Bart--Before taking it to the smith the bullets I was using were Sierra 32 gr BK. After that trip to the smith, I tried the Sierra 39 gr Blitz Kings with H4895 and was getting about 3500 fps from the most accurate load.
Three points:
1. The rifle was goofy from the get-go. Would not shoot anything I tried except Berger 35 gr worth beans. After a thorough cleaning it would take 15 rounds or so to get the gun to settle down, but it would be really good for another 50 or so, which was acceptable.
2. After the monkey circus shortage of components, Bergers were unavailable so I tried some of the 32 Sierra bullets I had on hand and got a fairly tight group out of Benchmark at near max load data. So, I ordered 500 of those bullets. The new lot was evidently an "updated version" or some darn thing, and wouldn't shoot for crap. They started to keyhole almost immediately. Went to the smith. He said the loads ere too hot. I Google the deal and found that Sierra had recommended using the 32 grainers with milder loads and lower velocities. Toned those down to about 3700 fps (which is 600 fps slower than the cartridge is designed for) and got fair groups---1 moa as I recall, not great for long range prairie dogs. So then I started with the 39 grainers to try and get the potential from the caliber. Key-holing started to become common place.
3. I had a few Berger loads that I had forgotten about (in my truck) and tried those and THEY key-holed some of the time. About this time I said to heck with it and got rid of the gun.
I would estimate somewhere over 2500 rounds. Since the shortage thing messed with the various component supply, there was quite a bit of work on trying different stuff to make that gun work. When it shot good, I loved it. I had replaced the factory trigger (which was terrible) with a Timney. It was the best trigger I have ever used. And with the 35 Bergers it was a sure enough tack driver after it got settled down.