My Plum Crazy build

[fivonut]

I wanted an AR-22 and was looking at the Colt M4-22's when the Plum Crazy lowers came available. I picked one up from Brian and started searching for a dedicated 22 upper. One of my criteria was that the upper have an aluminum receiver. I didn't like the feel of the S&W M&P 15-22 full composite setup. I settled on a Tactical Solution LT dedicated upper. Pics below!!







and the assembled rifle



I had some cycling problems at the range. It would fire and cycle a round but was not resetting the hammer. I thought maybe the spring weight of the hammer was too heavy so I worked on it a little bit to lighten it up and that didn't help. I actually lightened it to much and was not firing a round. I put the Tac Sol upper on my M&P15 lower and it ran fine, 100 rounds no problems, cycled perfectly. I met up with Brian to pick up a few things and we looked over the Plum Crazy lower and discovered scrape marks on the sides of the hammer. It appears the hammer is too wide and is slowing down the 22 action enough that it wont reset it. I'm going to see if taking a few thousandths off each side makes a difference. I'm 99.9% certain this should solve the problem. here's pix of the hammer.







I'll report back when after I run a few rounds through it.

[That_Guy]

Very cool i haven't had the chance to take mine out to my parents and let a few round off. Keep us posted on how the hammer deal works out.

[Lash]

How much did you get the upper for?

[Coops Brother]

Taking some material off of each side is the approved fix for the problem of the hammer sliding along the inside of the bolt carrier. The carriers are a bit narrower on the .22 conversions also noted was the 7.62mm uppers. I would think some of the other conversion uppers might need to have this modification done to the hammer as well.

It will not void the warranty.

[STANMAN]

Taking some material off of each side is the approved fix for the problem of the hammer sliding along the inside of the bolt carrier. The carriers are a bit narrower on the .22 conversions also noted was the 7.62mm uppers. I would think some of the other conversion uppers might need to have this modification done to the hammer as well.

It will not void the warranty.

If there is a warrenty issue, do we see you, or talk to Plum Crazy?

[Coops Brother]

Get ahold of me and I will take care of what is going on.

[fivonut]

How much did you get the upper for?

$540. There's a lot of composite uppers out there for under $400.

[STANMAN]

Get ahold of me and I will take care of what is going on.

Just for future reference. The 3 I bought yesterday have all had uppers attatched, all seems well! For the price, they are impossible to beat. Hell, the 4 position stock is worth $50.

[Coops Brother]

Just for future reference. The 3 I bought yesterday have all had uppers attatched, all seems well! For the price, they are impossible to beat. Hell, the 4 position stock is worth $50.

Bob, I am hoping this post means you installed uppers on them and not that there was an upper installed previous to your purchase.

Thanks of the purchase, glad that you like them so far.

[Crawlin]

I'm pretty sure that's what he means Brian I'm sure he's got enough uppers to go around, haha.

[STANMAN]

Bob, I am hoping this post means you installed uppers on them and not that there was an upper installed previous to your purchase.

Thanks of the purchase, glad that you like them so far.

I should have clarified, they all had uppers on them once I got them home and did some test fitting, not previous to picking them up. As stated, all seems well. When I get to shootzing them I will post up range thoughts as well. I am sure they will be

[fivonut]

Well, narrowed the hammer and still having resetting problems. I'm starting to think sear engagement is the issue. I also had light strike problems until I bent the leg of the hammer spring to get a harder hit. I think taking the material off the hammer caused it to lose too much mass. Before all of this I had already cut one leg of the hammer spring so maybe not doing that would have prevented the light strike after removing some material. Regardless, I don't think that this lower in factory form is ideal for a 22lr build. I'm going to try swapping in a DPMS lower parts kit, that will make all the parts metal. We'll see if that solves my problems. So far, I have a lot more money into this setup than I would have had into the Colt M4-22 I originally wanted.