I have a 14.5" that I am setting up as a dedicated NV rifle. I see most using red dots with their rifles, how many of you guys use a LPVO?
Pros and Cons, btw I have both on a lot of different rifles and usually dedicate all my red dots to my SBR's.

Would love to see pics also.

No other opinions

I use mine with a clip on, I've always felt a little leary weapon mounting my 14's, just me.  I have held my 14 up behind a nv compatible red dot though for s&g's...it didn't look very good.  I've got the kid this weekend, maybe I can try to get some thru the tube pics for ya of both. Maybe a dedicated night scope for a true dedicated night rifle?

Holding the MNVD behind the dot sight does not give you a clear idea of what the image resembles while using a decent weapons mount.

I sometimes run passive behind an EOTech. Part of the time I use a HIGH QUALITY 2X telephoto on the MNVD. I get decent results. The MNVD does not generally see very well through a magnified optic.

The PVS-4 works very well as a weapon mounted optic. The 95mm objective nullifies the Gen 2 deficiencies pretty well.

Passive use is for slow, precision work. Keep that in mind. An IR laser in conjunction with a helmet mounted MNVD is WAY faster for close work, though it fails in accuracy at distance.

The OP's question is too general and most of us probably can't make heads or tails of what he wants to accomplish. There is no single Best Night Gun Configuration for across the course use.

OP: What do you actually want to do with the carbine once it is built?

I realized I was a little to vague in the OP.
I was referring to a LPVO on the carbine with laser and helmet mounted NODs, I don't see that combination as much as I see red dots.
I just wanted to know if it was all personal preference of Red dot over lpvo, or was it a weight issue since you already have a laser bulking the gun down.

In my own experience, the laser/carbine is a shoot and scoot gun that provides decent relative accuracy. The red dot sight is a natural corollary for daytime use (fast and relatively accurate) and can be used in conjunction with the MNVD if needed. I use a great big 55mm belled 2X telephoto that gathers a lot of light and maintains the resolution of my MNVD when I mount it behind the EOTech. I have found resolution and light loss issues mounting the MNVD behind variable power scopes (or any magnification for that matter).

There is nothing wrong with configuring otherwise, it's just not as natural of a progression. It always feels like I am taking two steps backwards whenever I am trying to improve on what already works pretty well across the board.

I have an 18" gun with a nice Lothar Walter barrel that I configure with a fixed 4X scope for daytime. I pull the scope off of that gun and swap a PVS-4 for night use. That gun is a bit of a pig but it drives nails both day and night so it's a matched set also.

Does this answer anything?

Yes it answered some questions.

A LPVO would be useless in a no light scenario unless you used a very expensive clip on and even then it will mainly be useful as a hunting rig or for over watch position.

OP: Do you have any NV in hand? What are you trying to accomplish? A high speed carbine or a DMR?

If you have something like a PVS-14 then you can link it behind your variable optic with radiator hose to get a feel for what the image degradation will be like. It's not the best mount but it will give you an accurate idea.

Once you decide what you want to do the answers become more apparent.

Determine the need - then fill it.

Yes I have NV
My NV is helmet mounted and I will not be mounting it on the gun
I'm have a 14.5" carbine that I'm setting up with a laser
I was going to use a LPVO on it for my optic, but I see most people using red dots. I was just curious how come I don't see more LPVO on carbines when people use NODs.

This is were the rubber hits the road.

If you run a dot then there is usually enough room behind it to run a PVS-14 passive when needed. This is handy for zeroing a laser and also for validating  zero even if you never shoot with the MNVD weapon mounted.

Dots are decent Bindon Concept aiming references if you have a laser failure.

Dots are good aiming references if you are doing NV to white light dynamic transitions.

The primary concept is in keeping the nature of the gun constant through different light levels - fast through a complicated environment with the dot in the daytime, fast through a complicated environment with the laser and NV in the dark, fast through a complicated environment with the red dot and white light in transitions.

If I felt the need for the LPVO it would be in the DMR role and I would put a clip-on in front of it. If I needed to run an LPVO for dynamic white light transitions then I would consider capping the objective and running it Bindon style so I didn't spend excessive time trying to align the target and reticle.

Thank so that was the type of answer I was wanting.
I haven't shot with my NV yet, still waiting on a laser.

Prepare for blasphemy...

I recommend airsoft for MNVD training because of the safety factor. I like to be a master of an activity before I add deadly force to the mix. I don't like to be too reliant on any single piece of gear and that includes the laser. I can still shoot Bindon if the laser goes down and I can still shoot index if the laser AND the dot goes down. There is a degradation in the quality of hits but there is also still some level of maintained competency. Airsoft will let you experiment with all of this in relative safety until you are competent to shoot 5.56mm in the dark.

Blasphemy complete.

If you can't get access to the airsoft gear then you can still train for index shooting in the daytime. You should be able to shoot like that anyways, NVD equipped or not. Do not shoot your carbine under NVD until you master your carbine under daylight.

A RDS can be used looking through your  PVS14/Binos or super imposed with a PVS14, which is something that can not be done with a LPVO.

It all depends on what the end user is trying to accomplish. Are they doing a range gun for running around punching paper and ringing steel or a hunting gun. Many guys who are doing a range gun mimic the military setups so that means RD and IR laser. When it comes to hunting setups it runs the entire gamut.
I have never been a fan of IR lasers for my hunting and rarely use them. While I have both NV and thermal I generally use the thermal to detect and the NV to shoot. One of my setups is a Vortex 1-4 and another is a Vortex 2-10, I will put the Knights PVS-26 out front, but I can also go with the FLIR T-50.