# How Come



## Pierre Couture (Oct 28, 2004)

Methinks that I may have found a good bow for knuckle draggers...


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## Pierre Couture (Oct 28, 2004)




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## Rampant (May 3, 2005)

You weren't paying attention Pierre... I dropped hints about this months ago!

I've been shooting the Viper XL39 since August, and it's an awesome bow! It holds rock steady and is very accurate and forgiving, with a smooth, easy draw cycle. Speed is more than adequate for target, or you can opt for the twin cam Mamba XL39 if you feel the need for expeditious velocity!


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## Pierre Couture (Oct 28, 2004)

Rampant said:


> You weren't paying attention Pierre... I dropped hints about this months ago!
> 
> I've been shooting the Viper XL39 since August, and it's an awesome bow! It holds rock steady and is very accurate and forgiving, with a smooth, easy draw cycle. Speed is more than adequate for target, or you can opt for the twin cam Mamba XL39 if you feel the need for expeditious velocity!


Good to know Nigel. Thinking it could make a good bow for finger shooting at about 30.5-31 " DL...


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## Pierre Couture (Oct 28, 2004)

Does the draw stop allow to adjust the let-off?


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## Rampant (May 3, 2005)

Yes there's a few guys on here that have shown interest in the XL39s as finger bows. 
The draw stop on the one cam can be used to vary the let off a little, but there are no auxiliary draw stops on the twin cam. Small changes can be made on either bow by adjusting cam rotation, and varying the diameter of the cables can also change letoff slightly.


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## Pierre Couture (Oct 28, 2004)

I received an email from APA yesterday stating that the let-off wouldn't change on the Viper with the draw stop, and that only the width of the valley would be affected... if the let-off can be brought closer to 65%, that would be perfect for me.


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## peregrine82 (Aug 25, 2007)

I have owned a few APA's and worked on a whole lot more. One constant that they all shared was draw lengths consistently 3/4 of an inch long. Has this issue been addressed and are the 12's going to be much closer to the advertised length? The new 39 dual cam looks like a great target rig and should be perfect for 3D. The let off at 75% is a little higher than I like but I can live with that. I just need to know if I want my DL (28 1/4) do I need a 271/2 mod.


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## sagitarius (Sep 11, 2007)

peregrine82 said:


> I have owned a few APA's and worked on a whole lot more. One constant that they all shared was draw lengths consistently 3/4 of an inch long. Has this issue been addressed and are the 12's going to be much closer to the advertised length? The new 39 dual cam looks like a great target rig and should be perfect for 3D. The let off at 75% is a little higher than I like but I can live with that. I just need to know if I want my DL (28 1/4) do I need a 271/2 mod.


I would like to know about this as well. When I bought my King Cobra a couple years ago I had to go back to the archery shop and get mods for an inch shorter draw. And the dick that owns the shop charged me like $30 for the mods after I had just spent nearly two grand on 2 bows and accessories. There was a couple other things that made me unhappy with his service as well, Last time I was in his shop.

Anyways, my point is it would be nice to know what Draw Length to order your bow in the first time.


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## Rampant (May 3, 2005)

Despite the fact that I'm closely associated with the factory, I disagree with the assertion that the position of the draw stop won't affect letoff. If you're stopping cam rotation before you drop all the way into the valley, then the percentage of letoff has to be reduced. Draw stop coupled with varying cam rotation absolutely will affect letoff.

As for draw length, I've been shooting APA for two years now and have not experienced over-long draw lengths, although I've heard it complained about many times. I think the key may be keeping your string and cables in spec. The quality of some of the OEM strings has been less than stellar, as is the case with many manufacturers, as they strive for the fastest speed rating (and lowest cost) possible. Twin cam bows are especially prone to increasing draw length as the single string tends to stretch at a faster rate than the two cables, and is typically over 30% longer to start with. Even if string and cables stretched at the same rate, the string is constantly getting proportionately longer than the cables. For example, let's say a string set stretches 1% in the first 500 shots. A 60" string would be 0.6" longer, whereas the 40" cables would be 0.4" longer. That'll make a big difference in draw length. This problem is exacerbated by very high performance cam systems, such as those employed by APA. 

All of that aside, I know for sure that APA and most APA dealers would happily exchange draw length mods at no charge for someone that had just purchased a bow that turned out to be a little long or short for them. If your dealer doesn't have mods in stock, contact the factory, myself, or Crashman (Peter Ray) for help.


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## Pierre Couture (Oct 28, 2004)

Rampant said:


> Despite the fact that I'm closely associated with the factory, I disagree with the assertion that the position of the draw stop won't affect letoff. If you're stopping cam rotation before you drop all the way into the valley, then the percentage of letoff has to be reduced. Draw stop coupled with varying cam rotation absolutely will affect letoff.
> 
> As for draw length, I've been shooting APA for two years now and have not experienced over-long draw lengths, although I've heard it complained about many times. I think the key may be keeping your string and cables in spec. The quality of some of the OEM strings has been less than stellar, as is the case with many manufacturers, as they strive for the fastest speed rating (and lowest cost) possible. Twin cam bows are especially prone to increasing draw length as the single string tends to stretch at a faster rate than the two cables, and is typically over 30% longer to start with. Even if string and cables stretched at the same rate, the string is constantly getting proportionately longer than the cables. For example, let's say a string set stretches 1% in the first 500 shots. A 60" string would be 0.6" longer, whereas the 40" cables would be 0.4" longer. That'll make a big difference in draw length. This problem is exacerbated by very high performance cam systems, such as those employed by APA.
> 
> All of that aside, I know for sure that APA and most APA dealers would happily exchange draw length mods at no charge for someone that had just purchased a bow that turned out to be a little long or short for them. If your dealer doesn't have mods in stock, contact the factory, myself, or Crashman (Peter Ray) for help.


I agree with you on the let-off part, but here's a quote from the email I received. As I understand it, nominal let-off is probably always 80, or in this case, 75%, but I concur that modifying the DL before reaching the bottom of the valley would affect let-off.



> Thank you for your email regarding our Viper XL39.
> 
> 
> 
> Yes the left-off is adjustable via the draw stop....with a simple adjustment on the outside of the cam with an Alan key set. You can adjust valley deeper or shorter, but let-off will always be 80%.


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## Rampant (May 3, 2005)

Pierre Couture said:


> I agree with you on the let-off part, but here's a quote from the email I received. As I understand it, nominal let-off is probably always 80, or in this case, 75%, but I concur that modifying the DL before reaching the bottom of the valley would affect let-off.
> 
> _Thank you for your email regarding our Viper XL39.
> Yes the left-off is adjustable via the draw stop....with a simple adjustment on the outside of the cam with an Alan key set. You can adjust valley deeper or shorter, but let-off will always be 80%_.


I don't know who wrote that email Pierre, but I'm highly disinclined to trust it. It's contradictory, and misinformed; first saying, 'Yes the let-off is adjustable via the draw stop.' then saying, 'let-off will always be 80%'. Also, as you mentioned, claimed let-off for this bow is actually 75%. I put my faith in physics.


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## Pierre Couture (Oct 28, 2004)

Rampant said:


> I don't know who wrote that email Pierre, but I'm highly disinclined to trust it. It's contradictory, and misinformed; first saying, 'Yes the let-off is adjustable via the draw stop.' then saying, 'let-off will always be 80%'. Also, as you mentioned, claimed let-off for this bow is actually 75%. I put my faith in physics.


Her name is Adele :noidea: But yes, I too tend to trust physics :cheers: So, in your opinion, would a 65% let-off be achievable? I tend to think that it is, but I haven't been able to find out for myself. As for my purpose, it would be mostly bowhunting with a 30.5 - 31" DL.


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## peregrine82 (Aug 25, 2007)

As to the let off question, moving the draw stop closer to the limb reduces draw length, lessens the valley and increases the holding weight in pounds. Whoever Adele is she is misinformed and passing that misinformation on.

The Scorpion strings provided for APA are made by Jeff in Winnipeg. They are 8125 and I have always been impressed by the quality of the strings. The creep of the string has always been minimal in the bows I have owned and once a peep was installed rarely moved. I am not knocking the quality of Nibal's bows, I like APA and hope they stay in business for a long time. As I stated earlier my experience has been that DL's ran long and I don't believe it was a string creeping issue. I also agree that mods can be exchanged at no cost but it would be nice to get them right first time around. I have access to a number of 2011 APA's and I'll put them on a draw board to check DL's.


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## Rampant (May 3, 2005)

Pierre Couture said:


> Her name is Adele :noidea: But yes, I too tend to trust physics :cheers: So, in your opinion, would a 65% let-off be achievable? I tend to think that it is, but I haven't been able to find out for myself. As for my purpose, it would be mostly bowhunting with a 30.5 - 31" DL.


I have no doubt that 65% is achievable, but without playing around with it myself I'd be hesitant to guess at the resulting shootability. I suspect that a longer draw mod would be in order, perhaps coupled with a slightly shorter string to advance the cam... Sounds like a good after-season project.


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## Rampant (May 3, 2005)

peregrine82 said:


> As to the let off question, moving the draw stop closer to the limb reduces draw length, lessens the valley and increases the holding weight in pounds. Whoever Adele is she is misinformed and passing that misinformation on.
> 
> The Scorpion strings provided for APA are made by Jeff in Winnipeg. They are 8125 and I have always been impressed by the quality of the strings. The creep of the string has always been minimal in the bows I have owned and once a peep was installed rarely moved. I am not knocking the quality of Nibal's bows, I like APA and hope they stay in business for a long time. As I stated earlier my experience has been that DL's ran long and I don't believe it was a string creeping issue. I also agree that mods can be exchanged at no cost but it would be nice to get them right first time around. I have access to a number of 2011 APA's and I'll put them on a draw board to check DL's.


Hey Bobby,
Adele is APA's receptionist/secretary. She got the information from one of the guys in the shop, as Nibal will not be available to answer the question until Monday. She did the best she could under the circumstances.

I'm not going to comment on the quality of Scorpion strings, but I will say that 8125 is not nearly the most stable string material available. It is subject to considerably more stretch and creep than some other materials, but it is fast. 8125 will continue to stretch and creep throughout its usable life. Over the years I've taken OEM 8125 strings off various one cam bows and found them to be over 2" longer than spec. I'm not mentioning any names, it's mostly just the nature of the material, although construction techniques do play a part as well. Personally, I'd rather sacrifice 4 or 5 fps in order to use the most stable string I can get my hands on.

I'd be very interested in hearing about the results of your draw board testing! After your initial round of tests, would it be too much to ask you to measure and record the string and cable lengths, put them back to spec length, then re-check the draw lengths? That should answer any questions once and for all. I hope some of the bows you have access to are used...?


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## Pierre Couture (Oct 28, 2004)

Rampant said:


> I have no doubt that 65% is achievable, but without playing around with it myself I'd be hesitant to guess at the resulting shootability. I suspect that a longer draw mod would be in order, perhaps coupled with a slightly shorter string to advance the cam... Sounds like a good after-season project.


It would be worth looking into for sure... as for the 65% I'd personally feel more comfortable with it for a finger release.


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## Crashman (Jan 20, 2005)

I would have to confirm this, but I don't believe there is a pre determined position for the draw stop that would give you exactly 65% letoff. You would have to experiment with different positions until you found the spot that gives you the "feel" you are looking for. I am not a finger shooter, so I am not sure what is ideal, but for me shooting back tension, the let off is almost irrelevant as I pull hard in to the back wall and I am sure I lose a bit of let off with this style, but it works for me. The single cam is adjustable over an 8" range using two different draw length modules, I recommend not getting hung up on what your draw length is, just adjust the bow until it fits you properly and disregard what the module setting is because now the bow will be at your true draw length any how.  

And just for the record, I have found the draw lengths on APA to be a bit long in the past as well, this is normally due to cam rotation being out of spec, or string/cable stretch, but I have had similar experiences with almost all the other major brands out there. They are certainly not perfect, they are human.


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## Pierre Couture (Oct 28, 2004)

Crashman said:


> I would have to confirm this, but I don't believe there is a pre determined position for the draw stop that would give you exactly 65% letoff. You would have to experiment with different positions until you found the spot that gives you the "feel" you are looking for. I am not a finger shooter, so I am not sure what is ideal, but for me shooting back tension, the let off is almost irrelevant as I pull hard in to the back wall and I am sure I lose a bit of let off with this style, but it works for me. The single cam is adjustable over an 8" range using two different draw length modules, I recommend not getting hung up on what your draw length is, just adjust the bow until it fits you properly and disregard what the module setting is because now the bow will be at your true draw length any how.
> 
> And just for the record, I have found the draw lengths on APA to be a bit long in the past as well, this is normally due to cam rotation being out of spec, or string/cable stretch, but I have had similar experiences with almost all the other major brands out there. They are certainly not perfect, they are human.


65% or a bit lower is usually better for a clean finger release, but the somewhat *cough* low ATA  (How times have changed since I started 25 years ago) requires less finger contact on the string to achieve that as well.


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