I have a Rock river 243 with a carbine stock and would like to change it out to a full length fixed stock. It presently has a short spring and a buffer that is shorter than a carbine buffer. What do I need to change it out to? Full length spring and full length non carbine buffer?
Or a full length buffer and a carbine spring? Thoughts?
I have used Clint@heavybuffers dot com anytime I needed advice like that.
Email him and he can tell you what you need.
With the AR-10 nothing seems to be standardized like the 15.
You need:
Rifle Length buffer spring
Rifle Length buffer
Rifle Length buffer tube and stock.
To remove a staked castle nut from your carbine length tube, it can be done with a standard spanner wrench as long as you have the receiver in a clamshell vice block, secured in a vice. If it's staked and you don't have access to a receiver vice block and vice, then you can carefully use a drill to remove the staking. If it isn't staked or if the stakes are light, or if you used a drill to remove the stakes, you can have a friend hold the receiver while you apply the spanner wrench to the castle nut.
After you remove the castle nut, be careful you don't lose the small detent spring and detent pin that is held in the lower receiver by the end plate. If you lose either or both, then your rear pivot pin will not stay captured in your lower receiver.
If you use your carbine length buffer and spring in a rifle length buffer tube, you risk the bolt carrier gas key damaging both the buffer tube and the threaded receiver ring the buffer tube is screwed into.
I'm not a gunsmith, I'm only an M4/M16 Armorer, but you can PM me if you have questions.