SR6 72lbs vs RX1 at 83lbs pretty interesting speed results.

[Brandon_SPC]

I thought this was pretty interesting. Yesterday I went to have my Bowtech SR6 tuned. While talking to the shop owning he really wanted to shoot my 635 grain arrow through the chronograph and I wanted to shoot his 500 grain arrow just to see how my bow does with a lighter arrow.


Specs for each bow. Both bows are tuned, cams timed, etc.
RX1
- Draw weight 83 lbs
- Draw length 30"
- Brace Height 6"
- IBO for a 70lb versions 340 fps (not sure how to calculate the 80lbs)

SR6
-Draw weight 72lbs also on performance setting
-Draw length 30"
-Brace Height 6"
-IBO at 70lbs 352 fps

Speed results were the same with both bows.
RX1 shot the 635 grain arrow at 265 fps and the 500 grain arrow at 298 fps
SR6 shot the 635 grain arrow at 265 fps and the 500 grain arrow at 298 fps.
We both thought this was a flute and re-shot through the chronos again and every single time it would shoot the same. Pretty interesting results between the same bows because I honestly thought the SR6 was going to come in at about 10 fps less on the 635 grain arrow and about 5 fps less on the 500 grain arrow.

The chronograph used was a ProChrono Pal Chronograph and I have used a few of these in the past for load development and they have always seemed to be accurate. I also shot the SR6 through a different chrono about a week before. It shot a 585 grain arrow at 273 so the averages that came out from yesterday show that the chrono that was used is fine. Also if I recall him mentioning that he used the chrono earlier on another bow and it was producing the right numbers for that bow and the arrow weight used.

I thought some of y'all would enjoy these results.

 

[Florida Bow Hunter]

I thought this was pretty interesting. Yesterday I went to have my Bowtech SR6 tuned. While talking to the shop owning he really wanted to shoot my 635 grain arrow through the chronograph and I wanted to shoot his 500 grain arrow just to see how my bow does with a lighter arrow.


Specs for each bow. Both bows are tuned, cams timed, etc.
RX1
- Draw weight 83 lbs
- Draw length 30"
- Brace Height 6"
- IBO for a 70lb versions 340 fps (not sure how to calculate the 80lbs)

SR6
-Draw weight 72lbs also on performance setting
-Draw length 30"
-Brace Height 6"
-IBO at 70lbs 352 fps

Speed results were the same with both bows.
RX1 shot the 635 grain arrow at 265 fps and the 500 grain arrow at 298 fps
SR6 shot the 635 grain arrow at 265 fps and the 500 grain arrow at 298 fps.
We both thought this was a flute and re-shot through the chronos again and every single time it would shoot the same. Pretty interesting results between the same bows because I honestly thought the SR6 was going to come in at about 10 fps less on the 635 grain arrow and about 5 fps less on the 500 grain arrow.

The chronograph used was a ProChrono Pal Chronograph and I have used a few of these in the past for load development and they have always seemed to be accurate. I also shot the SR6 through a different chrono about a week before. It shot a 585 grain arrow at 273 so the averages that came out from yesterday show that the chrono that was used is fine. Also if I recall him mentioning that he used the chrono earlier on another bow and it was producing the right numbers for that bow and the arrow weight used.

I thought some of y'all would enjoy these results.

I don’t get where you think the Hoyt should shoot faster ? When you increase poundage, you must increase ibo arrow weight. I would assume it to be a wash on the Hoyt.

I see this as the Bowtech not blowing by the Hoyt. Granted the arrows weren’t in balance to the poundage.

For instance. On the 500 grain the Hoyt is @ 6.024 grains per pound.

Bowtech 6.944 grains per pound. Bowtech has a 12 fps higher rating.

How do you account for this discrepancy in weight variations per pound ? Not sure. But your test is showing a loss of 12 fps on every grain per pound.

I am not one to do the swap outs here, but I’d expect the Bowtech to prevail. I could and probably am wrong, but I’d expect a faster bow to maintain efficiency better.

Curious for someone to graph this out with one of those apps. I’m sure it could be done.

I’ll guess and say the Bowtech should be 2 fps faster. Let’s see what the techie pros come up with.




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[Brandon_SPC]

I don’t get where you think the Hoyt should shoot faster ? When you increase poundage, you must increase ibo arrow weight. I would assume it to be a wash on the Hoyt.

I see this as the Bowtech not blowing by the Hoyt. Granted the arrows weren’t in balance to the poundage.

For instance. On the 500 grain the Hoyt is @ 6.024 grains per pound.

Bowtech 6.944 grains per pound. Bowtech has a 12 fps higher rating.

How do you account for this discrepancy in weight variations per pound ? Not sure. But your test is showing a loss of 12 fps on every grain per pound.

I am not one to do the swap outs here, but I’d expect the Bowtech to prevail. I could and probably am wrong, but I’d expect a faster bow to maintain efficiency better.

Curious for someone to graph this out with one of those apps. I’m sure it could be done.

I’ll guess and say the Bowtech should be 2 fps faster. Let’s see what the techie pros come up with.




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I was looking at this from cam efficiency as arrows get heavier. I have seen some bows like heavier arrows better than others, such as hoyts and Elites. Which is why I was a little shocked but granted I'm not a tech guru so I could just be looking at this all wrong.

Also this wasn't a scientific test just a "Hey I'm going on an elk hunt next year can I shoot that heavy arrow through my bow to see the results?" and I did the same with his arrow.

 

[Swampcruiser]

It would be different below 29- that is where the SR6 efficiency blows. At 30 your getting almost full rotation and it’s really efficient. My 28” SR6 was a dog with heavy arrows.

 

[HookUp]

Can you post up your numbers fps/arrow weight shot through your SR6 at 28? I have a 28" draw and am looking at the SR6 to compliment my RealmX

 

[UglyJow]

It would be different below 29- that is where the SR6 efficiency blows. At 30 your getting almost full rotation and it’s really efficient. My 28” SR6 was a dog with heavy arrows.

It wasn't a dog with heavy arrows—it was a beast with light arrows. The SR6 has been accused of being "inefficient" with heavy arrows; the truth is that it is extremely efficient with light arrows. The SR6 is a bow where the archery calculators fail particularly bad. Bowtech made the bow extremely efficient with IBO weight arrows; the bow doesn't experience the same gain in efficiency as other bows when going to heavier arrows. This has given it the reputation of being "inefficient with heavy arrows".

 

[Mighty Mouse]

Those are interesting results, not what I would've expected. Possible explanations I can think of:
1) The Bowtech is more efficient than the Hoyt
2) The Bowtech has a "harder" and the Hoyt a "softer" draw profile (using the terminology of the picture below)
3) Combination of 1 and 2

 

[Swampcruiser]

Yup- my SR6 was doing 271 with a 480 gr Axis at 70#, if I went up to 29” (with performance setting for both) it was doing 284 - that’s 344 and 347 IBO.

Sorry I haven’t been on in a few days

 

[ontarget7]

Spot on from my testing of both
I’m not seeing some huge decline even at 28” out of the SR6 like some have stated and I have lots of bows to compare them to.


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[sndmn11]

It wasn't a dog with heavy arrows—it was a beast with light arrows. The SR6 has been accused of being "inefficient" with heavy arrows; the truth is that it is extremely efficient with light arrows. The SR6 is a bow where the archery calculators fail particularly bad. Bowtech made the bow extremely efficient with IBO weight arrows; the bow doesn't experience the same gain in efficiency as other bows when going to heavier arrows. This has given it the reputation of being "inefficient with heavy arrows".

My experience is the opposite. I was seeing 260fps with 672gr arrows, 30/72, d loop and Hamskea Raptor. That is above any calculator I can find and two different chronographs.

 

[Brandon_SPC]

My experience is the opposite. I was seeing 260fps with 672gr arrows, 30/72, d loop and Hamskea Raptor. That is above any calculator I can find and two different chronographs.

I got a 740 grain arrow at the house. I'm kind of curious to what speeds it will do.

The 75lb E32 with 80lb Deflection Option 7 limbs shot it at about 243 fps. I'm thinking the SR6 with a 740 will be around 251-255 fps.

 

[KHNC]

The easier solution is just to shoot 450 gr arrows at everything , with a great broadhead, and get the best of everything.

 

[Brandon_SPC]

The easier solution is just to shoot 450 gr arrows at everything , with a great broadhead, and get the best of everything.

I just like heavy arrows haha

But more than likely next year I'm probably going to build a micro 550 grain build and be done with it.

 

[UglyJow]

My experience is the opposite. I was seeing 260fps with 672gr arrows, 30/72, d loop and Hamskea Raptor. That is above any calculator I can find and two different chronographs.

This is a perfect example of why the calculators and misuse of them are so common.

Lets take the SR6 and the http://backcountrybowhunting.com/calculator/ We'll calculate speeds and IBOs in two ways: using the calculator and using KE. Let's use your specs, 30/72. We'll also stick with the default 20 grains on the string, as that gives an IBO speed for the bow that seems reasonable.

From the calculator, here are the speeds I expect. For an IBO arrow of 360 grains, the calculated speed is 347 fps. Most would consider this "making IBO". I decide that is awesome, and I want to buy an SR6. Going in, I know I'm going to shoot a 520 grain arrow, so I check that with my handy calculator. It says I'll get 299fps with that arrow! Awesome, the bow is a beast. Just curious, I decide to see what the speed of a 672 grain arrow will be. 253 fps? Well, thats not super-fast, but I don't shoot that heavy an arrow anyway.

Ok, now let's do the same calculations using the KE the SR6 produces. The IBO arrow produces 96 ft·lb of KE. I know that this bow is super efficient, so I don't expect that increasing my arrow weight will significantly increase that KE number. If I want to play it safe, I'll calculate heavy arrow speeds at 96 ft·lb of kinetic energy; this will ensure that I am calculating the minimum speed I expect with that arrow. But I decide to play it dangerously and assume the bow will see a modest 2% efficiency gain with heavier arrows. This is still a small increase, so the speeds I actually chrono will likely be higher than I calculate, so I have a bit of a cushion built in. I calculate arrow speeds for 97.9 ft·lb of energy. A 520 grain arrow with that much KE would have a speed of 291 fps. The 672 grain arrow should be pushing 256 fps.

It turns out the the second method is a much more accurate way of estimating the speeds you will get from your arrow. But the archers relying on the calculator in scenario 1 will see oddities. He builds his arrow at 520 and then chronos his arrow at 290-292 fps. Thats almost 10 fps less than his calculator told him his bow should shoot! Its a dog with heavy arrows. Bowtech is a lying, greedy, evil corporation selling crap bows and lying about their speed ratings.

Archer 2 builds a 625 grain arrow and chronos it: 258-260 fps! Wow, the bow is even faster than the archery calculator told him (253 fps)! It must actually be a 352+ IBO bow!

If you do this again with an 800 grain arrow (which will be traveling a minimum of 235 fps), the calculator will tell him the arrow should be pushing 215 fps. He's 20 fps over IBO!!! Monster bow!

Hopefully this demonstrates that: A.) Calculators are not great to calculate arrow speeds particularly over a large range of arrow masses, and B.) How two archers shooting different weights with the same make bow may think their bows are under/over-performing when using the archery calculators when each bow is basically exactly where it is supposed to be.

 

[ontarget7]

One of my SR6’s with a 495 gr arrow is coming in at 283 fps

28.5/72#


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[Swampcruiser]

Makes for a good read-- I love the bow either way. Its got a great draw (I love BT draw cycles) , I just seem to be better with my RX3 and I trust it. I've had a history with Bowtech that ruined a hunt - I have trust issues-LOL

 

[Brandon_SPC]

Makes for a good read-- I love the bow either way. Its got a great draw (I love BT draw cycles) , I just seem to be better with my RX3 and I trust it. I've had a history with Bowtech that ruined a hunt - I have trust issues-LOL

I'm assuming it was an older model? Limb problems?