#1/MK3 bolt heads

1. Converted MLM and MLE bolt heads with charger guide rails grafted on.

2. New manufacture SMLE MkI bolt heads with the charger guide rail.

3. SMLE MkI bolt heads with the charger guide rail ground away, for MkI** Navy and MkI IP rifles.

4. MkIII bolt heads with a notch.

5. MkIII bolt heads without a notch.

I would additionally posit that there are a sixth type I have not encountered or seen anywhere, which would be the first type with the rails ground off again. I have one Type I, about fifteen Type II, no Type III, one Type IV and a handful of Type V bolt heads, along with both types of striker.

The non-interchangeability of the notched and unnotched bolt heads is interesting. Now I want to start measuring them and see what the difference is - I wonder why in the middle of a war they changed thread specs? Seems like they should have left them the same so that a notched head and Type I striker could be swapped for a unnotched head and a Type II striker. I have heard Lithgow bolt parts cannot interchange with British and Indian bolt parts due to the whole mixup over the Enfield inch and US vs British equipment, but I have not tested that myself.