A KIT has a Barrel regardless of make that is LARGER then their largest bore back, so the python .683 going through a .692 barrel is the same as a .683 fin on a freak going through their .694 barrel.

Thats why inserts or backs are only about 2-3 inches long, thats all that is needed to direct the ball to get benefit of the bore size.

bore matching ONLY works at launch. so that the paint flys straight from the bolt initially rather then hitting the wall of the barrel or not going 100% straight. that is the ONLY purpose of a bore matched barrel.

the OPENING of the marker where you insert the barrel, is HUGE, and even the opening FOR the barrel, so the paint upon launch will have the tendency to, at the micrometer lever, ricochet along the barrel from the START, when you bore match, it flys TRUE from launch

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