I'm looking at starting to reload the .505 gibbs and had some powders lying around that I wondered if they would work. Imr 7828, mr 4000, and accurate 5744. I'm looking to use barnes tsx 525 grain. Or should I just buy a more suitable powder? Any filters needed in the case?

I only used H4831 back in the day 132 grs was my hunting load with the 525 gr. Woodleigh. also a 136 grs of IMR-4350, that's what everyone used..

Today some friends swear by 141 to 143 grs of RL-25 and claim to push that 525 gr bullet to 2400 FPS, not sure I want to shoot a 525 gr. bullet at 2400 FPS, much prefer 2250..

These are not starting loads, so cut back 5% and go from there..and all were Enfield actions except one that was a Mauser and another a pre war mod 70 and all were the 505 Rimless or 505 IMP. Recoil was up around 100 FPS and punishing to me..

If it were me which it will certainly not be, Id give that RL-22 and 25 a try, most I know are using it today, if for no other reason than bulk and it measures so well through a powder measure..The old powders I used cut grains to beat hell and each load was weighed..I don't recall using a foam plug in any caliber except on my doubles rifles. I see how much volume you get in the Gibbs and if it wasn't enough I use a 50 cal. plug..Westly Richards sells them as I recall..The can't hurt..

I use Australian powder AR 2213sc, US equivalent is 4831. 130 grains of powder and the 600 grain Woodleigh Protective Point. Very accurate and brutal on Australian Buffalo.