I was discussing targets on the equipment review when pretty much the topic changed to my arrow spine and tuning. I thought this thread would be better suited over here. Please offer your thoughts and suggestions. Thanks. brucelanthier Senior Member Semi-Hardcore I have never shot that other target so I don't know how it compares. The rinehart is much better than the Morrell yellow jacket BH target and another nice thing I like about the rinehart is that you can shoot FP's into it also. When checking my tune I shoot a BH and then shoot a FP. You can really tell if they "fly together" that way GFY Camp Senior Member Weekend Warrior Okay, I admit I am new to tuning so bear with me. But I thought that typically fixed heads will fly a little different than field points. Specifically in my situation, my broadheads group well at 10y, 20y and 30y (I have not shot 40y yet. Hope to do that soon). I have my sight set for consistant location for my BH's right now. But my field points all go 3” left at 20y and 30y and 4” left at 35y. What does this mean? Out of tune or just the nature of a fixed head comapred to FP? Furthermore, you said get your FP and BH’s flying together. Is that possible in every situation? brucelanthier Senior Member Semi-Hardcore There are other factors to consider but that may be the indication of your spine being a bit weak. You could check this by turning your limb bolts out a full turn which will lower your draw weight around 3 pounds or so. Then see where the FP's and BH's hit in relation to each other. Ideally you would set your centershot and nock point before starting to do any tuning but, for just checking, adjusting your DW will give you some good feedback for now. IMO, yes it is possible in every situation if you take the time to build the arrow correctly (correct spine, decent FOC, squared ends and inserts). I've shot different BH's on the same arrow and same bow with good results.I shot reconfigured arrows (different FOC/spine/BH) and they did well after tuning bow and arrow together. IMO, if you can't get BH's and FP's hitting together then something is wrong. From what I read on forums it is usually a spine problem with the arrow. My BH's and FP's fly the same to a minimum of 45 yds and I often check out to 55 yds. GFY Camp Senior Member Weekend Warrior Well if it is a spine issue I am NOT going to do anything for now other than tune. I have a dozen pretty new arrows (some not shot yet) and I am NOT going to replace them 1 month before the season. I could see as those arrows start to dwindle I will consider getting different ones. I've had two people tell me by looking at my signature that my spine is actually too stiff. Well according to this chart: http://dev.carbonexpressarrows.com/cms/sites/all/themes/gorillastandstheme/catalogFiles/2009_Arrow_Guide.pdf I should be using a 350 arrow based on my 58lbs draw and 31" long arrow. What is funny is if I had 57lbs or under draw weight it says to use a 250 arrow. So I am just at the low limit of this arrow. This arrow that I am shooting is what my bow shop recommended based on the fact I may choose to up my draw weight sometime in the future. So technically, by the book I should be Ok on spine. But from what I am understanding, these charts are just a starting point and I may be better with a 250 in the future.
It may not be a spine issue, like I said there are other factors to consider. But, if it is, part of tuning a compound bow is adjusting the DW.
I think I read some of that thread, may have even contributed, but here's a bit of advice/info... With that PowerHawk, you are pretty significantly over-spined using those 350's. Now take that for what it's worth, you can weaken the spine using a 125gr tip, but not enough, but at the same time, I've tuned a few 60# bows to shoot .340 spine arrow (which is what you have) and gotten them to shoot well. Too Stiff is better than too weak, and SAFER as well. With your set-up, you could actually get close to correct spine if you have those 350's in FULL LENGTH, and use a 125gr tip. It does sound like a WEAK spine reaction, or it may just be a TUNING issue. Like I said, I got .340 spine arrows to tune out of 60# bows, it just takes a little tweakin. If I were you, I'd move the rest about 1/32" to the left and see if the groups merge. There is a lot to learn and many different ways to tune a compound bow, and you're in a good place to pick-up some tips from some pretty knowledgeable guys, such as Bruce.
From what I have read on here. Paper tuning is bascially a waste of time due to the fact you should distance shoot tune (what ever it is called) anyway.
That is good info. But the part I am having trouble with is people are saying my spine is too stiff but yet if you look at the chart I am not. And why is my bow shop recommending these arrows if they are not right? I assume it is because they are going by the chart. What gives?
One of the BIG reasons I learned to do all of my bow/arrow work and why I studied so hard to learn about this stuff is because my local bow shops has guys that are clueless setting up bows for people. You go in to have work done, you trust them to do it correctly but you find out they know less than most of their customers. My neighbor, a young man I have been helping to learn this stuff, was hired by the local shop to do bow and arrow work. Until I told him about spine, FOC and tuning, his idea of arrow setup was: Pick an arrow that looked cool, use the chart to get one in the range and then cut it to your draw length or maybe shorter if you didn't want abunch of "extra arrow" LOL.
They may or may not be right, a lot depends on the length and tip, the configuration, of the arrow and also on your bow. I have two 70# bows and to get them to shoot the same arrow at the same speed I have to lower the draw weight on one of them 3 pounds lower than the other. The charts get you in the ball park as far as spine but building the arrow with an eye on dynamic spine, FOC and efficiency of the bow is what will make tuning smooth and easy. Tuning is to get maximum efficiency, energy transfer, from the bow to the arrow. If the arrow is too stiff or weak efficient energy transfer suffers, arrow flight suffers and the effectiveness of the arrow on the animal suffers. I have been watching a few hunting shows lately and am amazed at the number of arrows that are hanging out of the deer as it runs away. The deer die but I thought the idea was to try and get pass throughs.
Actually, I ran your numbers through a programmer, and you're off-the-chart stiff unless you're shootin a full 31" arrow with a 125gr head, you sneak onto the chart, but you're still pretty stiff. Try that rest adjustment and see what happens. Also, shops don't always give the GREATEST advice, sad but true, there are shops out there that are more about making money than giving good info. And a chart MAY put that 350 into your bow, but my programmer (which has you're specific set-up) takes into consideration cam aggression, tip weight, arrow length, etc, and gives you a spine range that is good for your set-up. For your set-up, it's right on a .400 spine arrow. But again, you CAN get those arrow to tune pretty close, it just will take a bit of effort. While it may seem what you are seeing is a "weak" spine, I usually tune to whatever I'm seeing, and if I cannot overcome it, then I would assume there is a spine issue I'm fighting. With my Hoyt Striker II, I had my .340 arrow hitting real close to my FP's at 40yds, and it was only a 62# bow maxxed out, and those were 29.5" arrows that spine perfect in my Trykon @ 70#'s.
Okay thanks for that. I will be looking into getting different arrows once my current supply is running thin. I just spent $140 on new arrows and I am not about to start over and spend another $140. These will just have to do for now. As long as my BH keep grouping good. Knowing my luck, I won't lose or bust an arrow for 5 years now. Edit: Is there a chart somewhere showing series of arrows and spine?
OnTarget2....go to Pinwheel Software and you can download a free trial version for 2 weeks. Pretty nice program, though it's speed estimation is almost always HIGH, it's pretty good.
