Tuning Beman ICS's

[Phillyman]

Hey I am in the process of plane tuning some Beman ics and am kinda stumped on how stiff they seem to be compared to my other GT's.

I shoot a 50# @28 recurve, cut to center. I currently am shooting some GT 5575 cut 30.5 and 250 grains up front and have them grouping together @ 20 yds.

Today I tried tuning up my new bemans 400's and started out full length 32" with the same 250gr up front. Expecting them to be weak. At out to 30 yds the bares grouped left about 4 inches,and defintly seemed to fly stiff. I had to increase point weight to about 415gr to get them to start shooting about an inch weak at 30 yds. The bare shafts fly absolutly great.

I'm really surprised about how much stiffer the supposely same .400 spine is different between brands. Has anyone else noticed this?

Or maybe I just got some mismarked arras

[leatherneck]

No, I think your OK. Another ganger on here shoots about the same specs as you and has to shoot the 500's with 350 up front. So I believe your right on track. But what the heck do I know!    

Mike

[sweet old bill]

Carbon carbon carbons they sure do not seem to be the same spine from one mfg to anothers. Just like you would go and get a 100 wood shafts that were spined already. I always would fine some that were more stiff than others. I for myself use the bemen and easton brands and am shooting a checkmate firebird that is 50 lbs at 28 inch draw, my actual draw is 28 1/2. I have the arrows cut to 29 1/2 inch and am using the 500 spine arrows. I just have the shaft filled with 1/8 inch poly rope, carbon insert, and 125 gr field point or BH... and they seem to fly just right for me. The arrows are made up with three 5.5 inch bananna feathers.

but like a lot of us using carbon what do I know.

Bill

[James Wrenn]

I don't know what the issue can be unless your GTs are really a lower spine.A 400spine arrow is just that no matter who makes it.What you are seeing is impossible if they are both the same spine.You don't see mismarked arrows with Beman so my guess is you are shooting 35/55 GTs that were marked wrong.GT has had lots of issues such as that. jmho

[Big Ed]

I thought they would be a little closer. I know that with Eastons/Beman they are pretty true to spine.

[lone hunter]

50#s @28 is pretty much the line between 500s and 400s. Depends on the shooter for which one to use. I would set one Beman up the same; length, weight, as the GTs and see what happens.I know shortening the arrow should make it stiffer but weird things happen with carbons. Length is probably more critical than point weight when tuning.
Of course I don't know much so you're probably better off listening to someone else.  

[rraming]

The GT 5575 and the Beman ICS 400 spine the same - I have checked them on a spine tester.

[Jason R. Wesbrock]

I agree with James about Gold Tips being mislabeled. Several years ago I got a dozen of what were supposed to be 3555's, except that half of them were really 5575's. It drove me nuts trying to tune them until I got out a spine tester and figured out the problem.

I've been shooting Beman ICS's ever since and have never had one labeled incorrectly.

[Phillyman]

Thanks guys, I'm going to spine test them just out of curiosity. Also I'll take the fletching off one of my GT's and double check I tuned them as well as I think I did:) Something seems impossible to me, as well, if they are the same spine.

[Hardhed]

For some strange reason, I've had full length carbons which I thought would be weak, actually bare shaft very stiff.  After cutting about 2 inches off the already stiff appearing shaft, they suddenly flew perfect with identical point weight.  

You might want to sacrifice one to experiment with, just keep cutting and see what happens.

[eagle24]

Originally posted by James Wrenn:
I don't know what the issue can be unless your GTs are really a lower spine.A 400spine arrow is just that no matter who makes it.What you are seeing is impossible if they are both the same spine.You don't see mismarked arrows with Beman so my guess is you are shooting 35/55 GTs that were marked wrong.GT has had lots of issues such as that. jmho

Exactly!  400 Beman = .400" deflection.  I shoot Beman 500's in several bows from 45 - 52 lbs.  I have a 54# longbow that is right between a 400 & 500.  Wish they made a 460  

[Rob DiStefano]

i shoot the exact same 29" beman ics 500 shaft/arrow from 40# to 55# bows.  i adjust the front end package to temper the overall arrow weight, gpp and foc.  my lightest arrow uses 170 up front, my heaviest has 350.  they all fly extremely well, with gpp's in the 9.5 to 11 range, focs from 23-29%,

fwiw, i initially found carbons to be difficult to figure out what spine works with what bows.  it may just be a personal thing and to each their own.  unlike alums, which are far easier to spine and work very close to the easton charts.

first thing i stumbled on was that the commercial carbon spine charts are severely lacking, and that weaker shafts just worked/flew better for me.

the only carbon arrow that almost universally works for everyone with most any draw length and bow weight from 45-75# are ad trads.  dunno exactly why, perhaps the tapered butt end.

good luck!

[R H Clark]

Hey Greg,Easton Redlines come in .460

Heardhead,you were probably getting a false reading from shelf-riser contact.Always confirm a reading by adding and removing point weight.

[Phillyman]

Well I'm convince the Bemans are in factd tuned well. They are full length and have 415 up front. Something like 29% FOC.  I don't mind that, even though I have had to adjust my aim a little especially out from 25 yards. But they fly absolutly beautifully. I think they may be mismarked though. As the GT's agree with Stu's Spine calculator and the Beman's "should" be way way weak accrording to his Excel prgram. If they are in fact 400 spine. I'll try mearuruing th spine on both shafts and see what I find out.

Oh and I did take the fletching off one of the GT's and it still flew good cut down to 30.5 and only 250 up front. So that tells me they are obviously different spine shafts

[Dartwick]

I would be curious to see a someone make tuning graph of a mechanical launcher shooting a range of these carbon arrows with FOCs around 30% and then comparing them to to aluminums from the same bows.
Id also be curious to see the a graph that left the arrows at full length.

I know bows shoot differently with a finger release and all, but I think we could use a better base line.