I have noticed that there are some opponents to this buff based on the fact that increasing close range damage will inherently increase long range performance as well by slightly extending the probable one shot kill range. 

So I will be revising my numbers to 36 damage per pellet up close on all pump shotguns. 

This is the minimum possible value that makes it so equipping the damage proficiency will result in a 2 pellet kill before the damage drop.  This has the smallest effect on probable one shot kill range increasing the 1887 with damage by 1.2 meters.  Everything else is effected less than that.  These new numbers will only increase shotgun's reliability not their capability.

Most of the problems shotgunners experience come from close range inconsistencies.  These new numbers give the pumps the smallest range of a 2 pellet kill possible bt that small range is still usually enough to cover the range where most of the inconsistencies occur.

The original reason I wanted 40 damage per pellet on the pumps is because the 1887 has a very short range to the drop off.  Giving them extra damage a little bit above the bare minimum of what we needed gave the 1887's slow damage drop a chance to catch up.  But for the most part the 1887 will still have sufficient 2 pellet kill range to cover most of the inconsistencies I have seen with it.

The model actually needs the biggest buff because of its larger hip spread.  It is only easier to use in the sense that it is easier to score a hit, but it is also increasingly more difficult to kill the enemy because the pellets disperse so wide.  The model loses its effectiveness the fastest of all the pumps without steady aim.  With steady aim it is only marginally easier to use.  The increased spread size and high damage at range basically cancel eachother out at a certain distance. 

The 1887 with damage is the most capable long range manual action in mw3 with steady aim, but the spas will outclass it with specialist bonus.  The spas' spread is tight enough that it can take advantage of its 4 pellet kill range with specialist bonus.  The 1887 can only make use of a small part of its 4 pellet kill range reliably because of its larger spread.  The 1887 is better without specialist with steady aim but a specialist spas will beat a specialist 1887. 

50-15 stock is far too powerful for the ksg  That gives stopping power level of damage to a level one unleveled shotgun.  Similarly the spas at 45-14 would have an incredibly long 3 and 4 pellet kill with range which could be a problem. 

The 1887 doing 40-20 might not be a bad thing since its damage drops so early.  It would still have a shorter 2 pellet kill range than the spas and ksg at 36 damage per pellet.  I think the larger spread and no attachments might make up for this concession.  I will revise it above and put the 1887 back to 40-20.

Well now don't you just feel silly.

I agree, I have found shotguns to perform fairly well at range.  I don't think they need a minimum damage buff with the excetion of the aa12 and a slight tweek to the usas. 

Most of the videos I have seen where someone gets a close range hitmarker with damage on it seems like they usually land 2 pellets.  So if they buff shotguns to make them a 2 pellet kill with damage on up close than most of those hitmarkers don't happen.