Cmmg dedicated upper question

[Paul053]

Thinking of buying a dedicated upper but wonder if it is compatible with my ar15s lower. Will I have to change out the trigger and/or hammer?

[Nutso]

The dedicated upper will work fine with any standard lower and trigger group. They don't recommend using a notched hammer but many have still had success even with a notched hammer.

I've used mine on several of my lowers ranging from standard mil-spec triggers to Geissele aftermarket triggers, all with great results.

I noticed you are in Pasadena. If you want to try out a CMMG dedicated upper on your lower just let me know. I shoot pretty often at Burro Canyon and as a member I can take a guest for free.

[triplestack3]

Thinking of buying a dedicated upper but wonder if it is compatible with my ar15s lower. Will I have to change out the trigger and/or hammer?

nope

slap it on and go

[pennys dad]

ditto, i got a CMMG dedicated upper on order and I have a Calguns lower in the safe waiting for it, I have made no changes and dont expect to make any

[NorCalDustin]

I've got 3 of these CMMG Dedicated Uppers... They've worked fine on all lowers I've put them on.

[donw]

i have a dedicated Spikes Tactical ST-22...the hammer and trigger works just fine with center fire uppers...no..you don't have to change the trigger/hammer unless you WANT to.

[JackRydden224]

What's the advantage of having a dedicated .22 upper as opposed to a complete .22 rifle like Colt Umarex M4? Both run about $350-400 online.

[Nutso]

I prefer using a dedicated upper that is set up to be identical to my 5.56 upper. This allows me to practice using the same layout with the same grip, trigger and stock as my 5.56 without the added costs of the 5.56 ammo.

[2shotjoe]

mine has feeding issues with blackdog mags, i'll have to order some cmmg mags to see if it will fix it.

[NorCalDustin]

mine has feeding issues with blackdog mags, i'll have to order some cmmg mags to see if it will fix it.

Whats your setup like? I.E., BHOA (If yes, what gen?)... What BDM mags exactly? What ammo are you using? Do you have a stainless kit? etc...

[2shotjoe]

Whats your setup like? I.E., BHOA (If yes, what gen?)... What BDM mags exactly? What ammo are you using? Do you have a stainless kit? etc...

CMMG Barrel and Parkerized Rimfire 16" 1/16trist + bolt assembly (barrel, bolt kits) in a spikes upper receiver, spikes bar rail. Black dog 10/27 mags that says it works with CMMG conversion kits.

I don't think I ever posted a current pic but here is the parts.

[NorCalDustin]

1) Have you tried different ammo (sometimes some ammo will not feed... I.E., In mine CCI Minimags have issues feeding

2) I would try using some purpose built 10rd magazines instead of 10/27 mags. I've never tried the 10/27's so I cannot personally confirm if they work or not.

3) If you are using a BHOA or Forward Assist Adapter I would remove them to see if the issue goes away.

4) Does the Bolt/BCG snap in solidly when placed into the upper?

5) Do you have a notched hammer (sometimes you can end up with feeding or extraction issues). I actually had one upper that ran fine for almost 20k rounds and then started having issues feeding/extracting. I did everything I could think of and finally put a smooth/rounded hammer in to replaced the notched and it started running fine. I'm not sure why it started happening all of a sudden, maybe I changed out the hammer spring at some point and forgot (totally possible)... Who knows.

[shadow65]

With some BDM mags, the feed lips are too long and can cause extraction pronlems. Trimming them back a few thousenths will fix the issue. Also, most BDM mags will have a loose fit. If you rest the rifle on the mag, it will change the feed angle.
Some bullet profiles like the Remigntons, will or can cause feeding problems.
Always start with buzzing the chamber if you are having feeding problems.
Dave N

[shadow65]

What's the advantage of having a dedicated .22 upper as opposed to a complete .22 rifle like Colt Umarex M4? Both run about $350-400 online.

Real AR parts versus fake.

[Cokebottle]

+1 on the ammo.

I own a Heritage .22lr revolver because I bought 5,000 rounds of Remington ThunderCrap-22.
Took it and the ammo to Burro... glad I took my two 5.56 and handguns or it would have been a short day. I managed to feed and fire maybe 3 rounds. I couldn't even manually force that crap into the chamber.
Winchester 555, no problems at all (with the BDM mags).

BTW: The Remington is a "tight fit" in the Heritage... it's just crap ammo.