A member of my club, now in his seventies, used a Parker Hale No4 Supreme for years for stalking large red and, in other countries, for shooting bear in Russia before the Iron Curtain fell. He used the standard 174 grain soft point loaded by Eley-Kynoch although says that he would have used the heavier 215 grain loadings if he could.
One "word of warning" as it were.
When the only sporting bullets that you could get for re-loading a lot of people for both sporting AND target use used Speer's 180 grain soft point round nose. IT HAS THE BALLISTIC PROFILE OF A BRICK. So the "drop" was far, far ore than the equivalent 174 grain spitzer (pointed) profile bullet. Be aware with the Speer that they will not shoot the same sight settings as a spitzer shape bullet of the same weight.
Also as chamber dimensions vary greatly you must totally full length re-size if the cases are to be shared between different rifles. This is a cartridge that will not chamber if you don't from one rifle to another.
Hmmm Interesting. I must be very ...................................... very lucky as even though at one time I was reloading for Eight .303 rifles I have never had a case head separate or partially separate and cause a gas escape and yes the cases were fully resized. Yet if one believes what is so often posted on the web one cannot reload the 303 cartridge without getting case head separations after a couple of reloads on a case.
I have had partial case head separations with old surplus ammunition one first firing though but none with hand loaded ammunition.
The majority of my reloading for the 303 was done using HXP 69 brass which I think is part of the success and it was excellent brass made to the correct dimensions which sadly is not the case with an awful lot of commercially produced brass. Winchester and R.P are undersized in the web area by at least 0.005" and are often undersized in the rim as well.
The Portuguese FNM brass has also proved to be good for reloading in my experience.
Now Hornady's 174 Grain RNSP proved itself to be very good in performance and grouping something which I did not find with the Speer 180 grain bullet. For deer the Sierra 150 grain spitzer was excellent although I would have thought that it's a bit light for Boar!
I was lucky enough to find and purchase a couple of boxes of original Kynoch 215 grain Soft Point bullets. One box was unopened the other had about a dozen missing from it. I also found a box of 50 Speer grand Slam 200 grain .303 bullets but sadly 50 is not a lot of use really. I had hoped to find more but it seems someone else had the same idea and when i went back for more after payday they were all gone

in hindsight I should have asked them to put them aside for me.
I am not sure exactly when
"enfieldspares" is talking about but I for one never found trouble is acquiring bullets for reloading the 303 cartridge. For target shooting I normally used FMJ types of course Mountain & Snowdon provided their 174 Mk V11 type FMJ's at a good price and suplus ammunition was cheap and plenty full. I bought two cases of HXP 69 and later acquired a fair quantity of HXP 80.
Interestingly I noticed that when sighted in for Surplus MkV11 ammunition hand loads with the Hornady 174 Grn Soft Point grouped either high right or high left depending upon direction of rifling twist. Those with Enfield LH twist hit high left and the American barrelled P-14 sporters, Century Arms "Centurion" rifles with new Six grooved barrels, they grouped them high right. Despite the fact they had new manufacture barrels fitted the bore dimension was well over size in both land and groove. One of the pair I was working with shot well and would hold good ammunition like that Greek HXP 69 in the Bull at 600 yards. The other was not so good and the chamber was so tight that it was not possible to size any case not fired in that chamber to fit it. We tried Four different die sets from three different makers to no avail.
Finally when I was left with the rifle after settling the nephews storage fees

I had the chamber reamed to 303 AI which solved that little problem. Oh yes and for the "Lee" haters my 303 dies are RCBS

.
If one is a mind too do so there are some very good suitable weight 303 calibre hunting bullets available form Australia but of course this does mean private importation.