Mr. Iorg I have a couple of questions for about some powders. I'm thinking of purchasing either H322 or IMR 3031 to use with 150gr bullets. Have you used either of these powders with 150gr bullets? If so how was the accuracy. The rifle I'm using is a 2002 Marlin 336A. I'm not after top velocity but good accuracy. I've tried both W748 and RL 15 so far, the resulting groups have been dismal for me.:(

It seems odd you had poor accuracy with Alliant Reloder 15. Reloder 15 will not quite shoot with Hodgdon Varget but it will come close in several different cartridges.
Hodgdon 322 workls quite well with the 150-grain bullets. I like 29.4 grains of Hodgdon 322 and have had my best accuracy with the Sierra 150-grain bullets in both the Winchester and the Marlin .30-30 rifles.
This load will exceed 2,050 fps in the 20” barrel rifles and will exceed 2,000 fps in the 16” barrel Trapper. In fact H322 is a good powder for the short barrel rifles.
IMR 3031 is seems to be affected more by barrel length. In the 16” Trapper 31.0 grains of IMR 3031 give me 1,937 fps and in the 20” Marlin 336 I got 2,169 fps. This is a good load and close range I have killed a few deer with it from the Trapper.
32.0 grains of IMR 3031 gave me 2,011 fps in the Trapper and 2,236 fps in the 20” Winchester Model 94AE. This is a little better load for both barrel lengths.
The problem with IMR 3031 is that it has been around a long time and you can gather a lot of older loading data which is quite warm for a lever action rifle on a hot day.
There is a thread here on Beartooth where several of us shot someof the older load dat. I have shot the 32.0 grain 3031 load with a 170-grain bullet – Once. This a warm for for a lever action on a Texas summer day. Use current data with IMR 3031.

Thanks for the reply William. On average how is the accuracy with IMR 3031? I haen't wrote RL 15 off totally just yet. I just loaded up some loads with the Sierra 150gr SP today. I'm thinking that I might of put to firm of a crimp on with the LFD with my other loads. I made sure not to put to much of a crimp on today.

Don’t overlook Hodgdon or IMR 4895. 4895 is an all-round powder for the medium-small capacity cases and you will it extremely useful in this cartridge with both jacketed and cast bullets.
At one time there were a few hunters on this Board from Oregon and coastal Washington State who were strong supporters of the 130-grain Speer bullets. We had several interesting threads discussing the light bullets for lever action rifles. A few hunters from Alabama and Georgia had a few favorable comments on the lights for DENSE brush shooting. Placed correctly the 130-grain bullets work very well on deer.
http://shootersforum.com/showthread.htm?t=4151&highlight=130+grain+speer
You might want to look at the l130- and 170-grain bullets to see if your rifle has a preference.