Polymer hammer and a 22 LR AR upper

Post by **kyswede** » Tue Jun 12, 2012 11:12 pm

I got a Chiappa 22 LR upper for my group-buy New Frontier lower. The hammer is too wide to fit in the channel of the bolt. Hammer measures .380" wide, channel in bolt is .327" wide. So I took a flat file and filed about .030" off each side of the hammer. I filed one side .030" first, checking with dial calipers to keep sides parallel. Then I filed the other side. I wasn't sure if the hammer still had enough mass to work, but I was going to buy a new blowback hammer anyway, so I had nothing to lose. I re-installed hammer in my lower, installed upper, loaded 25 rounds in a mag and took it outside. I fired all 25 rounds with no problems, using Remington Thunderbolt ammo. I loaded up another mag and took a video of shooting it. I can't seem to be able to upload a video, so here are a couple of pics of the hammer.

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Post by **guncrank1** » Tue Jun 12, 2012 11:29 pm

Err bout the vidiao , clicker onn de imaga and got to de vid on de photobuket

Swede chief from Muppet movie voice

Post by **kyswede** » Wed Jun 13, 2012 10:01 am

Thanks cranky.

Post by **mtchbrian** » Thu Nov 08, 2012 6:19 pm

gonna have to try this when ever our group buy goes thru

Post by **shelbygoat** » Thu Nov 08, 2012 8:56 pm

mtchbrian wrote:gonna have to try this when ever our group buy goes thru

CMMG .22 upper...no modification to the hammer

For pricing, at the time I got mine through Humlund Tactical

Post by **bigelowe** » Thu Nov 08, 2012 11:07 pm

This is what I plan to do with my NF poly lower when it comes in. havent made up my mind on the chiappa or cmmg though.

Post by **Wyldman** » Fri Nov 09, 2012 12:48 am

IMHO, the CMMG is a far better value and a whole lot less problematic.

Post by **CatMostFeared** » Fri Nov 09, 2012 8:07 am

Spikes tactical works with it

Sent from my iPhone using Tapatalk it spells what it wants

Post by **Armor-Hyde** » Tue Nov 20, 2012 8:46 am

FYI...I have one or two of the .22LR & sub caliber polymer hammers in stock (No filing required) & then you can swap back to the regular hammer for centerfire rifle use. $12ea
Note, you cannot intermix polymer & steel fire control components on the PlumCrazy or New Frontier Lowers.
Must use all steel or all polymer.

Kentucky Armory Club