Appropriate Velocity?

[TxLite]

I’m not one that’s ever worried about velocity before, but finally got a chance to test with my garmin with my bow so figured why not? Over 6 shots it averaged 237.7fps.

My setup is a bowtech realm X, 70lb on the “comfort setting”, 29” draw, 606gr arrow (easton FMJ, 150gr practice tip).

For those that are velocity focused, does this seem about right?

 

[Mighty Mouse]

Seems a bit slow. Starting with IBO conditions (345 fps/70#/30"/350 gr), subtracting 10 fps for your draw length, and adjusting for arrow weight, I came up with 255-260 fps. Comfort mode will reduce the effective IBO speed a bit and that particular model might lose a bit more than 10 fps per inch of draw legngth, but I would still expect mid-240's at 600 gr.

Have you measured draw weight on a scale? Maxed out limb bolts don't guarantee that you're reaching advertised peak weight.

Also, have you confirmed your arrow weight on a scale? Advertised component weights can be off a bit.

 

[TxLite]

Seems a bit slow. Starting with IBO conditions (345 fps/70#/30"/350 gr), subtracting 10 fps for your draw length, and adjusting for arrow weight, I came up with 255-260 fps. Comfort mode will reduce the effective IBO speed a bit and that particular model might lose a bit more than 10 fps per inch of draw legngth, but I would still expect mid-240's at 600 gr.

Have you measured draw weight on a scale? Maxed out limb bolts don't guarantee that you're reaching advertised peak weight.

Also, have you confirmed your arrow weight on a scale? Advertised component weights can be off a bit.

Confirmed both. Had a shop use their scale for draw weight and I used my reloading scale for arrow weight

 

[Mighty Mouse]

Confirmed both. Had a shop use their scale for draw weight and I used my reloading scale for arrow weight

Try shooting through another chronograph to compare numbers. Optical chronographs are known to be subject to error.

 

[TxLite]

Try shooting through another chronograph to compare numbers. Optical chronographs are known to be subject to error.

This is the garmin radar chrono. I got rid of my old Caldwell a few years ago so I don’t have a different one to test with

 

[Billy Goat]

How much shot to shot variation did you see?
Edit: see that answer in the lower right corner now.

With an arrow that heavy, my experience is it should be very consistent. 1/2 fps variation.



Taking your 238 fps, add 10fps for a 29" DL and then you have 256 grs over 350, which in my experience would be about 85 fps, puts it at 333ish.

Seems pretty fair to me.

 

[TxLite]

How much shot to shot variation did you see?

With an arrow that heavy, my experience is it should be very consistent. 1/2 fps variation.

1.1fps over 6 shots

 

[Spoonman]

On comfort mods you are right on.

 

[Billy Goat]

1.1fps over 6 shots

I saw it and edited my post.

Was that same arrow over and over or 6 different arrows assembled the same?

 

[jimh406]

I think that's good for a heavy arrow. If it isn't obvious, the really fast speeds that people get are with the light arrows.

 

[TxLite]

I saw it and edited my post.

Was that same arrow over and over or 6 different arrows assembled the same?

2 groups of 3 arrows, assembled the same. So in the pic below it would be 1,2,3 as a group and 4,5,6 as a group. I didn’t mark to see which is which

 

[Mighty Mouse]

This is the garmin radar chrono. I got rid of my old Caldwell a few years ago so I don’t have a different one to test with

The Caldwell (and similar) chronos I've used can give wildly different readings depending on lighting conditions. I have no experience with a Garmin chrono, so I can't say whether or not it might be susceptible to similar variations. It would be interesting to compare your Garmin numbers to another chrono under good conditions (indoor with light kit or outside on an overcast day).

I assume your Garmin readings were taken right off the bow, not some distance downrange?

If I put an IBO speed of 335 fps and a speed loss-to-draw length ratio of 15 fps per inch into my calculator, it estimates 243 fps at 606 gr. That makes your readings seem plausible given that you're shooting a bow with rotating mods in comfort mode.

 

[TxLite]

I assume your Garmin readings were taken right off the bow, not some distance downrange?

Correct. I had the garmin sitting directly beneath the stabilizer on a table

 

[sndmn11]

I think that's about right.

 

[mod-it]

606 is a pretty heavy arrow, 237 fps is pretty believable.
Here's some redneck math.
Realm-X is a 345 IBO bow. We all know that manufacturer's IBO rating is rarely attainable, so lets call it a 340 IBO bow.
340 minus 10fps for your 29" draw length (IBO is 30" DL), so now were at 330 fps.
330 minus another 10 fps for being in comfort mode, so now were at 320 fps.
IBO is tested at 70 lbs with a 350 grain arrow. It is estimated that for every 3 grains of arrow weight, 1 fps is lost.
606 grain arrow minus 350, divided by 3, equals 85 fps lost for arrow weight.
The previous 320 fps minus the 85 fps for arrow weight puts you at 235 fps.
Pretty darn close to the 237 you got.

 

[nphunter]

Seems slow to me, no way would I want that trajectory. I’ve also blown through multiple elk with a large expandable with a 27.5” draw and 450-500fr arrows.

 

[jbelz]

606 is a pretty heavy arrow, 237 fps is pretty believable.
Here's some redneck math.
Realm-X is a 345 IBO bow. We all know that manufacturer's IBO rating is rarely attainable, so lets call it a 340 IBO bow.
340 minus 10fps for your 29" draw length (IBO is 30" DL), so now were at 330 fps.
330 minus another 10 fps for being in comfort mode, so now were at 320 fps.
IBO is tested at 70 lbs with a 350 grain arrow. It is estimated that for every 3 grains of arrow weight, 1 fps is lost.
606 grain arrow minus 350, divided by 3, equals 85 fps lost for arrow weight.
The previous 320 fps minus the 85 fps for arrow weight puts you at 235 fps.
Pretty darn close to the 237 you got.

This is spot on

 

[Ho5tile1]

Seems slow to me my Realm at 72 pounds 29 inches in comfort was like in the 250s with 650 grains years ago but maybe my chronograph was fibbing. I killed a buck at 60 yards with that set up but would not do that again as I got very lucky the buck was broadside feeding when I let the arrow go by the time it reached him he had turned to walk away and I hit him in the back ham and it came out his front shoulder. He made it a couple yards and fell over. 30-40 is max I would do now if I had that setup still. I’ve since went to 82 pounds on my Mathews and hunt with 550 grains going 287fps..
Killed several deer with that 650 grain setup with zero issues other then that one at 60 that I got lucky with..


Sent from my iPhone using Tapatalk

 

[TxLite]

Thanks for the replies all. I generally limit myself to 35ish yards on game, but practice to 60. The bow shoots well so I’m not overly hung up on the velocity. Just curious as to whether or not the bow is hanging where it’s supposed to

 

[nphunter]

I just shot my Mach 34, it’s shooting - 612gr arrow at 248fps at 73.5lbs and 27.6” draw.

I would say that your bowtech is defiantly on the slow side. It will defiantly get the job done but it’s not doing as advertised.