light strikes with new conversion lower

Hi all.

I've been experiencing light strikes/misfires with a new lower for my 22 conversion.  12 misfire/light strikes in 200 rounds.

I popped the conversion on my wadgun lower.  It ran nearly flawlessly with only 1 misfire in 300 rounds using same ammo and mags.

I don't think it's the ammo CCI standard plastic box.

What are the most likely causes for this issue?

Thanks in advance for your help.

Paul

I had a similar problem years ago with a Marvel. Check to see if you have a chip in your firing pin and or a broken firing pin spring.

Bill

Who built the lower? What hammer spring weight is in the lower? Check firing pin, firing pin spring, and check to see if the chamber is too fouled up.

Maybe your new lower has to light of a mainspring. I wouldn't go lighter than a #18. Just a thought.

A friend who is a gunsmith built lower.

I'll have to check on the hammer spring weight.  The chamber is clean.  I thought I ruled out problems with the conversion since it runs nearly 100% on my wadgun lower. 

Firing pin/spring maybe since my wadgun has heavier trigger weight of about 3.5#.

Dedicated lower is at about 2.5#.  Maybe mainspring is too light.

knightimac wrote:A friend who is a gunsmith built lower.

I'll have to check on the hammer spring weight.  The chamber is clean.  I thought I ruled out problems with the conversion since it runs nearly 100% on my wadgun lower. 

Firing pin/spring maybe since my wadgun has heavier trigger weight of about 3.5#.

Dedicated lower is at about 2.5#.  Maybe mainspring is too light.

Sounds like it to me possibly. I called Nelson once and he said 17# can cause failure to fire (light strikes) that 18# was about as light as you want to go. 19# would be better.

Agreed about the mainspring.  Replaced that and almost all my light strikes went away.

Thanks to all who responded.  Going to replace mainspring next week for a brand new #20 one.

knightimac wrote:Thanks to all who responded.  Going to replace mainspring next week for a brand new #20 one.

May have to go to the 8lb recoil spring

Chris Miceli wrote:

knightimac wrote:Thanks to all who responded.  Going to replace mainspring next week for a brand new #20 one.

May have to go to the 8lb recoil spring

+1
Heavier mainspring may require the lighter recoil spring for proper cycling.
- Dave

8 and 20 have worked the best for me. Never could get a 9# spring to work perfectly with the ammo I use. I've had to go as light as 18# on the main spring with a Marvel that was giving  problems. Tried 17 but also had misfires.

Jim

I struggled with occasional light hit no fires for a year and a half with my Nelson conversion (toward the end of that time it was 1 in 50) .  During that I tried everything heavier springs, cleaned the firing pin port, and talked to the factory several times.  Finally I started looking the firing pin hits on my cases versus firing pin hits on cases from other bullseye guns.  I noticed that area of the dents that my firing pin left was between .5 times and 3 times as large as the dents from other bullseye guns.  I researched that on the internet and found someone with a Marvel conversion had reduced the area on his firing pin and solved his light hit problem.  So I reduced my firing pin area from .090" X .035" to .060" X .030", (which was still larger than most of the bullseye pistols I was comparing to).    Since I reduced the area on my firing pin, I have put about 3500 rounds through the gun and have not had any rounds that failed to fire due to a light hit. 
djw1cav

Hi All.

Reporting back-changeover to #20 mainspring from #17 spring has really helped.  In last 200 rounds only 1 misfire.

BTW, I also went to 8# recoil spring instead of #9 that I had in the conversion.  Won't lock open now but reliable!

I'm toying with idea of cutting off a coil or two off a spare #9 pounder to make an 8 1/2ish one.

I also noticed the firing pin strikes do look much bigger on my Nelson compared to my two Rugers.  The Rugers only which had one or two misfires a YEAR.

I hoping this has put me on the right path.  I just shot a 97 rapid fire last club practice on Tuesday (good for me)

Fingers crossed.

Paul

Your slide not locking back after the last round could be your slide release not getting picked up by the magazine that's what happened to mine after 10,000 + rounds. I called Larry and now I have a new one and the slide back every time. Congratulations on your 97 rapid fire.