No4 Bolt Heads - Heat Treatment

I have a No4 that has been commercially converted to .22 with a Parker Rifled (Sleeved) barrel.

The Bolt is missing, I have plenty of bolts but need to convert a standard bolt head.

For the extractor I was going to make from Gauge Plate and harden it enough so it is tough & wear resistance but not so hard that it will be brittle.

Firing pin I was going to use silver steel with the tip heat treated so it does not deform over time

As I need to plug the original striker hole & drill a new one, before deciding the best method of doing this I need to know are the No4 Bolt heads case hardened or hardened & tempered

Silver solder an insert into the bolt head striker hole. Anneal the bolt head, bore the new hole and then case harden the face afterwards. That's all you need to do. When I did it I used an SLR/L1A1 firing pin as the new .22" striker.

But surely these No9 type boltheads are readily available!

Many Thanks Peter

I will give it ago.