Pretty inexpensive upgrade, I think. For the 2nd Ethiopian, I got a Wolff spring kit https://www.gunsprings.com/index.cfm?page=items&cID=2&mID=98#533 which, disappointingly did not include the trigger spring. The Sarco did not have the correct tapers, so might as well go with the best.

Between the 2, the Wolff spings are better quality. for example the extractor spring and the mag release springs had the correct taper to hold the pins. The Sarco did not. The Sarco kit is working fine so far. When I first shot the M1 using Korean surplus ammo, I had a couple of failure to feeds. For the rest of the couple of hundred rounds I put through it, no issues at all.

On the "old model" 2nd gun, here is a pic of some new springs vs. old. The trigger pin was what appears to be a screw that was ground down to fit the pin hole. I can't really see this pin breaking so I'm guessing the pin was lost during a cleaning session. You can see that the reset spring is clearly past useful life. The 1st M1 really did not need the pin kit, the pins were fine. So I had a spare trigger pin to replace the jury-rigged part. Same with the trigger spring, 1st really did not need it, but the spring on the 2nd was shot, so I had a spare for that one, too.

Getting the hammer spring back in with this new spring was a challenge. I finally figured out to put a 3/16 drill bit in the spring to hold it in shape, so I could shove it back into the frame and get it on the hammer. As the hammer spring pit compressed the spring, it shoved the drill bit out the back. I await to hear the no doubt half-dozen other techniques to get the damn thing in.  I have told you mine.

 

there is a USGI tool for getting the hammer plunger, spring back to get the plunger on the hammer.

it is part number 6200985. It is sort of a multi tool as it is for pushing out pins, helps get the sear in place as well as guiding a spring.

It is cleverly located withing the carbine, so the good news is you do not have to go out and buy one.

Take out the slide spring and you should be able to find it.

http://www.uscarbinecal30.com/forum/sear-installation-tool_topic4938.html#37690" rel="nofollow - http://www.uscarbinecal30.com/forum/sear-installation-tool_topic4938.html#37690

Yeah, I tried that, but the new spring was not cooperating. It would do the Watusi and I couldn't get it under control with my thumb. I tried the old spring that way and it went right it.

   Jim