Bolt action New 177 Marauder Rifle

#1. Tank pressure has nothing to do with cocking effort.

#2. Use your thumb to brace against rear of action and pull the bolt with the fist muscles.

Bolt action are harder to cock than side lever action due to leverage, if it's not broken, it's probably normal .

i have both types and noticed this too 

I have marauder .25 that had the same problem. I found the cause to be that the slot for the trigger has ruff metal edges. Also the hammer can rock down as you cock the gun. What you are feeling is the hammer digging into the air tube. Mine was so bad I had to replace the air tub. The solution I found when I got my new air tub was I had to deburr the cut out parts including the air gauge whole. You will notice that your O-rings have cuts in them from passing over that opening. Once deburred on a cordless drill run a 1 inch 1200 grit polishing hone inside the tub over the cut outs. Run it in both directions to smooth it out. I put a WAR SSG hammer in place Crosman's hammer system. The cocking pin on the hammer and the bolt need to be tight and lock tightened. I used a light coat of BG grease where the hammer slides. My rifle shoots at 855 fps average over 24 shots from 2950 to 2450 with a standard deviation of 8 fps. I can get 32 shots for an average of 845 fps shooting down to 2050 with a standard deviation of 14 fps. My marauder cocks as smooth as any of my powder burners.

Is your Marauder unmodified? No HDD? if there is an HDD then there is your problem. If it is unmodified, DO NOT ATTEMPT TO TIGHTEN OR MESS WITH ANY SCREW ON THE GUN and return it for an exchange for one that works as it should under warranty. You shouldn't have to fix a brand new gun you just got that is not working correctly. The cocking should be easy straight out of the box.

Good decision, send it back, let them fix, adjust or replace.