The .510 Whisper (13×47mm) is the second of two .50 in (13 mm) rounds developed by J. D. Jones with a specific focus on the Thumper concept and subsonic use.
Earlier J. D. Jones had already developed the similar .500 Whisper round, which has a roughly .4 in (10 mm) longer belted bottlenecked case based on the .378 Weatherby Magnum.
Despite the large bullet, this round is very quiet when using a suppressor due to the subsonic nature of the cartridge.
[4] Sako TRG-S test rifles have achieved minute of angle, and better, accuracy with this cartridge at 600 yd (550 m).
The Thompson Center Encore is also suitable, but is rather lightweight for shooting this heavy recoiling cartridge, especially when using 950 gr (62 g) bullets.