I have a 22" 308 MX rifle.
My rifle is an early one and is the most accurate, "out of the box," tubular magazinerifle I have ever encountered.
With any carefully loaded ammunition or factory loads you can set down at the bench and say: "Watch This."
Three shot groups inside a one inch circle are not difficult. Five shot groups are a different story, the rifle will do it but your bench technique had better right for each shot. Use a goodie black rectangle target, aim for a corner and align you your crosshairs on the edges of the rectangle.
When the rifle came out there was no ammunition and no load data. We were regularly overloadingthe cartridge with no difficulty until the first fax loading pages came out from Hornady. Then we reduced our loads to meet the Hornady velocities.
The rifle has a careful.y fitted verticle locking bolt which fits the recess in the sliding bolt closely. It also has nylon slide strips under the forend.
The brass is easy to make from .308 Winchester but I had to ream the inside of the necks.
.307 Winchester and .444 Marlin brass requires less labor.
Here is a thread from back then on making brass.
I will test it to see if it works. I am on a tablet so it is hard for me to work with links.
https://www.shootersforum.com/threads/308-marlin-express-brass.39328/#post-281114I
