POI (Point Of Impact) issues with fixed blade broadheads

[Bowhunter57]

Back in the aluminum arrow days, I was shooting a Darton MX400 that was a "blistering" 220 f.p.s. with 2213s. I could remove the 125 gr. field tips, install 125 gr. broadheads and go hunting groundhogs. The broadheads, no matter if they were 3, 4 or 5 blade configuration, would hit at the same POI as the field tips...at all yardages.

Fast forward to carbon arrows and a bow that exceeds 290 f.p.s....and there's not a chance of repeating that performance. Mechanical broadheads has been the only fix for this issue....until yesterday.

My Obsession Fusion 7 is sighted in to 80 yards with field tips and produces a "bullet hole" on paper tuning. The arrows are PSE Radial Weave 200, which are a 400 spine, 2" Blazer Vanes with a slight off set, a 100 gr. field tip @ 27" length and 340 grains of total arrow weight. Mechanical broadheads will hit the same POI as field tips at all the same yardages.

While shooting a Muzzy 3 blade, Slick Trick Standard, Magnus Stinger, NAP Thunderhead and a Muzzy Phantom (All 100 gr.), everyone of them would hit 8" high at 40 yards. Just for morbid curiosity, I happen to shoot a traditional 2 blade with a 1 1/4" cutting diameter that weighed 135 grains. Bullseye...dead on at 40 yards. I was thinking that if a broadhead was going to go crazy, it would be a 2 blade, but the weight difference got me to thinking.

So, I added two 20 gr. tip weights ( 40 gr. total) to the inside of the insert. 20 gr. and 50 gr. tip weights are all I had on hand. I installed the Slick Trick and shot it at 40 yards...Bullseye, again. I was able to repeat this performance with all the previous fixed blade broadheads at 40 yards. Now, I can shoot fixed or mechanical to the same POI.

I don't understand the added weight allowing the same POI, but it works.
If the arrows were hitting left or right, I would have suspected a spine issue, but not in this case.

Your thoughts?
Thank you, Bowhunter57

 

[jagermeister]

I shoot 150 grain stingers out of my Strother Infinity and they hit with field points all day long, 50 yds and beyond. Same thing for any other broadhead I screw on the end. The fact that you tried several broadheads and they all "hit 8" high" leads me to believe your setup is not tuned nearly as well as you think it is. Maybe your nock height isn't perfect. Or maybe your cam sync is slightly off. A bullet hole through paper doesn't necessarily mean you're tuned sufficiently. Adding weight to your arrows is changing the dynamic spine and is in some way helping to give you more consistent results.

 

[Bowhunter57]

The fact that you tried several broadheads and they all "hit 8" high" leads me to believe your setup is not tuned nearly as well as you think it is. Maybe your nock height isn't perfect. Or maybe your cam sync is slightly off. A bullet hole through paper doesn't necessarily

jagermeister,
I'm inclined to agree with you. I have yet to find an owner's manual for my bow. The cam timing was set when I purchased it, 3 months ago, but the string/cables could've stretched enough to change that to show the POI that I'm experiencing. The shop where I purchased the bow, was changing the cam timing by twisting one or another of the cables. I may be making a few trips to a local bow shop, to check a few things.

Thank you, Bowhunter57

 

[jagermeister]

jagermeister,
I'm inclined to agree with you. I have yet to find an owner's manual for my bow. The cam timing was set when I purchased it, 3 months ago, but the string/cables could've stretched enough to change that to show the POI that I'm experiencing. The shop where I purchased the bow, was changing the cam timing by twisting one or another of the cables. I may be making a few trips to a local bow shop, to check a few things.

Thank you, Bowhunter57

Just keep in mind that cam timing and cam sync are not one in the same. Cams in time may not be in sync, and cams in sync may not be in time. Definitely do some research on that particular bow before heading back to the shop so that you're fully informed. It may or may not be the cause of your BH flight issues, but it's certainly one thing you can potentially rule out.