Huh, I thought they all came with one since the TM 4.3, 1911, and MEU models all have them I assumed it would be the same for the 5.1, but it seems like they included them in every model
except the 5.1. Nevertheless, having a recoil buffer would help take the impact off certain parts of the gun, so if you can pick up the
AS recoil buffers your gun will like you more.
Try lubricating all the contact points of your slide catch. Check to see if the firing pins are smooth and bouncy too and if they're not, try lubricating that as well. I know I sound like a newbie who slops lube on everything, but give it a try. You can always wipe it off if it bugs you.