Taper crimp. Most bottleneck rifle cartridge reloading dies are set up to offer taper crimp, just a matter of how you set up your dies. If you're not getting enough taper crimp tension to hold under recoil, you can use collet crimping dies like the Lee Factory Crimp Die to add additional non-rolled crimp tension. How you set up your expander should dictate plenty of grip behind the bullet to prevent set back, so your taper crimp just needs to prevent the bullet jumping out under recoil.

It IS possible to add tip protectors to your mag boxes, I'm not sure if anyone makes them for sale anymore. Cut a triangular prism out of plastic (can use aluminum, or rubber, depending upon your belief), glue it in place in the front of the magazine, stringing vertically. For a stagger feed, one in the middle is usually enough, for a center feed, two on the sides. The idea is to make the triangles with a steeper angle than the bullet ogive such that your block will contact the bullet "shoulder" and prevent the tip from hitting the front of the mag box.

Similarly, since you're using a bottleneck cartridge, you can insert ribs in front of the cartridge shoulder on the walls of the mag box (works for centerfeed and stagger feed boxes) to stop the cartridge from sliding forward.

Adding weight to the rifle can also help stop bullet crimp jump and somewhat help prevent bullet set back due to mag box impact.

None of these modifications should be necessary with a good taper crimp, especially with an added Lee FCD crimp.