Major, I'll try to answer your question, base on observations of my own .45 Spencer.
It all starts with the fact that this action was designed around a 50+ caliber rimfire round. These rounds had bullets with pointed noses, and rather sharp curves (Ogives) to the nose profile, for better feeding thru the action.
So the smaller caliber rounds need something in the sides of the action to help guide them thu this action. THus the twin blades, IMHO. Howsumever, most modern ,45 bullets now designed for tubular magazines, tend to have very generous nose flats, and low radius ogives. Think of the Lee 255 RF, or the popular Magma design used by most commercial loaders.
So as the round enters the reciever, it comes from the left at an angle. As it does, the edge of the nose flat , or even just the ogive of the bullet, can sometimes catch on that right blade. Now you have to force it past, and in doing so it tends to force the bulllet upwards, where that large flat/ogive can once again catch, this time on the chamber mouth. Thus you have an increase in force levering the action, and a double hitch or jiggle to clear and chamber.
Removing the right blade is a partial fix. It solves the nose clearance poblems, and usualy the round "Bounces" off the right side of the reciever to generaly align with the chamber. Usualy.
A better fix, IMHO, is a bullet with a more suitable nose profile. The one I have found that feeds particularly slick, and in fact has solved my feeding problems entirely, is the Lee 230 Truncated cone. The nose flat is plenty large for magazine safety, while the steep angle of the cone provides the clearance and guidance needed for hitch free feeding. Crimp just below the cone in the first driving band, using a Lee FCD, it probides a smooth profile, and good case capacity beneath.
Works for me in any case.