AR Buffer questions

[JJ0341]

Picked up a Ruger SFAR today and wondered if anyone had any insight on the buffer spring it uses. Top spring in pic is out of another 556 AR and bottom is out of the SFAR. Pics with receivers will show the tube is a little longer on the SFAR with total length of a hair above a standard ar15 tube @ 7 3/4”. I want to run a silent capture spring in it but not sure if the OAL of the JP spring will fit on the .308 model. I have a 556 one and it’s about 3/4” short. Anybody running a .308 one give me the OAL of yours? Can’t find it online.

 

[Ryan Paden]

In for info

 

[JET 5.45x39]

No personal experience with the Rugers but could it be a rifle length spring like you’d find in an A2 stock? Otherwise I’d suggest calling ruger. They have a bad habit of doing there own thing when it comes to some of their ARs as opposed to using industry standard parts. As an aside is there any reason for wanting a silent capture?

 

[JJ0341]

I have a condition that I have to modify everything I own lol. I’ll probably give them a call today and see what they say.

 

[Asbestos]

Carbine length springs are 37-39 coils
Rifle length is 41-43 coils

If I remember correctly.

A silent capture should come with a spacer for rifle length but I see those as a downgrade vs an upgrade from like a sprinco spring. However, I’ve been in the same rabbit hole so, no judgement here.

 

[cmshoot]

Your receiver extension could be proprietary, but it’s hard to tell by the way you measured it. Also, a tape measure can be pretty inaccurate.

A standard carbine receiver extension length is 7.25”.

A Vltor A5 carbine receiver extension length is 7.9375”. Yours may actually be this length.

A standard carbine buffer spring length is 10 1/16” - 11 1/4”.

A standard rifle buffer spring length is 11 3/4” - 13.5”. Yours may be right around 13.5” in length.

I agree with Asbestos that, reliability-wise, the JP SCS is a downgrade from a quality standard buffer system, and a big downgrade from something like the Vltor A5 System.

All in all, from what I can tell from the pics, you may have a system that is the length of the Vltor A5.