When I went down from 16 to 15, I noticed an increase in hook, but not much else, depending on how free your swing is, you might see timing issues, or an increased swing speed. Difference in hitting power is negligible between 14 and 15, more so with modern core/coverstock combinations. It should reduce the stress on your body though, so no harm in trying it.
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Reporting from England

Personally, I see an increase in light hit carry with 16 lbs versus 15 lbs.
I'm a lower speed bowler, 15 MPH @ Pins, so that may have something to do with it.

If you can throw heavier weight, do it, its more force directed at the pins, period.

Well I have been throwing 14 lb equipment for the past 3 years.  I have held the 5th highest average in the house for the past 2.  So to me I don't believe there is much change with 14lb.  I would agree with the fact of 15 kicking the coners out.  The biggest thing I have ever noticed is with ball comanpies when you get to 14lb equipment they tend to raise the RG and lower the differential.  Only problem this has created for me over the past couple years is finding a good heavy oil ball.  

Hope this helps..
ELF

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Yes I am a Lefty
Good scores to all  Elliott
Arsenal:=Columbia-Action, U-turn Pearl,Super Trooper, Hyde, White Dot
Highest series 718 done 4 weeks before shoulder surgery
Highest series after surgery to date: 740 done 10-24-06
Highest sanctioned series ever 740
300 Game shot with Super Trooper 10-17-06