LSS-XL chassis System

Availability: In stock

Increase accuracy and ergonomics with our LSS-XL chassis system. The LSS-XL is a longer version of our LSS chassis system. The forend has been extended by 3", and is designed to take fixed buttstocks without the need of an adapter.

The LSS-XL allows you to convert your bolt action rifle to a highly versatile rifle allowing you to adjust the ergonomics with the use of AR-15 buttstocks and grips, and at the same time converting it to an external box magazine fed rifle.

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From: CA$499.00
Product Description


LSS V-shaped beddingCut view of chassis showing flat spots where the action touches the chassis.

The LSS-XL chassis system is a variant of our highly popular LSS chassis. The LSS chassis was designed for compact use, short barrelled rifles. A lot of customers liked the LSS chassis, but wanted to use a fixed buttstock, and use it with longer barrel systems.

This prompted us to design the LSS-XL chassis system which has a forend extended by 3" and is designed to accept fixed rifle stocks without the need of using any adapters. Also, the Length of Pull (LOP) is 1" shorter than the standard LSS, as fixed rifle stocks generally are longer than collapsible.

The chassis is designed with v-shaped bedding, allowing you to drop your rifle right in without the need for additional bedding. The bottom of the action housing has been kept round and close to the action without touching keeping maximum strength. The LSS-XL chassis will free float most factory heavy barrels.

Recoil lug area allows for thicker lugs.

Important Notes:

Using our Skeleton Rifle Stock V3 - We do not recommend using our Skeleton Rifle Stock V3 on the LSS-XL. It will work on our LSS using the fixed stock adapter. But on the LSS-XL with a shorter Length of Pull, the cheek riser will be in the way of the bolt. (it does work on some actions if the cheek riser is raised). But please check our Skeleton Rifle Stock Light, which was designed specifically for this chassis!

Please note important action specific information at the bottom of this page.

Mounting and Compatible Accessories

The LSS chassis is designed to accept any AR-15 buttstock and pistol grip (purchased separately), offering the option to customize from the wide variety of  Accessories available on the market.

The LSS chassis uses external box style magazines in .223 and .308 caliber for Short Action and .300WM or .338LM magazines for Long Action rifles, and supports the installation of bolt on MIL-STN-1913 accessory mounting rails. Mounting holes are spaced for Magpul style L5 (11 slots) and L3 (7 slots) rails (1.600” / 3.200”) to be used on the bottom of the forend up to 6.5" in length.

Note: Long action magazines come in 3 different lengths: 3.715", 3.775" and 3.850". Our chassis use 3.715 length magazines.

The max thickness of recoil lug we recommend is .350" (8.9mm)


  • Increases accuracy by up to 21%
  • CNC Machined from 6061 Aluminum
  • Cerakote Finish in Black or Flat Dark Earth
  • Hole spacing for Magpul L5(11slot) and L3(7slot)Rails
  • Designed for fixed AR-15 buttstocks, including Skeleton Rifle Stock V3
  • Accepts most AR-15 Pistol Grips
  • Lightweight, free-floating modular forend
  • Will accommodate barrels up to 1" diameter.
  • Compatible with AICS style magazines in .223 or .308 (SA) and 300WM, 30.06, (Long Action Magazine length 3.715)
  • Weight: 1.8lb - 2.1lb

What you get, and what you need

The LSS-XL chassis system comes as a 1-piece chassis, with all required mounting hardware included. This includes new action screws, nd a screw for the pistol grip.

To complete this chassis on your rifle, the additional items you need to purchase are:

  • Any AR-15 buttstock. (Fixed stocks are best suited. For Collapsible stocks consider our LSS Chassis)
  • A buffer tube for your buttstock. (Both mil-spec and commercial work on our chassis)
  • An AR-15 Pistol Grip. Ideally without a beavertail, or use a soft (bendable) beavertail.
  • At least one magazine

Please also see our HS3 Chassis System.

Important Notes

Howa 1500 / Weatherby Vanguard actions
Only our polymer magazines will work in the short action rifles with minor fitting sometimes required. The long action rifles will work with the metal 3.715" magazines without fitting. 
For .223 models the bolt stop may be too long. This can easily be modified.

Savage models 10/110 11/111 12/112 16/116
For rifles with the bolt release at the bottom, the bolt release can be engaged through the side of the chassis, using a pin or tool. (Not included)

Savage Long Action in 338 Lapua Magnum
Savage Long Action chassis systems all use 3.715" AICS magazine wells. The BA in 338 Lapua Magnum uses 3.850" magazines and have recently switched to a thicker recoil lug which will not fit our chassis. We will be releasing a version of the ESS in mid- 2017 which will be specifically designed around the current BA 110 in 338 Lapua Magnum. 

Tikka T3 - Long Calibers
Only our Metal 3.56 magazine will fit with the chassis for this action and needs to be purchased separately.


Dimensions shown are based on a Remington 700 Short Action.
The length of Pull can be increased by 1" using a Magpul PRS or similar buttstock.

LSS-XL Dimensions

Product Reviews

Customer Reviews 7 item(s)

Impressive fit, improved shooting ergonomics and accuracy
Bought the LSS-XL for my Savage 308 FCP-SR with a 24" barrel. Perfect fit, the longer barrel definitely warrants the longer chassis for balance.
Very easy install, but with one wrinkle:
On this particular rifle, the hole for the action screw is tapped all the way through the action and comes out under the bolt in the chamber mouth. The screw supplied with the chassis was a touch too long and protruded enough to obstruct the bolt from closing. Not a biggie, 3 minutes on a belt sander to take down 3 mm from the screw length and the problem was fixed.
In combination with the adjustable MDT fixed stock, I find that the ergonomics of "getting behind the rifle" are much better than the factory stock. I shot about 80 rounds with the new setup, and I am still not sure that I have it dialed in quite right - but the options for adjustment are there, it just needs time and attention. Did not notice dramatic improvement on my 100 m grouping, but it is noticeable at 200 m - when I do my part of the job. I'm now able to keep sub-MOA with more consistency.
This is an issue which MDT warns you about ahead of time, the cleaning rod will not fit past the fixed butt stock (unless you remove the cheek riser, or the whole stock). I am now ordering the folding stock adapter which will be an elegant solution for this problem.

Overall, I'm very happy with this purchase, it was a great upgrade for my rifle.
Review by Milan / (Posted on 5/29/2017)
Outstanding products and quality.
I put my Savage 12 6.5 Creedmoor short action in the LSS XL. In the factory stock it held a respectable.5 moa. With the LSS XL it's below .25 moa. Totally pleased. I then ordered a HS3 and am preparing to order an ESS. Keep up the good work and innovation. mDT.
Review by Randy / (Posted on 3/19/2017)
A+ Stock 5 minute install and go shoot, this chassis closed up my groups right out of the gate. I'm very pleased to point I bought two of them. Can't go wrong with this chassis, excellent quality, staff is very knowledgeable and answered all my quesitons.
Review by Don / (Posted on 9/3/2016)
Good stock, good value.
This is a very nicely finished and well thought out Chassis. There are, however a few small problems. First is the hand position, it seems that because the Chassis uses the stock trigger and an AR grip the hand is significantly lower relative to the trigger than on an AR. this is somewhat unsettling as one slips into position to shoot and ones trigger finger is too low on the trigger. Secondly, again compared to an AR the stocks are somewhat low in the comb. I installed a Luth -AR stock and adjusted the comb up to give me a good view of the reticle.

Despite the two small quibbles above, I very much like this stock, it is a huge improvement over the plastic stock that came on my Savage.
Review by Steven / (Posted on 8/29/2016)
Execellent Products
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.
Review by tackdriverX / (Posted on 3/30/2016)
Great chassis
Great chassis, fit on my Savage 11 without any issues, very light and durable, I will buy again.
Review by Dante / (Posted on 2/29/2016)
Great chassis for Savage LA
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 proffesshional. 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.
Review by russell / (Posted on 2/20/2016)
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