broadheads not grouping?

[sakoshooter]

Rad, I believe you forgot one more item that can get up to upwards of 50% - human error.

[HighCountryHunter88]

Ok went out with the shuttle ts and did some rest moving and got them pretty dialed. The I moved back to 30 and the tailwhip moved impact point again..

Fullabull, I printed it and will be reading up.

Here is a pic of the stripped arrow test this happened exactly the same 3 times at 20 yds

[RadSav]

I think there are times when guys understand gun analogies better to help explain archery related issues.  This might be one of those times.


Trying to get an out of tune bow to shoot broadheads well is about like taking a 6 MOA rifle and trying to get it to shoot like an RBros simply by working up a load.  Fact is an RBros rifle is going to shoot nearly everything you put down the tube well.  Those 6MOA rifles are often in need of bedding and fine tuning before load development will result in anything at all.  That is the nature of a well tuned rifle and that is the nature of a well tuned bow.

As archery hunters we shoot some rather long and heavy bullets.  Imagine trying to shoot a long heavy bullet out of a 300 mag with a twist rate of 1 in 20.  Regardless of having a high BC and perhaps a boat tail design even your RBros is not going to excel in that regard.  Yet so many archery hunters can't figure out why they have inconsistency issues with straight or slight offset vanes when tuning their broadheads.  Gyro or centripetal stability from a proper twist rate is the nature of a well tuned rifle and that is the nature of a well tuned arrow.

You find yourself on the rifle range with a 5 mph crosswind.  You've got 15" square of steel hanging at 800 yards and you need to chose a round for the task.  Your RBros Long Range Hunter in 300RUM is the perfect gun for the task and is tuned perfect with both your pet loads.  One of these loads is a 150 grain Nosler Partition with a .387 BC and the other is a 210 grain Accubond LR with a BC of .730.  Muzzle velocity be damned just about any sane person is going to choose the high .730 BC bullet.  Yet so many of these same folks will sacrifice FOC for a few fps in arrow speed.  And then wonder why their broadheads don't group at 80 yards.  High BC is the nature of a well tuned long range bullet as FOC is the nature of a well tuned long range arrow.


Neither speed nor barrel twist nor high BC bullets are going to make a difference if we don't first tune the platform that shoots them.  And while we do not need an RBros rifle to shoot at the ranges we are archery hunting we still need to have our weapon tuned precisely if we expect any level of consistency with a broadhead tipped arrow.  That perfectly tuned bow and properly matched arrow absolutely must come first.  Otherwise we are simply trying to work up a pet load for a 6 MOA rifle.

[HighCountryHunter88]

I think there are times when guys understand gun analogies better to help explain archery related issues.  This might be one of those times.


Trying to get an out of tune bow to shoot broadheads well is about like taking a 6 MOA rifle and trying to get it to shoot like an RBros simply by working up a load.  Fact is an RBros rifle is going to shoot nearly everything you put down the tube well.  Those 6MOA rifles are often in need of bedding and fine tuning before load development will result in anything at all.  That is the nature of a well tuned rifle and that is the nature of a well tuned bow.

As archery hunters we shoot some rather long and heavy bullets.  Imagine trying to shoot a long heavy bullet out of a 300 mag with a twist rate of 1 in 20.  Regardless of having a high BC and perhaps a boat tail design even your RBros is not going to excel in that regard.  Yet so many archery hunters can't figure out why they have inconsistency issues with straight or slight offset vanes when tuning their broadheads.  Gyro or centripetal stability from a proper twist rate is the nature of a well tuned rifle and that is the nature of a well tuned arrow.

You find yourself on the rifle range with a 5 mph crosswind.  You've got 15" square of steel hanging at 800 yards and you need to chose a round for the task.  Your RBros Long Range Hunter in 300RUM is the perfect gun for the task and is tuned perfect with both your pet loads.  One of these loads is a 150 grain Nosler Partition with a .387 BC and the other is a 210 grain Accubond LR with a BC of .730.  Muzzle velocity be damned just about any sane person is going to choose the high .730 BC bullet.  Yet so many of these same folks will sacrifice FOC for a few fps in arrow speed.  And then wonder why their broadheads don't group at 80 yards.  High BC is the nature of a well tuned long range bullet as FOC is the nature of a well tuned long range arrow.


Neither speed nor barrel twist nor high BC bullets are going to make a difference if we don't first tune the platform that shoots them.  And while we do not need an RBros rifle to shoot at the ranges we are archery hunting we still need to have our weapon tuned precisely if we expect any level of consistency with a broadhead tipped arrow.  That perfectly tuned bow and properly matched arrow absolutely must come first.  Otherwise we are simply trying to work up a pet load for a 6 MOA rifle.

Ok gotchya so what do I do to get it tuned to a well oiled machine? Take it to a bow shop?

[lamrith]

Blasted Rad, STOP MAKING SENSE!  This is the intarwebz!

So based on the pictures Rad would you saw that he needs more bow tuning given that the unflectched arrow is so sideways? One would want even the unfletched arrow to be hitting straight into the block I would think?

No offense intended Highcountry, trying to learn myself here...

[HighCountryHunter88]

Well I would assume that to but I don't know what I'm doing! Lol

[Johnb317]

You mentioned it had been professionally tuned. 
I'd take it back there.   Mistakes happen, your d-loop could have slipped, or the new strings could have stretched.

I need to make or buy a broadhead target soon, hopefully not in the same boat.

Good luck

[dreamunelk]

Something you can fairly easy is paper test it.  But, I wonder if you had it tuned why did they not have you take a few shots through the paper?  You may want to tell the guy's on here the area you live in and maybe they can recommend a few shops.  You may get real lucky and find a member hear buy with all the equipment to help you out.

[HighCountryHunter88]

Well I don't know if they "tuned" it or not I'm not sure what that all entails I didn't see any paper and I think I did all the shooting getting the peep and all that set up and getting some arrows done so I should call them and see if they can help get it tuned, I'll shoot them a call tomorrow

[RadSav]

So based on the pictures Rad would you saw that he needs more bow tuning given that the unflectched arrow is so sideways? One would want even the unfletched arrow to be hitting straight into the block I would think?

Well it is so hard to tell with bare shaft testing at 20 yards and outdoors.  Too many variables to be sure of anything.  As a general rule if that arrow was shot at 10 to 15 feet I would either assume the arrow rest is too far right or the spine was too weak.

Bare shaft testing at distances beyond 10 yards is very difficult to read and a safety hazard.  I once decided to bare shaft test in a huge sand pit.  Figured I was safe as could be.  All was great at 10 yards!  Then I got some fool idea to bare shaft test a broadhead at 30 yards.  A slight wind caught the broadhead and lifted it up the sand bank until it hit more wind at the top lip of the embankment.  The arrow then made a complete U-turn and ended up landing behind me   I've never shot a broadhead tipped arrow without fletching since.

Bare shaft testing/tuning can be useful, but best done inside and with field points.  Bare shaft testing is most useful when the bow is already tuned well.  It is then used as a means to verify proper dynamic spine deflection.  As such it is most useful for traditional bows.

[dreamunelk]

I think they should have had you fire a couple of shots through paper at about 6 feet or so.  If you google it you will see this is something you can do your self.   I do very little work on my bow.  I am lucky to have  friend who is sponsored by a the same bow manufacture I bought my bow from.  I take my bow to him occasional just to check.  Usually the problem is me.  I am twitchy and have form issues from time to time.   After he gives it the once over for the obvious he pulls out the bow square and tape measure and measures.  Once he is satisfied with that he has me shoot through paper.  One he is satisfied with the paper it is out to his range we go.  Usually shoot one broadhead and one field point multiple times at different yardages.  both arrows should be in close proximity to each other every time.   :chuckle:Unless I have a twitch    If not it is back to the shop we go until he is happy.  All of this take at most two hours.  Includes a beer break.

Is it a new bow? It could be the shop forgot to tell you to shoot it awhile and then bring it back for some more tuning.  For me it took a couple of trips when the bow was new.  Things need to settle in.  Sometimes a bow needs a few trips to get dialed in.

Also note that if you make any adjustments to poundage, check the tune.

I don't know if form would cause some of your problems but, you may want to check that also.

[RadSav]

You mentioned it had been professionally tuned. 
I'd take it back there.   Mistakes happen, your d-loop could have slipped, or the new strings could have stretched.

Is it a new bow? It could be the shop forgot to tell you to shoot it awhile and then bring it back for some more tuning.  For me it took a couple of trips when the bow was new.  Things need to settle in.  Sometimes a bow needs a few trips to get dialed in.

   Professionally tuning a brand new bow is almost a fools gamble.  Best to wait until at least 100 arrows are shot and all the creep and molded stresses have been relieved.  Then by all means if you know a great bow tech have them do 'er up!  However, even then most shops can only tune the bow about 85-90% on a 20 yard indoor range.  Usually need to further fine tune at distance.

Most of my bows are broadhead tuned by chasing field points with broadheads.  Starting at 5 yards and working back to 50 yards.  Making notes with every incremental step in the process.  If you never can get them to meet I then know I need to bare shaft test for dynamic spine (or as another option drop or increase poundage until they meet).  But, to do that I need to go back to the place where they were the closest...that is where the notes come into play.

Myself I prefer to shoot a particular arrow spine and brand no matter what bow I am shooting.  So I may have a single cam Bear bow that shoots a 340 spine properly at 72# and a Bowtech that shoots that same arrow properly at 62#.  Once you find the sweet spot of that arrow try to make record of arrow speed.  If you get a new bow or have major work done to your current bow you can always go back to that arrow speed and know you are in the neighborhood for proper spine.  And then fine tune again from that starting point. 

I currently have five different bows that I enjoy shooting with the same exact arrow.  Draw weights very from 64# to 72# and all have a true arrow speed within 5 fps of each other.  That is the energy level where that arrow performs it's best and proves flawless broadhead flight regardless of blade configuration or relevance of blade location to the fletching.

[sakoshooter]

Spine hasn't been hit on too hard here other than Rad mentioning it as "sacrificing FOC for speed". I run into guys all the time that shoot slightly underspined arrows all target season but cannot get them to fly worth 2 cts come fall with broadheads. Broadheads will grab air with any lil flex and magnify it. From being out of tune in one form or another to improper form to weak spine.
FP's are very for giving even with a bad flinch or a terribly tuned bow. Broadheads will exagerate every lil thing that is wrong.
You obviously have a tuning problem but trying a stiffer spine shaft or cranking your bow down a little might be worth a try also. At 29" and 67#?, you're pushing the spine of those GT7595's. They're a 340 spine.

[sakoshooter]

Darn. I clicked on the 'post it' button over an hour ago and just came back in the room to see it still sitting here with the stupid question at the top "someone else just commented, do ya still wanna post this?" Anyhow, I clicked yes but it's kind of late.

Anyhow, spine can be an issue and you're close to the top of your limit on with your set up. Especially when it's waaaaaaaaaay out of tune.

[Fullabull]

Use the tuning guide, it will teach you how to tune your bow well. Get a spin tester and arrow squaring tool and you will be set. Once you learn to tune your own, you can do it in field/camp if need be.