Hello, Marrakai:
Thank you for your indications. My cartridge is the straight tapered 3 1/4 one. In fact, the previous owner sold it as 450 NE. Really, I am not 100% sure the rifle is chambered for the 450 BPE, 1920 looks too late for a black powder catridge and the barrel twist is 1:14, and it is very nimble for a 450 NE; in any case, I do not want to risk my face and the rifle and 300-350 gr of bullet at 1950 fps looks really good for the boar hunting we have in Spain and Europe, normal shots are very fast and at less than 100 yards.
When I adquired the rifle, the said owner was shooting 54 gr of IMR 3031 and a 300 gr Hornady with felt wads, and the shots were 6" open at 50 yards. Recoil was light and I think it was a very mild charge. My preliminary charges are starting from 62 grains of Tubal 5000 and a 300-350 gr Hornady bullet, I will keep you posted about the results. Tubal 5000 is rated in the ADI guide as similar to Varget. I use it in my Merkel 9,3x74R and a bolt action in 375 H&H with good results. In Spain we have Vectan and Norma powders, and some times Vihtavuori.
I think I can get Woodleigh bullets in Spain. Are they very different from the Hornadys? What effect they have regading regulation and pressure?
What are the pressure levels of a BPE cartridge? I have been unable to find them, only NE figures. I suppose they should not be very different from those of a 45-120 or a 45-70 in old rifles, am I very wrong?

Regarding the Graeme´s book, I have been told there will be a new edition in 2008. I think I will have to wait, I don´t know where to seek. If anyone wants to sell his...

Thank you again.