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ebf the barrel twist and rifling quality its an internal change not an external change.
like worst case you shoot a 75g from a 1-12 twist 223 with near worn out barrel the bc will be terrible...

rifleing type and rate makes a difference to your bc. A rough finish will cause bc to drop as will cases not deburred causing scraps on the jacket.

Unless you have used them all, how can you tell whats best? And what makes it the best? theres alot that goes into them. trasol is probably the most powerful calculator but not easy to use or updated...

most good calculators will run a truing option. If it doesn't get another one.

The only way to get a true BC for your rifle is to shoot to distance from your rifle and true your data to suit. AB have already started to notice big shifts in BC in rifles as they wear let alone...