It has been suggested that the "lightening cuts" made to the receiver body and the barrel could have caused the problem - anyone got an opinion on this?
Firstly, lets deal with the No5. The two most obvious and well-known probable causes of variable accuracy in a No5 are (1) bad stocking-up (abovementioned), which can happen to any rifle, (2) the conical flashider up front not being concentric to the bore (itâs a heat-shrink fit, was done by a big hydraulic press. This is why many civvie-made No5 repros are buggered from the start).
When SASC did conduct some tests on the No5, they could reach no finite conclusion, but instead came up with a couple of vague theories. The point to be understood here is that SASC in 1947 were clearly not a research establishment equipped with the scientific tools needed to carry out proper materials or stress analysis â they were simply a military body whose usual methodology was to fire thousands of rounds out of a weapon and report which component broke first.
Urban myth states that âthe lightening cuts in the receiver weaken it too muchâ. This was one of the SASCâs theories, but of course was never tested in any meaningful way. An easy counterpoint to this theory is that (a) there are two small scoops out of the receiver wall and butt socket â the receiver remains a substantial No4 structure and is hardly likely to be affected; (b) if you compare the No5 receiver with the preceding models of No1/ Long Lee/ Lee Metford, you can see that it is massively reinforced by comparison â and none of those weapons suffer strange receiver distortions.
Another SASC theory which has come to light recently is âif you fire thousands of rounds through the rifle until the barrel becomes red hot; so hot that the heat spreads back into the receiver, then this causes receiver distortion due to the lightening cutsâ. This shows the sort of rowlocks that was being promulgated: i.e. the field reports of âwandering zeroâ clearly had nothing to do with weapons being rapid-fired until glowing red hot, and the SASC clearly did not have the technical capability to make such an analysis.
Secondly â Enfield receiver strength.
As mentioned above, it is common wisdom that the rear-locking system â which stresses the whole receiver upon firing â is significantly weaker than the Mauser/front-locking system. From an engineering standpoint this is obviously most likely true, but from a standpoint of âx says you shouldnât fire .308 out of this rifle because its not strong enough, blah, blah, etcâ, its another case of ill-informed myth.
(1) c.12 million Enfields of all models were made, including some thousands which were converted to 7.62mm NATO.
(2) Every weapon originating in UK or later sold on the civilian market has been through Proof â during which +30% pressure (approx) rounds are fired through the weapon.
(3) Millions of those Enfields were also fired during wet service conditions (ie the poor bustards in the trenches, etc); wet ammunition is similar to oiled proof rounds which negate the chamber-gripping ability of the brass cartridge case, and instead throw much of the recoil forces back onto the bolt face instead.
(4) Hundreds of thousands of Enfields are now over 100 years old and have been through 2 or 3 wars, several barrels, and all sorts of gimp owners. Despite this, they remain within headspace on their original bolts, and shoot perfectly well.
Despite the above, there is not ONE single verifiable account of an Enfield catastrophically failing (ie âblowing upâ and causing shooter injury) when used with normal ammunition. (Yes, people have blown them up by using pistol powder in wildcat rounds, but thatâs just Darwinian selection at work.) Sheer statistics should show that â if 12 million rifles havenât produced any sort of history of problems â then the rifles are clearly much stronger than popular myth has it.
Some No1s do eventually fail (probably some of the 4 million made during WW1 didnât get proper heat treatment). When they do fail, the receiver simply cracks and distorts until the bolt binds and they become unusable. Personally, Iâve never heard of any No4/5 action failing, even the ones being used for heavier 155gn 7.62mm ammo (I have an Envoy that is still tight on its â0â bolthead despite being shot-out with 155gn use), or the hotter .308 loads that some daft spams use.
There was one interesting website â maybe someone knows where it is â where a Canadian (?) college used a badly-abused (receiver full of drill holes for scope mounts, etc) SMLE for a destruction test. Iâve lost the link, but they basically tried ramming mud into the barrel, without effect. They then progressed to driving spikes into the muzzle (parts of the barrel then blew off, but the rifle kept working), before finally killing it by using a spiked muzzle and pistol-powder load. The SMLE finally died in the sort of âsoftâ failure I described above. RIP SMLE, but a remarkable testament to its unsuspected strength.