The HK51? Close, but no. Take a look at the PTR PDWR in this video by Administrative Results... "The HK51 is a legendary compact firearm that traces its roots back to Heckler & Koch’s G3 rifle platform. By drastically shortening the barrel and overall length, the HK51 was designed to provide devastating firepower in a much smaller, more maneuverable form. Its compact nature made it ideal for close-quarters combat, but the trade-off was extreme recoil and muzzle blast, making it difficult to control in rapid fire. The HK51 became infamous for its raw power, offering a formidable presence in the hands of those trained to handle it.

The PTR PDWR is a modernized version of this concept, produced by PTR Industries, known for their faithful reproductions of classic roller-delayed blowback firearms. With the PDWR, PTR has managed to maintain the compactness and power associated with the HK51, while incorporating improvements in ergonomics, reliability, and overall handling. The result is a more refined weapon that offers greater control and usability, making it suitable for modern tactical scenarios where close-quarters mobility and firepower are essential."