Alright, some of you know this was coming, so here goes...
[font colour=#FF3300 size=4]WARNING: This post contains long
content. Proceed at your own risk.[/font]
Well, before i set off, i have a couple of things to make clear.
Firstly, i personally do not use the terminology 'pin action' to
describe anything other than kickbacks, pin deflections and
messengers/scouts. THerefore, i assume (if i lost the plot, please
correct me) that for heavy ball bowlers, the question of this
thread is "How to carry".
As people know, the heavy ball bowlers strike consists of only
ball-pin contact with the pins 1-3-5-9 (Those of you who don't
know, start another thread on this). Lefties, sorry. Just
reverse everything you read in this post. :p That means
that the only 'pin actions' necessary for a strike are practically
idiot-proof once proper 1-3 pocket is made. If the pocket is hit
without a strike as a result, there exists a lack of "carry".
Secondly, I think the only people who should be concerned about
'pin action' are spinners, because that is what gets them the
strikes. Their ball doesn't so much carry as deflect. This isn't
meant to knock spinners, because there are very good ones out
there. I'm just trying to explain my standpoint so readers to this
can understand what i'm dishing out later. 
Alright... now for the good part:
As i've said, carry is the only thing a heavy ball bowler should
concern him/herself with as far as strikes (or large pocket spares
are concerned), because relying on messengers and lively sideboards
is never reliable, to say the least. IMO, there are 3 main factors
to carry:
1) Weight
2) Angle
3) Friction
Weight
Weight, unfortunately for those who have been trying to convince
themselves that lighter doesn't mean less, does matter. Mostly, the
difference between 15lbs and 16lbs is negligible. 14lbs suffers a
little, while anything below that is not too good due to the design
and composition of the weight block. But weight is a factor in
carry not because of the weight block (which affects angle), but
simply because of deflection. As heavy ball bowlers know (if you
don't, start another thread), deflection kills carry - because it
spoils the 1-3-5-9 chain. Simple physics dictate that more mass is
harder to move. That's it. Still follow me? Good. Next
factor...
Angle
Angle is the reason why people like myself try week-in and week-out
to "Do the twist" and make a plastic sphere move in an arc instead
of a straight line. A straight ball will defect more than a ball
which enters at an angle, destroying the 1-3-5-9 thingy again.
Different people have different optimum angles. Recall your friend
who can carry with a light pocket but you end up with corner pins.
This is because of different aspects of each person. Heavier ball,
more grip on impact, etcetera.
Basically, angle is the reason why a lot of people think
revolutions are important to bowling. I don't think so. Revs are
important to selling balls, that's all. Revolutions help the ball
turn, because a ball hooks when its core is trying to return to a
stable state (if you don't know... ). And it does this by slowly
shifting a little with each revolution - hence flare tracks. Thus a
ball with more revs 'refreshes' its cover quicker than others, all
else being equal. This is why
Revolutions = More turn at breakpoint =Angle
But with the core technology today, simple pin placement will
produce the same effect for the rev-challenged (dun understand? you
know what to do).
Friction
Friction, also known as grip, is crucial for one thing -
energy.
Friction levels over 60 ft of lane surface affects energy levels
retained in the ball. Energy is needed for everything - break,
hook, roll... And the less of it one has left at the pocket, the
more deflection there will be.
Friction also affects angle like this:
Friction = Turn @ breakpoint = Angle
Friction is affected by the hardness rating of the cover, which is
brought up by Airgrinder. Although i do not agree with the quote. I
suspect it's a misquote from the article. The hardness of the cover
affects how much bite a ball has on the lanes (softer = more bite;
vice-versa), which determines how much angle there is. Some people
do not carry with soft covers, because the ball bites so hard, it
expends too much energy getting
to the pocket. This results in deflection off the headpin,
which gives very designer-looking split/spare combinations.
As for the point about using a rubber vs. a plastic ball is not
representative because the grip levels of the balls aren't equal.
Sometimes, more grip = more carry, sometimes, the opposite
happens.
That's my 2 cents. 3 factors for carry. Please note that most other
things trace back to these 3 key factors (much like how all colours
are derived from 3 primary colours). A point to note is speed.
Technology is so advanced nowadays that speed control is the number
one priority now, mainly because of friction. Coverstocks are now
so aggressive, a little earlier or later in the pocket makes a
world of difference to your carry percentage. Other than that, I
would refute the notion that the technology is the determinant for
carry. Afterall, the only true "tap" or "chop" in bowling is the
solid pin 8 or 9, regardless of which hand one plays with (this is
why PBA player Pete Weber is so famous - his ball has too much
carry - he leaves the highest percentage of solid 9s on tour than
anybody else).
Left a corner pin on your last shot? Don't look around. It's you.
------------------
Always remember: It's easier to spare from a channelball than a
split. 
