How does the cleanliness of the choke and barrel affect pattern performance?
If you are punching paper it matters a lot. If you are shooting a turkey it won't make the difference between killing cleanly or not killing.
Depends I guess.
If your gun is marginal to start, then I would want to know how it shoots dirty vs clean. Some on the patterning boards find a totally clean barrel not as good, but I wonder if that means some oil residue. I would tend to think if you are in the 140-170 range at 40 yards, a dirty barrel would likely still kill a bird just fine. With my guns, I know what they do.
SA-459 20 - a little difference. still very huntable
879 youth - very little difference
879 12 - Hevi (old school Remington)- very little difference. It actually shot no better after I did the full bore polishing. None. Averaged exactly the same. Now I don't believe that would be true with my gun and different choke/load combos, but with my load/choke it made no difference.
My 870 supermag patterns better after it's had 3 or 4 rounds through it.
My new 870 youth shoots fine. I just wipe the barrel out and take it hunting. Killed 2 nice birds with it already.
Like g8rvet said, it depends. For me, a few shots after a deep clean not so much. Ten, a lot.
During the season, pull a dry bore snake through it between shots, assuming the pattern is pretty good to begin with. You should be good to go till the end when you can take care of it.
My 870 20 ga shoots better dirty, both of my twelves it matters very little. The best way to find out is range time.
after a shot in the field I run a dry bore snake through then a single patch of rubbing alcohol, it clears debris and build up.
I always clean mine with a bore snake in between shots if I am patterning just to maintain standardization of the process as best I can.
Clean mine before and after no issues even with patterning my 870 shoots same with no cleaning between shots