Mathews atlas arrow question

[Pmiller45]

I have a long draw length 33.5-34 depending on the bow. My Arrows are 32.5 throat to outsert, that does bring the point or Broadhead onto the shelf but it’s never been a problem. Some long draw guys even use a overdraw to make arrow choice a little easier. For pin gap I would suggest going to lighter weight arrow. Also go to a 250 spine arrow. Find out what your actual draw weight is. I had a Atlas and when it was in spec it didn’t hit the mod weights. Get the tune right and then see where things go. The Atlas is no speed bow but you can get some more out of her by changing some things and doing some checks.


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[Wannabebowhuntr]

This thread makes me wish I had a long or even just longer draw length lol

 

[831hunter]

Thank you everyone for the input. After talking with the shop they are going to switch out that axis build for some rip tko auto around 450 grains. That should help out thank you for input will update with new arrows!

 

[DB29]

That's at 34" draw. The real IBO is equivalent to 310 IBO at 30" draw. The Atlas is NOT an aggressive bow. Try 310 IBO and see what the program shows.


Keep your fingers out of the way. I shoot at just under 33" draw, like 32 7/8" and all my arrows are cut to 30" carbon to carbon. I'm shooting RIP TKO 250's with 200gr up front with 75gr brass HIT's and 125's. They come in right at 500gr and are shooting 294fps out of my Mathews Traverse with 1/2 a turn out of the limbs. Everything tunes up great. If I add more limb bolt twist, bare shafts will go left with nocks right. If I turn the bolts out at all, the bare shafts will go right with nock left.......the opposite. So this is my sweet spot.

Also, I wouldn't have a problem with those pin gaps for hunting. Just more room for visibility. But if you want faster arrows out of that bow, I'd try the RIP TKO's.

For software purposes the IBO is the IBO.

qSpine accounts for the DL, it is a separate input in the software.

The IBO input, along with the other bow specs in the software gives a baseline for the energy the bow is capable of creating. The software then takes that figure and accounts for DL and other data points to give a decent gauge on the appropriate spine.

 

[DB29]

Thank you everyone for the input. After talking with the shop they are going to switch out that axis build for some rip tko auto around 450 grains. That should help out thank you for input will update with new arrows!

Good on the shop for trying to make it right.

But if you want to understand what is going on instead of relying on what others tell you, I encourage you to keep asking questions and go deeper into the rabbit hole.

No worries if not. Archery is a ton of fun no matter what.

 

[Mighty Mouse]

For software purposes the IBO is the IBO.

qSpine accounts for the DL, it is a separate input in the software.

The IBO input, along with the other bow specs in the software gives a baseline for the energy the bow is capable of creating. The software then takes that figure and accounts for DL and other data points to give a decent gauge on the appropriate spine.

A bow's advertised speed rating is generally assumed to be measured at 70# draw weight, 30" draw length, 350 gr arrow weight. In the case of the Atlas, however, Mathews specifically says its 350 fps speed claim is at a 34" draw length. 350 fps at 34" equates to approximately 310 fps at 30". 350 fps at 70#/30"/350 gr would be very fast for a bow with a 7.75" brace height...a very aggressive cam would be required to achieve such speed with that tall of a brace height. Most bows capable of 350 fps at 70#/30"/350 gr have brace heights of 6" or less.

qSpine's IBO speed field assumes a 70#/30"/350 gr basis, so entering 350 fps for a Mathews Atlas will significantly overestimate actual speed (and say dynamic spine is weaker than reality). Entering 310-315 fps in the IBO speed field would give much more accurate results for an Atlas.

 

[831hunter]

Good on the shop for trying to make it right.

But if you want to understand what is going on instead of relying on what others tell you, I encourage you to keep asking questions and go deeper into the rabbit hole.

No worries if not. Archery is a ton of fun no matter what.

Yes! I’m going to build a mini pro shop in my garage as I love to tinker and don’t like the feeling of being stuck with just taking it to someone else.

 

[DB29]

A bow's advertised speed rating is generally assumed to be measured at 70# draw weight, 30" draw length, 350 gr arrow weight. In the case of the Atlas, however, Mathews specifically says its 350 fps speed claim is at a 34" draw length. 350 fps at 34" equates to approximately 310 fps at 30". 350 fps at 70#/30"/350 gr would be very fast for a bow with a 7.75" brace height...a very aggressive cam would be required to achieve such speed with that tall of a brace height. Most bows capable of 350 fps at 70#/30"/350 gr have brace heights of 6" or less.

qSpine's IBO speed field assumes a 70#/30"/350 gr basis, so entering 350 fps for a Mathews Atlas will significantly overestimate actual speed (and say dynamic spine is weaker than reality). Entering 310-315 fps in the IBO speed field would give much more accurate results for an Atlas.

Thank you and good to know! I was about to go shoot an Atlas. At those specs it seemed like a dream bow!

 

[DB29]

Here is the qSpine at 315 IBO.

 

[whoami-72]

The bow is shooting 255 fps via the chrono. The shop is going to attempt to cut an inch off the arrow and remove the insert. Shop claims arrow is not under spined. I admittedly am not squared away on all the details of archery. So just going on the shops word. My foc is currently around 12 and I asked since we are removing the weight that will drop my fox and shop said it didn’t matter?

If you're shooting this slow, you've got something else wrong. I'm shooting a similar weight arrow at ~65lbs and 32" draw at high 270 fps. I'm also shooting the atlas.

 

[whoami-72]

After reading this thread. I'd be cautious about listening to that pro shop. Even though I'm not hunting with the atlas this year since i got all rifle tags, it's a flipping sweet bow. Let me know if you have any questions. You should definitely be able to shoot heavier arrows at fast speeds and do not want to settle. The bows not a speed demon but it's way faster than what you're getting. Also, keep in mind that shooting the way lighter arrows might push you over 280 fps. Which isn't bad but could (emphasis on could) cause issues with broadheads planing.

 

[831hunter]

If you're shooting this slow, you've got something else wrong. I'm shooting a similar weight arrow at ~65lbs and 32" draw at high 270 fps. I'm also shooting the atlas.

What else you figure could be going on with the bow? Its brand new probably 100 shots. Thanks

 

[whoami-72]

I went back and got my actual results from the times I've speed tested my bow so I'm not just making stuff up anymore. Using the numbers I'm getting out of my bow, then correcting to your arrow and draw conditions. Your bow should be shooting around 275-280fps.

If I were you, I'd start double checking everything. It sounds like you don't have the tools yet but did they let you pull the bow with a scale? For reference, mine pulled 66lbs when I left the shop and it had 70lb mods and the limbs were completely tight. I found out later it wasn't exactly in spec anymore cause the cables and strings had stretched after being a demo for a year plus. So, don't always just trust the mods. The tech even said most Mathews he works on are +or -2lbs of the mods usually.

Similarly, are you able to put it on a draw board and double check its in time? In a pinch, you can check the holes at rest. Then go to full draw and have your wife take pics of the draw stops touching the cables. Be careful not to hurt someone doing so. Also, keep in mind it's not exactly an accurate method with you at draw. It's only going to tell you if they are wildly off.

At the same time, have your helper mark the spot on your arrow that crosses the burger hole. Measure and use that for a rough determination if your draw length is on.

Did the shop have you paper tune it? If not, see how the arrows are flying. I know others have talked about the arrow being under spined. I've personally only shot a .250 spine black eagle catnivore out of my atlas and arrow spine is kind of a black magic and not always consistent amongst manufacturers. But, I'd bet it would show on paper if it's significantly off.

 

[Pmiller45]

Plenty of things “could” be wrong with a new bow. I would start with making sure the cam bearings are ok. Then put the bow in Mathews factory spec. Check the poundage on a scale. Set the timing, tune the bow with shorter and lighter weight arrows.


I wouldn’t put any faith in published IBOs as it relates to long draw lengths. Just shoot the bow through a reliable chrono and use that data if you plan to use calculators.


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[831hunter]

I went back and got my actual results from the times I've speed tested my bow so I'm not just making stuff up anymore. Using the numbers I'm getting out of my bow, then correcting to your arrow and draw conditions. Your bow should be shooting around 275-280fps.

If I were you, I'd start double checking everything. It sounds like you don't have the tools yet but did they let you pull the bow with a scale? For reference, mine pulled 66lbs when I left the shop and it had 70lb mods and the limbs were completely tight. I found out later it wasn't exactly in spec anymore cause the cables and strings had stretched after being a demo for a year plus. So, don't always just trust the mods. The tech even said most Mathews he works on are +or -2lbs of the mods usually.

Similarly, are you able to put it on a draw board and double check its in time? In a pinch, you can check the holes at rest. Then go to full draw and have your wife take pics of the draw stops touching the cables. Be careful not to hurt someone doing so. Also, keep in mind it's not exactly an accurate method with you at draw. It's only going to tell you if they are wildly off.

At the same time, have your helper mark the spot on your arrow that crosses the burger hole. Measure and use that for a rough determination if your draw length is on.

Did the shop have you paper tune it? If not, see how the arrows are flying. I know others have talked about the arrow being under spined. I've personally only shot a .250 spine black eagle catnivore out of my atlas and arrow spine is kind of a black magic and not always consistent amongst manufacturers. But, I'd bet it would show on paper if it's significantly off.

A lot of this makes no sense to me. A lot of good info tho I will dive in this week and make it make sense. Recommendations for a book or something that is a definitive guide to bow tuning?

 

[5MilesBack]

Using the numbers I'm getting out of my bow, then correcting to your arrow and draw conditions. Your bow should be shooting around 275-280fps.

With a 596gr arrow in that bow? I don't think so.

 

[DB29]

A lot of this makes no sense to me. A lot of good info tho I will dive in this week and make it make sense. Recommendations for a book or something that is a definitive guide to bow tuning?

Shoot bareshafts and fletched starting at 20yds and see if the hit the same spot. If they are close to each other you can likely get it in tune with small movements on your rest.

 

[whoami-72]

With a 596gr arrow in that bow? I don't think so.

Didn't he say 566 in the original post?

 

[Mighty Mouse]

Didn't he say 566 in the original post?

He did say that but forgot to include nock and vane weight, which would add another 25-30 gr (or more).

 

[831hunter]

He did say that but forgot to include nock and vane weight, which would add another 25-30 gr (or more).

We weighed the arrows at the shop yesterday. They were 600g