I would want to clear up the tuning issues before I went to a mechanical. An arrow that isn't flying perfectly will cut down on penetration
I agree. Heres a quick step by step
1) Buy a spinner, pretty cheap, and check each arrow with BH to make sure its spins true. May be the insert, arrow etc, but if off wont fly straight. Also make sure spine is OK per chart etc.
2) Remove field point and draw back. If your arrow doesnt stay on your rest as you hit full draw you have nock pinch...not good. Loosen the nick diameter in loop and add a small piece of serving under nock. Will allow for downward pressure and no pinch.
3) Then, start with paper and get as close to perfect as you can, but dont go crazy if JUST a bit of a tear. If you have a big tear, move the rest IN THE DIRECTION OF THE FIELD TIP to correct.
Here is a decent tear above (what you want at about 6 feet), vs below
To correct below, move rest to the right by 1/16" to start.
3) Then....Modified Walk back tune (heres a simple way for winter)
Shoot at 3 yards (9 ft) and
sight in arrow with pins to hit just below the "X" on a bale
Then move back to 20 yards and aim at same point with same pin. If off a bit right...DO NOT MOVE YOUR PIN.
MOVE THE REST
Move the rest a smidge (1/16") to the left if miss right of first arrow.
And if miss left, move rest to the right.
Then go back to 9 feet and shoot at X again, eventually, the 20 yard arrow will be perfectly in-line with the 9 foot arrow, but higher. Then sight in for 20 yards with your pin and your done.
Once you get this, and arrows spin true with BH attached, no nock pinch and good spine you have accomplished a solid tune:
Your Center shot will be perfect and you can test that with a fixed blade, which should hit same spot as field point. If just off, again, move rest in direction of field tipped arrows...always chase the fieldpoints.
B) Mechanicals or FBBH...doesnt matter now as you are tuned and can shoot anything you want-I often tune with big fixed heads....
...or arrows with no flecthing (see far left arrow).
If your off, that arrow goes crazy. But if your tuned...you can shoot right with the fletched AND KNOW THAT THE PATH OF THE STRING IS DIRECTLY IN LINE WITH THE SHAFT