When installing Tru Glo sights on a Marlin 336 W you should be careful not to do what I did.
First I laid the barrel on a solid surface ( a vice ), and used a small punch to remove the front sight. The factory sight was very tight, and took some effort to remove.
The new Tru Glo front sight was very tight, and only seemed to go in from one direction. It took quite a bit of tapping with a hammer ( no punch ), to get the sight to go in all the way. Here is where I made a big mistake. When I was tapping the sight with the punch to get it to the middle of the barrel, the base of the front sight fell off. The reason it fell off was, I did not have the base of the sight supported on the solid surface. I had the barrel resting on a solid surface. You have to have the base of the sight supported as you are tapping the sight into position. The screw that holds the sight base was pushed sideways, and popped out. The screw did not break as I originally thought, but it was pulled out of the tapped hole by my hammering with a punch. I removed the new sight from the base, and I simply rescrewed the base screw back into the tapped hole, to rethread it back into the hole, to make sure that it would hold the base in place. Once I realized that the screw would hold the base in place, I screwed the base back on the barrel. This time when I used the hammer and punch to install the new sight, I made sure that the base was on a solid surface, and not just the barrel. The new sight lined up perfectly, and the base is solid.
To remove the factory rear sight, I removed the adjustable hight ramp first, then I used a hammer and punch to gently tap the base out. The rear sight came out alot easier than the front sight. I could install the new sight, just by pushing it in by hand. The Tru Glo rear sight is held in place by a screw. I simply tightened it up after I re-aligned it.
The front sight of the Tru Glo sight is twice as high as the factory sight.
The sights are lined up perfect for me. When I raise the gun to my shoulder, the sights are already lined up, and ready to go.
I hope this thread keeps someone from making the same mistake that I made installing these sights on my Marlin.