What ReloaderFred said, good information.
Stick to bullet weights considered normal for the M1 (150 to 180 grains) but folks, including me, have had good results with bullets down to 110 grains. Accurate at 100-200 yards and takes a bit off the recoil. I have only tried spire points though.
Keeping pressures safe for the op rod are key. If you use powders safe for the M1 and at M1 loading levels, things will be fine with the standard gas plug. Varget is a good powder for the M1.
If you use bullets lighter than 150 grains, there are a couple members on the CMP forum that have posted good loading information for the light bullets in the M1.
If you stray from what is considered safe for the M1, an adjustable gas plug is required to protect the op rod. If you use commercially available hunting ammunition, an adjustable gas plug is a must.
For your information, in case you have not heard, the concern for the op rod in the M1 is based on the port pressure, not chamber pressure. The port pressure with newer, slower burning powders is too high for safe operation of the op rod and bending the op rod becomes a real possibility. Sticking to powders safe for the M1, such as Varget, H4895, IMR4895, and a few others, the port pressure is at a safe level for the op rod.
Hope this helps and enjoy hunting with your M1.
