LIMA SIX Belt Fed Upper Receiver / A5 buffer system included

***READ LEAD TIME DISCLAIMERS AND SHIPPING RESTRICTIONS BELOW BEFORE PURCHASE***

Why we like these:

Well, we didn't see this coming.  But these things are undeniably badass.  We got a chance to meet these dudes at Shot Show 2026, and after shooting this thing in the desert we were sold.  So when we got the opportunity to become a dealer for them, the answer was an unequivocal "why the hell not?"

These things are built extremely solid.  They have adjustment points to tighten everything down so there's no wobble, and with the included A5 buffer system they shoot impressively flat.  We're talking tight groups at 300+ yards with controlled bursts.  Pair these with an FRT, or put it on a full auto lower and you have an easy way to empty your bank account.

Official Description From LIMA SIX:

The Lima Six is a game-changing upper receiver that installs on any mil-spec AR15 or M16 lower receiver and provides belt fed capability. While a few parts must be swapped on the lower receiver, no permanent modifications or gunsmithing is required. Please read the entire product description for important technical information before ordering.

The Lima Six belt fed upper receiver WILL NOT FUNCTION with a standard AR15 buffer setup. This is because the Lima Six has a stretched upper receiver, which requires more room in the buffer tube to cycle. There are two options for buffer configurations that work:

1. A shorter buffer (AR10 length, 2.5″ long) in a standard 7″ carbine length tube (SEMI AUTO ONLY)
2. A standard buffer (AR15 length, 3.125″ long) in a longer A5 7.75″ length tube (required for full auto) *INCLUDED IN THIS KIT FROM PANTHER CITY TACTICAL*

The Lima Six features a patent-pending stretched upper receiver, which provides an additional ~3/4″ of bolt carrier group travel compared to a standard AR15. This is a critical improvement for a belt fed firearm, as this additional travel assists in delinking rounds from the links. It also results in lower perceived recoil, and a more controllable rate of fire. No other belt fed AR15 on the market has this upgrade!

Additionally, the Lima Six features a top cover unlike any other belt fed top cover available, with a tensionable front pivot, two-point latch engagement, and an adjustable set-screw to take up any slack that may be present. These features result in an extremely reliable ability to hold zero even after repeated opening and closing. Initial testing shows that sub 2-MOA accuracy is achievable, which is unheard of for a belt fed firearm.

The Lima Six is compatible with standard AR15 barrels, although certain considerations need to be considered before swapping barrels. Please refer to the technical information section of our discussion forum for complete information regarding barrel swaps.

Includes:

• Complete Receiver
• Bolt Catch
• Buffer Spacer
• Recoil Spring

• A5 buffer system upgrade with A5 Buffer Tube, Sprinco Orange spring, H3 Buffer

Specifications:

• 5.56X45mm NATO
• 7075-T6 Upper Receiver and Top Cover, Type III Hardcoat Anodized
• 18” Chrome Lined Chrome Moly Vanadium Heavy Barrel
• Midlength Gas System (Direct Impingment)
• Midwest Industries 10” T-Series Combat Quad Rail
• Billet Machined Hardened 17-4PH Feed Tray
• K-Spec bolt with Dual Ejectors
• 8620 Bolt Carrier, Full Auto Cut
• Tool Steel Belt Feed Components
• Billet Machined Aluminum Charging Handle
• Threaded ½-28 with A2 Flash Hider

LEAD TIME DISCLAIMER, OTHER NOTES, and SHIPPING RESTRICTIONS:

LEAD TIME:

These will only show 'In Stock' so that you can place an order.  We DO NOT HAVE THESE ON HAND.  This is the ONLY product we carry on our site that has a lead time and requires payment up front.  PLEASE BE AWARE THAT THESE MAY NOT SHIP OUT FOR AT LEAST 8-16 WEEKS!  When you place your order, we are then placing the order with LIMA SIX.  They will send it to us, and we will send it out to you.

*If you would like to order other products from our site and want them shipped immediately, please place a separate order.  Otherwise they will be shipped at the same time as the LIMA SIX.

A5 Buffer System

We are automatically adding the A5 upgrade kit to all LIMA SIX orders.  This is not a normal A5 kit, as it runs a standard AR15 buffer and a different spring.  The fine folks at LIMA SIX have determined that this setup is the best option for running their uppers reliably in FRT or full auto, and we want our customers to have a good experience.

****Shipping Restrictions Policy****

This is the shipping policy set by Lima Six, and we will be implementing the same policy for this product.  This is mostly copied/pasted from the L6 website, with a few small edits.

Panther City Tactical ships belt-fed upper receivers for AR-15s to customers within the United States, subject to the following restrictions. It is your responsibility to ensure compliance with all federal, state, and local laws regarding the purchase, possession, and use of our Products.

• Prohibited Jurisdictions: We do not ship Lima Six complete belt-fed upper receivers or build kits to the following states and jurisdictions, where semi-automatic firearms with belt-fed ammunition systems are completely banned or pose significant compliance challenges due to magazine capacity or assault weapon laws:
  • Washington DC
  • Washington State
  • Illinois
  • Massachusetts
  • Puerto Rico
  • Connecticut
  • Delaware
  • New York
• Restricted Jurisdictions: In certain states, there are restrictions on what we can ship. Buyers must assemble build kits into a compliant configuration (e.g., a featureless rifle with no pistol grip, folding stock, or flash suppressor, and a belt or magazine not exceeding state capacity limits). Buyers are solely responsible for verifying compliance with all applicable state and local laws, consulting a local Federal Firearms Licensee (FFL) or attorney if needed, and acknowledging that Control Dynamics Corporation is not responsible for ensuring compliance.
  • California: After purchasing a build kit or complete upper receiver, we will email the purchaser requesting a copy of their drivers license. Address on the license MUST match the shipping address on the order. Purchaser must also electronically sign acknowledgment of AB 1263.
  • Colorado: Buyer must certify compliance with local laws during checkout process. No sales to Boulder County, Vail City, or Denver. 
  • New Jersey: We can ship parts kits direct to your door. Complete uppers must ship to an FFL who is willing to pin/weld a muzzle brake (not included).
  • Rhode Island: Buyer must certify compliance with local laws during checkout process.
  • Virginia: Buyer must certify compliance with local laws during checkout process.
• Permitted States: Lima Six complete belt-fed upper receivers and build kits may be shipped to the following states without specific restrictions on semi-automatic belt-fed firearms, provided buyers comply with federal age requirements (18 per our Terms) and other applicable laws:
  • Alabama, Alaska, Arizona, Arkansas, Florida, Georgia, Hawaii, Idaho, Indiana, Iowa, Kansas, Kentucky, Louisiana, Maine, Maryland, Michigan, Minnesota, Mississippi, Missouri, Montana, Nebraska, Nevada, New Hampshire, New Mexico, North Carolina, North Dakota, Ohio, Oklahoma, Oregon, Pennsylvania, South Carolina, South Dakota, Tennessee, Texas, Utah, West Virginia, Wisconsin, Wyoming, Vermont