posted
Relatively new to the traditional sport but have been shooting my BW for about 6 months now. Here's the set-up, 62" PMA II, 30" draw at 53 lbs. I checked my draw with this bow and I am pulling the full 30 inches. Also checked the poundage and believe it or not the scale said 53lbs at 30 inches. BW are cut 3/16 past center. I've been tinkering around with Stu's formula a bit but was wondering what you guys would come up with. I'd like to shoot either 55-75s or 75-95s GT that weigh 600-650 grains with a high FOC.
What combination would you come up with that should fly well or at least get me very close before tinkering. Thanks.
Posts: 34 | From: MN | Registered: Oct 2009
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posted
I would go with the lighter spined of the two if that's the arrow choice you want to use. The 55/75's may even be too stiff? I would suggest going to a pro shop and just buy one of each and try them before you spring for an entire dozen. Or check around on some archery sites and see what you can find there, lots of guys selling arrows right now.
I found that with my recurve the lighter spined arrows shoot broaheads better. I started out practicing with an arrow spined exactly for my poundage of #48 @28" and they shot field tips well, then when it came time to put a broadhead on they started shooting left. So I went back to sanding them down some more and ended up with a spine for a #42 pound bow and the broadheads shot great. Yes, I switched to wood shafts, cedar to be exact. They now shoot very well that I got my spine right and I'm right at 475gr. total wt. for my #48 pound recurve which is near perfect.
I think the broadheads do more pulling of the arrow this way and that and need more flex from the shaft to straighten out. So basically, just because that's what the chart says and even if they shoot field tips just fine doesn't necessarily mean they will fly straight when it comes time to slap a broadhead on.
Another thing about carbons, you can't adjust the spine... all you can do is go with a longer shaft, or cut them down to a shorter shaft, or add/take away weight on the tip to simulate a spine change. That's another reason why I shoot cedar, I can adjust them till they fly perfect using only a piece of sandpaper. Just my 2 cents.
-------------------- ~Varitas Vos Liberabit~ John 8:32 ~Genesis 27:3~ Of all the things I've lost, I miss my mind the most. Posts: 2867 | From: Missouri | Registered: Aug 2010
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posted
The problem I keep running into using Stu's calculator is I can't get an arrow in that 600 grain range with efoc to spine correctly. Best combo it seems I can come up with is a GT 7595 at 31", 190 gr point, for a 573 gr total and 16.4% foc. With my bow inputs the required spine is 73.1. The strike plate measurement makes a huge difference. I had always just used 0 out of ignorance, but then I was on BW's sight and saw that they were cut 3/16 past center. So it seems with my bow I am limited to what it will do which I guess is true of everything. But my gutt tells me my long draw length and shooting 53lbs I should be able to get a 650gr arrow to work. I'm I using the calculater correctly? Or is a 575gr arrow about the max my bow will handle? Thanks.
Posts: 34 | From: MN | Registered: Oct 2009
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posted
First, what arrows have you been shooting for the past 6 months? Wood/carbon/alum??
I've taken a cue from one of the old time TG members who's been shooting all his life. He told me that the carbon spine charts just don't seem to work; but he's found that the heavier you go up front, the better.
So, I tried it, and it does work. I'm shooting 28"BOP, 500 gr GT Trad 35-55s with some 40-45#, mild r/d Mohawk Longbows. I've got 200-225 gn up front.(The difference being in the Trad shafts vs the lighter wt 35-55s without the "trad" wrap on them.)Granted, they're a bit stiff for the lighter bows, but will still group, and having one arrow size simplifies my life. Of course, having only one bow would really simplify life; but it wouldn't be as fun!
My method: I cut my shafts to the length I wanted to use, and made up six bare shafts, along with my fletched shafts. I found that the fully fletched shafts would shoot down the middle with most point wts, but the bare shafts would move left to right of center, by going from 145gn to 250gn points. The bare shafts with 200 gn pts would shoot down the middle along with the fletched shafts. Having done this testing at 10 yds, I moved out to 20 yds with the same results.
Now, I keep the bare shafts available and repeat the drill every now and then to see if my shooting form improvement causes any changes. So far, nada.
posted
Why yes it is. Nobody ever said it was easy, but wouldn't you think that if the Indians survived by killing all their food with just a stick and string, no modern tools or even sandpaper and using rock points that this should be much easier? All this about spine, FOC, point wts, Right Fletch, Left Fletch, tiller, string material, and the list goes on and on.......It gets a little mind boggling and very frustrating at times. It does feel really good when you finally get something to click right. I let out a huge sigh of relief when I finally found my perfect spine and now I can shoot several different broadheads accurately. There's absolutely something to be said about a properly spined shaft that's tuned for your outfit, it offers so much more forgiveness.
-------------------- ~Varitas Vos Liberabit~ John 8:32 ~Genesis 27:3~ Of all the things I've lost, I miss my mind the most. Posts: 2867 | From: Missouri | Registered: Aug 2010
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S_H, I agree that we cause our own problems by getting over technical.Our main problem has become too many choices, choices that those early hunters didn't have.
I can honestly say that I've found it easier to get properly spined woodies than to do the same with carbons. There really is something to be said about the "KISS" principle! Posts: 290 | Registered: May 2010
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You guys aren't helping! Please save all soapbox discussions until after I've found my setup. What I current shoot are 31" 5575 GTs with 5" feathers and 180 grains up front including insert etc. 145 grain point, insert, and small brass weight. Seems like these arrows flex, paradox, or whatever leaving the bow but shoot ok holes through paper. 140 grain Magnus fly excellent, same poi. Total arrow weight is around 490 grains.
Posts: 34 | From: MN | Registered: Oct 2009
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posted
I cannot tell you what will fly best out of your bow with your shooting style, release etc.. but I will say that the earlier reply suggesting carbon charts are innacurate is an understatement in my experience. I shoot a Toelke "Curlew" take down recurve, 62" and 54 lbs. at my 29" draw. Beman 500s 30 1/2" throat of nock to back of point with a 100 and a 75 grain brass insert and a 145 grain field pt. bareshaft and when fletched paper tune and fly like bullets. This set up is a couple of counties away from Beman charts but it works! All this said, center shot recurves are pretty spine tolerant creatures and I can shoot less front end weight and still get good flight but I like the e.f.o.c. and the 640 grains total. If I were you I would try 3555s as well as the 5575 Goldtips you have mentioned.
Posts: 841 | From: Louisiana | Registered: Feb 2007
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"Seems like these arrows flex, paradox, or whatever leaving the bow but shoot ok holes through paper.....
"140 grain Magnus fly excellent, same poi."
How far away is your drawn arrow point from your shoot-through paper?
Is your "Strike Plate Position" still -3/16" as in negative 3/16"? Or is it something else because of a possible arrow plate or something?
Without knowing every single input you have, we cannot begin to tell you if your DSC results are correct.
Can't follow just what your arrow flight quality is, "flex, paradox, or whatever" really tells us nothing definitive.
Have you tried bareshaft testing at 20 yards, using your fletched arrows as a reference to compare your bare shafts?
I'm giving your homework sheet back to you with red ink all over it, I suggest you re-do it and then clearly state just what is in your kit, then we might be able to help you.
-------------------- "We were arguing about brace-height tuning and then a fistmele broke out" Posts: 680 | From: Wisconsin | Registered: Dec 2006
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To answer some questions. Paper was around 6' away. Strike plate is still -3/16 but I didn't account for the BW leather web. It's thin, but maybe we could say it's -1/8 with that. When the arrow leaves the bow it doesn't fly like a lazer. I can catch it wobble a bit before it straightens out. I shoot everynight in the basement at about 14 yards. My arrows group very consistently, enter the target level, and all are entering the target consistently. I bareshafted at this same distance and they hit right in the same group as my fletched arrows, however, the bareshafts all enter angling down with the nock high. My fletched arrows are all horizontal to the floor.
Posts: 34 | From: MN | Registered: Oct 2009
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posted
Any chance you can get to a shop and try a bunch of different combos? With your draw length, the 400 spined shafts would likely be a good place to start.
Posts: 969 | From: Australia for now, Oregon USA at heart | Registered: Apr 2008
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posted
I'm not sure what you define as high FOC.It is harder to get higher FOC with bows cut 1/8" or more past center but it isn't a big deal to build out the side plate and change that.
I had to go to a .300 spine arrow to get the FOC I wanted out of a bow cut like that.I found some .300 spine arrows that were the same weight as the 75/95's but total arrow weight still came out slightly over 700 grs.
While you are working with Stu's calculator,punch in some figures for a thicker side plate and see what you come up with.Having a longer draw length also makes it a little tougher to get real high FOC as you can't shorten the shaft as much as some people to gain stiffness.You can gain a lot by changing your sideplate thickness though.This may be the key to getting where you want to go.
Keep in mind,when designing a set of arrows,you may have to compromise some when juggling arrow length,FOC and overall weight.
It tried to get an overall arrow weight of 650 with a certain length and FOC but was only able to get either a 585 gr arrow with lower FOC or the FOC I wanted and a 700 gr arrow.
That is the nature of the beast.There just is a bigger jump in spine groups with carbons,as opposed to aluminum or wood.
Posts: 3026 | From: Montana | Registered: Aug 2008
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JimB that's helpful information, thanks. Is it normal for my bareshafts to group the same but enter the target at a downward angle or does that indicate a nock position issue?
Posts: 34 | From: MN | Registered: Oct 2009
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For me it is.Go to bowmaker.net and read the tuning information.He uses the planing method which is shooting bare shafts and fletched together and judging results only on how well they impact to the same point and disregarding how the bare shaft leans.The reason being,that form issues can influence that nock lean with a bare shaft but when they impact together,out to longer distances and ultimately broadhead arrows also,you are tuned.
When I bareshaft,no matter where I put my nocking point,they hit nock up.It is a form thing.My broadheads impact right with the field points though,out to 30 yds and that is the whole point in tuning.
I follow the bowmaker tuning information to the "T" and it has taken the confusion out of it for me.He emphasizes over and over,change only one thing at a time.That's very important.Changing nock height and sideplate thickness is two things.One thing at a time.
I draw 29" and like a 30" arrow as any longer and it hangs out past the tip of my 56" bows,when in the bow quiver.Most of my tuning consists of a 30" arrow and I use a wide variety of field point weight.When I think I am close,I fine tune with 5 gr weight washers and sometimes side plate thickness.Once I have my point weight determined I match that by using a glue on broadhead,steel adaptor and a little lead shot up inside if needed.I have several bows that are cut close to center or not quite,that use a 30" 7595,FOC is 26 % and total weight is 709 grs.I have actually grown to like this arrow weight.
My bow that is cut closer to yours,uses .300 spine arrows,same length and FOC is 28.9 % and arrow weight is app 711 grs.
At some point you will want to find a place where you can shoot farther,out to 25 yds or more to verify how well things are tuned.
Another option in arrow shafts is the Victory V Force HV's.I have just started to experiment with these but they are 2 or more grains lighter per inch than Goldtips,take the same size inserts and seem to be as tough.They do cost more.I am working with a set of their .300's right now and they do seem quite a bit stiffer than my Vapor Pro .300's.I plan to get a set of their .350's soon.A light,stiff shaft like this gives a few more possibilities.
Good luck with your tuning.
Posts: 3026 | From: Montana | Registered: Aug 2008
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