I was just looking at a couple of buffer springs I have and something looked off, one was from a carbine (entry stock actually) and another was from a rifle (A2) stock. there was not much difference between them. I started measuring the springs in my AR's and I came up with the following lengths:
10.75"
11.25"
11.875"
12.50"
12.75"

I recall seeing the specs for the range of spring length for carbine and for rifles but cannot locate it now. Does anyone have that info?
would I be better off using a spring at the long end of the range in eaqch application?
Your help and info would be appreciated since I am going to place an order from PK soon (today or tomorrow) and I would like to get a couple mopre rifle springs IF the ones I have now are too short....Thanks....<><....:)

From:
TECHNICAL MANUAL
ARMY NO. 9-1005-319-23&P
AIR FORCE TO 11W3-5-5-42

RIFLE: 11 3/4 Inches (29 85 cm)
minimum to 13 1./2 inches (34 29 cm)
maximum

CARBINE: 10 1/16 inches (25.56 cm)
minimum to 11 1/4 inches (28.58 cm)
maximum.

That's good info to post. I'll bet 90% or more never even checked those measurements.

SO

Thanks guys, and thanks for those measurements MMcfpd, that is ecaxtly what I was looking for. And I believe you are correct SpecOsp-13, I got some of these (carbine) springs fron people who sold them as rifle springs.
Does anyone have any info/ideas/opinions if springs at the longer or shorter end of the acceptable length range would be better in a particular application carbine or rifle)? For example, would a rifle spring, which is within specs from 11.75 to 13.5 inches be better closer to 11.75 or better at the longer end of the range, 13.5"?...Thanks all....<><....:)

So what spring length would apply towards a midlength? Sorry I'm a noob

QUIB: That's very good info for people to learn. The pictures will help them easily understand.
SO

Depends on what receiver extension you're using.

If you're using a carbine-length receiver extension, use a carbine spring.  If you're using a rifle-length receiver extension, use a rifle spring.