Ishapore 2A1 bolt head question

Good afternoon, I have a question reference the Ishapore 2A1 bolt head. I think I’ve read every post on the Internet talking about this issue without coming to a good answer. I recently purchased a barreled Ishapore 2A1 action, and I’m working on building the rifle. I have all the parts, to include the bolt and bolt head but that’s where the main question comes into affect. Some say it must be a 19 ton bolt head marked 19T, What other say you can use the No 1 Mk3 fault as long as the size is correct and then of course they had space is right.

Thanks Goosic, makes since. That means the 19T was used for the L42 and L39 I believe. 

Sorry for the confusion, no I will not use the no 4 bolt head, i will use a no1 bolt head.

I checked my copy of Skennertons book, the Lee Enfield Story.  He states that EN steel and “advanced” heat treatment was used, but didn’t specifically state on which components.  It would have been at least the action body, but also perhaps the bolt body and bolt head.  

britrifles wrote: I checked my copy of Skennertons book, the Lee Enfield Story.  He states that EN steel and “advanced” heat treatment was used, but didn’t specifically state on which components.  It would have been at least the action body, but also perhaps the bolt body and bolt head.   I’ve also read somewhere, can’t remember where, that Ishapore had problems with failing 7.62 proof tests, so they changed the proof test procedure and/or proof cartridge.  The RSAF Enfield concluded in the late ‘50’s early ‘60’s that the No. 1 rifle was unsuitable for conversion to 7.62 NATO due to the limitations in strength and stiffness of the action.  Conversions then proceeded with the No. 4 rifles.