Strike Industries has launched new compact AR-15 receiver extensions that are designed for AR pistol builds. These are extremely short buffer tubes that are still compatible with mil-spec AR-15 lower receivers and bolt carrier groups. I think it is safe to say that such a short receiver extension is one of the most if not the most valuable part for a pistol build if you want it to be as compact as possible.
As shown in the video embedded below, despite being about two inches shorter than the standard carbine length receiver extension, this new SI buffer tube is still compatible with the mil-spec bolt carrier groups. This is achieved by having a very short tungsten filled buffer and a flat wire recoil spring of an increased spring tension.
The Strike Industries short buffer tube is machined out of 7075-T6 aluminum and has an anodized finish available in one of the following color options: black, FDE, red and blue. The rear portion of this buffer tube has a QD sling socket milled into it. This receiver extension is compatible with the majority of stabilizing braces available on the market and it will also be compatible with the upcoming Strike Industries Viper Pistol Stabilizer.
This new receiver extension set will work with standard AR-15 lower receivers, end plates, and castle nuts. It also features an anti-rotation extension that aligns and locks it over the buffer retaining plunger. The overall length of this new SI buffer tube is 5.28″. The diameter of the tube is 1.145″ and it weighs 3.8 oz. The buffer weighs 1.8 oz. This receiver extension comes as a set that includes the buffer tube itself, the buffer and the spring.
Images from www.strikeindustries.com