Question || Arrows & grain tips

[Bow_mon]

Hello.

I was originally going to post a what kind of broad heads question .... but as I've been researching I realize I have a pretty large gap in my knowledge. Hopefully you all can help me understand:

I'd like to learn and understand the relationships between DL, DW, arrow spline, gram weight of arrow tips and how that all plays into IBO Speed and, (what I think is more important) kinetic energy.

For example: my DL is 28.5", my DW is 65lb, I shoot Easton Axis arrows and they say 400 on them. Riverside is my go to bow shop and Gary usually just takes care of it for me but I'd like to learn. I don't know if I've got 100 or 125 grain tips. I weighed them on my food scale  and they were 6 grams if that means anything. Also what does the 400 mean on my arrows?

I'm not a speed freak and looking to maximize my IBO, but rather I just want to a) understand how this all works b) figure out what grain broad heads to pick up for my bow/arrow combo.

Thanks in advance I appreciate any and help insight.





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[Widgeondeke]

Tagging to maybe learn something also

[Rider]

The higher the draw strength the more force that is applied to the arrow. The more force the faster the speed leaving the bow.

Arrow spine must match draw weight. The number is a reflection of the stiffness of the arrow. The stiffer the arrow the more force that can be applied to it and it will recover faster. Consult the arrow manf chart for appropriate matching.

Arrows are measured in grains not grams.1 gram == 15.4323584 grains. Minimum legal arrow weight is 6gr * draw weight OR 390grains OR a minimum of 400 grains. The heavier the arrow the more force is applied at impact but the slower it flies.

FOC is Front of Center and is extremely important. Ideal is 11-13%. The steps for finding this are published widely so I will leave it to you to look up.

For reference I shoot 50# draw weight with 500 grain arrows with a 100gr BH/FT on a 12%FOC. I shoot ICS Beeman Hunter 400. They fly straight without fishtailing and are enough to drive the arrow into an elk without going all the way through.

I am happy to show this all to you hands on if you wish.

[DaveMonti]

Bow_mon,
Jimmy and I can walk you through it.  There is a lot of information online, but the key about arrow stiffness is that you have to have an arrow that is not too stiff nor too flexible for your draw weight. 

The 400 on your arrow refers to the deflection in inches that the arrow will undergo with a 1.94 lb weight hung in the middle of the arrow cut at 28 inches and is supported on both ends.  Therefore, your arrow deflects (or sags) 0.4 inches when a 2 lb weight is hung on it.  The STIFFER the arrow, the SMALLER the deflection  and the SMALLER the number (for Easton/Beman, carbon express, and a few others).

Arrow manufacturers have charts that use the draw weight and draw length of a bow to match the correct spine arrow to it.  I'm sure your bow tech has you using the correct arrow.  I shoot at 70 lbs and a 28 inch draw and have Beman 340s, slightly stiffer than you arrows.

The stiffer the arrow, the heavier it is, and the slower it will fly at a given draw weight.  Most folks want FAST arrows, so they use light arrows (of the correct spine), lightweight broadheads, short vanes to minimize drag, and lightweight nocks, etc.  However, lighter weight arrows penetrate game less.  For deer and elk, I'm sure you are OK as far as arrow weight as you are shooting 65 lbs with a 100 or 125 grain broadhead. 

There may not be much you can do now to increase your speed except lighten your field points and broadheads, but that won't do much from a speed standpoint.

I see Rider lives in Monroe.  I'm about a mile from down town Monroe, and JKThomps have been over here shooting.  Maybe we can all get together and shoot at my place.  I can shoot out to 80 yards here (I have 5 acres). 

I hope this helps. 

[Bow_mon]

Hey Rider and Dave —

Thanks so much for the information! I really appreciate it. I'm going to look up FOC and double check where my arrows are at. @Dave I would absolutely be down to cruise out at shoot at your property. Thanks for the offer and perhaps when JKThomps gets back from the woods we can set something up.

Thanks again to the both of you two gents for the info. I really appreciate it.

Cheers

[theleo]

The easy way to remember this is the arrow spine is a measurement of how much the arrow flexes. Shorter arrows or lower poundage draw weights don't require as heavy of spine to keep them from over flexing. If you take a branch off a tree and your looking to get a certain bend out of it when you put a weight on each end, the shorter you go the skinnier more flexible (liter spine) branch you'll need. If you add more weight to each end you'll need a stiffer, thicker (heavier spine). If you want to use a longer branch but still have that ideal bend with the same weight, you'll have to yet again go with a stiffer (heavier spine) branch because the weights are further from the fulcrum in the middle.

Kinetic energy is not as important as many make it out to be. If the energy is not applied correctly, then it's just wasted energy. If you're coming from the firearm world a good example would be something like my 280AI when I use it to push a 110 grain varmint bullet to 3400 fps vs. a 45-70 pushing a 405gr lead bullet at 1300fps. The 280AI has a lot more KE but won't exit a coyote at 70 yards but the 45-70 will shoot through a buffalo without a problem at the same range. In archery this relates to using a large cutting diameter, steep blade angle broad head vs. something with a smaller cutting diameter and/or shallower blade angle. The bigger badder, broad head with more KE may just end up failing to do what you want it to where the setup with less KE but distributes that energy via longer wound channel would suit you perfectly.

A balanced setup has to do with arrow weight, draw length, draw poundage, and broad head design. All have to be considered to get the results you want, whatever they may be.

[Rider]

Hey Dave I am in. I just posted stuff I've learned from reading HuntWashington and on the internet.

I also have a Chrono, arrow saw, and other stuff. My SIL has my fletching jig but I can get that back.

[Bow_mon]

Guys this sounds great! I work out in Snohomish so I could bring my bow to work one day and perhaps we shoot after work?


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[jkthomps]

Count me in! Just let me know when!

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[DaveMonti]

OK Jimmy, you're the toughest guy to schedule, so let me know when you can make it and we'll give it a go!

I'm headed to Montana late next week.  I'm practicing pretty much every day.  I've only got one bag and a block, so additional targets would be good!

I've got a shop and made a jig for my table saw to cut arrows.  I've got a fletching jig, but it's old school.  I also have a bow scale, plenty of tools, pretty much everything we will need (I have not yet made a bow press, but it's on the design agenda). 

Maybe we can get @Rainier10 to show up with some of his 3D targets!

Tuesday of next week would probably be the only day that can work for me before I head to MT.

Dave

[Bow_mon]

I've got a block target I can bring. Tue might be tough for me as my wife works late that day and I got to get kiddos from school but let me see what I can wiggle around.


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