this is just a suggestion, which i highly doubt tht you want to pay.
but stiffi makes 23" barrels with a5 threads but the down fall is it is $125 lol, but its a cool idea,
STIFFI - X7/A-5 CLASSIC BARREL 23" | Special Ops Online Store - Special Ops Paintball

and yeah like Cleric said maybe 1" if not less

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"LOUD AND PROUD"

Primary- A5- polished internals, vortex, tech-t squishy paddels, ape board, lapco 12" Big Shot, x7 hopper, air-through lapco mag, saw stock, homemade air through, homemade stubby.

Secondary- 98- polished internals, a5 to 98 barrel adapter, 14" whisper barrel or 16" linear barrel, 6 stage adjustable stock, drop forward, double trigger.