I was looking for a cheap way to add some weight to my carbons.
Normally, without points, they weigh in at 295 grns or so...
I took some wire I had laying around ....
and cut it just about an inch and a half longer than the arrow shaft...
after shoving it inside until it hit bottom, I folded the end so that just a bit was sticking out, enough to insert into the not to hold it steady....
then put the nock on being careful to get the wire to sit inside the nock for quiet and steady holding
The new weight... 378 grns... this puts my arrows with points at about 550-600 grains depending on points... up from the 475 I had before.