Regina Rifles Regiment

I'll take a crack at some of them.
P & A, Pay and Allowances.

A30 was a Canadian Infantry Training Centre located at Utopia NB.

X list, I 've never been able to figure that all out. Usually it is followed by a number. If I remember right X3 is Hospital and X4 is Detention. I've seen the numbers run as high as 13 on Pt II Orders