SMLE & Lee Enfield Bolt Heads

[delta8672]

Greetings!

Would anyone please tell me how many types of Bolt Heads exist for the various SMLE and Lee Enfield Rifles?

I thought the No.1 and the No. 2 took the same Bolt Head while the No.4 and 5 took the same Head.

I have some SMLE No.2A Heads which appear not to work on a No.1 MK III. They do not screw far enough into the Bolt to align with the Bolt Guide. That prevents insertion of the Bolt into the Action.

Any information will be much appreciated.

Help, Please!

BlueSkies! Q

[Niner]

Welcome to the forms Delta8672. Looks like you know as much as me on bolt heads for the Enfield. I'm sure some experts will step up to the plate pretty soon to take a swing at it. One thing I do know is the 2A and 2A1 bolt heads, although they look very much like the MKIII bolt head, are actually different. For one thing, being made for the Nato version of the rimless .308 round, the extractor is different from the MKIII made for the .303 round with the rim. The extracter is actually more pronounced on the 2A because of this. Another thing, the bolt head on the 2A is said to be tempered for the more powerful Nato round, although this may be just one of the internet assumptions passed on from time to time.

[delta8672]

Greetings Niner!

Thank You for your information.

At present I am a bit perplexed about these Bolt Heads, so I welcome any input.

Hopefully one or more of the experts will educate me.

Thanks Again!

BlueSkies! Q

[Woftam]

I would make it 10 variations. Different boltheads were used for -
1) The very early MLM's (MkI & MkI*)
2) The MLE & SMLE.
3) The No4 & No5.
4) The .22 trainers based on the MLE & SMLE used essentially a modified version of the standard bolthead with a separate offset firing pin.
5) The No5 .22 trainer used a unique bolthead.
6) The British No7 used a bolthead longer than the normal No4 style to compensate for a shorter bolt body.
7) The Canadian No7 used a different bolthead again and the one on the No9 was apparently similar.
8) The No8. used a unique bolthead.
9) The MkI-MkI*** had the sliding charger guide on the bolthead
10) The No4 MkI* had minor differences to the MkI.

Not owning one or being familiar with the Indian enfields I can only guess. The India 2A & 2A1 boltheads I imagine would be based broadly on the No1 design but using a differing steel specification and as pointed out by niner a different extractor. Perhaps the thread is longer to handle the greater pressure of the 7.62 round ?

[brewstop]

Ishapore 2A/2A1 boltheads are identical to No1 MkIII items - in fact many of them are either recycled No1 boltheads (ie with visible older British or Indian inspection marks) or otherwise indistinguishable from the concurrent .303" No1 production items from Ishapore.

[BTW, so far there is no evidence that 7.62mm 2A1 rifles are made of any different materials or processes than normal Ishapore .303 rifles. The few tests that have been conducted under proper laboratory conditions seem to indicate that the 7.62mm receivers are identical to .303 receivers.]

The problem you have is that there is manufacturing variation in the bolt & bolthead thread starts. Enfields were never designed to be serviced by civilian owners buying one or two boltheads and trying to fit them - in service the armourer would have test-fitted a dozen or so boltheads from his stock of a hundred or so, in order to find one which (a) lined up within about 10 degrees past the rib (b) provided the correct headspace.

Whilst No4/5 boltheads had a rough size increment indicated by numbers 0-3, No1 boltheads not only came in unmarked size variations, but the armourer was expected to grind down the face of a "long" bolthead if necessary to achieve the headspace.

The 2A1 boltheads will fit a No1 rifle (including the .303 extractor & spring), but you may need to try several in order to find one that lines up correctly. Also be aware that new boltheads were often intended to be force-fitted by use of a special clamp (a spanner with an aperture in the shape of the bolthead) and filing to the threads - ie the bolthead starts off under-aligned to the rib, but the threads are adjusted to give a tight line-up.

I would caution about the need to change boltheads. Due to internet hysteria about headspace, a lot of owners seem to be compelled to go out and fit a "longer" bolthead. Whereas slack headspace in an Enfield makes little difference to rifle safety or performance (and this was exhaustively trialled), poorly fitted boltheads can lead to bolt damage (ie if the bolthead over-rotates too much, the recoil force is transferred to the bolt threads, and not directly to the bolt body), and over-tight headspace quickly causes wear in the locking lug surfaces - the quickest way to scrap the receiver. Most Enfields have lasted up to 100 years perfectly well on their original bolthead....

[Niner]

It wouldn't take much to know more about the subject than me, Brewtop. However, I still believe that the .303 extractor can't reach in and hold the rimless design of the 7.62 Nato cartridge well enough to hang onto the spent case long enough to get it to the ejector. The 2A extractor has to have the claw extend in closer to the center of the bolt face to make the rifle function right with the rimless cartridge case and thus it is different. I think the spring is also possibly a little different in size, although I am only surmising this.

On second thought, the extractor on the 2A perhaps extends out from the bolt face a fraction more than the .303 extractor rather than reach in closer to the center of the bolt face. Whatever is happening... I think it is different in some real way from the .303 extractor.

[brewstop]

The 2A1 extractor claw itself is about 1.5 mm longer than a .303" item, but otherwise all of the components are the same. Some 2A1s do turn up with coil springs inside the bolthead, but these are probably just "local repairs"....

A 2A1 receiver has the ejector screw about 8mm further forward than on a .303 receiver, to take account of the shorter 7.62mm case. On all Enfields, the main ejection comes from friction between the case and the inner receiver wall - ie the case is flicked out before it even reaches the ejector screw. The ejector screw mainly deals with unfired rounds (maybe the greater mass of an unfired round means that the friction is insufficient to rotate the case out of the receiver?).

[delta8672]

Greetings Niner, Woftam and Brewstop!

Thank you for your assistance. I think I now know how to deal with the problem.

Fortunately I do not have to deal with the Ejector and its Spring as I shall be using the existing parts.

Thanks Again!

BlueSkies! Q

[Niner]

Brewstop... I'll take your word for it. None of my MK111's and 2A's have bolts that will exchange equally. I have no idea where the mesurements change from one to the other. They stick in various places, or not close when trying a 2A bolt in a MK111. And it's not the bolt head number that is the difference, I'm pretty sure.

[Woftam]

Brewstop,
thanks for the info. As I said I not nothing about the 2A/2a1's and I was assuming Delta's comment "They do not screw far enough into the Bolt" meant that there was a significant amount not screwing in rather than just not quite lining up properly.
With regard to the steel specifications for these rifles is there any reference to the testings ?
The reference to the upgrade is quite common (Skennerton quotes EN grade and advanced heat treating for example) and I have previously seen mention of the testing that says it is no different. However these references have always been fairly brief and lacking detail.