I have  a 1911 commander built buy a gunsmith my dad was buddies with.   Gun has light primer strikes about 33% of the time with any ammo.   I have already changed out the firing pin spring and that did not fix it.   Is there something I can replace next?   1911s are not my thing.  


 

You may have a weak/light mainspring installed. Make sure the gun is unloaded, stick a pencil in the barrel, eraser first. Point to the ceiling, cock the hammer and pull the trigger.  The pencil should eject 2 or 3 feet past the barrel if you have a factory (or close to it) spring installed.

This, someone probably stuck in a lighter then stock spring [NOT recoil spring]. They VERY seldom actually wear out.

However, it could also have an issue with the FP safety or someone dinked with it. [series 80 FP safety] I'd also carefully inspect the actuating levers for it to make sure someone didn't booger it up by trying to install the slide improperly and ramming the rear of it into the lever.

This. Since the slide is series 80, check to see if the firing pin block plunger is installed in the slide and if so, see what firing pin you have installed.

Next look at the frame to see if its a series 70 or 80. Series 70 frame and 80 slide with no firing pin block = good to go, series 70 frame with 80 slide that has firing pin block installed is a no go.

Also look at the trigger and does it have an overtravel screw? If it does and the overtravel screw is improperly adjusted, that can affect the safety lever timing allowing the hammer to hit the firing pin before the firing pin block clears the firing pin.

Did the gun just start misfiring or has this always happened?

I don't know if this has always been the case.   My father passed and this was in his safe.   I doubt that he ever fired it.

If the disconnector isn’t centered in the cut out in the under side of the slide you can get failure to fire.  I’ve seen this trying to use different slide on a different frame.  It sounds like the series 80 firing pin block might be the issue or replacement parts.   A replacement hammer spring is inexpensive and is easy to replace.   If everything else looks OK I’d inspect the hammer spring and replace with factory spec.

Factory spec 1911 Colt hammer Spring is 23 pounds.   If it won’t fire with that spring there is another problem.

https://www.brownells.com/handgun-parts/trigger-group-parts/hammer-parts/hammer-springs/1911-hammer-spring-prod16533.aspx