1911Forum banner

Springfield ILS Mainspring: Advice Needed

1082 Views 5 Replies 5 Participants Last post by  steveracer
Okay, I'll admit that I'm one of those apostates who likes having the ILS system on his guns. On one gun, however, the mainspring seems a bit stronger than on the others, so I'd like to replace it. My questions are:

1. What is the strength (poundage) of the standard factory ILS mainspring?
2. Can I simply replace the mainspring with another, or do I need a special ILS mainspring? (I'm wondering if there's a length difference to account for.)
3. What is the next-lower-strength mainspring that I can use instead?
4. Where can I buy such a spring?
5. What sort of performance difference should I be watching for after I replace it?

Thanks in advance.
1 - 6 of 6 Posts

· Premium Member
Joined
·
2,689 Posts
Yes, there is a length difference. The ILS spring is shorter. I used a regular 19lb mainspring and then trimmed it to the length of the ILS spring. That kept the ILS operational and made a difference on the trigger. I put about 5000 rds through the gun that way and never had a problem.
 

· Banned
Joined
·
1,659 Posts
The easiest thing to do is replace the ILS parts with standard parts. Then you can use whatever power mainspring you want. I have experimented with many and have come to the conclusion that the best combo of springs for me for reliable ignition and clean round stripping is a 18# mainspring and 18.5# recoil spring.

Deez.
 

· Banned
Joined
·
7,478 Posts
John's solution will preserve the ILS. My add-on may sound complex, but read it over anyway.

The issue here is the compressed length of a standard mainspring is too long to fit in the housing when the pistol is cocked. It's not the free length that's important, it's the compressed.

Mic the SA ILS spring coils, count them, and determine the compressed length. Do the same with your candidate standard M1911 mainspring and cut to length. If the coils are the same diameter it'll be fairly easy, just match the coil count. The coils should not botton out with the pistol is cocked. (I'm sure there's a technical term for this, but darned if I can remember it right now.)

-- Chuck
 
1 - 6 of 6 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top