IMR 4320 in Garand

[WSM264]

I have an abundance of IMR 4320 and a friend that wants to start loading for his Garand.  Traditionally IMR 4895 and 4064 are good for the Garand's op-rod.  My info shows 4320 close to 4064 in burn rate.  Will using 4320 in his Garand damage the op-rod?

[Larry L]

IMR 4320 is at the absolute slowest end of the "acceptable" burn rate for the Garand. It's going to depend on the rifle if it's going to work or not. Just my experience says it's probably not going to work but you could give it a try. I use IMR 4320 for 243 loads only so I don't use much of it. As you already know, IMR 4895 is the powder for the right pressure curve for the Garand. Might try trading the 4320 for 4895. IMR 4320 is a decent powder but few use it for some reason.

[shot1]

There is a gas plug made for the M1 Garand that is adjustable. With these you can tune your rifle and use most any powder you want to control the port pressure. As has been said IMR 4320 is listed as the slowest powder that is recommended for the M1. I would give it a try with some 168 to 175 gr bullets. Use any primer except FEDERAL. Federal is the only primers that I have had or ever seen slam fire issues with.