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Main Boards => PowWow => Topic started by: Jake Diebolt on February 06, 2012, 12:43:00 PM
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When bareshafting (and occasionally during a really bad release) I hear a 'clacking' sound as my arrow goes. I'm pretty sure this is the arrow striking the riser.
My arrows are 2117 31.5 inches BOP. Point weight is 125 grain. My bow is a 50#@28 Martin Hunter, right handed. I've been told that 2117 is WAY too stiff for this bow, but they've been left pretty long. Stu's calculator tells me the shafts are too WEAK by about 7 lbs. Needless to say I am confused.
When the bareshafts come off the bow they fly way left (indicating stiff). I'm wondering if this is a 'false stiff' from the impact with the riser.
So, the question in the end: Does the arrow striking the riser on release indicate an arrow that is too weak, or too stiff? Or can it be both? I just want to know before I go and shorten the arrow to stiffen or buy new points to weaken.
Any input would be helpful! I'll be shooting at a range wednesday night, going to try some more bareshafting then.
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With Stu's calculator, don't forget to enter the plate thickness if you're using the Martin Hunter numbers he provides in the calculator. I've had arrows that were too stiff hit the riser, but not experienced it with weak arrows. More commonly, I've had arrows hit the shelf when the nocking point was too low for that particular bow. Have you tried raising the nocking point to 3/4" or so then working your way down a little at a time while bare shafting?
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I'm going to go with Nock point is too low. Raise it little by little till you dont hear it anymore and your arrows will be centered.
shawn
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An arrow hitting the riser can mean either one. From shooting similar weights and trying 2117's myself, I'd guess you were too stiff. If it were me, I'd add about 100grns to the point and see what happens. Could be a low nock point too, like was mentioned above.
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Pay close attention to your bow hand on release. Moving it a little or flinching on the release can give you all kinds of false indications as well.
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If you're drawing 28 inches, the 2117s are too stiff. A low nock point, too low brace height, torquing the riser and plucking can also cause the arrow to strike the bow, but I'm betting the arrows are too stiff.
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I'm shooting 2117s from my 50@28 recurve and I'm drawing 29.5". Arrows are an inch shorter at 30.5", but I have 175 up front and no indication they are too soft.
Ron
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Something you said about having more problems with a poor release.
I can't tell you how many wood arrow shafts I ruined years ago trying to bare shaft tune my set up.
My release was the culprit. I was torquing The string really bad. There was no way I could have accomplished bare shafting.
I found out by having a friend stand behind me and what he found was my elbow and fore arm were not aligned with the shaft etc.
Ron
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Grab some old arrows and work on the release, and then check the nock point.
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I don't think that there is a "false stiff" in this case. The arrows are flying left because they are deflecting off the riser... if you shoot righty. You are probably just too stiff as is.
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I may be beating a dead horse here, but here goes:
I just manually verified all the settings put into Stu's calculator. I verified the weights of all my components, measured my arrows from throat of nock to back of point, and manually measured the cut of my riser (it's 1/8 past centre, just as the default is). I also measured the width of my strike plate, which is 1/16th. With those punched in, I get that my bow needs 67.5 for dynamic spine. The current dynamic spine of my arrows is 62.0.
Checking 3 rivers arrow chart, for 125 grains at 31.5 inches, with a bow weight of 50#, 400 (aka 2117 for the xx75 GG) is bordering on too weak.
That being said, I can't ignore evidence. I'm going to go and bareshaft tune the arrows on wednesday. At least I'll get my nock point figured out and isolate one variable.
I'll try and ignore the calculator, since it just seems to confuse me right now. Does anyone else find that Stu's (and arrow charts) gives them overspined setups?
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Don't know how one figures the dynamic spine, but I do know the the static spine of a 2117 is 81-8$#, depending on the aluminum grade. You told us what your arrow length is, but not your draw length. If, you're in fact drawing close to the arrow length, i.e., 31 inches or so, the 2117 might be a bit weak. However, if you're drawing 28 inches with a 125 grain point, it will be stiff.
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I should also mention that Stu's calculator doesn't work at all for me. I tried it, got all confused, gave it up, and bareshaft tuned without it. I get great arrow flight now, and quit worrying about Stu. Must just be something about my release.
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I might be wrong about this, and if so somebody straighten me out. I'm paraphrasing here but the comment has been made that depending on draw length the 2117 shafts could either be stiff or weak. I think this is incorrect. The shafts are 31.5 " and regardless of draw length the shaft length remains constant. And, in this case the point weight is remaining constant. So, the spine is the spine regardless of draw length. The only way that would change is if the shafts were shortened. The one thing that would have some impact relative to spine of shafts would be the addition or subtraction of a couple of pounds of draw weight due to varying draw length. But, draw length alone, doesn't change the stiffness or weakness of the shaft. Whew.....somebody set me straight if that is wrong, or perhaps unclear.
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Check for marks on the arrow shelf. If the marks occur behind the rest (string side) the shaft is too stiff. If the marks occur on the shelf in front or the rest it is too weak.
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Charlie, Never knew to look for your previous diagnosis. I will save that one.
Thanks!
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Yukon, the static spine doesn't change, but the dynamic spine sure does. The difference in 3 1/2 inches of draw length is about 10# of bow weight acting on the shaft. That will flex the arrow more at release.
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I'm pulling 27 to 28 inches when I have good form. That puts me between 47 and 50 lbs probably.
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Update for anyone interested:
I upped my nock point to 3/4 inches and worked my way down to 1/2 while bareshafting and the grouping levelled out - no more riser strikes. And from the way the arrows flew this time I'd say they're just a little stiff - the groups are about 3-6 inches apart (and my grouping isn't exactly laser-guided at 20 yards). As soon as I can get some heavier points I'm going to see if that will bring the groups together.
Thanks for all the help and advice!
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Glad you got it figured out
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Yep. At 27-28 inches, the shafts are borderline stiff. Heavier heads should straighten them out. BTW, if your draw is 27-28 inches, why are you shooting 31-inches behind the point arrows? Most folks leave about an inch overhang past the riser, plus point. Could take a couple inches off the length. That will make them (dynamic spine) stiffer yet, of course. Folks shooting carbons tend to accept that they'll have to shoot longer lengths because there isn't a lot of choice with carbon spines. If you shoot aluminum, you don't have to. Just get a lower spined arrow. Good luck.
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Orion, the reason I shoot them so long is I was using leftover arrows from my compound shooting, when my draw was about 29". So when I got new arrows, I cut them to the same length (not knowing that that affected spine). I figured that I would draw shorter when I started shooting and eventually get to a longer draw length, so I left the arrows long - better too long than too short. Then, when I found out that shortening arrows stiffened them and changed their flight, I figured that I should leave them the same as long as they were flying OK, as I didn't want to affect the spine.
I suppose I could get a weaker spine and cut them so they're not so long, but aside from the look of the thing having long arrows shouldn't affect much, right?
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Right. If they're spined right for your bow, having more arrow hanging out won't make any difference. The few extra grains of added weight (20-40) won't matter much either. I prefer to use shorter arrows because they're a little easier to maneuver in tight hunting situations (on the bow or in the bow quiver). Also, if in a bow quiver, they're a little less likely to hit brush on the nock ends when moving through the woods.