13.7 barrel and KAC QDC CQB suppressor / handguard fitment

[Jwknutson17]

So I picked up a Noveske 13.7 Infidel barrel and sent it of to Mr. Pitts for a dimple job. I plan on running the longest handguard possible with my new KAC QDC CQB can. What Im looking for is the longest possible handguard to fit the can. I know my MK18 with M42000 is about as close as it gets. 9.55 rail on 10.3 barrel. This is exactly .75 inch difference. Im assuming that the longest I should run is a 13 geissele or something alike. I found this.. http://www.avguns.com/components/uppers/KAC-sr15-e3-mod1-135-upper-receiver.html and was thinking WTF. 13.5 KAC URX 3.1 on a 13.7 barrel with a AAC 51T??? So something is not correct. Maybe a large spacer/shim to make it fit. Not going that route. That's for sure.. But If it would be possible to run a URX 3.1 on the 13.7 barrel, and still run the KAC can, I would go that route. Not interested in a shorter then 13 inch rail really. If anyone knows any clearance specs with the KAC before I went and bought a handguard that would be appreciated. I know I could run one of my surefire cans on the 13 inch rail with 13.7 barrel, but not going to buy a new SMR if its not gunna work. After a 4 month Form 3 wait, the can is finally headed my way.

Also, has anyone else run a can on a 13.7 mid-length gas system rifle? Have plenty of 14.5 mids, but curious what this 13.7 is going to be like.. Cant find much info on the net. If this is already covered somewhere, please send me the link.

Thanks in advance.

[tom12.7]

A rifle length URX3.0 works fine on a 13.7. Only a smallish gap remains. Those barrels are gassed pretty hard, I prefer to cut down the longer Noveske mid barrels and cut them down to 13.3-.4" or so to use a smaller port and close the gap down.

[sua175]

I know that with a surefire can a geissele 13 in rail on a 13.7 should work. I have a 14.1-14.2 in barrel and a urx 3.1 and a surefire can clears it. There isn't a lot of room but it clears. Just make sure to measure your barrel when it comes back to make sure it is exactly 13.7 because I know if you have less than half and inch of clearance it probably will not mount. That link you sent is interesting, not sure it that combo is made for suppressed use though. What can are you running and this 13.7 gun?

[tom12.7]

I'm pretty sure the above link is a 14.5". I think 13.5" was a typo.

[Jwknutson17]

I'm pretty sure the above link is a 14.5". I think 13.5" was a typo.

Thanks. Yea something seemed a little off with the numbers. I kinda figured it would have a larger gas port.. but are we talking needing a adjustable gas block big? Like my grossly overgassed Mk18? :(

[tom12.7]

It's not grossly over gassed, but you may not like the results with a can. For me personally, on a factory Noveske 13.7" mid, I would run a good adjustable gas block.

[Jwknutson17]

It's not grossly over gassed, but you may not like the results with a can. For me personally, on a factory Noveske 13.7" mid, I would run a good adjustable gas block.

Thanks for the advice. I have a SLR adjustable gas block on one of my SBRs and have had really good results so far. Looks like another one, or the Syrac, will be on the list. Thanks again.