Help, new M380 making scary noise

[ijb]

Dear fellow Excalibur owners,

I need help. I purchased a Matrix 380 about a month ago. I also purchased the C2 crank as I found that using the cocking rope quickly tired my arms and back which did not help my shooting accuracy. I probably shot the bow about 100 times in the first 2 weeks after I got it and it was working fine. After that I went on vacation for 2 weeks. I took the bow out today and experienced the following.

First, as others have reported, the 4 screws holding the scope rail had all come loose. While this was annoying, it was not the scary part. I removed the screws, applied blue Loc-tite and reinstalled them. By the way, I believe these screws take a 3/32" allen wrench.

Second, and this is the scary part where I need help, when I was cranking the bow to cock it, just before the string got to the ADF latch, the bow made a loud ping and I felt a vibration up through where I was holding the stock. Rather than continue to draw the bow, I unwound the crank slowly. I checked all the bolts on the limbs and the bolts holding the riser to the rail. I also ran my hands over the limbs and flexed the limbs as best I could, but I did not find any problems. Finally, I checked over the crank and the hooks that pull the string. Again, I found nothing.

I tried cranking the bow a second time. It made the same ping in exactly the same spot, just before the sting reached the ADF latch. Again, I slowly unwound the crank and repeated the above inspections and again found no problems.

I tried cranking the bow one more time and again, the ping noise occurred in the same place and again I felt a sharp vibration through the stock. Through all of this, I could not tell what part of the bow was making the sound.

Until I figure out what is going on, I am not going to cock or fire the bow. I am thinking about going back to the local dealer who sold me the bow to ask the dealer to inspect and determine the problem. Meanwhile, I would really appreciate any ideas.

Thanks

[Normous]

Welcome to the forum. Can you possibly post a very short video of the noise?
Try hand cocking with the rope cocker to determine if the noise is coming from the C2.

[Deerstalker]

I think the noise is coming from the cocking string inside the crank that piles up on top of itself & then slips off under lots of force when it reaches a certain point. Do you see the main string slip back a small distance at the moment when you hear the noise? Do you hear the ping when you cock the CB using the rope cocker?

[ds762]

Welcome to the forum. Can you possibly post a very short video of the noise?
Try hand cocking with the rope cocker to determine if the noise is coming from the C2.

this was exactly my thoughts ..

[ijb]

I think the noise is coming from the cocking string inside the crank that piles up on top of itself & then slips off under lots of force when it reaches a certain point. Do you see the main string slip back a small distance at the moment when you hear the noise? Do you hear the ping when you cock the CB using the rope cocker?

Thanks for the suggestion. I'm concerned the problem is with the bow, not the crank for the following reasons.

First, I did completely unwind and rewind the crank string between the first and second times this happened, so the crank string would most likely have piled up differently after being re-wound. However, the ping noise occurred in exactly the same spot on the second and third attempts. Second, this never happened on any of the previous 100 shots when I used the crank and I was using the crank the same way as all the other times. Finally, the second and third times this happened, I did watch the bow string closely and it did not slip back.

I am reluctant to use the rope cocker as I'm concerned that the noise may indicate a weak limb or tip and I don't want to stress the bow further that the point at which the noise occurs. In order for me to cock the bow with the rope, I have to pull fairly quickly. Doing this, I don't think I could easily stop if the noise occurred again.

[Kegbelly]

Maybe enlist a friend that can pull it back slow and steady with the rope cocker? You won't really know until you cock it with the rope cocker to see if the noise repeats itself. The "ping" sound you describe makes me think of a string slipping under tension. I've never heard of a weak limb or tip making a sound like that, but that doesnt mean it can't happen.

[Normous]

There are 300,000 +/- parallel strands of fiberglass in each Matrix limb. These limbs just do not snap or break under normal tension, one would start to see spintering occur first in various degrees. The OP should not worry about a catastrophic limb failure when using the rope cocker.

[Michiganhunter]

I am no expert here by any means but if you don't want to risk cocking it with the rope then take it to a bow shop and have them use a different cocking mechanism. I would bet it is the cocking mechanism that is generating the ping noise. Process of elimination....rule the cocker out and go from there.

[ijb]

You all were right. I used the cocking rope and very slowly pulled to the point where the noise occurred and there was no noise. I then pulled just past the ADF latch and no noise. Then I pulled to fully cocked and no noise. I took a shot and all worked fine.

Then I went back to the crank and watched the string very carefully. The crank is definitely catching on something as the noise was back in the same spot and the bow string did jump slightly. This time I continued cranking to full cocked and all was fine.

Thanks to all who offered advice.

[bob watkins]

on my 380 my cranks slip a little never been a problem shooting,but it has worn some finish off my stock they all seem to rock abit i have 3 different cranks they all do it hope this helps

[Deerstalker]

These Excals are very tough, accurate, maintenance free, reliable and lots of fun to shoot. Glad that you found the problem to be in the C2 crank. Good luck hunting!

You may want to replace those 4 scope rail screws with the Torx head screws and if you do a search on this forum there is lots of posts on them.

[robertyb]

It is your string slipping on your crank. Mine does the same thing from time to time. Always in exactly the same spot when cranking.

[Newmer]

I also experience that same noise with the C2 crank, when used on my 380.
Same spot, every time. No noise with rope cocker.

[Squirrel]

That noise is probably coming from the rail because it's hollow. Nothing to worry about if the limbs are fine and nothing is loose.

[amythntr]

Dear fellow Excalibur owners,

I need help. I purchased a Matrix 380 about a month ago. I also purchased the C2 crank as I found that using the cocking rope quickly tired my arms and back which did not help my shooting accuracy. I probably shot the bow about 100 times in the first 2 weeks after I got it and it was working fine. After that I went on vacation for 2 weeks. I took the bow out today and experienced the following.

First, as others have reported, the 4 screws holding the scope rail had all come loose. While this was annoying, it was not the scary part. I removed the screws, applied blue Loc-tite and reinstalled them. By the way, I believe these screws take a 3/32" allen wrench.

Second, and this is the scary part where I need help, when I was cranking the bow to cock it, just before the string got to the ADF latch, the bow made a loud ping and I felt a vibration up through where I was holding the stock. Rather than continue to draw the bow, I unwound the crank slowly. I checked all the bolts on the limbs and the bolts holding the riser to the rail. I also ran my hands over the limbs and flexed the limbs as best I could, but I did not find any problems. Finally, I checked over the crank and the hooks that pull the string. Again, I found nothing.

I tried cranking the bow a second time. It made the same ping in exactly the same spot, just before the sting reached the ADF latch. Again, I slowly unwound the crank and repeated the above inspections and again found no problems.

I tried cranking the bow one more time and again, the ping noise occurred in the same place and again I felt a sharp vibration through the stock. Through all of this, I could not tell what part of the bow was making the sound.

Until I figure out what is going on, I am not going to cock or fire the bow. I am thinking about going back to the local dealer who sold me the bow to ask the dealer to inspect and determine the problem. Meanwhile, I would really appreciate any ideas.

Thanks

...why not update your registration to indicate where you are from. Just possibly, a more seasoned forum/Excal member might live close by who might be able to assist you or assure you what you are hearing is not an issue!

...welcome to the forum!

Anthony