So Maybe

[Kegbelly]

I guess I misunderstood your speeds. That does change things a bit. There has been a lot of discussion about the 380 not being up to advertised speed but I thought that was with early models and the issue had been addressed. Interested to see what the other set of limbs do...

[paulaboutform]

Dan, if your Matrix 380 is getting 335fps with a 408gr arrow something is very wrong. As you know, a heavy string will rob speed, but not that much. Limbs have different deflection, but not that much. I was getting about 367fps with a 28 strand Force 10 string and a 387gr zombie. Even losing, let's say 20fps for lower deflection limbs and heavier string, you're still not in the ballpark. Perhaps your chrono isn't behaving? If that's not the case your M380 isn't performing as it should. Are you able to run a 350gr arrow through it with the factory string and a 1/4" brace height to see what speed you're getting? That'll tell you a lot....also shooting outside in overcast or with a light kit on your chrono from about 20" away from your chrono?

Paul

[xcaliber]

I can on the arrow, String nope, that is sold with other parts. I shot my 355 Micro same arrows, same day, etc. It's the bow for sure. I'm going to swap limbs when they arrive and go from there. Again I'm not terribly upset over this. I'm thinking it's the riser, or limb straps. The 355 Micro with arrow weight and 4 FPS subtracted for the Flemish String came in at 353 BTW.

[xcaliber]

Measured the entire rail length based on a suggestion from a very wise man. Now I'm stumped. I'm looking hard at the riser, and the gap under the limb straps. I wish to thank several guys for sending me messages on things to check, you guys have taken this on like it's your own bow, thanks a million. I also have learned a few things along the way, so that's a big plus too.

[url=https://postimg.org/image/c4xrfzab9/]

[RobD]

Well, the length of the rail matches my Matrix 380, so you've got the right rail. For reference, I took pictures of my 380 and my 350LE where the limbs attach. I know the 380 was sent in for replacement limbs somewhere late 2016 or early 2017 by the previous owner, not sure it received any of the "upgrades" like the new bolts or the redesigned/shaved riser.

Here are the two bows, the 350 is the one on the left (has Mossy on the limb). https://photos.app.goo.gl/XHrp2sT0R8b34uO92

In terms of speed, this is what my bows (not the 380, I did these when I had a 355) chronographed at with an 18" Diablo and 150gr fp, so about 400gr.
The Sapphire with Mike's 24-strand speed string did 277fps
The Matrix 355 with Mike's 36-strand durable string did 319fps
The Matrix 350 with the stock green string did 338fps
The Matrix 355 equipped with full Dr Stirrup kit (silences & stirrup) and 26-strand string did 322fps
The Matrix 350 (a stock bow) with the 26-strand string did 337fps

[xcaliber]

Thanks, good information. I think my issue is in the riser and possibly the limb straps. I have a plan to hopefully highlight the issue. I'm going to put my Matrix 330 limbs and riser on the 380 stock, and chronograph that. This will tell me right away where my issues are.
Thanks for the tips guys.
Don has been more than helpful!
Peter gets back next week from vacation, hopefully I have more to share with him to get this figured out.

[Kegbelly]

Dan, before you swap any parts out why not chrono a 350 grain arrow just to get a baseline and see where you're at. Just a thought.

[xcaliber]

John, honestly it's two bolts and I'm ready to shoot. i don't know if i have all the components to make a 350 grain arrow. I think the calculations for arrow weight will convince me enough to make the right decisions to speed her up. If i don't get to 380, using deductions, I'm not going to flip my lid. Trying to keep my stress level down at my age!
Thanks for the info. and concern. You guys have helped a lot, and offered great suggestions. I'll keep you guys posted as this progresses.

[janesy]

To get more accurate results, put your bag up level with the chrony. Shooting over a chrony at an angle like that increases the distance an object has to pass over the screens and then makes the chrony read slow. Not saying thats your issue at all. But certainly isn't helping.

[xcaliber]

Thanks.