I bought this Enfield No4 Mk1 last week on a purely sentimental impulse. I had one about 15 yrs ago and thought it would be nice to have one again. What can I say, I'm a history buff and Milsurp junkie! Its a 1942 manufacture. Can anyone provide info on the "XU" stamp on the breach? I can't find any info on this mark so far on the web. Thanks.