F1 Engineering Billit Lower Receiver
While working on prototypes for a sub-contractor on the U.S. Joint Service Small Arms Program, specifically the Lightweight Small Arms Technology Program (LSAT) we needed to cut a magwell to extremely tight tolerances for the future caseless ammunition.
Broaching the magwell was not an option with the material we were using, as was using wire EDM, the two methods used by the industry for cutting magwells.
Our design staff came up with an inovative solution to the problem, ran the design through stress analysis software, and made a few prototypes in the machine shop. An M16 test rifle was assembled with one of the prototype lower receivers made for conventional brass cased ammunition and taken to the test range. It performed flawlessly through 3000 plus rounds of M855A1 5.56 x 45 NATO ammunition.
The new design consisted of basically cutting the side off the magwell, machining the cavity to the tight tolerances required by our customer, then machining a cover plate to bolt to the side of the open magwell.
Our customer approved the design, and prototypes for use in further testing of caseless and polymer case ammunition were manufactured and shipped ahead of schedule.
One big advantage to the design is that different cover plates could be made to incorporate data aquisition and test electronics as well as round counters, lockout devices and other accessories.
We decided to patent the design and, after submitting a prototype of the AR15 platform to the Bureau of Alcohol, Tobacco, Firearms and Explosives (BATF) for approval we are now able to offer the lower receivers for sale to the general public. The side cover is supplied in a standard ribbed design or as an optiona a picattiny rail is machined into the cover.
When Eugine Stoner first designed the M16 in the early 60's the strongest aluminum alloy available for forging was 7075, since then of course many improved high strength alloys have been introduced.
With our extensive background in professional motorsports and in aerospace machining we have aquired a large knowlegbase of materials and for this application, although slightly more expensive than the traditional 7075 we decided to go with alloy 2024 billet bar stock in the T851 condition. Used extensively for aircraft landing gear and for race car suspension and engine components this alloy is stronger and is less prone to stress cracking than the alloys used by other receiver manufacturers.
All receivers are glass bead blasted to Mil Spec. to relieve machining stresses, give a uniform finish and to reduce glare.
We offer the lower receivers in two calibers, .223 / 5.56 x 45 mm and .308 Winchester / 7.62 x 51 mm as well as "80%" models of both for those who wish to finish their own rifle.
The .223 and .308 finished receivers are available in standard bead blast finish or in hard type 3 black anodize at no extra cost, we also offer all lowers in a Cerakote color ceramic finish for extra cost.
The "80%" lowers are also available in the bead blast finish, type 3 hard anodize black or in the optional Cerakote colors.
The lower receivers all come with the standard ribbed mag well cover and all special screws and keys. The optional cover featuring a picatinny rail is available for all models
|Item||Available In Store|
|Model||F1556 5.56X45MM MULTI|