MDT LSS-XL Chassis

  After winning a Savage 11 at a raffle, I was looking around at what I could do to it. I started looking at chassis for it and ran across Modular Driven Technologies (MDT for short). I contacted them and they said they would send me a chassis for review. They sent me the LSS-XL, their new lightweight stock, and one of their AICS pattern magazines

  The LSS-XL is an all aluminum chassis that can use AR stocks and pistol grips. It comes either cerakoted black or FDE. It can use their stock also, which I'll talk about later. Since the chassis they sent me was for a Savage, I'll talk about it, but all of the LSS-XL's are basically similar. The first thing I noticed was the nice sized paddle magazine release. It has good spring pressure and is easily accessed to remove a used magazine. I also noted that it came with a sling swivel stud mounted, perfect to attach a bi-pod on. Next up is the trigger guard that has enough room for gloved hands, but is could be larger.  The stated weight is 1.8-2.1 lbs, which is just the chassis without a stock or pistol grip. My scale broke, so I am taking the weight off of the MDT website. Now the LSS-XL has a longer forearm than the LSS, but it is about the same length as the stock forearm. Even though the chassis is about the same length as the factory stock, it is much thinner and is flat on the bottom and sides. It also has plenty of mounting holes on it. These holes are spaced to fit Magpul L3 or L5 rails. Of course MDT makes rails to fit also. On the Savage style chassis, it has a slot in the side above the trigger. This slot is for Savage actions with a bottom bolt release. After installing the LSS-XL, to remove the bolt, you have to now put a pin, nail, screwdriver, or whatever in this slot and move it rearward to remove the guns bolt. The chassis also comes with a little spacer washer, that you install on the front bolt, depending on which action length you have. Older Savage's have a slightly different bolt spacing on the action than the newer versions. Using a rounded inlet with flat spots, for the action to ride on, this design is said to aid in accuracy and strength. Along with this system, the chassis can accept barrels up to 1" diameter while still free floating the barrel. 

  One of the great advantages to the MDT LSS-XL is it ability to accept the AICS style magazines. The stock magazines that come with the Savage are junk compared to the MDT magazine. MDT's magazine is polymer and holds 8 rounds of .308, .243, .22-250, or 6.5 Creedmoor. They also make a magazine for the smaller .223 rifles. My rifle is in .243 winchester, and the magazine function was flawless. I am also able to get 9 rounds in the magazine and still have it function. Being that the LSS-XL uses the AICS pattern, I also tried a Magpul 5 round AICS magazine. It did not lock in place at first. I modified it slightly by removing some plastic in front of the feed lips and now it works also. Basically I made it look like the MDT magazine. 

  Along with the chassis, MDT also sent their "Skeleton Rifle Stock Lite." This stock is meant to compliment the chassis, and it does a decent job of it. The stock is adjustable for length of pull and cheek weld. Now it does not have infinitely adjustable screws, instead it has notches in the riser and buttplate mounting stems. The buttplate and riser are moved by pushing an elongated button, and then moving them to the desired adjustment. I really liked this button system as it was easy to use, and held the plates in firmly. MDT also makes the stock out of aluminum and it is cerakoted to match the chassis. Another nice touch on the stock is its ability to accept mounting rails like the chassis. This makes it possible to install a monopod or such device under the stock. As with most stocks these days, there are also built in sling swivel cups. One problem I had with the lite rifle stock was the rear but pad and cheek riser get in the way of cleaning your rifle. Even if you take the cheek riser off, the design makes it impossible to run a cleaning rod straight through the rear of the rifles bore. If you want to do this, you must actually remove the stock completely. I did not have the same problem when using a standard AR stock. 

  There are a couple of items to note. The stock's length of pull was too short for me even when the buttplate was fully extended. And there is no radius where the top of the grip meets the stock. AR grips with beavertails don't really work. So it kind of pinches your hand between your thumb and forefinger. I noticed it more with a collapsible AR stock. The MDT stock was way less noticeable. 

  The MDT LSS-XL chassis, Skeleton rifle stock lite, and magazine make for a really nice stable shooting platform. MDT offers these chassis for lots of different rifles, and all of them at a very reasonable prices (for a chassis system). 

Firearms Insider Reviews - 8 Key Points

Claim to Fame:

Lightweight chassis system. Uses AR parts

Target Market:

Precision rifle shooters, varmint hunters, or anyone wanting a stable shooting platform.  

FNBs (Features & Benefits of this product):

  • Drop in chassis

  • All aluminum

  • Cerakoted

  • Improves accuracy

  • Free floats barrels up to 1" in diameter

  • Weighs about 2lbs

  • Uses AR-15 stocks and pistol grips

  • No Bedding needed

  • Uses AICS magazines

  • SRS Lite stock is adjustable for length of pull and cheek weld

What other aesthetic options or finishes are available?

Flat Dark Earth

What others are saying?:


LSS-XL for Savage Long Action: This is a great chassis system. Form, fit, and function ate all very nice. The chassis is very light so for the heavy recoiling calibers, it is something to consider. The machining is done very well. Cuts are precise and the finish is very uniform and professional. My rifle is sub MOA with this chassis and I think it will drastically improve as I get more comfortable with the setup. I always shoot from prone so taking me out of the equation to eval the chassis can be difficult. My rifle comes in at 14.5lbs w/ Leupy Mark 4 16x, Leupy steel rings, steel one piece base, 26" bull barrel 300WM, bipod and MagPul MOE stock. Great chassis at almost half the cost of many others.


The products were high quality and my R700BDL 6mm Rem fit like a glove. Very easy and quick installation. I am considering also getting the LSS-XL for my Savage 12 Low profile.

Price point:

MSRP = $499 for the LSS-XL

$279.99 for the SRS Lite stock

$39.99 for the Magazine

Retail = $499 @ Tactical Works

$279.99 @Tactical Works for the SRS Lite stock

$39.99 @ Brownells for the Magazine

I need it now! Availability:

Modular Driven Technologies

Our Rating:


  • Very cost effective

  • Models available for many different rifles

  • Uses AR-15 stocks and pistol grips

  • Lightweight

  • Uses AICS magazines

  • MDT magazine works well

  • Swivel stud pre-installed

  • Sling swivel cups in stock

  • Push button adjustment on stock

  • Large trigger guard


  • Small fore-end

  • Slight pinching of hand

  • Short length of pull with SRS Lite stock

  • Can't clean bore without removing SRS Lite stock

Score: 8.0 GREAT!


Chad's Favorite Link: U.S. Tactical Supply