The numbers designate the size of the arrow. The first two numbers are the outside diameter of the arrow in 64 ths of an inch. Yours are 22/64. The last two number indicate the wall thickness off the arrow in thousandths of an inch. The 2216 will have a 16 thousandths wall thickness (.016"). The 2215's will have a 15 thousands of an inch wall thickness (.015"). So they will be slighty lighter and weaker in spine.

I would have to look at a chart and compare it with what you shoot to see if they would be too weak or not. I suggest go to a shop and have them help you pick the correct arrows.

I don't like what you are doing from the sounds of it. Archery is an individual sport. You can't just grab someones bow and shoot it well (compound bow). It needs to fit you and be set up for your size. Just grabbing daddy's bow and heading for the woods is setting yourself up for failure in my opinion.

I would suggest going to a shop and seeing what your draw length is and a comfortable draw weight. Then see if your dad's bow fits you or can be made to fit you. Then practice a lot. Once you determin the fit and parameters of the bow the shop can help you pick the correct arrows.

Now if your shooting a recurve or longbow things are a bit different. However if you and your dad are different sizes and have different draw lengths you will have to get different spined arrows.

If you just wanted to wing target tipped arrows around the back yard it would be one thing, but if you are wanting to hunt there is a lot more to it than just grabbing someones bow, getting some arrows and heading to the woods.

Now if the bow already fits you, then dissregard what I said. I just don't want you to be misslead and set yourself up for failure before you even start. Bow hunting is hard enough when everything is in your favor.

I know this is not what you wanted to hear, but it's the best advice I can give.

Paul