Finding the right balance between speed, spine, arrow weight, KE, and momentum?

[deerslyr]

I just up'd my poundage and restrung my bow with Winners choice strings and I need to buy new arrows so im trying to decide how to get the closest to "perfect" arrow for elk with my set up. I'm probably completely over analyzing this but what the heck its the off season and I want to maximize the performance and penetration out of my bow set up.
Currently Im shooting a mission maniac, 27in draw, 70lbs, pushing a 391 grain beaman camohunter (400) 250 fps. I can tell the 400s are walking just a bit right but its hardly noticeable until 60-65 yards.
My questions are:
1.)which spine should I go with? Ive searched the internet for some sort of calculation to figure out the perfect spine for your set up and have found nothing but generalized charts.

2.A) The more I Increase my arrow weight the more my speed and KE decreases, but my momentum increases.  Would I be better off to increase my weight to gain the momentum but lose the fps and KE to get more penetration?

2.B) Am I over analyzing and should just stick to a 400ish grain arrow and mid 200 fps because the difference increase grains will have on penetration is small at this point? 

So lets hear it from all of you out there, what arrow/grains would you choose for this set up for maximum terminal performance on elk?

[jechicdr]

Download free trial version of OnTarget from Pinwheel software.  You can pick optimum spine and setup without even buying the program, but program has several other features that may make it worth purchasing.

[BULLBLASTER]

To hunt in WA you need to have an arrow weighing 6 grains per pound of draw weight. That would mean a 420 grain arrow or back your bow down to 65 lbs. Either would be plenty sufficient for any game in WA. I shoot 64 lb and a 385 grain arrow and go through both deer and elk. I will be building some heavier arrows for next year as I am hunting moose in BC and the outfitter likes 400+ grain arrows.

[Johnb317]

     At 70lbs the 400 is a little light spined.  I shoot the Beeman camohunter 340 at 10gpi  matched with 100gr slick trick and 4 fletch blazers.  Arrow weighs around 420 gr.     Broad heads fly just like my field points.   
Currently shooting a whisker biscuit but looking at other options.

[Antlershed]

I am shooting a Mathews Z7 Xtreme set at 68lbs. Arrows are Easton Axis 340's cut at 27 1/2" for my 27" draw length with 100gr muzzy 3 blade broadheads. I shot my elk last year at 40 yards and the arrow passed thru. She went out and stopped at 65 yards so I decided to put another arrow in her. That one went in and stuck into the opposite shoulder. My arrow is only a few grains over legal but im confident I have enough energy. 

[wrongway]

I would shoot a ACC 3-60 at 30'' and a 100 gr tip, should shoot around 275 fps.

[demontang]

I shot the beman 340 ics hunters and goldtip series 22. Both ended up meeting min weight for wa rules and both shot really nice. The ics where way stronger but the goldtips shot tighter and I didn't have to check and match/grade as many arrows but for the money I cant complain about the bemans they are great arrows and I shot one through two 1/4 pieces of lexan put together and it survived where the series 22 broke after it went through them. It was a distruction test to see what would happen if it hit bone

[Fullabull]

What you shoot depends on what you are doing, target, hunting etc.. For hunting, go with the heavier arrow for KE + it has to be legal. I have a 70# EVO coming and had to change arrows. I will be shooting the Easton FMJ's in 340 spine at 29" draw and arrows are 28 1/2" length. Weighed the arrows with 100grn BH's on and they are 470grns. Should pack a wallop 

Some folks say I should go to the 300 but I'm going to try the 340's since the FMJ's are heavier and see how it goes.

[deerslyr]

I should of mentioned I dont hunt in WA any more and the rules in MT is any thing over 300 grains.

[MIKEXRAY]

This is a debate we have been having for a couple of years,  most guys are gravitating towards a heavier arrow & heavier head. I am shooting 400's with a 100 gr broadhead & to be honest am barely legal on arrow weight. My buddy last year went with a heavier set up for penetration . ( Supposedly ).  I had him shoot one of my practice arrows instead of his to see what the trajectory difference was & shooting at a standard Block target ( 40 yards ) he cleared the top of the target by well over a foot.  What I saw was a 2 ft extra drop @ 40 yards with his arrow combo.  I have shot both deer & elk with my setup and have had great penetration on all animals , I don't think ( in my opinion ) that I want to give up the flat shooting & better accuracy from my setup  and go to a heavier / more kinetic energy setup trying to achieve more penetration when I feel my penetration has been fine.  Mike

[et1702]

70lbs is marginal for a 340 spine arrow w/100gr tip.  You also need 420gr min total weight.  If you can get them to fly correctly, I'd suggest a 340 spine and up the BH to 125gr minimum, which would give you much better FOC.  Personally, I shoot 300spine, 11gpi arrows w/150gr BH.  The more FOC the better.  My total arrow weight is about 525gr and 85ft/lbs of KE @ approx. 270fps.  FYI, the reason I shoot the 300 spine arrows is my draw is longer than yours at 31"  With your shorter draw, the 340 spine and 125gr BH should be about perfect.  If you want to get more FOC, use a brass BH insert or upgrade to 150gr (or more) BH.  Also, with more FOC, your arrows will stabilize faster off the bow and be much more accurate with more retained energy down range.  Mine fly like darts and I have same impact point as field tips.  Also, w/extra KE, I busted rib bones on both sides of my elk last year (entrance and exit) and had a complete pass thru!

BTW, if you want to experiment with FOC, go to the Alaska Bowhunting web site and buy some of their field tips.  http://www.alaskabowhunting.com/Field-Points-C65.aspx

Cheap option for testing purposes and they have 100 thru 200gr in 25gr increments, plus 250gr and 315gr field points.  Lots of good info on extra FOC regarding penetration increase too.

ET

[et1702]

Just noticed you were from MT.  But, to safely shoot your bow, most manufacturers suggest at least 5gr per pond of draw weight, so 350gr min at 70lbs.  Also, if you ahve a lot of 100gr BHs, you could still try some brass inserts w/your BHs to get more FOC.

ET

[deerslyr]

I started playing with archery reports calculator to see what my arrow would be doing if I went by washingtons law of 420 grains for 70lbs and the results were surprising.
Currently my set up has 54.209 lbs of KE and .4336 lbs p/s of momentum. I used the general rule of thumb 1fps loss for 3 grains added. So at 420 grains my arrow would be doing approximately 240 FPS. Heres the kicker I actually lose KE at 53.6 lbs and gain very little momentum at .4472.
I think ill stick to my arrow weight as is and change to a stiffer spine of .340.

[et1702]

I started playing with archery reports calculator to see what my arrow would be doing if I went by washingtons law of 420 grains for 70lbs and the results were surprising.
Currently my set up has 54.209 lbs of KE and .4336 lbs p/s of momentum. I used the general rule of thumb 1fps loss for 3 grains added. So at 420 grains my arrow would be doing approximately 240 FPS. Heres the kicker I actually lose KE at 53.6 lbs and gain very little momentum at .4472.
I think ill stick to my arrow weight as is and change to a stiffer spine of .340.

I think you might be underestimating the speed of your current setup and overestimating speed reduction at 391gr vs 420gr.  I get approx. 262fps w/current vs 253fps w/420gr setup.  http://www.backcountrybowhunting.com/articles/calc/

That being said, your KE is still about the same at approx 60ft/lbs with either setup.  So, it would make sense to stay at the lower weight and have a little more speed (i.e., flatter trajectory).

ET

[deerslyr]

I had my bow chronographed at 250.1 fps, I wish I was underestimating lol Thats pretty much the reason why I started this thread because I shoot such a slow bow I want to maximize penetration in any way possible. Im thinking of switching from my g5 montecs to  blade magnus stingers as well.