I am currently using a 125grn broad head on an aluminum shaft.  I found some nice 200grn broad heads that i would like to try.  My question is what will the extra wright do to the flight of the arrow?  Should I see a major flight change?

If your arrows are properly tuned with the 125 gr. heads, the additional weight should have the effect of weakening the spine.   If you don't compensate and form is consistent, your point of impact will be to the right of aim (if you're right-handed).

I agree, 75 grains is a big jump without double checking the bow tune and probably going to a stiffer shaft.

What may happen with the current shafts is that you might not see a major flight change at normal hunting distances. But it could be that(assuming the bow is tuned with the 125 grain heads)you maybe relying on the fletchings to stabilize the arrow with the additioanal weight up front, which is a good thing, but it may not be optimal.

If it were me, I'd check and also be open to a different shaft before considering the 75 grain jump.

75 grs of point weight will weaken dynamic spine roughly 15 lbs.That's a lot.If you haven't bareshaft tuned your current arrows and they are too heavy,it might work.If they are tuned now,it won't.

JimB, I find that an intersting fact that a change of 25 grains will make a 5 lb change in arrow spine.  I often wondered that question what point weight and how much would equal in spine weight.

It will vary a lot with each setup but when estimating a point weight to choose,it can give you a starting point.I have some setups where 17-18 grs seems to equal 5lbs.1" of shaft length is also roughly 5 lbs of spine.If you play aroung with Stu's calculator you can get some idea of how all the different aspects change dynamic spine.

If they show weak with 200's you mite try building out your side plate a little bit.

The 200 grain points should make your shafts weak assuming they aren't stiff with the 125 grain point.

For me, when paper tuning with 50-55 lb longbows and 28 inch arrows, I get 1 lb spine for 7-8 grains of point weight.  Changing the shelf depth, poundage and arrow length could change that ratio some.

Mount one of those 200's, shoot it and see what happens.

Thanks for the info guys right now I am shooting a martin vision 50# at 28" my arrows are 2117 aluminum and are 29 1/4 long. I am running an arrow weight of around 538grn with my setup. I am still very new to the whole "setup the bow correctly" BUT very interested in learning the correct way.  So any help and suggestions are of great appreciation.
 Thanks Matt

Field points are cheap and will answer your questions without guessing.

Actually,for that setup,I think 200 grs would be closer to what you need.If you haven't,go to bowmaker.net and check the bow tuning information.Really good information and very well explained.

Matt, a helpful site is the A&H archery site. You can google A&H archery and on the left side of the site is a tab "knowledge base" click on it and it will give you OL Adcock's tuning info. I recommend you print it all off and use it as a guide for tuning your arrows. Check it out, it will answer your questions.

QuoteOriginally posted by onewhohasfun:
If they show weak with 200's you mite try building out your side plate a little bit.

X2

Here's the link to O.L. Adcock's site as mentioned above:

http://bowmaker.net/index2.htm

Click the link and then click "bow tuning". Very good info there.