Kynoch, Eley and Nobel all offered cartridges with a 135 grain Spitzer FMJ bullet for target shooting and these were also available ready loaded in clips. The bullets shape is not really important if the original cartridge overall length is maintained or very close to it. If using a bullet that is pointier than the original round nose than one cannot reduce the COL significantly without causing the ammunition to jam in the magazine with the third round as said above however even semi-spitzers such as the Woodleigh 140 grain Protected Point will still feed perfectly with the COL reduced quite a bit, providing the nose does not drop down too much when at the bottom of the magazine.
The main criteria is to maintain the original COL regardless of the bullet shape. With bullets in the 140 to 160 grain range seating them deeper makes no sense anyway as the base of the bullet then starts to reduce the available powder space. The above mentioned Woodleigh 140 grain PP for instance when seated to the same COL as the 160 grain RNSN has its base finish directly at the junction between the neck and the shoulder of the cartridge giving maximum powder capacity with a full neck grip and still feeding flawlessly.

Matt.