Correct me if I am wrong, but are you speaking of the situation where your ball is just not finishing or is laboring to get back to the pocket?
If so it could be carry down or it could be a lack of head/midlane oil.
Most of the time if a ball is laboring to get back or if I am leaving weak corners i will either move 2/1 in or ball down and square up a little simply because the head oil is more likely to go before the oil gets down the lanes with todays agressive resin balls. This was not the case 8-10 years ago, rather a result of the way bowling and equipment has evolved.
If it is true carrydown, for instance a 2nd shift league fowling a women's league (plastic down the middle) going to a weaker ball and moving to a straighter line or slowing down a little is a good option. Also a ball with decent survace and a low flare drilling will work well with a straighter shot...might not carry everything, but will get to the pocket on a consistant basis (depending on the operator of course).
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"...do or do not, there is no try."
St. Louis USBC Sport Bowling
Best Bowling Pro Shops Inc., St. Louis MO.