PDA

View Full Version : Need help tuning my 2012 Bengal Pro



longshot1154
02-26-2012, 12:11 PM
Greetings,

I have been trying to tune my Bengal Pro and need some help. The ATA is supposed to be 31" and brace is supposed to be 7". I had paper tuned it with a fletched shaft a couple weeks ago and had a pretty good lower left tear going. I moved the nock point up and it solved the low tear, however the nocking point was up around 3/8" higher than level. I also got rid of the left tear by moving the rest all the way to the right. I have the bow maxed at 70 pounds, and am using GT 7595.

Arrow flight was good after doing this, but I really didn't like how high the nock point was. Today I decided to start all over again and set the nock point level with the arrow going straight through the berger holes. I tried bare shaft paper tuning and again had the low left tear. This time I attempted to adjust the rest and got rid of the low tear, but the arrow lined up below the berger holes and had a pretty good downward lean.

I brought the bow inside and measured ATA and both sides and there was a difference from left to right of about 1/8" between the two sides with the ATA measuring approx. 31 1/4". The brace height was about 6 3/4". I removed the cable and twisted it and now both sides are around 31 1/8". One side is just a bit longer. Now the brace height is 6 13/16".

Looking for input on how to proceed getting this bow closer to spec. and would the way this bow was, give me the low left tears I was observing.

Need to leave for work but will check in when I get there.

Thanks in advance,

Keith

Hutch~n~Son Archery
02-26-2012, 12:53 PM
Hey longshot1154, I moved you into the proper category and fixed your title for you. Now all we need is some experts to answer.







Hutch:cool:

longshot1154
02-26-2012, 06:09 PM
Well, I looked through the easton tuning manual again and see that they recommend setting the nock point 1/4" high to begin with for a mechanical release, so I guess my nock point wasn't as out of wack as I thought. I should have pulled the manual up first but was running out of time as I needed to get to work. Guess the next step will be pulling the string and cable, factory installed, and making sure they are within spec. I have already noticed some serving separation down near the cam, so I need to decide if I want to throw a new set of strings on, as I will have the other's off. Only about 100 arrows through it at this point.

Hutch~n~Son Archery
02-27-2012, 01:17 PM
See that longshot1154, Your smarter then you thought. Glad your all set.
Oh BTW I am jealous my Bengal's only a 2010 and yours is a 2012 that's just wrong lol!






Hutch:cool:

daveearles
05-06-2012, 07:05 AM
Hi Keith,

I am shooting a very similar set-up to you & have been experiencing great difficulty in getting the correct paper tuning results. This is the first bow I have owned so I could be missing something??

My set up:
2012 Bengal Pro, 68# (max it will go with 70# limbs?) 29" draw, Trophy Ridge Hitman 5, g5 1/4" meta, d-loop, QAD Ultrarest HDX, GT Expedition Hunter 7595 29" with NAP 2" ST Speed Hunter QuikSpins, 100 grain field tips & 100 grain Muzzy MX4 Broadheads, Apex Attitude 4oz Stabiliser, wrist sling.

Story:
When I got this bow it was set up with an octane hostage rest. The accuracy was pretty impressive after getting it sighted in I could put together a 5-6 shot group that had all arrows touching each other from 20m, well by the time I had put 50 arrows through it, it was as good as worn out so under recommendation, I set up a whisker biscuit power shot rest, I could never get the perfect paper tune result with this rest so ended up settling for the best I could. The groups were not anywhere near as tight as they were out of the hostage rest. When I swapped from field tips to broadheads the flight was sufficiently accurate enough & only required me to drop my sight by a small amount to have it dialed in close enough for hunting. Although the whisker biscuit is great for the spot & stalk type of bush hunting we have been doing, imo it is not the most accurate rest for shooting good tight groups on target. After doing some research I decided on the QAD Ultrarest HDX, I set it up according to the instructions & took it straight out for a shoot. I was blown away!! Groups from 20m were tight, all arrows touching most of the time, I took it right out to 60m and at that distance was getting a 6-8" group ( not too bad considering it had not been paper tuned ).

At this point I had not paper tuned it but was interested at seeing how it would fly straight off with a broadhead on. Now I probably should have started out at 20m with this but decided that where I was shooting a miss at 60m would not be the end of the world & the arrow could be found. I nocked up a broad head, set my sight pin on the bull & released waiting for the thud of the arrow hitting the target.... well, it never came, the arrows path was well right of the bull by 12-15" & low by at least 10".

Time to head back to the shed & try some paper tuning, I had a terrible result/tear, the arrow tip was hitting the paper lower & to the right of the vanes, I looked at the chart & saw that there was obviously more than one thing wrong. I tried moving the nock point to get until I just got a left tear. This wasn't working & nothing I could do would tune out the left tear.

Yesterday I got our local archery expert to check the cam timing & check the centre shot, we also lengthened the cable from the rest to the downward bus cable to make sure the rest was dropping early enough to avoid contact with the vanes, we took it out to the target & put a few more shots into the bag, I could tell by the way the arrow initiated its flight that it was dropping & steering to the right as it left the bow before straightening out again. One of the suggestions was that the arrow spine was too weak? On the goldtip chart, 7595s are perfect for my draw length & the bow poundage rating, I put the bow setup into the archery program along with the arrow data. Their scale showed this arrow being under spined for the bow as well.

We had a couple of Gold tip big game hunter arrows kicking around so we decided to throw a couple of field tips in & see how straight we were shooting. Arrows were side by side & looked to be coming out of the bow straight & not looking like a sidewinder missile tracking something. This was a good enough indication that the arrows were shooting straight so i threw a broadhead in one of them & had a shot aiming at the same point as before. the line was perfect but a little high. That backed up the fact that maybe we were under spined. Back to the shed for more paper testing. By adjusting the nock point I could get the arrow to a point where it was only showing a left tear, this is the big game arrow at 29", I cut one of the 7595s down to 28" to see if this would stiffen things up a bit. Now I was getting a similar tear from both the arrows. (the longer tears were from the 29" 7595s.

I still can't seem to get the left tear out of my shots, the shots were taken at a distance of about 8-10 feet from the paper. I will try baby powder on the vanes to see if any contact is being made tomorrow. It is becoming frustrating not being able to get a good tear pattern & especially not knowing how to remedy it??? I do not hold the grip on release, it is sitting in my hand with only my thumb & fore finger touching each other so I don't believe I am torquing the shot on release?

Keith, I would be interested to know what the dimension you have from the riser to the inner line of the arrow shaft? This way I can check my set up for some comparison.

Does any one have any suggestions that I could try to get these arrows to bullet hole? I would really like to get this sorted as it is prime time for fallow deer hunting here at the moment. I want to know that when i take a shot it is going to go where it should go.

Thank you all for your time & I hope someone can offer some experience & advice.

Dave

Simple Life
05-06-2012, 07:30 AM
Hey Dave,have you tried to lower your poundage to see if it has any effect?I recently got a pack of Muzzy 4 blade to try and and can not get them to hit with my FP.I shoot Slick Tricks,Montecs and 3 blade Muzzys out of my bows and hit with my FPs.I have heard of other people having trouble with the Muzzy 4 blade.

daveearles
05-06-2012, 04:13 PM
Hey Dave,have you tried to lower your poundage to see if it has any effect?I recently got a pack of Muzzy 4 blade to try and and can not get them to hit with my FP.I shoot Slick Tricks,Montecs and 3 blade Muzzys out of my bows and hit with my FPs.I have heard of other people having trouble with the Muzzy 4 blade.

Hi, Thanks for the reply. Yes I did try lowering the poundage down to about 60lb but still struggling with getting the paper tears correct.

I bought my 9 year old son some NAP 85 grain Thunder Heads to use on his Bear Apprentice 2, his bow is running a whisker biscuit & without paper tuning it was putting the broadheads pretty much right on his FPs, so I bought myself some 100 grain to try out as well.

These were the first broadheads I tried when I had them miss the bag all together. I intend to try out the stiffer Big Game arrow & the shortened 7595 with the FPs for reference & then the Thunderheads & the Muzzy MX4 to see what is going to be the most accurate, will let you know the results.

Dave

Thermodude
05-06-2012, 04:47 PM
I dont have a Bengal but with my Pantera and my Onza Im maxed out on poundage, and am shooting around 73lbs on both. Im at 29" draw and Im shooting 27.5" GT XT Hunters "5575" and they fly great.......broadheads fly same as Fts and I shoot a fixed blade head.

wscywabbit
05-06-2012, 05:12 PM
It looks like you've got your nock point / rest height right on, and that you just need to move your rest to the right. I've gotten to the point that when I paper tune, it's just to get my nock set. Then I go out and do a french tune and/or walk back to dial in in the center shot:

FRENCH TUNE
Go out to your target, run a piece of tape vertically top to bottom in the center. Then move to about 3-5 yds from it and fire an arrow at that strip. Move your pins left/or right (follow the arrow so if it hits left of the line, move your sight left).

When you can hit the tape dead on, move back to 20 yds and fire at it again. This time move your rest away from the arrow (if it hits left of the tape, move your rest right). When you get your arrows hitting the tape, go back to 3 yds and start again.

Rinse repeat until you don't have to move anything to hit the tape at both 3 yds and at 20.

I like doing that because it sets up your sight to center as well. You can also do a walk back, which i less involved;

WALK BACK
Using the same tape setup, fire an arrow at 20 yards at the top of the tape, don't worry about where it hits. Move back to 30 yards, shoot again. Move back to 40 yards, shoot again.

You will end up with line of arrows close to the tape at the top, further away at the bottom. If the gap is on the left side, move your rest right towards the tape, and vise versa.

Repeat the process until you get a vertical line of arrows that parallel the tape. Now your center shot is set and you can go to work adjusting your site.


Hope that helps!

** All of this is done using only your 20 yard pin **

daveearles
05-06-2012, 09:20 PM
I dont have a Bengal but with my Pantera and my Onza Im maxed out on poundage, and am shooting around 73lbs on both. Im at 29" draw and Im shooting 27.5" GT XT Hunters "5575" and they fly great.......broadheads fly same as Fts and I shoot a fixed blade head.

Thanks for this, one of my buddies shoots a Martin Sabre at 70lbs with 29" 7595's & he has no problem either with arrow stiffness, although the cam on his bow does not have such an aggressive punch as it comes off the let off so is not expriencing the sam violent acceleration I am guessing.

Your arrows are 27.5" long & since I cut mine down from 29" to 28" the arrows are handling much better & stiffer. I'll do some more tuning according to what wscywabbit suggests & see if this resolves the problem.

daveearles
05-06-2012, 09:24 PM
It looks like you've got your nock point / rest height right on, and that you just need to move your rest to the right. I've gotten to the point that when I paper tune, it's just to get my nock set. Then I go out and do a french tune and/or walk back to dial in in the center shot:

FRENCH TUNE
Go out to your target, run a piece of tape vertically top to bottom in the center. Then move to about 3-5 yds from it and fire an arrow at that strip. Move your pins left/or right (follow the arrow so if it hits left of the line, move your sight left).

When you can hit the tape dead on, move back to 20 yds and fire at it again. This time move your rest away from the arrow (if it hits left of the tape, move your rest right). When you get your arrows hitting the tape, go back to 3 yds and start again.

Rinse repeat until you don't have to move anything to hit the tape at both 3 yds and at 20.

I like doing that because it sets up your sight to center as well. You can also do a walk back, which i less involved;

WALK BACK
Using the same tape setup, fire an arrow at 20 yards at the top of the tape, don't worry about where it hits. Move back to 30 yards, shoot again. Move back to 40 yards, shoot again.

You will end up with line of arrows close to the tape at the top, further away at the bottom. If the gap is on the left side, move your rest right towards the tape, and vise versa.

Repeat the process until you get a vertical line of arrows that parallel the tape. Now your center shot is set and you can go to work adjusting your site.


Hope that helps!

Thank you, this makes definite sense!

Should I be doing this type of tuning with my FPs or with my broadheads?
Dave

wscywabbit
05-06-2012, 09:33 PM
Field points, definitely. Until the bow is tuned, your broadheads won't fly with your field points, they'll have different trajectories... unless you're shooting an expandable or something.

I usually don't even fire a broadhead (I shoot fixed blades) until I'm done tuning. Oh, and when doing the tuning I described earlier, just use your 20 yd pin. I just edited my previous post to include that... ;)

daveearles
05-07-2012, 12:03 AM
Field points, definitely. Until the bow is tuned, your broadheads won't fly with your field points, they'll have different trajectories... unless you're shooting an expandable or something.

I usually don't even fire a broadhead (I shoot fixed blades) until I'm done tuning. Oh, and when doing the tuning I described earlier, just use your 20 yd pin. I just edited my previous post to include that... ;)

I just did the french tune method with FPs & did not take much adjusting to get the centre shot lined up. I did not do the walk back yet as it is quite windy at the moment & haven't been able to get down to the range.

I have attached a pic of my results showing the difference in placement with the different shaft weights.

With the 7595s cut down to 28" & with a FP on are hitting the bag pretty much on vertical @ 3 through to 20 yds

Tried the GT Big Game 100+ and the same results.

Through a NAP 100 grain thunder head on each of those 2 different shafts & look at the results. The FP & the Big Game 100+ with thunderhead is pretty much on the money, the difference in positioning can probably come down to shooter error I'd say.

If you look at where the thunderhead on the 7595 hit it was clearly to the right & down. I have not had a great deal of experience in Archery but from what I have learnt, is this not showing that the 7595's are not stiff enough? The flexing of the shaft on release or "Archers Paradox" as I understand is obviously far greater in the 7595 allowing the broadhead to steer the arrow off course too much to be re corrected by the fletchings once settling down in flight.

Can I then assume that a stiffer arrow is needed despite others saying they are successfully using the 7595s with higher poundage bows??

Its all a bit confusing for a new boy!!
6451

daveearles
05-07-2012, 06:09 AM
From these results is it safe to assume that my arrows are underspined despite the fact that others are shooting higher poundage bows with the same arrow?

Is there anything else that I could be missing before I go & order myself some stiffer arrows? If I do need stiffer arrows, could I get away with ordering 1/2 doz for my hunting arrows & then just use my 7595s cut down to 28" for practice with FPs as the big game 100+ with the thunderheads were not far off the FP flight? I suppose I should test out to 50-60 yards for confirmation before buying new shafts?

What do you guys think?

Thanks
Dave

daveearles
05-08-2012, 04:21 AM
Still trying to figure this out?

bfisher
05-08-2012, 11:57 AM
An easy way to tell if the BG 100's are underspined (I doubt it) is to turn the bow weight down two turns and try again. Nobody ever reads Easton's Tuning Guide thoroughly. At the bottom of page 7: Release shooters sometimes get opposite results than finger shooters". In other words the 10s's hitting right can be indicative of a shaft that is too stiff. A shaft hitting lower might be because of greater FOC.

daveearles
05-08-2012, 04:31 PM
An easy way to tell if the BG 100's are underspined (I doubt it) is to turn the bow weight down two turns and try again. Nobody ever reads Easton's Tuning Guide thoroughly. At the bottom of page 7: Release shooters sometimes get opposite results than finger shooters". In other words the 10s's hitting right can be indicative of a shaft that is too stiff. A shaft hitting lower might be because of greater FOC.

thanks for the reply. It was never a question if the BG 100's are underspined, they are the arrows that are shooting straight with the broadheads on.

Given that the BG100's are a stiffer arrow than the .340 spine of the 7595, then if we go by what you have said above would you not expect then for the BG100's to be hitting right of centre if they were indeed too stiff? It is the 7595's that are way off to the right & low not the BG100's. The arrows shot in my test used the same nocks & same weight FP & broadhead, the only difference was the shaft lengths & spine weights between the 7595's at 28" to the BG 100 @ 29".

So if we look at the result again:

The .340 spine GT7595 @ 28" long with 100 grain FP hit pretty much bang on where it should have.

The .340 spine GT7595 @ 28" long with 100 grain Broadhead hit low & to the right.

The .280 spine GT Big Game 100+ @ 29" long with 100 grain broadhead hit at correct height & only slightly right (further shots proved its vertical line to match FPs on 7595s)

The logic & arrow selection software suggests that I need stiffer arrows than the GT 7595's. I've only been shooting for a few months so was hoping that someone else with more experience could explain my results otherwise before going out & buying more shafts.

Thanks

bfisher
05-08-2012, 06:01 PM
The key word in that phrase from Easton's Tuning Guide is "sometimes". "Sometimes a release shooter gets opposite results...." I misinterpretted your explanation of what was going on. I agree with you and your software that the 340 (7595) is probably not stiff enough. They may have been OK with a softer cam, but more agressive cams often require that we use stiffer arrows. The software confirms this whereas the GT arrow chart may not. It's kind of one of those things where nothing is written in stone.

Although you confess to bein fairly new I can tell from your info and the way you are conveying it here that you have a pretty decent understanding of things. I've only been at this for 40 years and still learning new stuff as the sport and equipment evolve. In saying that I apologize if I confused you.

daveearles
05-08-2012, 06:51 PM
The key word in that phrase from Easton's Tuning Guide is "sometimes". "Sometimes a release shooter gets opposite results...." I misinterpretted your explanation of what was going on. I agree with you and your software that the 340 (7595) is probably not stiff enough. They may have been OK with a softer cam, but more agressive cams often require that we use stiffer arrows. The software confirms this whereas the GT arrow chart may not. It's kind of one of those things where nothing is written in stone.

Although you confess to bein fairly new I can tell from your info and the way you are conveying it here that you have a pretty decent understanding of things. I've only been at this for 40 years and still learning new stuff as the sport and equipment evolve. In saying that I apologize if I confused you.

Hey, no problem for the confusion & many thanks for helping me out.

My next question is do I go for a .300 spine like the GT Velocity XTs or do you think I would be safe going with a .280 like the BG 100s? I haven't had a chance to try the BG 100 from any distance yet to see how much drop there is with an all round heavier arrow?

The reason I have chosen the velocity XT over the kinetic hunter is that the id is the same as the 7595's @ .246", this means all my lumenoks, spare nocks & inserts are not going to waste.

Given you have a lot more experience than me, what would you suggest & your thoughts on arrow model selection be? I want these arrows for hunting, the biggest game animal we have locally is the red deer so red deer, fallow deer, goats & wild pigs would be the main targets.

Thanks
Dave

droppixel
05-08-2012, 07:48 PM
I'm shooting GT Velocity 300s at 28" Carbon 2 Carbon out of my Bengal at 65# with great results. Changed to these shafts for my Alien X and happened to start shooting them out of the Bengal at the same time, much better than the 5575s I was shooting prior.

daveearles
05-08-2012, 07:52 PM
I'm shooting GT Velocity 300s at 28" Carbon 2 Carbon out of my Bengal at 65# with great results. Changed to these shafts for my Alien X and happened to start shooting them out of the Bengal at the same time, much better than the 5575s I was shooting prior.

Thats what I like to hear! My Bengal max out is 68.2# so I'm guessing if I go the same 28" carbon to carbon that they should cope with that extra 3# alright then?

Thanks

daveearles
05-12-2012, 03:05 AM
I'm shooting GT Velocity 300s at 28" Carbon 2 Carbon out of my Bengal at 65# with great results. Changed to these shafts for my Alien X and happened to start shooting them out of the Bengal at the same time, much better than the 5575s I was shooting prior.

I've ordered some GT Velocity Hunter 300, will let you know how they go once they arrive. Thanks guys

bfisher
05-12-2012, 04:27 PM
My gut would say to give the BG 100 a try for now. You already have them, right? Why buy something else if they work. I did check the GT website and the BG 100 has an inside diameter of .246 so you can use all the component you have. That arrow is going to shoot a lot slower than the Ultralights, but you did say it was for hunting and I don't imagine there will be much long range shooting involved.

Now if you find a need for speed and flat trajectory there is always the 22 Series at 7.3 gpi. They are a .300 spine and can be fitted with Easton 215/2117 unibushings that should work for the Lumenocks. This setup would be crazy fast. LOL.