You can load one in the chamber and one in the tube if you are worried about using pointed bullets.
I believe it is a Mike Venterino book where he points out the Marlin 1881 in 45-70 failed in military testing due to detonations in the tube. I believe they were using round nose bullets.
Remington 30-30 ammo is round nose. Never had one detonate a round in front of it in any of my guns.
Somewhere in my pile of gun books, I have one article where tubular magazine guns were put through a drop test. Pointed soft point ammo was used to see if it was really a problem. When dropped from a warehouse roof, one instance caused one round to fire off the primer in the round in front of it. The case simply burst in the tube and no other rounds in the mag detonated.
I don't think two instances indicates a trend.
Tubular magazine accidental discharge Has there ever been a pointed bullet/magazine tube cartridge detonation ? 
