"THAT" rifle... SLR freaks need not get excited.

#1
I was a having a few beers with mates and talk turned to the best rifle an infantryman could want. The blessed SA80 came up in conversation and some bloke claimed that as the propellant ignited that at some point there was the equivalent of 20tons to the square inch in the chamber. I suggested "Bollocks". There are a few Pints riding on this. Anyone got any idea?
 
#2
55000 psi as a maximum SAAMI spec., so about 27 tons or so.

Get 'em in, and bad luck!
 
#3
For two pints and a packet of cheese and onion crisps, I'll produce a post saying that it's only about 10 tons. You could then print it off, show it to your mate and collect the winnings. Deal?
 
#5
When the propellant ingnited in an SLR the pressure was equal to 1 megaton.

Nursey? Nurse!
 
#7
I think I'm in the clear if I put my pedant's hat on... so far I've seen 19 tons and 27 tons... not 20. Puttessinmyhands, yer on! Let's fix it at 14.7 lbs to the square inch...
 
#8
I think I'm in the clear if I put my pedant's hat on... so far I've seen 19 tons and 27 tons... not 20. Puttessinmyhands, yer on! Let's fix it at 14.7 lbs to the square inch...
20 tonnes "20T" is the current UK and CIP proof test for 7.62mm and .308W rifles. This is a slight increase from the 19T that used to the standard from the 1960s to the 1990s.

Operational pressures are about 70% less than the proof load. Oiled ammunition produces a thrust on the bolt face of about 50% less than the proof load.

(Oiled cases allow a limited rearward movement of the case - hence increasing pressure on the bolt - before the oil is squeezed out and the case grips the chamber walls)

Hence .303" has about 8-10T dry ammo pressure, 12-13T oiled ammo pressure (on the bolt), and an 18T proof load. Even the proof load is well under the safe limit for a typical rifle - Lee Enfield No1 rifles were easily capable of withstanding sequential 30T proof loads....
 
#10
4(T)s post reminds me of the almost eternal debate about 308/7.62 converted Lee Enfields and how they were allegedly unsafe. L42A1/L39A1 were perfectly OK in my experience, which in the light of 4(T)s post is hardly surprising.
As an aside even 357 Mag proof load produces about 35000 psi or 17 tons ish. 9mm is about 32000 psi.
 

ugly

LE
Moderator
#11
We can all thank NZNRA for that particular balls up!
 
#14
4(T)s post reminds me of the almost eternal debate about 308/7.62 converted Lee Enfields and how they were allegedly unsafe. L42A1/L39A1 were perfectly OK in my experience, which in the light of 4(T)s post is hardly surprising.
.

A combination of the septic internet urban myth industry, compounded by outrageous fabrication and fcukwittery by UK NRA....
 

CanteenCowboy

LE
Book Reviewer
#15
Jesus, with all this technical knowledge flying about it looks like this thread has been taken over by some 'ginger haired stepchildren' from the SASC.
 
#16
Jesus, with all this technical knowledge flying about it looks like this thread has been taken over by some 'ginger haired stepchildren' from the SASC.
We've hardly started. Did you know that development of the SLR involved more than twenty modifications to the FN design that involved changing the radii diameter of machined edges on various parts of the receiver?
 
#17
20 tonnes "20T" is the current UK and CIP proof test for 7.62mm and .308W rifles. This is a slight increase from the 19T that used to the standard from the 1960s to the 1990s.

Operational pressures are about 70% less than the proof load. Oiled ammunition produces a thrust on the bolt face of about 50% less than the proof load.

(Oiled cases allow a limited rearward movement of the case - hence increasing pressure on the bolt - before the oil is squeezed out and the case grips the chamber walls)

Hence .303" has about 8-10T dry ammo pressure, 12-13T oiled ammo pressure (on the bolt), and an 18T proof load. Even the proof load is well under the safe limit for a typical rifle - Lee Enfield No1 rifles were easily capable of withstanding sequential 30T proof loads....
Are you trying to muscle in on my promised beer and crisps?
 
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