ....I have measured many, many types/manufacturers of commercial and NATO ammo via cartridge "headspace" gauges as well as "in rifle" checks. If anything, I have found various NATO ammo to be in much tighter headspace/chamber compliance than commercial ammo..... if you intend to shoot .308 commercial in a military arm chambered for 7.62MM, first check the headspace with .308 commercial gauges first. You may get a surprise." These comments are just a condensed version of the complex headspace discourse which may, or may not, make any difference.

Steve@303British.com gives a different story; he says "the SAMMI and Military gauge sets are different in two areas - chamber size and cartridge makeup. With many military rifles, their chambers can be significantly longer than, say, a Remington 700. Note that the military chamber would fail a NO GO check, but pass a FIELD check using the proper shop (military) gauges. There can be a .013" difference [that's less than a fingernail width] in chamber length however, between these two "Safe & Serviceable" rifles! " What is Ok in a 308 Garand might not be in an FN or Ishapore, based on condition and chamber size.

So, if this left you confused, sorry -- it seems you could take all the information and get totally tangled in the discourse. Perhaps the best way is the old fashioned test -- if it's too tight or too loose, don't mess with it. The Chamber Head Space check might help, but be sure to know what gauge to use.

That said, thousand of rounds have been safely fired interchanging 308 and NATO. Go figure. Apparently in ~99.9% (or more) of the situations, the conversation is irrelevant, but you don't want to be the ~.1% (or less) that runs into a problem of blowback. Apparently, the older the weapon or conversion, the greater the chance of a problem. Personally, I've never encountered it, don't know of anyone who has encountered it, and didn't even know it was a problem until recently. Wonder what others have found?