L4 Firing Pin Mark

[peregrinvs]

Hi,

Could someone confirm my suspicion that fired British 7.62x51mm NATO cases with an ovoid shaped firing pin mark on the primer were fired by an L4?

I ask as I picked up a belt of fired 7.62 blanks at a car boot sale a few months ago and it included about 5 blanks with an ovoid pin mark.

(I actually bought it as the belt included a few nice WWII dated .303in drill rounds that had been stuck in for some reason)

The blanks are all Radway Green L13A1 dated between 1977-80 so I assume they're the right era?

Thanks,

Mark

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[Brit plumber]

Sounds very much like it, I think the GPMG had a normal type firing pin but its 15 years sincle I last worked on one.

[tankhunter]

Sounds very much like it, I think the GPMG had a normal type firing pin but its 15 years sincle I last worked on one.

You are correct. The L7 GPMG has a straight Firing Pin that goes completey through the Breech Block. The Pin tip is a Normal round profile.
The Bren (.303") & subsequetly Modified LMG (7.62mm) Utilised the same Bren Firing pin with the distinct OVAL tip Profile.

[peregrinvs]

Thanks for that. On closer examination, they've also all got a rectangular dent to the side of the base that I assume is the mark left by the extractor?

(Perhaps I shall add them to my 'L4 collection' whch currently consists of an L4A1 magazine and an LMG oil can)

Very sadly this now means that I shall probably start looking at the bases of fired .303in and 7.62mm cases to see if they had the good fortune to give their all in a Bren.

Cheers,
Mark

[tankhunter]

Thanks for that. On closer examination, they've also all got a rectangular dent to the side of the base that I assume is the mark left by the extractor?

(Perhaps I shall add them to my 'L4 collection' whch currently consists of an L4A1 magazine and an LMG oil can)

Very sadly this now means that I shall probably start looking at the bases of fired .303in and 7.62mm cases to see if they had the good fortune to give their all in a Bren.

Cheers,
Mark

Hi Mark, Without seeing the case I obviously cannot give a Definitive Answer.
But from what you discribe, it certainly sounds like the extractor claw marking the case. With regards adding to your L4 collection. The GREEN canvas SPW & Spare Barrel bags are readily available, & also the contents that go within. Good Hunting!
Kind Regards: Mike

[Brian Dick]

Sure sounds like they were fired in the L4.

[Peter Laidler]

The rectangular mark that sits 1/3rd the way across the base is from the flat ejector that whacks them out of the gun. I remember in the early 80's, we had a load of 'foreign' blank that was in boxes marked with a green/white/green band. One of the ammo techs told me that it was Nigerian from some as-per-usual one sided trade deal where we gave them, say, 1,000 as new FTR's Bedford RL trucks, worth millions and they gave us £50,000 worth of pure horse manure blank ammo from some bankrupt crooked ammo plant, owned by the big Bwana's son. But I digress as is usual...........

Anyway, this stuff was full of dynamite mixed with ammatol mixed with PE4 and a bit of semtex for good measure. Even on the lowest gas setting, it was shaking the poor Bren guns apart and the cases flew out, hit the ground with such force, they bounced up and flew into orbit around the sun. Anyway, they took it all back and replaced it with some RG stuff after a few months, when the need for rear echelon TA troops in training was well past... as is usual!

[peregrinvs]

Thanks. For my own sad amusement I pulled all the 'Brenned' cases out of the belt. There are ten of them and they are all 1980 dated RG. Following on the theme of sad amusement, I pushed a few in my L4A1 magazine - but promptly stopped when I discovered that fired 7.62mm L13A1 blanks *really* don't like coming out of the mag as the spread open crimp catches inside.

One lives and one learns...

Mark

[Bruce_in_Oz]

The rectangular mark that sits 1/3rd the way across the base is from the flat ejector that whacks them out of the gun. I remember in the early 80's, we had a load of 'foreign' blank that was in boxes marked with a green/white/green band. One of the ammo techs told me that it was Nigerian from some as-per-usual one sided trade deal where we gave them, say, 1,000 as new FTR's Bedford RL trucks, worth millions and they gave us £50,000 worth of pure horse manure blank ammo from some bankrupt crooked ammo plant, owned by the big Bwana's son. But I digress as is usual...........

Anyway, this stuff was full of dynamite mixed with ammatol mixed with PE4 and a bit of semtex for good measure. Even on the lowest gas setting, it was shaking the poor Bren guns apart and the cases flew out, hit the ground with such force, they bounced up and flew into orbit around the sun. Anyway, they took it all back and replaced it with some RG stuff after a few months, when the need for rear echelon TA troops in training was well past... as is usual!

I had the dubious pleasure of trying that stuff in blank firing rifles for film and TV in the late 80's. The best thing about it was the box it came in. The re-chambered M-1 Garands did not like it one bit and the L1A1 s with their regulators on max exhaust setting still flung the empties a fair distance. Changing the restrictor plugs in the bores to one with a bigger hole was not entirely successful as the reduced bore pressure reduced the combustion efficiency of the ammo and thus filled the rifles with partially burnt powder. Worked well in bolt-actions though, until the unburnt powder buildup got out of control!

Custom blanks were always better, anyway, as you can tune ammo to guns and control the amount of flash and, to a certain extent, noise, a whole lot better. A small addition of Pyrodex adds a nice bit of cinematic flash and smoke to 9mm blanks, for instance.

It was all a bit bizarre working in the fantasy factory. Classic example was the art director on one production demanding more flash from an M-16 muzzle. Specifically, he wanted to know why he could not have that "star" pattern flash like in the movies. (Art imitating art, there is a lot of it about!). I briefly considered explaining that the flash hider was working as advertised and HIDING most of the flash, but instead disappeared to the workshop. There I built new bore restrictors that extended half the length of the flash hider. Around the circumference were six tiny holes that lied up with the slots in the birdcage. One in the forward end to complete the set and voila; spectacular flash patterns from a flash "hider".