Fitting and head spacing a barrel on a BSA International MkIII

The humble .22 BSA International target rifle, we have all shot or owned one and if not, hopefully you will one day.

This one is a MkIII with the floating barrel and it came in for a re-crown and re-time//head space the barrel. At some point the barrel had been twisted very slightly which was enough to cant the fore sight over, yet still operate correctly. The head space was also out. Now interestingly, there seems to be some mystique about these things and I remember reading on a forum quite recently that they were factory pressed together and could not be adjusted. OK, well here is one in bits on the counter so you can see how they come apart and the process is remarkably easy:

Drop the action parts out of the receiver and place them some where safe.

Remove the two knurled cap-head screws from the left hand side of the receiver, they are going to be tight so you have been warned!

Now pull the barrel out of the receiver, it might be quite a snug fit!

What I do is pop the barrelled actioned in the barrel vice (I use a 25000kg hydraulic press) I then flood the barrel tenon with Plus-Gas and make myself a coffee. I then attach my universal action wrench with masking tape or aluminium shims to protect the receiver.

Nip the wrench up very lightly, if you do it up tightly the receiver will tighten on the barrel tenon.

 

Now get hold of the action wrench and rotate/pull back and the receiver should detach from the barrel with a bit of effort.

I make my own wrenches and here are a couple of examples. They need to be robust as they do take a fair amount of abuse on occasions. The top one is the one I use most of the time for British Service rifles and the block with cut-out alongside is for SMLE rifles. Below is a wrench I mostly use for revolvers however it also does a good job on parallel sided receivers.

With luck, you should end up with something that looks a like the adjacent image.

Clean everything carefully and inspect, in this case it went into the lathe and was crowned.

OK, back in the vice, clock the front sight base to zero (Or use a precision level)

Now push the receiver onto the tenon and fit the two screws loosely, I usually nip them until the receiver will no longer rotate and back off a 1/4 turn. You should have a few degrees of rotation.

Fit the action internals ensuring everything has been thoroughly cleaned as we really do not need a piece of grit to mess up things right now.

Fit the GO head space gauge, push the receiver forward and ensure it is level, now nip the screws up and check everything. Did you fit the GO Gauge before fitting the receiver? Start again

Open the action keeping a hand over the load port or be prepared to spend an hour or so looking for your gauge.

Check with the NOGO and if all is good you can put the rifle back together.

One small detail, the fore end support is held in place by the front screw so you do have one last chance to mess things up, which, hopefully you will not.

So there you go, a BSA International MkIV stripped and head spaced.

…and why am I telling you this? Because you need to know.

Leave a Reply

Your email address will not be published. Required fields are marked *

HTML tags are not allowed.

341,706 Spambots Blocked by Simple Comments