View Full Version : Silencer finally setup..speed questions.

08-22-2011, 06:38 PM
Finally got the new Silencer setup this evening.

28" draw length
68#'s dw
390 grain arrow
80% letoff
Only thing on the string is a meta peep (1/4") and a string loop.
A2A was 32"
Cams timed perfectly after minute adjustments.
7" brace height as per spec.

282 FPS.

Is it normal when you bottom out the screws not to get to 70#'s? Sure, that's only worth about 4FPS, but still that's an ez 4fps.

I can easily drop the point from 100 grains to 85 grains for a 5FPS increase and till have 77KE. I can also go to a lighter arrow and get down to 346, still within IBO and still have 72 KE, 13fps increase.

Doesn't changing the leftoff to 70% increase FPS by 10? Worth it?

Are any of these worthy of the effort? Am I too hung up on speed? Suggestions?

I did remove the TRG/SOS and put the cable/slide/STS on it. This is my 1st new bow in 10yrs, so take this with that in mind. This bow is smoooooooooth and the backwall is outstanding! Feels great in hand, light, little to no vibration/shock and quiet. I do know I will shoot with a stabilizer, which I didn't shoot with this evening, so that will add some weight to the bow. I don't see the need to add string silencers.

I'm glad of my purchase and the Cabelas crew took their time, measured everything and took the time to setup the bow very well. Cost for 1 1/2hrs of their work? Nothing.

They had a chart of all their bows they sell on the shop wall... all setup by them to IBO specs (70, 30, and 350) and the speeds listed. I can't remember most of them, but did recall that the ONZA was off by 20fps. PSE bow madness (this was my 2nd choice for a new bow) was only off 4 fps...The Bear Carnage (my 3rd choice, too much $$ though) was super off, 40fps+.

Going by what I'm shooting and the arrow speed calculators, I'm off 11 FPS, I should be shooting 293.

08-22-2011, 07:49 PM
I wouldn't worry to much about speed. The deer can't tell the difference. The biggest thing you can do is practice and make sure you can hit where you are aiming.

08-23-2011, 02:39 AM
First off I'd say this. There is some variance for bows. The listed draw weight can vary up or down by 3# or so and still be within allowable tolerances. Scales can vary by a couple pounds also, although the digital scales are usually more accruate. That being said, if you really think you need that extra 2# you can add a few twists to the cable(s) to raise the weight to the listed 70#. Frankly, I wouldn't worry about it too much.

The speed you are getting is quite acceptable and the KE is more than anything needed for the largest of North American game. For instance, I routinely have had pass throughs on deer sized game with outfits producing as little as 39# of energy. Speed and energy are nice things to know but in reality are just numbers.

What is of greater importance is having a properly spined arrow that is flying true so when it hits flesh all the momentum is straight behind the broadhead to drive it through. And this depends on whether you can place the arrow in the vitals without hitting bone (ribs are acceptable).

Decreasing letoff to around 70% will, according to all my tests, increase the speed by about 4 fps. To do this you'd need to shorten up the draw length using the draw stop which also makes for a very short, maybe non-existant, valley. You can try it and see how it feels to you, but most like the 80% for hunting purposes.

Really, if the bow is quiet and smooth for you then I'd just be happy and shoot it. As I said, don't get all hung up on numbers.