Re: 300 wby ultralight been a real pain....any ideas??
I have one of those .300Wby Ultralightweights,
I had problems with the extractor slipping off fired cases, just posted my problems on "Montana Actions thread".
The accuracey of my rifle is acceptable after finding the right load.
Nomra MRP powder (substiute Reloder22 if you can't get MRP)- 84.5gr with 180 Barnes TSX or 200 Nosler Accubond. Both bullet with this powder charge give me approx, 5/8" groups at 100 yards.
I might mention that the rifle sits on its original integral aluminum bedding (stock is molded around aluminum insert). No bedding of anykind done. Rifle does have the original pressure point at the forearm. Mine is approx. 14lbs (I put the barrel on a grocery scale and pulled down on the forearm until I could see the forearm lift away from barrel surface. Not the best way to do it but is quick and dirty. Fixtureing the rifle and hanging weights as mentioned above is much better way to go, as you can have your hands free to take measurements. Since each rifle is different, experimental shimming is the way to go. I have tried shimming under barrel with piece of bicycle tubing and it worked great for a .243, but not for a .257 or .300Wby. Need harder mat'l for Magnums.
Hope this helps a little,
P.S. Just had my .257wby Ultralight rebarreled. New barrel is thicker, free floated, no freebore and I am just getting ready to test it out tonight. It may be a couple of weeks before I have everything worked out and a report ready. Also, if all fails, your barrel should be ready to replace after 1,000 rounds, so keep testing, you'll be there before you know it, just like I was.