MilDotMaster

Just got back from running my 443 grain arrows through the chronograph outside with a 5 mph cross wind. No assumptions on speed with this post, these are the facts straight off the chrono. The speeds are not as high as I was expecting. It is 10-15 fps below what I think it should be. I'm going to the shop to verify that I'm getting a true 70 pounds on draw force.Note: all shots are true readings since I was actually shooting the arrows through the chrono at target impact ranges from 10-60 yards.

Bow and Arrow Specsin Hunting Configuration:

2006 BowTech Old Glory
31 inch draw length with 80% let-off
70 pounds with speed cams installed
Bow was fully loaded with all accessories, loop, all silencersand hooded super ball peep with1 inserts installed, served in 1.5 inches on both sides of peep housing.
Arrows are exactly 443 grains with 4 inch plastic VaneTech vanes at2 degree off-set.

Speed at 3 feet was 270 fps averagewith 72 ft pounds of kinetic energy.
[ol][*]10 yards 265 fps with 69 ft pds KE[*]20 yards 259 fps with 66 ft pds KE[*]30 yards 256 fps with 64 ft pds KE[*]40 yards 250 fps with 61 ft pds KE[*]50 yards 245 fps with 59 ft pds KE[*]60 yards 241 fps with 57 ft pds KE[/ol]
That is all I have, I couldn't shoot through the chrono at any further distance without hitting the chrono brackets.[:@]

I posted this here to help others figure out their speeds by making small modifications based off of your equipment. For example: For every 3 grains less of arrow weight add 1 fps to calculate your speed.

newman1

Whats wrong with that?If you take into account the speed you gainwith the extra inch of draw and subtractthe 31 ft per second you lose with extra arrow weight that would put you right where you are now.Or am i missing something?

Rob/PA Bowyer

That's excellent. Why yearn for more, that'll do the job on every animal in NA.

Matt / PA

I'd be verifying the chrono results themselves........I get almost those identical numbers out of my Allegiance at 30".......and 60#[:-]
My 410gr A/C/C 3-60'swere shooting278fps with a fully loaded string (loop, 2 tied in nock sets, leeches and Tru-Peep) That's 70ft lbs of KE at 1" less draw length and 10# less draw weight.
(Granted the Allegiance is a faster bow but consider the specs I'm shooting)

Even with smooth mods at 31" you should ge getting high 70's to darn close to 80ft lbs on average.

Something is screwy with the calculations or chrono.

What was the BC number that it shot that came with that bow?
Even the slowest shipping SMOOTH mod on 30"/70# bows will shoot 70ft lbs of KE.......the speed mods at the low end for a 30" bow will do 74-75ft lbs.
With an extra inch of powerstroke the numbers you are getting don't make any sense

MilDotMaster

People let this post be a lesson for all of us. I just got off the phone with BowTech Tech Services. He shot a 70# 2006 Old Glory with 31 inch draw length through the chrono for me using a 450 grain arrow and got a consistant 288 fps. That's with an arrow that is 7 grains heavier than my arrows. After further evaluation we found out that my bow has 6 dots showing past limb andit issupposed to be at 5 dots past limb. He said that required 3 twists for the top and 3 twists for the bottom to bring it within factory specs. We also agreed thatthe twistswouldn't make up the entire loss of speed, so I put a mic to my limb pivot spacers and found out that they are only .110 thick and they are supposed to be .230 thick. The wrong pivots were installed from our best guess. The thicker the pivot, the more load is put on limb and thus more speed in generated. I have the "tall" pivots on order through local shop since my bow has the short pivots installed.

What can we learn from this??? Once again local dealers don't always know everything and in a busy time of day may give you incorrect info. I specifically asked my dealer if I needed to check or "rig" anything on this bow on date of purchase after kicking down over $750 for this bow. He said nothing needs to be done since it is a binary cam system. Well those 6 dots have been showing since date of delivery. Then I find out today I need 3 twists on top and bottom to bring bow to 5 dots. Go figure.

Second lesson always know what your bow specs should be and inspect it before purchase. I wonder how many people are out their shooting bows that are not set-up correctly. I have been and I tend to notice most problems. Please double check your new bows.

BowTech has been great to work with on the phone and I look forward to resolving these issues. I only post this topic here so others may be able to learn what to check for and how to inspect their new bows.

Best Regards

MilDotMaster

315fps with 350 grain arrow at 30 inch draw using speed cams.Now add 10 fps for my 1 inch increase in DL and thats 325 fps for a 350 grain arrow. 325 fps subtract 31 fps for heavier arrows= 294 fps. Subtract 12 fps for my super ball peep and loop on string and that is 282 fps. I am currently at 270 fps. Giving up 12 fps isto much toignore.

newman1

I agree 12 fps. is to much to ignore.I did not mean any offence by my statements,if you took it that way i am sorry.Now what exactly are you talking about when you say "dots" this is new terminology to me.

MilDotMaster

The BC number attached to bow was 306 fps with smooth cams at 30 inch cams/DL. Add 9 fps for speed cams and that is 315 fps. Add another 10 fps for my 1 inch increase in DL (31 inches) and now the bow should be spitting out 350 grain arrows at 325 fps. You already heard the rest of the story, just wanted to answer your question directly.

I want to know how this thing left the factory making those speeds on birth certificatelacking 6 total twists and having short pivots installed? Maybe the local dealer best friend is smiling with his new set of tall pivots installed on bow? HA! Just kidding.

MilDotMaster

I didn't take any offense, you brought up a good question for all of us to learn from. Many readers may have been thinking the same thing as you. I was happyto answer the question.

The dots I'm refering to are located on both cams and are machined in place as tuning aids. They lookabout the same size as a punch mark for pre-drilling holes. According to BowTech Tech Services with my bow and draw length they are supposed to be at 5 dots and they are a little over 6 right now.

newman1

Is that a new thing with the 2006 models or should i go check out my 2005?