View Full Version : Need help from someone with a Larue QD LT-104 mount

05-28-2009, 10:49 PM
Can someone with one of these mounts tell me what the distance is from the bottom of the scope tube to the top of the flattop?

Also, If I choose the 1inch rings option, are the rings actually different than the 30mm rings, or does larue use the 30mm>1in spacer rings they sell? I'm asking because I'm not sure if I want to use it with one of my 1in scopes or 30mm scopes, and if they just use the spacers I'll just get the 1in model.

Thanks in advance.

05-28-2009, 11:03 PM
They are NOT spacer. The base is the same, the rings assembly is different. I *think* if you call them up they will either switch or will sell you different ones when you need them.

I cannot tell you the distance, but if you tell me the obj size of your scope, I can tell u if they will work.

They are designed for the AR, so they do give you appropriate optic height, and the appropriate optic height for AR generally will clear the largest objective lens....

05-28-2009, 11:20 PM
Well the 1in scope is a 40mm and the 30mm is a big honking 56mm objective. I'm pretty sure even the 56mm will clear since larue sells my scope with the mount as a package.

I'm really just worried about getting proper head position/cheek weld. I'm running right now a YHM scope riser (which is kind of a POS IMHO) with short (i think) leupold QRWs for my 3-9x40. It still feels a bit low to me. The scope just barely clears my ARMS 40L which I believe is one of the shortest BUIS around. I really screwed up buying the short QRWs but got them for a killer deal I just couldn't pass up. I bought them during the phase where I was trying to build my AR relatively inexpensively, but since then have caught BRD and parts for my AR seem to keep landing at my door.

I've got a 5.5-22x 56mm NXS sitting around I might use, its just awefully heavy, but makes the 3-9x40 look like a POS.

05-29-2009, 7:45 AM
The goal with AR optics is to have the scope centerline at or a little above the iron sight height above the rail, which is 1.4". Some people like it even higher, but not many like it lower. This is way too high for traditional rifle rings, as you've found.

For the YHM adapter, which is 0.5" tall, you'll generally need high rings with about a 1" centerline. All ring makers have different heights, so you have to check.

The LT-104 centerline heights are 1.5” (30mm) and 1.41" (1"). To get the distance to the bottom of the ring, subtract 0.59 (30mm) or 0.5" (1").

As Jicko says, the ring assemblies are different, and LaRue will sell you an extra set of rings to convert from 1" to 30mm, or you can get the 30mm and a set of 1" adapters.

Several people make good ones, like GG&G:

05-29-2009, 12:18 PM
The goal with AR optics is to have the scope centerline at or a little above the iron sight height above the rail, which is 1.4".

This is so obvious I can't believe I didn't get it before. When I look at my AR (which still has the front sight) the scope centerline is nowhere near the level of the front sight.

...guess its time to go spend more money

05-29-2009, 12:22 PM
Get the Larue 30mm version, and use the NF.

If you want to try the 3-9x40 (which is quite suitable for the 223 caliber), just buy a 30mm->1" adapter..... ARMS, or badgers, there are many of them....

Or ask Larue how much is the extra set of rings.... at the end if u want to get rid of them... it is easier to sell the adapter than the Larue rings.... but, they are low cost items anyways.