Buffer spring rates? [Archive] - M4Carbine.net Forums

Reagans Rascals

12-07-11, 14:13

Looking for pressure rates of the various buffer springs available. Not just the weights or dimensions of the springs, or the buffer itself, but the actual ft. lbs. of energy they exert.

Anyone have that info?

Iraqgunz

12-07-11, 21:38

May I ask why?

Looking for pressure rates of the various buffer springs available. Not just the weights or dimensions of the springs, or the buffer itself, but the actual ft. lbs. of energy they exert.

Anyone have that info?

viperashes

12-08-11, 00:08

Wouldn't that be a linear equation? I would think that a spring would exert more of the force it is capable of as it became more compressed. At the very least, it would be a 'mass x energy' type of equation. Also, I think the data would vary. What are the controls for finding accurate data? How would it be collected to positively reflect exactly what you are looking for? I don't think anyone has ever gone that far into depth on the subject. At least nothing that I have seen. I'm curious as to what relevance this information holds as well.

Bad Hammer

12-08-11, 04:28

It's definitely a valid question.
One I've often pondered myself.
Actually, I'd be interested in the data also.

viperashes

12-08-11, 04:51

I'm slightly interested myself. I'm just curious as to how the data would be concluded and what it would be relevant to.

markm

12-08-11, 07:19

Are you planning an ejection pattern reverse corralation regression analysis? :dance3:

nimdabew

12-08-11, 09:21

Are you planning an ejection pattern reverse corralation regression analysis? :dance3:

Is that fancy talk for "where does the casing land with different spring rates?"

markm

12-08-11, 09:33

Is that fancy talk for "where does the casing land with different spring rates?"

I guess. :confused: I just plucked a bunch of 5 dollar words.

Bad Hammer

12-08-11, 09:39

I guess. :confused: I just plucked a bunch of 5 dollar words.

You got a pretty good bargain...at least two of them are $8 words.:lol:

Reagans Rascals

12-08-11, 09:41

I'm considering a custom build, and without getting too far into the details about the recipe before the pig is cooked it would be helpful to know the different spring rates, as far as what amount of force they exert.

It would be a linear equation however there are quite a few very important details missing before one could derive the right numbers, such as the modulus of rigidity of the material, number of coils, wire diameter, outer diameter of the spring, Lfree and Ldef, and the applied load on Ldef.

I was just hoping someone had a published list of the rates on hand, like for example "the standard carbine buffer spring rate is usually 18 ft lbs." or something similar.

I guess If needed I could secure a standard carbine in a bench vise and use a pull gauge on the charging handle to measure pounds of force to compress the different springs...

Casull

12-08-11, 11:21

There's points of equilibrium and all the potential energy stuff that coincides with gravity, weight, friction, air resistance, ect...

In the end, I guess none of it matters :p

markm

12-08-11, 11:30

Just buy colt USGI springs and never look back. :confused:

Iraqgunz

12-08-11, 16:19

I am just asking because quite frankly I think too many people are worried about things like this when they needn't be.

I'm considering a custom build, and without getting too far into the details about the recipe before the pig is cooked it would be helpful to know the different spring rates, as far as what amount of force they exert.

It would be a linear equation however there are quite a few very important details missing before one could derive the right numbers, such as the modulus of rigidity of the material, number of coils, wire diameter, outer diameter of the spring, Lfree and Ldef, and the applied load on Ldef.

I was just hoping someone had a published list of the rates on hand, like for example "the standard carbine buffer spring rate is usually 18 ft lbs." or something similar.

I guess If needed I could secure a standard carbine in a bench vise and use a pull gauge on the charging handle to measure pounds of force to compress the different springs...

TangoSauce

12-08-11, 16:47

http://i1117.photobucket.com/albums/k596/TangoSauce/ARejectionpattern.jpg

What more do you need to know?

(Credit to whoever made this originally, I just find it handy.)

ucrt

12-08-11, 17:41

http://i1117.photobucket.com/albums/k596/TangoSauce/ARejectionpattern.jpg

What more do you need to know?

(Credit to whoever made this originally, I just find it handy.)

===================================

Uh ohhhh!

You did it now....
:(
.

Clint

12-08-11, 18:08

The dreaded chart rears its head...

ST911

12-08-11, 18:10

The dreaded chart rears its head...

What's that line?

"I hate the (ejection) chart and all it stands for!"

:D

rsilvers

12-08-11, 18:12

See link: https://www.m4carbine.net/showthread.php?p=1163871#post1163871

TangoSauce

12-08-11, 18:54

Didn't know that chart would get people roused.

Carry on.

Reagans Rascals

12-08-11, 19:28

See link: https://www.m4carbine.net/showthread.php?p=1163871#post1163871

thanks for the link, that's pretty much what I wanted to know.

Has nothing to do with case ejection or anything of the sort, as my inquiry has nothing to do with 5.56 or the operation of the AR-15/M4 in any capacity.

I have a custom build in the works, for which the spring rate needed to be known in order to continue with forward progress. It is critical the spring rate not be above a specific number and from the data listed it looks like it will work.

I'm not going to say what or why, but more details will be available as the build is completed.

polydeuces

12-08-11, 19:39

Reagans Rascals

12-08-11, 19:53

Pressure rate of buffer spring? That's some funny shit, really...
With all due respect, when i start wondering about stuff like that I know it's time for my meds.
Perhaps more time shooting and less time giving a rats ass about something OCD like that.

But really...just to answer your question, sort off:
Get a sprinco Blue or White depending on what your "need" is and be done with it.

you have no idea what you are talking about.

As I have stated, more than once, this has nothing to do with the M4 or the 5.56 cartridge.

I require a spring pressure rate at/below a specific value, if the spring exceeds that value it is of no benefit.

When something will only operate within specific parameter X, you can't just slap in Y and Z and "be done with it"

In terms of being "OCD" about something I am investing money and time into, designing and machining, then yes I will gladly admit to that.

Next time, perhaps you should just refrain from speaking and be done with it.

polydeuces

12-08-11, 20:00

polydeuces

12-08-11, 20:03

Just to be be helpful:

https://www.m4carbine.net/forumdisplay.php?f=10

Reagans Rascals

12-08-11, 20:07

Since there seems to be "confusion" about context: please check the header in which you are posting.
Last time I checked - this is ALL about the AR15/M4, 5.56 et al.
Maybe time to move this thread to avaid further "misunderstanding"?

Just saying.........

did I not ask about the AR15/M4 buffer spring? As in the spring itself, used in the AR15/M4.

I fail to see your logic here. An individual component from the AR15/M4, cannot be discussed by itself, without bringing the entire platform into the discussion?

dpaqu

12-09-11, 01:59

I’ve always wondered if some sort of progressive spring could bring the smoothness of a H3 buffer without the risk of shortcycling the gun.

rsilvers

12-09-11, 10:49

I’ve always wondered if some sort of progressive spring could bring the smoothness of a H3 buffer without the risk of shortcycling the gun.

I don't know, but I doubt they are a good idea as spring force is already increasing with displacement, all that would change is the rate. It is like the progressive income tax - it is not needed, as people who earn more already pay more. Same with progressive rifling. The bullet starts out at zero fps, so the rpm is already increasing at a controlled rate as the bullet accelerates.

Clint

12-09-11, 21:09

I’ve always wondered if some sort of progressive spring could bring the smoothness of a H3 buffer without the risk of shortcycling the gun.

The closest you get to ideal in this application is a really low rate spring with good amount of preload.

Compared to a higher rate spring of equal average force, the low rate spring provides more installed force and less force at recoil.

dpaqu

12-10-11, 00:47

The closest you get to ideal in this application is a really low rate spring with good amount of preload.

Compared to a higher rate spring of equal average force, the low rate spring provides more installed force and less force at recoil.

Thats more along the lines of what I was thinking with a slight increase in rate at the end of the BCG travel.

Reagans Rascals

12-10-11, 00:59

Thats more along the lines of what I was thinking with a slight increase in rate at the end of the BCG travel.

although this is for a Glock, this might be similar to what you were thinking

http://glockstore.com/pgroup_descrip/7/2139_Stainless+Steel+Guide+Rod+w+Dual+Spring/

armatac

12-16-11, 11:05

You must be doing a blowback gun.

Springs are ideally linear, F=1/2(spring const*displacement), near solid height is a variation.

I don't have the data but there are spring calculators, that take more into account so you enter coil count, wire diameter, material

So you can use the equation to solve for the spring constant,

K = 2*force/(displacement)

so you could load it with a force, or weight, measure displacement and get the spring constant--be careful with your units.

All good in theory, but I would use it only as a reference.