Need some specific arrow advice re-spine.

[SquidHC]

Hey All,

I shoot a 2016 Hoyt Defiant 34" at 29.5" and 72 lb draw.
Please note, I'm not looking for different arrow brand/type recommendations. I'm trying to figure out some tuning issues related to spine (I think).

The first arrows I purchased for this bow were the Gold Tip Pierce Platinum 300's (according to most charts I should shoot a 300 spline arrow). I messed with tuning for weeks and could not get these arrows to shoot less than a 1" tear through paper. After playing around a bit with other 300 spine arrows I gave up because I could not get them to tune with 100 or 125 grain field points.

I decided to try a 340 Axis 5mm and am shooting bullet holes with this arrow.

I am now considering playing with a heaver arrow for hunting and am going to build some FMJ's. I am assuming I also will shoot a 340 spine, but am considering messing with 50 and 70 grain HIT inserts. I will likely shoot 100 grain heads, but am also interested in the 125 (shooting Kudu Points and like the slightly larger cutting diameter of the 125).

I would also like to run lighted knocks and/or wraps for visibility, which will add some weight on the back end.

Any suggestions on spine for this set-up? If I go with the inserts for more FOC do I need to bump to a 300 spine? This is my first time trying to build custom arrows and need all the advice I can get. Would you run a 50 grain insert and a 125 broadhead, or a 75 grain insert and 100 grain broadhead? Or?....

Are there software solutions you are using that help solve this type of issue? I know there are several out there, and as an Engineer I like to play with numbers so I'd be interested in picking up something like this if it is worthwhile.

THanks for the advice and sorry this post is a bit of a mess. It's a good representation of my confusion.

Cheers!

 

[blackovis]

Archer's Advantage is honestly the easiest and best way to play around with spine, FOC, etc and find out about where you want to be. What is your current arrow length carbon to carbon?

Without looking I would say you'd need a 300 spine FMJ to shoot that kind of weight up front especially if your arrows are over 28-28.5" the 50/125 or 75/100 grain question depends more on what broadhead you would like to shoot but the 50/125 option would yield slightly higher FOC since the bulk of the weight is farther forward. Very minute difference.

 

[OR Archer]

If you're going to run a brass insert you will need to run the 300s.

 

[dangerousD]

The above advice is good. Without running the setup numbers, my gut also says 300's with any brass is what you'll need. I'm perplexed why you could not get the 300's to tune. Seems to me that it may be something other than the spine. Is it possible that you were getting some contact? I shoot a Carbon Matrix at 70 lb DW @ 29" DL with 27.25" long 340 spine FMJ and 100 gn head. I tried some 250 spine Black Eagle's out of my identical setup and got damn near perfect hole in paper without additional tuning work. I'm also an engineer and enjoy the technical aspects of archery. Lately I've been using Archers Advantage Online to run my setup numbers. It's very inexpensive for an annual online subscription. Good luck!

 

[jmez]

How long are your arrows? Either the .340 or .300 would likely work out of that bow. If you are using a brass insert I'd definately go with the .300.

I shoot a Carbon Spyder turbo. 28.5 inches at #71. My arrows are 28 inches and I shoot a 125gr head with the regular HIT's. I shot .340's for a couple years without issue. I wanted a heavier arrow so I switched to the .300 for the extra weight. I haven't had any trouble with either arrow in a similar set up.

 

[SquidHC]

The above advice is good. Without running the setup numbers, my gut also says 300's with any brass is what you'll need. I'm perplexed why you could not get the 300's to tune. Seems to me that it may be something other than the spine. Is it possible that you were getting some contact? I shoot a Carbon Matrix at 70 lb DW @ 29" DL with 27.25" long 340 spine FMJ and 100 gn head. I tried some 250 spine Black Eagle's out of my identical setup and got damn near perfect hole in paper without additional tuning work. I'm also an engineer and enjoy the technical aspects of archery. Lately I've been using Archers Advantage Online to run my setup numbers. It's very inexpensive for an annual online subscription. Good luck!

Anything is possible, but I find it unlikely. Myself and two of the better techs at my local shop spent several hours messing with it to no avail.

 

[SquidHC]

How long are your arrows? Either the .340 or .300 would likely work out of that bow. If you are using a brass insert I'd definately go with the .300.

I shoot a Carbon Spyder turbo. 28.5 inches at #71. My arrows are 28 inches and I shoot a 125gr head with the regular HIT's. I shot .340's for a couple years without issue. I wanted a heavier arrow so I switched to the .300 for the extra weight. I haven't had any trouble with either arrow in a similar set up.

My arrows are 29 5/8". I built one 340 spline with no inserts tonight. Will see how it goes shooting tomorrow. Going to make up an arrow of each variation and see how they fly.

 

[SquidHC]

Thanks for everyone's advice thus far. Might check out archers advantage.

So I grabbed Archer's Advantage, and the default arrow speeds for my bow/arrow combo are a bit suspect to me. I've only shot one chrono but I remember it at like 285; Archer's Advantage says it should be 300.5. I'll shoot the one at the shop tomorrow.

It actually shows my current arrow as "very weak", and even shows the 300 spine FMJ as "slightly weak". The 4mm FMJ at 280 spine says it's perfect.

More confused than I was before.

 

[jmez]

With that length arrow I would go with a .300

 

[Beendare]

THE #1 thing with a hunting arrow.....don't be underspined....it can cause all kinds of tuning nightmares.

I have the same specs as you and shoot 300's in my compound....have for almost 2 decades and they tune great. A little overspined is the way to go IMO.

 

[tipsntails7]

THE #1 thing with a hunting arrow.....don't be underspined....it can cause all kinds of tuning nightmares.

I have the same specs as you and shoot 300's in my compound....have for almost 2 decades and they tune great. A little overspined is the way to go IMO.

Agree.

At this point with modern compounds I don't think you can be overspined.


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[SquidHC]

I get that you guys all think that you can't be over-spined and such but the simple fact is the 340's are shooting flawlessly and 300's are shooting terribly... Doesn't make sense on paper, but in real life it's what I'm seeing.

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[jmez]

I'm guessing your problems were more related to the arrows not the spine. Try a .300 FMJ or Axis and see how they shoot.

 

[Brendan]

I had some issues with Pierce Platinums last year. Arrows were straight, outserts were not. Have you spun them or put a dial indicator on them to look at runout? Rumor has it they made some changes to the outsert after issues early on, but I can't remember where I heard that.

Are you running the same vanes on both arrow setups?

 

[SquidHC]

Went into the shop today and put together a 340 FMJ. Also grabbed a half dozen VAP Elite 350's with glue in 100g inserts to play around with. Tomorrow I'm going to put together a 300 FMJ with a 50g HIT insert, and a 300 FMJ without an inset. Then I'm off to the range to broadhead test them all.

Just for fun I shot them all through the chrono (mainly wanted to check the FPS vs what Archers Advantage said it would be).
Axis 340 with 100g field point was 286.5 FPS - bullet holes in paper
FMJ 340 with 100g field point was 269.9 FPS - about an 1/8" tear in paper
Victory VAP .166 350 spline was 306.0 FPS - about a 1/4" tear in paper

I'm really liking the speed of that FMJ (280 FPS is my target speed). I know the 300's will be heavier and slower so we will see how they fly with a broadhead at 80 yards and go from there.

 

[Beendare]

Squid, Its hard to say whats going on. A bow/ arrow is a "system"....bow,rest,arrow, fletch....all need to work together. As Brendon astutely noted....perfect arrow assembly is very important...as is tuning. Paper tuning is a good start...but are testing at multiple ranges; 6', 12', 25'?

It could be you are getting fletch contact that is giving you crazy results....but I can tell you that overspined [with a modern compound] will make things a whole lot easier in the long run. I've been preaching it for about 15 yrs on these sites....it seems now folks are finally coming around.