how to check what weight recoil spring is?

[mag360]

When I bought my g20 it came with an upgraded recoil spring I believe 20 or 22lb how do I check to see which one it is?

Ive seen some of you guys ppst saying the 24 works good with everything and ive been considering stepping up to that.  I should probably post a picture of it.

[The_Shadow]

I used a small "C" clamp with cardboard/card stock as pads, clamped to the rear of the slide, as a place to hook my digital fish scale.  Pulling the slide rearward with the scale to the point just before, at which the slide locks back, should be your spring weight.  You will want to hold steady to get the reading.  Take more than one reading to verify your measurements.  That's just a quick and dirty, simple way to measure the recoil spring.

You can make a fixture to test with but that takes time and extra materials...

[dakota1911]

I was ordering some parts from Brownells and noted they had a Universal Spring Tension Tester so I ordered one but have not got it yet.  Should be interesting.

[BEEMER!]

I was ordering some parts from Brownells and noted they had a Universal Spring Tension Tester so I ordered one but have not got it yet.  Should be interesting.

Does it measure tension springs or compression springs or both?

For recoil springs I have used a spring scale, a wood dowel that fits inside the spring and a washer.  I put the dowel in the spring, stand it up on the scale, and put the washer over the top and push down on the spring while reading the scale.  It is as accurate as the scale you have.

[Gabbar Singh]

The rated value of the spring should correspond to the force required to compress it one inch.

[The_Shadow]

The rated value of the spring should correspond to the force required to compress it one inch.

I would have to disagree because when I measured the recoil springs, as installed in my Glock 20 and 29, both factory and aftermarket, the peak reading of the spring did not show until the slide was fully retracted and at the point at which it would lock open on empty magazine.  This is slightly over an inch based on the length of the 10mm cartridge 1.2500" and the even slightly more so to have the slide at full travel. 

You could hold the spring at any point before and it would show less than the full rating, until the point where the slide locked to read the advertised spring rate.  (See the actual measurements below.)

What was really the most interesting to me was the point at which the slide and barrel start to unlock...the non captive recoil spring showed a distinct advantage of holding lock up with more pressure than the captive factory setups.

Glock 20SF spring test Wolff Gun Springs 22lb RSA installed
It takes 6lb 4oz to start the slide to move from the locked position
Full retraction at 22lb 9oz at lock open

Glock 20SF spring test Wolff Gun Springs 24lb RSA installed
It takes 7lb 6oz to start the slide to move from the locked position
Full retraction at 24lb 1oz at lock open

Glock 20Sf Factory spring test
It takes 5lb 3oz to start the slide to move from the locked position
Full retraction at 18lb 0oz at lock open

22-Slightly over a pound difference 1lb 1oz to start the slide to move from the locked position
24-Slightly over a pound difference 2lb 3oz to start the slide to move from the locked position
22-Slightly over a 2 pound difference 2lb 9oz at lock open
24-Slightly over a 6 pound difference 6lb 1oz at lock open

[dakota1911]

Oh yes, the link for the Brownells sourced spring tension tester:

http://www.brownells.com/gunsmith-tools-supplies/handgun-tools/magazine-tools/universal-recoil-spring-tester-sku100011593-56227-115946.aspx?sku=100011593

For recoil/return to battery springs I have also used a 12 x 1.5 inch piece of plastic drain pipe and a good scale.  Don't have to take the gun apart or anything.  Just be sure it is unloaded.  With a little testing it gets you very close and you get a feel for force required to compress the spring.  Works with multiple spring setups as in the Colt Delta also.  It works with FLGRs also and the plastic pipe does not mar the pistol.  If you have a "bag o springs"  to look at then the Brownells spring tester might be a better bet.