Is buffer mandatory?

[HuntinandBanjos94]

I plan on starting to reload shotshells in the near future and this is basically out of curiosity. IN my RCBS shotgun reloading manual It gives me a load for lead buckshot but it says to use buffer. According to what I've read it is used to tighten patterns among other things but my shotgun is cylinder bore so i dont think the buffer is going to do much on the patterns. So can I just do without the buffer because that is just another step that if it isn't needed I don't want it.

[Ken Rummer]

Lyman manual, 4th edition, pg 69, Buffered shot, says:
"Whenever a buffer is added to a shot charge it greatly alters the fluid dynamics of the shot charge.  This change creates increases in the pressure generated by the load; therefore, the powder charge must be reduced accordingly"
 
It seems adding buffer raises the pressure, I would assume not using buffer would lower the pressure.  This is my personal guess.  Use with caution.