Enforcer - Accurising – and Pecar scope

Not sure if I’ll need a tin hat for this!
Help/advice sought.
I’ve had an Enforcer for several years, shooting 10 – 20 shots say half a dozen times a year.
Trying to test its potential accuracy.
Scoured this forum for a lot of useful information but could do with a bit of clarification on the following points.
1. Generally I have only used issued RG ammunition (L12A3). No misfires.
Recently handloaded .308 PPU MATCH twice fired cases (second firing in the Enforcer to chamber size, then necksized, length trimmed and loaded). From this third firing of 15 rounds I have had 3 misfires. On rechambering the empty misfires it seems the bolt handle was not always turning fully shut (circa 1/8” short gap to wrist band). On trigger release the sear nose disengages from the full face bent and the striker moves forward until baulked by ?????? – not catching in the half cock.
Unload by pulling back the cocking piece and lifting the bolt handle – with care.
Has my 2nd firing expanded and necksized case produced too little headspace? – or what?
Any suggestions please.
2. Posts on forum refer to the King screw and associated collar and or reinforcing seating plate on Nr 4/L42/L39/Enforcer but I am confused. This Enforcer has the screw and reinforcing plate and a split locking washer under the sling swivel screw but no collar. Is this correct or is there any benefit in adding a carefully fitted collar. I’m not sure about the locking washer – can see the reason for it but doesn’t seem like a normal Enfield solution.
Oh, and whilst I have your attention, anyone out there know the whereabouts of Pecar scope numbered 72647 – I would love to do a swop plus cash for it.
TIA
John

Found Peter Laidler's articles on Trigger Pull-off and these resolve my query 2 thanks.

John