Short Arrows & Spine

nettereo16

Well Known Rokslider
Joined
Feb 7, 2017
Messages
946
Location
NC
How close is too close for BH distance to the drop away rest? As a side project, I'd like to cut down a couple of arrows very short and add some brass inserts. With my DL at 28.5" (drawboard measured), a 26" arrow is about 1/2" in front of my rest. I shoot small fixed BHs and my fingers are curled down. My BHs on my normal setup are already over the shelf and I'm not too worried but I don't want to cross any danger-lines!!

I'm comfortable with paper/bareshaft/BH tuning and can usually get my BHs shooting well. I've never experienced a "weak spine" and don't really know what to look for. Is it mostly BHs will group better out of a stiffer arrow and be more forgiving?

Here are two 340 spine setups, with 125 vs 100 gr heads. Both are "Good" in OT2. I'll shoot them both to see but would be interested in any feedback on my spine. Thanks!

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Billy Goat

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May 6, 2018
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7,260
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Shenandoah Valley
Too short is when the nock is pulled from the string because the BH contacts the rest. If using a drawboard ID want at least 1/2" in front of the rest before the closest part of the broadhead, keep in mind some heads come back over the shaft some. Meaning, might want 3/4 or 7/8 of shaft at a minimum in front of the rest. At a point of excitement you might draw and go a little ways into the stops, causing you to overdrawn, won't likely happen with a limb stop bow, but a cable stop it can definitely happen.


In a centershot compound bow I find weak spine to just show as erratic arrow flight, especially with broadheads. If you are having trouble getting consistent broadhead impacts, it's likely a weak spine. Nock tuning can clean it up some, and straighter arrows help, but a lot of times in those cases you are still getting a relatively reliable impact point, just a larger group than you should. A weak spine your impacts will be jumping around from arrow to arrow. Quick test is to turn poundage down and see if it cleans up.

I think you will be just fine on spine.
 
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