Broadhead tuning

[Ehunter]

Ok, I've tuned my FC400 using paper tuning, walkback tuning, and shooting at vertical and horizontal lines. It is a tack driver with both field points and broadheads. The problem I have is, I can't for the life of me get them to group together. Last night I was gettng 4 inch groups at 70 yards with broadheads. I get the same with field points. Problem is, the groups are at least 2 feet apart at that distance. Roughly 4 inches apart at 20 yards. Field points hitting to the left of the BH's. I have moved the rest left and right, VERY slowly, (1/32nd of an inch at a time), and it never improves beyond this point. I have shot heavier spined arrows, and get the same result. Any Ideas? Thanks guys!

[justin]

i would try a differnt broadhead.... ive shot 340 spine arrows with brand x 3blade fixed heads and they impacted perfectly with my feildpoints. but brand y 3 bladers were way off!! brand y hit dead center with 400 spine aarows though, and brand x was way off...... bolth 100 grain points and it seemed ther were only nominal differances in them......

[wscywabbit]

I have had fairly good success with the broadhead tuning section in the martin manual. HOWEVER, last year I tried to switch to a four blade broadhead, and they wouldn't tune for crap! Put my old muzzy 3 blades back on, and whalla. Sometimes you can tune and tune, but it won't make any difference. Good luck!

[Destroyer]

What heads?

Try a heavier field point with the same broadhead and see if they are closer.

[Ehunter]

Destroyer, the heads are Shuttle T-Locks. Are you thinking I am overspined by suggesting I shoot a heavier FP? Arrows are 28.25 inches, 350 spine (actually a 310), 70# draw@28.75 inches true draw. I'll try a heavier FP tonight, see what that gets me.
If the thing wasn't shooting such good groups with BH's, it would make more sense to me. I'll probably try shooting my Slick Tricks as well, see how they match up.

[Destroyer]

If the thing wasn't shooting such good groups with BH's

If its shooting so good then don't worry about getting the field points to hit the same spot. Is there a real need to have them hitting the same place?

Are you thinking I am overspined by suggesting I shoot a heavier FP?

Not so much overspined but a different affect on the spine depending on the type of head, that some broadheads weaken the spine a small amount in comparison to field points of the same mass weight. That's why I suggested you try a heavier field point, to change the spine of the field point arrow slightly and see if it equals up a bit. If it makes no difference then it must be something else like the aerodynamics of the head, etc.

I'm not a fan of group tuning anyway, I don't think its as easy as it use to be getting them to hit in the same place. With faster bows, shorter ATA's and much lighter arrows, its showing up some of the old methods of tuning.

[MLN1963]

Have you tried a true 350 or 400 spine arrow since yours are 310? I don't know much about it but I thought if you couldn't bring the FP and BH together with rest movement it was a spine issue?

[Destroyer]

Its a bit 'hit and miss' anyway, I don't use it anymore. All I do is paper tune with a field point to to see if the bow will tune, then I paper tune the broadhead. If its ok I sight in @ 20 yards, then walk back tune to 60 yards and if there is no problem, I sight in up to 60 yards.

[Ehunter]

Well, the only reason for me trying to get both to hit in the same general area is that I like shooting from longer distances for practice, and I wanted to be able to do that without moving my sights back and forth. I'm one of those guys that once I get something set to my satisfaction, I leave it alone. lol As good as it's grouping, I guess I'll just mark where I have the sight set for broadheads, then move it back for FP shooting for the summer. Should be easy enough to move back and resight in for BH's this fall. Still gonna try the FP weight change and BH change though. Thanks all!

[Destroyer]

Well, the only reason for me trying to get both to hit in the same general area is that I like shooting from longer distances for practice, and I wanted to be able to do that without moving my sights back and forth.

Understood and a good reason. Not everyone can practice with broadheads and not everyone can have two differently setup bows, one for practice and one for hunting.

Let me know how the heavier field point goes. Tuning a field point arrow to hit where the broadhead arrow does might just work!