Assuming you mean 3031, that is a hot load.
If you don't have any powder yet, I would suggest a slower powder, such as 4895 or RL15, with RL15 being my favorite.
If you have 3031, it is an excllent powder, but start testing at 34 grains.
I assume you are loading for accuracy. Load 10 rounds each of 34 to 38 grains. Shoot them carefully off a rest, each at a clean target that you can take home for evaluation. One load, hopefully, will stand out.
If you are lucky, it won't be a hot load. A hot load in a Lee Enfield stretches the brass and it does not last very long. If you have a P14, the brass does not stretch.
When you reload your cases, size them just enough so they easily chamber. A full size will shorten case life.
Hope this helps.
Here is a picture of my first accuracy test ammo loaded for a #4T. I am surveing 5 shots at a variety of loads with two bullets and two powders. I hope to come home from the range with a good idea of which bullet, which powder and about how much powder is worth exploring.