My latest 1911 arrived yesterday, a stainless Kimber Target II in 9mm.

First thing I did was strip it down for a clean and to change the plastic mainspring housing to a stainless mag well fitted housing. That's when I noticed that unlike my Springfield and Ranger (Norinco made but unbranded) 45 1911's,which have a fairly flat mainspring, the Kimber factory fitted spring has a distinctive curve forward from the frame cut the spring bottom fits into up towards the disconnected and sear position.

I was wondering why this is? Is this a Kimber mod? Even the spare replacement springs I carry in my tool kit are flat and need to be tweaked a bit when fitted.

The 1911 mainspring is a coil. Are you asking about the sear/disconnector/trigger spring?

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Gunsmithing since 1961

Based on your post I'd guess your talking about the sear spring and not the mainspring. The mainspring is inside the mainspring housing. The sear spring sits in between the frame and the mainspring housing. The mainspring is a coiled spring.

Regarding the sear spring - I have noticed that some are more curved than others but I guess I haven't ever thought too much about it. If it works I just go with it...

All of them I have ever had has at least some curve to them, none were ever flat. The mainspring is the coil spring inside the mainspring housing. Did you not install a new one when you put in the new mag well/housing?

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H Richard
SWCA1967 SWHF244

Tweaking the flat spring is one way to lighten the trigger pull.

There's a variant of that spring that has four prongs. They're usually called 'Videcki' springs but a lot of companies make them. One prong pushes the trigger back into battery. With this system, the trigger pull is considerably lightened.

Oops. Yes it is the sear/disconnectir spring.

The housing I had is a spare. It was sans spring, retaining pin and housing retainer (the cone shaped pin at the base that sits in the groove of the housing pin).

Yes I gave the centre prong a slight pull backwards. It lightened the trigger slightly. Thinking about giving it another tweak later today.

When the hammer starts following down, you've gone too far.

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Science plus Art

Okay, so I gave the spring another tweak a few evenings ago, and I then went and did the same on my Springfield Armoury .45 ACP. Big mistake as I found out today on the range.

First up was the Springfield, supposed to be my last practice session before a level 3 IPSC match on the 17th (this weekend it is set up the 12 stages and the range is closed until the 16th when the pre-shoot starts). First mag went through no problems, same with the second (5 rounds each in a set drill I perform).

Third string and the second round wouldn't chamber. A nick in the case mouth had rolled over preventing chambering. Dropped the mag, locked the slide open, removed the offending round. Put the mag back in and hit the slide release. The slide went forward and the gun fired with my finger well clear of the trigger.

As the next round didn't go off full auto style I unloaded the pistol and dry fired it a couple of times. Even went so far as to hold the trigger back and work the slide to make sure it reset properly. Convinced it was working as it should I again locked the slide back, replaced the two expended rounds in the mag before inserting it again and dropping the slide a second time. Again the pistol fired as the slide went into battery.

Unloading the pistol I went back to the safety zone with my range toolbox and stripped the housing, grip safety and spring, the centre prong of the sear spring I tweaked back to where it had been.

Retuning to the firing line I wen through the whole loading from a locked slide routine and the gun worked flawlessly for the rest of the day (180 rounds in total).

Put the .45 away and got out the 9mm. Loaded two mags with 10 rounds. First shot went off as it should, same with the second, but the third shot would not fire. It seemed like the trigger had not reset. No matter how hard I squeezed the tigger the gun would not fire. The hammer was back, the slide in battery but it would not go 'bang'.

Dropped he mag, cleared the pistol and put the mag back in. Racked the slide and 1 shot, 2 shots then again nothing.

So a second return to the safety zone, strip the pistol down. repreat the reverse tweak of the springs centre prong and put it all back together again.

Return to the firing line, reload and away we go, no more problems (well not with misfires but.....).

So thanks OKFC05 for your warning on over tweaking the spring to lighten the trigger pull. Next time I'm tempted to tweak something I'll just leave it alone.