I'd like to ask those who have some real technical golf knowledge to look into the following and tell me if my assumptions are correct.
I'm a beginner, playing with a second hand set (except for the driver and the putter).
My irons have aluminium shafts and probably date from the late 60's to early 70's.
Today I learned that the weight of the iron-shafts is about 130 grams.
Today's graphite iron shafts often weigh about 90 grams or even less.
I found information on the net, saying that a weight loss of 20 grams (in the shaft), could generate extra club-head speed up to 5 mph.
Assuming that 40 grams lighter shafts could generate up to 10 mph higher club-head speed, this could, theoretically, generate a gain in distance of 20-25 yards (correct???)
However, I also found out that the length of my iron shafts is actually 1" shorter than what is currently used for irons.
Knowing that the short irons differ 1/2" per club, and there is a difference in distance of 10 to 15 yards between each club, this could mean, IN THEORY AND UNDER IDEAL CIRCOMSTANCES, a total distance gain of over 50 yards (25+30) if I would switch for modern days graphite irons.
This seems to be confirmed by the fact that, 1 year ago, while practicing with a rented graphite 7-iron, I suddenly started hitting 10-15% of my balls around 200 yards and more, instead of the usual 150-160 yards (unless the yardages on that driving range were wrong off course!).
Can anyone confirm this, or is there a mistake in my reasoning?
The reason I haven't changed my irons yet, is that 1) some of this information only came to me in recent days, and 2) after this short period of success, I've hardly been able to play or practice and lost virtually everything I had build up before.
Thanks for the answers!