Thread: Enfield Bolt Head Conversion
Retrieved: 10/20/2013

Has anyone tried, or know of anyone, who has modified Enfield bolt heads to bring headspacing into specs? Is it feasable to take say, a #1 bolt head, weld the face and mill it down to #3 specs? What ya think? Thanks

45Auto
11-04-2010

I suppose it's possible to weld a shim onto a bolt face and turn it down. One would have to check the reworked head for stress cracks now and then... However, most folks cure Enfield headspace problems by changing the bolt head. If you have a fast and highly effective way of doing something why do it the hard way?

LX Kid
11-04-2010

Have you tried finding a #3 head for under $75? They ain't cheap and very hard to find. When you can find one that's about 1/3rd the price for the whole rifle just for a bolt head. Hmmmm

ktr
11-04-2010

I've never collected or had an interest in the #4 Rifle and have only worked on the earlier No1 but this is what I did to correct some problems in those No1 MkIII rifles:

No numbered bolt heads for the #1 rifle as there is for the #4. The armourers fix was to just try different heads till a proper or acceptable headspace was achieved. They had the pleasure of a few buckets of bolt heads most likely to choose from.

In the past I've silver soldered a shim onto the face of a few of them, then fitted it back to the proper headspace.

I took the bolt head face down a bit first to allow a shim of some thickness to work with,,instead of trying to silver solder a paper thin piece onto it.

I've never had a problem with one,,they are not a locking lug. The originals were case hardened IIRC, but many I've worked on could be easily cut with a file.

If you wanted to recase-harden after the shim implant, attach with braze instead of silver solder. Braze will stand up to the heat of case hardening where even high temp silver solder will not.

As I say, I've never seen the need to go that route but it is an option.

I believe the Aussies used the same silver soldering technique in altering the bolt head in their conversions to 22Hornet and other small base cartridges.

Real 'silver solder'!... not silver bearing soft solder BTW...

FWIW I've also silver solder fixed a few where the bolt head 'jumps the track' and comes unhinged so to speak from the side rail. Usually from wear to the rail and or bolt head.

The armourers fix was to bend the right hand receiver rail outwards a bit with a dog leg shaped tool able to engage it from the inside and be struck with a hammer from the left side.

I milled a tiny bit off the bolt head hook that engages the receiver rail to get a clean flat surface. Then silver solder a small piece of steel back on to allow for fitting back to the rifle and a new and better fit.

They are all still doing quite well with no ill effects.

Mauser308
06-11-2011

The old-school way (parker-hale, other 'trade' gunsmiths converting SMLE and No4 to .22 trainer config...) was to bore the centre of the bolt head out, thread it, shorten the head slightly, make up an insert with matching thread, screw in to maintain alignment with some flux underneath and silver solder. Then redrill the firing pin holes, firing pin protrusion set by the back of the bolt head and recut the extractor slots.

The point of the excercise is to increase bolt head length without inducing an accuracy stuffing cant to the bolt head. The bolt face MUST remain perpendicular to the bore on all dimensions, no ifs buts or maybes. Hand stoning a bolt head down is a good way to introduce a cant, better to set up a grinding tool in an old lathe and grind that way...

kp321
06-11-2011

I remember some discussion back in the '60s or '70's about chrome plating the bolt face to decrease head space. Don't know a lot about chrome plating, but apparently you can add several thousandts of an inch if careful. The down side was the fact that the firing pin hole became "sloped" rather than straight sided causing primer cratering. Now, to find a plater that would do one face of a small part.

Ordtech
06-11-2011

I was thinking of that as I read down the thread. I've seen it on one Enfield, an old no-name .22, and a '93 Mauser. They hard chromed the whole 93 Mauser lug end to increase both the lug and face dimensions. The other two I assume were electroplated just on the bolt face.

Clark
06-12-2011

I tried to find some longer Enfield #3 mark I or II heads ~8 years ago, but they are all gone in the US and Canada.

I made a fixture for turning the bolt head and Silver soldering a shim to the bolt face in a water bath.

I bought 10 bolt heads without extractors.

It turns out that those new old stock bolt heads had not been clocked to the threads.

The other problem is that the firing pin hole was reamed from the back side.

When I did this stuff years ago, on the internet some Brit gentleman in Florida said he had already done the same thing for his older #1 Enfields.

I wish they had not called the rifle models number one through 4 and then called the bolt head sized number 0 through 3.

That can really make some confusion.

We must always label the bolt head sizes for meaning.

No 4 bolthead sizes:
  0 - .629 to .625 in.
  1 - .625 to .630 in.
  2 - .630 to .635 in.
  3 - .635 to .640 in.