What gives with my arrow flight?
 

So whats the deal with this: I've been shooting Easton FMJ 400s, cut at 29 3/4" with 100 gr heads off my HCA Iron Mace for the better part of the year. No issues with flight or anything. I shot a bear shaft last week and noticed I was getting a bad wobble with the arrow sticking in the target with the nock to the left of the point of impact. This would indicate a weak spine. Correct? I tried both 85 and 75gr points. I was shooting 64#s, but have backed it off to 60#s. I am also trying some ACC 3-49s, same length. I am noticing some odd if not erradic flight. I am assuming that the spine is just too weak. The bow is tuned, and though I'm not perfect, my shooting is solid enough to rule it out, and I have a few other semi-professional opinions on that. Is my problem my arrow spine? The charts say I should be right on or even a little bit too stiff... I don't really want to throw out $300 worth of FMJs and ACCs. What can I do?

RE: What gives with my arrow flight?
 

Swamp,

Did you run your set-up through OT2 or another program? If you'd like post or send me your set-up specs and I'll run it. The Iron Mace is a very fast bow and I'd bet that due to the speed and energy produced by it the arrows are underspined. You need to add weight to the rear to increase spine or shorten the arrows or do both. I had to do that with the GT 7595's fpr my Allegiance.

RE: What gives with my arrow flight?
 

Go to a stiffer arrow and keep your FOC up to at least 12% you will get noticeably better arrow flight and groups. I shoot 400's at 60# cut to 27" with great results out of my Allegiance;)

Dan

RE: What gives with my arrow flight?
 

I cannot cut the arrows any shorter than they are already. 29 3/4" is just enough for the broadheads to clear the shelf before the shaffer lifts the arrow up at full draw. My draw length is 29.5".

I have dipped and crested my FMJs, and fletched them with blazers. What I don't get is why they "seemed" to be flying great before, but now are noticably jacked up. Everything is tight, and everything is the same except I've turned the # down, which should have helped if anything.

How can I add more weight to the back of my arrows. I don't exactly have $300 sitting around to buy two dozen new arrows this time of year. Lumenocks are non-compatable with ACCs, as they don't make a G nock. Might work in the FMJs.



Dave; I don't have any sort of program like that. What exact number do you need? I'll throw a few at you and hopefully it will help. My bow is set now at 60#, 29.5"... has a 7 3/8" brace (which is spec), my arrows are Easton ACCs 3-49 cut at 29.75" with a 100gr tip. Blazer vanes, no crests or wraps. The Mace has Trinary cams, which are the same deal as the Bowtech's Binary's. I'd say its a bit more aggressive though perhaps, as the BTs, even with speed mods don't seem to load up quite as much. Shooting it on 60#s is kind of nice though. Those ACCs are weighin in at 404gr, and speed with the radar chrono is right at 278fps. Plenty fast enough for me. Thats the arrow that shot the best last night of the two I have... so I'm going to run with it. Let me know what the computer spits out at you. Thanks in advance.

RE: What gives with my arrow flight?
 

That should be enough info. Thank you. I'll run it tonight. Longer draw lengths have problems with being underspined with a high performance bow.

Have you checked out your rest at all? My arrows started doing a little tail wobble and it turned out that my rest had moved a very, very small amount. Less than 1/32"

RE: What gives with my arrow flight?
 

On another note I did shoot 400's out of my 70# Allegiance with good results, but they were cut off to 27" and that's a lot of different than 29.5";)

Dan

RE: What gives with my arrow flight?
 

The draw force curve of the Iron Mace is close to the BT Pro 40 Dually draw force curve.

That with your 29" draw and 29.75" arrow your current arrows are under spined you really should be shooting the 340's or ACC 3-60's with a 100gr head.

Adding a wrap to the back of the arrow is not going to do a thing for your current arrows.

RE: What gives with my arrow flight?
 

Although the Iron Mace has a pretty radical draw curve, I'm shooting 29" Easton Axis 400 arrows out of two different 61 lb. bows and the spine is perfect with 100 grain heads. The fact that you said things were good at first, and now have gone down hill, makes me wonder if you suddenly don't have some sort of clearance issue. What sort of rest are you using?

RE: What gives with my arrow flight?
 

On my Ontarget using aussie's suggestion about the bowtech Dually 40, I show you are weak, even at 60lbs. I agree with ausie, that a 340 might be in order. A 340 shows a tad stiff at 60lbs, but you can always raise it to 65#.

RE: What gives with my arrow flight?
 

For the OT2 guys. The Iron Mace is listed in the selection guide under "Newburry Iron Mace", not under HCA. You don't have to use the BT Pro 40 Dually. Not sure why they do not have it under HCA. I didn't find this out until this morning so my output was based on the Dually.

Also, if you haven't done so make sure to derate the IBO to match the speed for the arrow and DW that Swamp listed. WhenI ran the derated set-upthe arrowwas spined propery for 'Target' and 'Both' catagories and low for 'Hunting'.If that is the case I would think that for tuning purposes the arrow should fly properly? I'm going to run using the Newburry model tonight and see if there is any difference.

RE: What gives with my arrow flight?
 

I was told by larry at pinwheel software that you don't want to derate the IBO but insert real IBO for a real IBO setup and then the program derates according to draw, extra arrow wieght, silencers, peepwieght, etc, and then use he performance slider to adjust for real measured velocity if you have that on hand.

RE: What gives with my arrow flight?
 

Hey swamp is 29.5" your true draw length or your AMO draw length. I was told I should use AMO draw length in Ontarget2 which is 29.5+1.75"=31.25 if 29.5" is your true draw length.

RE: What gives with my arrow flight?
 

That conflicts with what Larry told me. He stated that you should adjust the IBO based on a known DW, known arrow weight, and chrono'd speed. And that the performance slider is strickly for people who want to play around with their set-ups. I've done it the way I've stated for my bowand everytime I change DW or arrow weight I get exactly the same speed on OT2 that the chrono shows. This has never been the case using the slider. I've had to move the slider with every arrow or DW change to get the same speed.

A few other guys on here also derate the IBO with good results and have the smae issues with the performance slider.

RE: What gives with my arrow flight?
 

I ran your bow through using the Newbury Iron Mace and am surpised at the results. Even for hunting the Eastom ACC 3-49's are spined good.


I tired to do it by adjusting the performance bar. However, the bar will not go down far enough to get to 278 fps with that arrow at 60#. The lowest velocity was 282 fps.

RE: What gives with my arrow flight?
 

Dave, you set the DL to 29.5. I thought on ONtarget they tell you to use the AMO DL. It actually makes a big difference.

RE: What gives with my arrow flight?
 

If I use AMO DL, assuming Swamp is giving True DL, and adjust IBO down to 278fps with 404gr ACC, I still get way weak. I have tried it both way using slider and IBO, and the result is the same.

RE: What gives with my arrow flight?
 

Swamper - you might pick up a shaft or two in the 340 series and try them - with and without fletch. See if that clears up the problem. Not real technical of a solution,but it should tell you if the arrow is the problem.

Looking at the charts, and considering the extreme force curve of the bow, it very well be a weak arrow at that length.

I have some 340 series arrows that I left full length (31"), and they are spined pretty well for my 61 lb. bows. Too bad you can't cut those FMJ shafts backsome. I think you would need to trim them about 1.5"to get rid of the HIT that's in there now.

RE: What gives with my arrow flight?
 

You do realize that when you buy a bow that has 29.5" on it that the AMO is 29.5"? Bows are listed with their AMO DL. The reason that OT2 posts the 1.75" is for people who actually measure the true DL and want to be more accurate than just saying 29.5". The true DLwould be if you draw the bow back and have someone measure from the nock to where your hand touches the grip. (Or Burger hole) to convert to AMO you would add 1.75".



According to OT2 the force curve for the Iron Mace isn't that different to the Allegiance. Furthermore, if you are not going to use the Newburry Iron Mace you can't use "2 Cam Hard" for the cams. On OT2 the Newbury comes up with "1 Cam Soft" just like the Allegiance.

RE: What gives with my arrow flight?
 

Well, of course, but you do realize that most manfactures are off and some up to 2" or more as len at macrotech showed us on several bows. Which I sure won't actsilly like some and so arrogant to act like I know everything and was taught. I didn't write the code, so I am always willing to learn a new thing or two about it. Thats the reason, its good for someone to know the true DL, which is the reason, I asked him the true DL, because thats the only thing that would make the model accurate.

But I am sure you probably already know all this.;)

RE: What gives with my arrow flight?
 

If he says his DL is 29.5" then I'mmaking the assumption that most people would make. That he is going by what is on the tag.Until otherwise I stick tothe infoI gave him.

RE: What gives with my arrow flight?
 

i've measured a lot of bows, and not one of them has ever come in at exactly what the sticker says - never.

RE: What gives with my arrow flight?
 

My PSE is over 1.5" off. My liberty is right on the money. My commander is 0.5" long.

So for any model or simulator to be correct, you have to have correct numbers.

RE: What gives with my arrow flight?
 

2 points.
1. The Iron Mace has a higher IBO than my allegiance. I shoot a 396 gr arrow at 63# at 284 fps w/ a 30# DL. If I shot it at 31.25# it would be over 290 fps. i talk to a guy that has an Iron mace a lot about how the Iron Mace compares to the Allegiance with standard weight arrows and they are close. From that I draw the conclusion that he is shooting with a 29.5" AMO DL.

2.Until he gives the actual DL just use the sticker DL.Even if the sticker is wrong I'd doubt it's off by that much. Definitely not 1.75". And you wouldn't just create a number. With any calculation use use knows as much as possible.

gibblet, even if they are not "exactly" what it says I'd bet that most new bows are pretty close. And even though you'd never admit it you know that you wouldn't just pull some number ...Deleted by CalHunter... to size an arrow. ...Deleted by CalHunter...

RE: What gives with my arrow flight?
 

Agreed 100%.. Hey Gib, didn't Russ invite you on our Axis hunt? If he didn't I'll slap his hat off today if I see him. :D

RE: What gives with my arrow flight?
 

I'm sure big really appreciated you guys trying to bail him out. ;)

RE: What gives with my arrow flight?
 

i'd take that bet any day of the week, because even if you considered 1/4" close - they'd still be - on the whole - way off.
...Deleted by CalHunter... :D:D:D:D

RE: What gives with my arrow flight?
 

I feel a show coming on.:D

RE: What gives with my arrow flight?
 

rev, any idea what the above quote means?

RE: What gives with my arrow flight?
 

Yeah I did and he said he had some $11 per pound MM's last night and is too hoytie toytie for us now:D

dont know about Bob but I don't;)

RE: What gives with my arrow flight?
 

[/quote]

rev, any idea what the above quote means?
[/quote]


Yep I do, seems like someone is talking ...Deleted by CalHunter... [&o]

RE: What gives with my arrow flight?
 

1/4" is a lot. However, Swamp was asking about his bow at 29.5". Not 29.75, Not 31.25". I'm simply stating that the info i gave is for the info he gave.

You guys really need to be a little more mature. [:'(]

RE: What gives with my arrow flight?
 

IMO, the dip and crest added enough weight to screw up your FOC. You're probably under 8% with tips that light, and I think you're seeing more of a lack of stability than spine problems. You've backed off the draw weight from 64# to 60#. That should be enough to try something. Stick some 100 gn points on 'em and see if getting your FOC back over 9% will straighten out your arrow flight.

Also, how were your arrows fletched before?

If those are the only two things that have changed about your setup, and everything was fine before you made those changes, then those are the only two things that really need to be examined.

RE: What gives with my arrow flight?
 

I've seen this when the fletchings come loose. The arrows normally shoot fine but all of sudden they are going all over the place when one vane is not completely tight to the shaft.

I just wonder if this what's changing the POI. for him?

RE: What gives with my arrow flight?
 

Hey Art, whats the general wieght of a dip and crest? I have never done it but thought about it for my Cedars.

RE: What gives with my arrow flight?
 

There's no hard and fast answer to that, bigcountry. Depends on what kind of paint or lacquer you use, length of the dip, how many coats you do and how thick you make them. It can turn into significant weight. I've seen as little as 10 grains and as much as 45 grains.

I don't fool with dipping and cresting much either. It looks nice and everything, but I don't want any more weight on the tail end of the arrow than I absolutely have to have.

RE: What gives with my arrow flight?
 

Right now on my PO Cedars I am at 12% FOC. And show a little weak reaction with my recurve, and thought it wouldn't be a bad idea to add some wieght. Thanks for the info.

RE: What gives with my arrow flight? UPDATE
 

Hey everyone I really appreciate all the thoughts. I appologise for not being around to respond to some of the questions you all posed for me. I was (go figure) hunting. I let a few smallish and one almost shooter deer go, as well as a host of does, as I still have some meat left over from last year, and I shot a fawn (can you say veal) back in mid October.

Anyway... I have no clue what some of y'all are talking about with relation to the OT2 program itself. I can however, tell you this much in part from experience and the rest from observation. My draw length itself, as it pertains to me, mesures out at anywhere between 29.25 and 29.5 inches. Depending on who is holding the tape. The Iron Mace I shoot is a long draw model, set at 29.5". That said, I, like gibblet, have seen bows that were supposed to be 28" (for example) end up being 27 and on other bows 29. They can and do vary greatly. If anyone knows where the industry standard for actual draw lenth on a bow is.. please let me know. I have heard the front of the riser, the low point of the grip, the center of berger button hole and that there isn't one and most makers just try and come close to what they think should fit someone with X length.

I whacked the fletchings off one of my FMJ 400s and one of the ACC 3-49s. Again, I can't shorten them anymore than they are. I shot them bareshaft, and both (at 15 yards) stuck in to the bail nock left of point of impact. To me, thats weak spine. I'm shooting a Schaffer rest, as I mentioned earlier, and haven't noticed the first bit of clearence problem with it since I've had it. Honestly, I think it may well have just been me. I still do think the arrows are a bit weak spined. But the wiggle has seemed to have gotten better. I reset my nock point, tied on a new loop, recentered and just basically started over. I still a weak reaction with a bare shaft, but the wiggle with a fletched arrow has drasically deminished. Who knows... barometric pressure or some sh*t?....?...?.... No telling. Odd think though, my arrows are square, and spin test as such. My fieldpoints, after tuning (french/walkback) with broadheads and sighting in and all, are a good 2" left of my point of aim and point of impact with broadheads. Again, I'm shooting Montecs, and I know for a 100% fact that no matter what head you shoot, it will NEVER be EXACTLY the same as field points, but 2" is more than it was. Infact, I couldn't hardly notice before.. maybe an inch, but small enough for me not to notice... but its noticable a beer can diameter to the left now. I'm almost losing confidence in myself and the equipment. Its frustrating as all hell.

RE: What gives with my arrow flight? UPDATE
 

They (some proshops) claim they cheat on AMO Draw for speed.

It definately sounds like a weak spine. And if you taking a tape and measureing from the string to the handle, then this would make sense. Sounds like you definately got to go stiffer. It sucks buying new arrows, I know. You know you could also get a new rest like theQAD, and cut your arrows. You can move that and others rests back pretty far. Not sure if you like your current rest.

Hope hunting goes better. I am off for the next 9 days for bow hunting. Hope I things right.

RE: What gives with my arrow flight? UPDATE
 

one thing i didn't ask - is what kind of target are you shooting into?

RE: What gives with my arrow flight? UPDATE
 

Swamp,

If the bow is set at 29.5" then that is the DL. Yes, it can be a little off but will not be that far off. In another post I stated that the DL is measured from the nock at full draw to where your hand touches the bow grip curve+1.75"

Are you saying your BH's are 2" right of your FP's? If so, move your rest a very small amount(1/32") left and see what happens. My BH's hit where my FP's do with Wac'em Exits and the QAD rest.As I've stated before, I had the same problem and it was the rest that was the problem. Small wiggle with fletched arrows abd BH's off. I also had the arrows sticking in nock left. Take it for what it's worth.