Not for ar10, but ar9 is ok - FM Products PCC Heavy Buffer w/.308 Carbine Recoil Spring

read this before you buy. description said ar9 and ar10....it will work with AR9 and not AR10 due to the length of the buffer. it is too long if you are using a carbine buffer tube. you need a shorty buffer for AR10 that is about 2.5 inch long.

if you are going to use this, you should try A5 buffer tube or rifle buffer tube