I haven't tried it yet but bought a pound to try. I've been using n570 but my edge has stopped shooting how it use to so I'm not going to shoot anymore until I install a comb riser on the stock and bed it. If I get around to trying it before you get some info I'll post here.
For what it's worth, with retumbo n570 and 8133 being so close in burn rate, I ran 1 shot only with same charge over my magneto with a 225 eld m in my 300 Dakota. The retumbo and n570 were 32 fps of each other with retumbo being higher. The 570 seemed to be lower pressure judging bolt lift and looking at case head and primer. The same charge of 8133 came in 100fps slower than the retumbo and seemed to have more pressure than 570 or retumbo.
I haven’t used it either, IMR powders aren’t available here.
I use RE33 or Retumbo in mine, H1000 is slower in velocity.
Powder choice here is limited unfortunately.
I will be trying H50BMG soon, just waiting for a shipment to arrive, have a feeling it may just be too slow of a powder, RE33 seems to be the slowest this case capacity likes.
RE33 is a tad fast in my 338/416 Rigby Improved, but works well.