In the past few years, we have covered plenty of neat VR controllers here. This Magnetic Rifle Gunstock for Oculus VR platform is also worth a look. It combines with your VR controllers to help you aim better. It has a large magnet for your dominant hand and a smaller one for reloading with 90lbs and 60lbs pull force respectively.
This kit snaps on the controllers without any additional tools. You can order yours on Etsy.