brass barrel bore size advice
i am raising money for a custom built brass nasty spring-feed pump.
i have 2 options for bore size
.678 and .686
i have used a unisizer ATS for most of my play, so bore never mattered a damn bit...now im lost. i have read a lot about over and underboring but i want to hear from the borg collective on this one.
what is better generally? i will be almost always using field paint so you never really know what they will be selling that day for sure.
I also live in toronto canada. indoor fields are generally fairly cool to play in, outdoors in the summer is brutal hot here half the time, i dont know anything about humidity levels but id say it can get bloody humid here.
whats my best bet between the two...but first you must know that i aim to double or even triple pump this sucker to get 2-3 balls stacked into each barrel for a 4-6 shot buckshot blast (for milsim room entry drills and general awesomeness).
but when i dont do that, id still like decent efficiency. i figure no matter what, i should get 30 shots (60 shots due to the double barrels) out of 2x 12g's that are in a buffertube air stock
accuracy i assume will always be quite good on a brass closed bolt system.
the .678 will also cost me about 75$ extra in build price, so matters a bit. but not if it will net me huge improvments
please correct me if im wrong in my assumption and shoot your advice this way, thanks for your input guys