SMLE Bolt Head details

[The_Champ]

I recently snagged a slightly larger bolt head for my SMLE in hopes of tightening up the headspace a little on the cheap. I hope it will go a little easier on my brass, and maybe improve accuracy a hair.

For those curious my old bolt head length (measured from bolt face, to above the threads) was .6310 inch, while the new one is .6360 inch. Will this make a significant difference? Who knows, probably can't hurt though.

What I did find curious is that my old bolt has an additional cut made on the bottom through the threads, while the new bolt head does not. A quick image search turned up both varieties.

Does anyone have any idea what this cut is for?

New bolt on the left, old bolt on the right, with extra cut through threads:

 

[maple_leaf_eh]

I'm going to throw a random solution at your problem. Forget about the bolt head. Bully some 14-yr old with braces for a bag of their orthodontist elastic bands. Put a small diameter rubber band over the bullet so it rests on the shoulder of your .303 cartridge. Fire it as per normal, but when you reload never full length resize those cases. What you are doing is fireforming cases for your sloppy chamber. Don't blame the British, blame the No.1 for having such loose tolerances to meet wartime production requirements.

 

[Cottage Hill Bill]

Agreed. Go here http://www.milsurps.com/forumdisplay.php?f=72 and search for Peter Laidler's articles on Lee-Enfield headspace and educate yourself on the subject so you understand how headspace and the various LE bolt heads are supposed to be used. Then understand about segregating your brass by rifle and neck sizing reloads. In 40+ years of collecting LEs and having a couple hundred pass through my gun safe I've yet to have one that was truly out of spec for headspace.

 

[GAIRLOCHIAN]

What about the OP"s question on what the cut out is for?

 

[green]

RHS bolt head is cut for the early striker which had a lug on the collar for screwing to the cocking piece rather than the two grooves.

 

[Ganderite]

I just had a SMLE re-barrelled with a new production barrel. (I used one of my old 308 target barrels. Cut off the old chamber; re-chambered to 303; re-threaded).

The bolt has a good camming effect on closing and I can feel it engage the case rim and compress over the last half inch of the bolt knob arc.

With such a bigger bolt head, you might feel that compression. Means your headspace is less than zero.

 

[The_Champ]

RHS bolt head is cut for the early striker which had a lug on the collar for screwing to the cocking piece rather than the two grooves.

Ah now I see. I reviewed Oathias' video on the SMLE because I recalled one short lived iteration of the SMLE where you could remove the firing pin without a special tool, and indeed he does it with a bolt head cut like that. My SMLE definitely has a normal later firing pin, removed with the tool, so not sure how I ended up with this bolt head. I guess extra old parts could have been placed on updated rifles.

Thanks for the answer!