AR15 light firing pin hits

[smithers599]

Recently put in an ALG "Combat" trigger. Lately, I get occasional light firing pin hits/failure to fire.
I really, really don't want to send the trigger back if I don't have to. Too much trouble. Is there an easy fix, like does somebody make an extra power trigger spring?

 

[Lobo2087]

Alg has a "purple" spring you can order to resolve the light strikes. Its 6-7$

 

[smithers599]

Thank you! Will do, posthaste.


ETA: Ordered. Thanks.

 

[XJThrottle]

You sure you put the hammer spring back in right?

Only ask because I've done it. My CMMG 22LR conversion wouldn't run for sh... Light strikes. Ran on 556 just fine. DOH, hammer spring in backwards. LOL

 

[smithers599]

Damn! Looks like I was supposed to order the tan spring, not the purple spring.

https://algdefense.com/alg-defense-purple-spring.html

Description: ALG Defense Purple Hammer Spring, can be installed onto your ACT hammer to provide an approximate pull weight of 4.5 lbs. This spring is perfect for those who are using their rifles for recreational purposes and target shooting. When shooting the ACT with the purple hammer spring and firing military grade ammo or ammo with harder primers, light strikes may occur. If there are light strikes, it is recommended the user switch to the tan hammer spring. The Tan Hammer Spring will give you a pull weight of 6.0 lbs., which meets the minimum required pull weight of 5.5 lbs. in the M4 Carbine specifications.

Oh well, I'll try the purple when it arrives, and see what happens....

 

[338lapua]

If you are using 5.56 with FC, LC or WCC head stamps it could be the harder primers.

 

[smithers599]

OK, problem solved.
I don't deny the possibility of backwards installation of the spring; I have done stupid things like that in the past, and will again in the future. However, the gun has worked fine for a long time, and only suddenly started with occasional failures to fire. So, I'll rule it out in this case.
I installed the purple spring, and as expected, failures to fire went to 100%. (While trigger pull weight went from 4.5 to 3.5.)
I was about to order the tan spring, but remembered I have a few spare springs in the parts bin. I picked a sturdy looking one and installed it. Went to C2 Tactical at lunchtime and put 2 mags through it, including 20 Federal American Eagle 5.56s. Runs 100% now, but the trigger pull weight is 7 pounds.