Marstar in Canada should have the parts you are looking for. Phone number is 613-678-3173. Those Enfields are very popular in Canada. www.303british.com
is an excellent site.
Some of them did not come with much rifling to begin with and are rough. Have you tried really scrubbing it to bare metal? As long as you can see rifling, it should shoot. Try and measure the bore diameter. If it is over .311, go with the Hornady 150sp. They shoot very well and are the largest commonly found bullet at .312". I use them in all my Enfields.
If the bore is closer to .310, Speer and Sierra bullets become alternative choices.
H335 has always worked well for me. I use it in surplus brass and Win LR primers. I moly coat my bullets and it really helps with these rougher bores. Fouling is still there but at least you can get reasonable vel. before pressures start to spike.
Check the headspace and change the bolt head if necessary.
I use the Lee Collet die and like many others, have found this to keep brass life reasonable. If you FL size, chances are your brass will separate on the second firing. Commercial brass will not last as long as military brass.
If I can be of any help, let me know.