Broadhead Tuning

[Pops423]

OK, so mybow is shooting great with field tips. I put my broadheads on last night and i'm shooting about 4 inches to the left of my field points at 20 yards.

I've read all the posts here and at the Mathews forum and have tried all the suggestions and am confused and frustrated.

I tried moving the rest away from the broadhead group like the easton guide suggests. But I'm reading lots of posts on this forum and it seems to be conflicting info on which way to move it. It seems that when I moved it, I started getting fish tailing and bad arrow flight. So I tried moving toward the BH group and same results.
Mathews Outback
Draw length is 29.5"
Arrow length is 31 1/4 (from where the string sits in the nock to the end of the insert)
Draw weight is 61#
Easton Epic 400
Fletching is straight (which I think is part of my issue.)
Thunderhead 100 grain hit 4 left at 15 yards. Field Points are dead on.
Thuderhead 125. Same results, in fact, I shot them (100 & 125 grain BH) in consecutive shots and damage the 1st arrow from the broadhead slicing thru it. on the second shot.The shafts were touching and I had to pull them out together.

FOC is 15.8 with the 100 grain BH
FOC is 14.2, with the 125 grain BH

I can't turn the poundage up any higher so I am stumped. I just had the bow in the shop and everything is in specs, ATA, brace height. Cam timing

If I'm reading all the documentation correct, it appears the arrows are overspined for this setup. what else can I do?

Just frustrating when my Hoyt MT Sport shoots perfect BH's with no adjustments and then have all this frustration with this bow.

[WA Shooter]

The Easton tuning guide is correct, move the rest away from the broadhead group. You should only move this VERY little, 1/32" at a time. After you move the rest, you need to shoot target tips again and adjust your sight to move them back on target. Then re-shoot a target tip and a BH and see if they are closer together. You should see an improvement. I just went through this with both my BowTechs, and both tips will shoot the same point of impact.

Good Luck.

[Grandviewer]

Fletching IMHO must be a right or a left helitcal for better broadhead controlled flight. Straight fletching does not give you enoughflight control after the first 3 yards to over compensate the over steer the fixed blade broadheads planing.

And I'm of the opinion that Thunderheads are very hard to get consitant flight out of them. I took them off and put two other types of fixed blades on and got quick results for accuracy. I won't use a thunderhead after that exercise in futility.

[lte_622]

i think your arrows are underspined actually.
that kind of length would require a 340 spine I think

[Dave at Work]

Are you bh grouping just as well as your fp, but just in different places?

[Pops423]

Thanks for all the suggestions guys.

I did shoot the FT and they had really bad arrow flight so I moved it back to the original location and shot the again to get them shooting dead on. Then I tried the other way just as a test and same result.

Yes the broadhead group just a good as my field points. just in 4 inches left.

I think the fletching is my issue. I have a Hoyt that I shoot the same BH on and they shoot great.

I'm going to get them refletched and see if that helps.

Also I shoot a Wisker Bisquit, and always thought the arrow was a little long. How far past the bisquit should the arrow tip be?

[JOE PA]

Just for kicks, and a no-cost experiment, try actually gripping the bow lightly instead of letting the bow roll around in your hand without gripping it. Not too tight, just loosely. See if that helps. I have had that left-grouping broadhead stuff on many bows too. I think it is torque, even though I take care about the grip, etc. You would probably benefit from at least offset fletch, if not helical, but if the broadheads are grouping tightly, and flight looks good, It doesn't seem like control is off that much. If things are right, and the heads spin true, it shouldn't matter too much what head you are trying to shoot.