Lee Enfield #4 bolt head fit

[Hardcast416taylor]

I have 3 Lee Enfield #4 Mk1 rifles. I had them out cleaning them all at once today. I did 1 at a time so as to not confuse parts from 1 rifle with another. When done I was struck with the idea of the bolt heads being interchangable with each other. The heads are a #0, #1 and #2. What I found is I couldn`t interchange any of the heads with another bolt body! The heads would not screw on all the way to let the bolt assembly be placed in the action. I was always of the thought that these heads were interchangable and you merely had to acquire a replacement head screw it on and you were done. Metal would need to be relieved from the head or bolt body to let them be used on a different bolt. Anyone else ever come upon this non interchangeability of bolt heads with Enfields?Robert

[Multigunner]

Don't remove metal from the front of the bolt body or mating surface of the bolt head.
If the replacement bolt head does not clock in and underturns you are ahead of the game.
Bolt heads were fitted using a wrench or spanner with opening that fits the front of the bolthead and the extractor lug.
Once clocked in there should be no noticeable overturn of lug past the guide rib. They allowed very slight overturn for the No.4 boltheads, but the SMLE was not meant to have any overclock. Zero overclock of a No.4 is desireable as well for most solid lock up but not necessary.
Overclock of either past 20% is cause for the bolthead to be replaced according to Instructions to armorers.

PS
Don't switch bolt heads around without good reason. Once a tight fitting BH has been fitted the threads will usually be loose if the original head is restored to that bolt body.