SMLE bolt will not unlock.

Someone good at computer graphics should do up a nice video of the action in operation.

The way I understand it is the safety stud on the bolt prevents the striker from accidentally going forward if the bolt is not fully closed or fully open. In such an event this lug will contact the one on the cocking piece and rotate the bolt one way or the other depending on exactly where it was to begin with. A sheared safety lug is a serious problem but I don’t think that by itself would cause the bolt to lock closed, and someone please correct me if I’m wrong. Could the long cocking groove on the underside of the bolt or the cocking piece lug be damaged also? There’s a lot of leverage going on in that spot as the bolt is opened.

A likely scenario is that someone tried very hard to open the bolt with the striker assembly at "half-bent". This could not only shear the bolt's safety lug but also mash the cocking piece's safety lug sufficiently to prevent the assembly camming smoothly from fired (long cam notch) to open (short notch) position.

This all gets much easier to understand if one takes an undamaged bolt assembly out of the rifle and twists/pulls the cocking piece about while observing the interplay of safety lugs and cam notches/slots. There's a much more complex dance going on in there than the uninitiated might think.

I apologise before I even start if this sounds a tad smug. So apologies first. A skeletonised rifle across your lap is all you need to understand the action of the mechanism and the inbuilt mechanical safety. Plus many years experience and depth of knowledge. Then it all just falls into place

Just a question for Peter or others given the age of the weapons is this a common thing I.E does the metal suffer fatigue, is this part of the lock up or for the safety to engage into, it is just a few questions as the bolts cop a bit of pressure spike each time we fire a round. (Just thinking out loud)
As always I appreciate your time in responding to my query.

Age certainly does strange things to steels. It's just the locking logs that take the huge instantaneous explosive pressure load and I have only ever seen a few of them fail - but the long one has never failed so far as I know!

B in O and JM are the metallurgists. That's a degree subject in its own right

From that "other forum" on this same question.
"That's the dohickey that allows the bolt handle to lift without flying open when firing. Might want to be real careful fixing it right."

Welded the bolt and it now cocks ok, I did order a new bare bolt from springfield sporters which I will fit to replace this and keep both bolts with the rifle.

https://www.milsurps.com/images/impo...olt007vi-1.jpg

I would ask you to scrap the defective bolt. The reason being it is safe while in your possession as you know it is a re welded safety stud. However when you die and the rifle goes to auction / gets bought / moved on, who knows it's defective? If it is used and fails not ony does someone get hurt or killed it puts the use of ALL old rifles under scrutiny. Everytime an old rifle fails there are scaremongers trying to bring in new regulations from insisting that they be re submitted to proof every time they are sold to bans on their use on ranges. You have to remember that large numbers of shooters are stupid and many will hear what they want to hear, the debate on DP rifles highlighted that. It is another reason why the 'MAX load / Max velocity' / All powders are much the same' brigade have to be asked to see reason, its not just themselves they put at risk it is the whole historic arms shooting community they put at risk. If we do not act sensibly we will be the last generation allowed to fire these rifles.

I couldn't agree more Robert 303. You are clearly a good welder Jagman - but not a metallurgist. The rear end of that bolt, which le loaded to a proof pressure of a lot, is a complete unknown now