Rifle upper on a carbine lower

[runningbear]

I have a KAC MOD 2 carbine, and I have a 20 inch Compass Lake Engineering upper coming. In a perfect world, I would love to just slap the new upper on and head to the range. Am I going to run into any trouble? Will the current buffer and spring work, or will I have to change anything out? I've been trying to reach KAC for 3 days via phone calls and email, but so far, no response. So I have already tried them first before posting here.
Thanks!

 

[DP425]

I have a KAC MOD 2 carbine, and I have a 20 inch Compass Lake Engineering upper coming. In a perfect world, I would love to just slap the new upper on and head to the range. Am I going to run into any trouble? Will the current buffer and spring work, or will I have to change anything out? I've been trying to reach KAC for 3 days via phone calls and email, but so far, no response. So I have already tried them first before posting here.
Thanks!

You should be fine. That isn't always the case, but 999 out of 1000 it is.

 

[Downtown]

Yeah, you're probably fine. I have a eighteen inch barrel with rifle gas system on a carbine lower with no issues. You'll find out quickly if your bolt speed is to fast. Won't pick up a round, depending on your mag spring strength. Either way, no harm done.

 

[2ndamendfan]

Spring and buffer have more to do with which buffer tube and hence which stock is on the gun. You should be just fine.

 

[Rerun7]

Nah man, that junk is gonna blow up if you do that. I wouldn't do it. : )

j/k it will run just fine. If you find that you have any cycling issues you can grab a heavier buffer and probably straighten it right out.

lowers are lowers so there is no difference there. Buffer weights and spring tensions have to do with gas pressures, dwell time, cycling, etc. I run heavy buffers in my carbines and precision rigs and would reco them.

 

[longshot2000]

Some of the KAC "carbines" use a rifle length gas tube in the first place. Generally less recoil with a longer (rifle) gas port

 

[101stinfantry]

Your good, I'm running a carbine lower w/ H2 buffer, and a flat-top 20" rifle upper.

 

[Sierra770]

I have this set up on several rifles. It is a smooth shooting combination in my opinion. I have run them with carbine, h1, and h2 without an issue.