.308 action springs

[Disciple]

What are the properties of the .308 carbine (https://www.aeroprecisionusa.com/308-carbine-buffer-spring) and rifle (https://www.aeroprecisionusa.com/308-rifle-buffer-spring) buffer springs? Like this chart from crosseyedshooter.



https://i.imgur.com/gT8kawx.jpg

[17K]

What are the properties of the .308 carbine (https://www.aeroprecisionusa.com/308-carbine-buffer-spring) and rifle (https://www.aeroprecisionusa.com/308-rifle-buffer-spring) buffer springs? Like this chart from crosseyedshooter.


Looks like the Tubbs flatwire in an A5 is a little weaker compressed than a standard rifle spring and carbine spring.

That sounds like the opposite of what you would want to strip rounds out of the magazine.

[Disciple]

That's not what I see in the chart. F1 force is between 7.3 and 7.8 pounds for the Tubb/A5 at F1, versus only 6.0 to 6.1 for standard carbine, or 6.8 to 7.1 for rifle/A5 springs. Total energy of Tubb/A5 is higher than any other combination besides the Tubb spring in a carbine RE (causing higher preload).

[17K]

I was looking at the F2 numbers of the Tubbs / A5 tube.

The F2 numbers are not really any more than the other rifle springs.

Total energy is higher, is that a function of more coils?

I’m still thinking about my A5 problem and I’m kind of wondering if I just got some shitty springs that barely made it to 1K rounds. I haven’t pulled them and measured free length yet.

I did order a few Tubbs Ar15 springs to try out though.

[Disciple]

I believe increasing F1 without substantially increasing F2 is the goal of the Tubb springs. (I'll embed a video below.) That comes from using a longer spring with a lower spring constant. Energy is the integration of force throughout; the average force times operating distance.


https://www.youtube.com/watch?v=8fMVZbrnvu8

[Disciple]

I had forgotten that the video above included a Sprinco .308 carbine spring. The reported values are L1 = 13.9 lbf and L2 = 24.8 lbf.