.22 Benjamin marauder pellet choice?

Currently using the Benjamin discovery .22 14.3 grain pellet (can purchase at the local store) and they shot good I'm getting a little bigger than a quarter size group most of the time. My brother gave me some jsb match exact jumbo Diablo .22 15.89 to try and they seemed to have a nicer grouping with a few same hole shots and his gun performs well with them. 

Im sighting in at 20 yards. The gun is stock and I've only had it a month and ran around 150 shots threw it.
What are the majority using? How many trial shot are you taking before you try a different grain pellet or switch brand and start over?

My purpose for this gun is some target shooting on paper. Shooting metal targets like can on fence at family parties and the back yard critter that end up in the garden.
 
@396ranger
It depends on the individual Marauder as to what it prefers. The old adage Crosman guns shoot Crosman pellets can be true with your Marauder. Try a Crosman Ulltra Mag, which is a pellet of the same weight (14.3 grains) but doesn't have the small hollow point in the dome. My next door neighbor's .22 Marauder shoots these very well, but will not shoot any JSB pellet accurately. Having said that my .22 Marauder will only group well with a JSB Jumbo 18.1 grain pellet. I have also found that a Crosman Premier (CP) is a more accurate pellet in all of my Crosman airguns than a Benjamin Discovery pellet even though they are the same shape and weight. Congrats on your Marauder as it is an awesome PCP airgun that you can grow into and enjoy without spending a thousand plus dollars. A Marauder is a wonderful place to start on a great hobby. 
 
My Gen 1 Marauder seems to shoot Benjamin Discovery pellets the best. I've also tried JSB, Benjamin Kodiak, and Crosman Premiers from time to time, but the Benjamins seem to be the most consistent in my rifle. JSBs were a close second.

It really is all up to trial and error. Rifles are finicky creatures. Two like rifles may like two completely different pellets.
 
6k rounds in 2 months through my new .22 Mrod...Anything JSB or AA in ~16 or 18 grain diabolo will be the best possible. Polymags are great too. H&N’s are hit and miss in my Mrod. The Baracuda match 21 grain shot very accurately and I’m hoping the Baracuda 18’s that I just got work as well as the jsb or AA 18 grain. Also Baracuda Hunter extreme are very accurate too.


Anything in 16 or 18 grain from those 3-4 brands even though 3 of them are owned by the same people...
 
Kind of off topic but has anyone else had a problem with Crosman and their Benjamin Marauder getting it repaired. They have had mine three weeks now and still haven't finished repairing it! They won't even tell me what was done to it!

I got it back after three weeks, 4days. No real answer as to what was wrong with it. The repair ticket said something about a gauge but not very specific. Kind of disappointed with them! Don't think I will use them again. Didn't even tell me they were shipping it. I got notified by UPS!

Tested with FX Chronograph H&N 19.1s and 21.4s now at 654 fps large hole at 15yrds. Adjusted the hammer spring and now at 824fps. Almost hole in hole!