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Discussion Starter · #1 ·
I'll keep this brief and round off numbers. I'm trying to get opinions on what I found.
I have a Wilson CQB and have been using Wilson 18.5 lb. springs since the gun was new. I have been changing recoils springs about every 2,000 rounds just like Wilson says, but I was kind of surprised at how rapid the springs lose their spring rate. I thought I would try some ISMI springs. I bought two 18 lbs. springs and a 20 lbs. spring. I put in an ISMI 18 lbs. spring and cycled the action by hand. The spring felt very weak. I took the spring out and decided to check the spring rates. Here's what I found using my SDM Fabricating spring tester:
Wilson 18.5 spring(new)
overall length- 6.25 in. long
coil bind- 19 lbs.
open pressure- 18 lbs.
closed pressure- 11 lbs.

ISMI new 18 lbs. spring( both springs) tested the same)
overall length- 6.25 in. long
coil bind- 12 lbs.
open pressure- 11 lbs.
closed pressure- 6 lbs.

ISMI new 20 lbs. spring
overall length- 7 1/8 in. long (really needed to trim 1 or 2 coils off of length because length of spring at coil bind is almost too long).
coil bind- 18.5 lbs.
open pressure- 18.5 lbs
closed pressure- 10 lbs.

I have always checked my Wilson springs and they have been consistent so I believe I am using the tester correctly. Has anyone else found anything similar to this ? Could I simply have a couple of bad springs from ISMI? I have not talked to ISMI about this since it is a holiday. I like the ISMI springs I have used in my Glocks. Not trying slam ISMI. I am just wondering if anyone else has a spring tester or has seen similar figures.

I always use Wolff springs, I actually remove all of the springs from my guns no matter who built them for me and replace them with new Wolff springs.

At that time I also loctite all of the removable screws/pins (except the grip screws), check the plunger tubes and check and smooth all of the action areas of burrs and rough marks. On 1911s I also remove any "tight/Wrench fit bushings" throw them in the spare parts bin and fit a finger tight bushing, while removing and tossing any trigger stop screws.

Then the gun goes in the test bag and will later become a "carry" gun.
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