Hi all, would like to know if any of you Colt AR 9MM upper owners leave the 9MM hammer installed in your dedicated lower when you switch over to shoot your 5.56 upper. It is a bit of a hassle to have to switch between a regular hammer and the 9MM when you shoot. Question is can I use my 9MM hammer with a 5.56 upper asy. without detrimental effects, seems to work fine when dry fired. I have the 9MM removable mag block type.I also realize to exchange the proper bolt carrier groups and buffer assy. when I switch over to 5.56 to shoot.Thanks. g2.
Colt 9mm Ar Hammer Question
- Thread starter gladius 2
- Start date
The 9mm semi auto hammer relies on the extra "hump" that the 9mm bolt has on the bottom, for cocking. So if used in a 556 upper, some 9mm hammers will be cocked on recoil, some won't with a 5.56 bolt. Especially if using the commercial 5.56 Colt bolt that has the cut out, just in front of the firing pin, sometimes an M16 bolt will fix the problem.
However sometimes when using the M16 hammer with a non "ramped" 9mm bolt will cause the hammer to be bumped closed when the action/bolt is closing. This happens when the same 9mm bolt "hump" grabs the extra portion on the leading edge of the M16 hammer. Causing almost a hammer follow effect, usually without the ignition, rather just a failure to fire as a result of the hammer being forward.
All of the foregoing is using complete Colt parts. Other manufacturers of bolts, hammers/internals may prove different.
And sorry if I made this too confusing.
Gladius, just come over and I'll show you. It's easier.
However sometimes when using the M16 hammer with a non "ramped" 9mm bolt will cause the hammer to be bumped closed when the action/bolt is closing. This happens when the same 9mm bolt "hump" grabs the extra portion on the leading edge of the M16 hammer. Causing almost a hammer follow effect, usually without the ignition, rather just a failure to fire as a result of the hammer being forward.
All of the foregoing is using complete Colt parts. Other manufacturers of bolts, hammers/internals may prove different.
And sorry if I made this too confusing.
Gladius, just come over and I'll show you. It's easier.
contact148 said:
Ya, I've had guns that ran well using it with either.
Out of the 15 or so 9mm guns, I've run into the odd problem. They've all been fixable. One problem was as a result of the mix n match upper and lower height differences.
If you have one that works with both, great, most do. Just some don't.
For me the extra work has been worth it. That's why I am looking to find someone ramp a 9 bolt for me right now... Know anyone?
Colt 9mm Hammer
Hi, thanks for the advice guys, recieived my Colt 9MM hammer and fitted it, it works fine I had tried a regular 5.56 hammer before with 9MM bolt and found that it would jam when cocking, trapping the BC to the rear, not allowing the hammer to continue rearwards to engage the sear and lock back and the hammer not allowing the bolt to travel forward again without having to disassemble it, the BC in a rearwards position would not allow the weapon to be seperated either, I would have to drive the hammer pin out and allow everything to pop loose to allow the BC to come forward and seperate the upper and lower halves, so a 9MM hammer certainly works and prevents this.
I was thinking that after dry fire testing that the 9MM hammer will work with a 5.56 upper, the only difference could be a slightly faster ignition time or lighter strike as there is less mass in the hammer than regular AR hammers. I used some Prussian blue to mark the strike on the hammer from the 9MM firing pin usig the 5.56 upper and found it was roughly in the meatier part of the hammer strike face, so hammer strike location seems fine not to high or low. I think it will work, just wanted to know who has tried it as I will be taking my 9MM to the range w/ a 5.56 M4 upper.Hate swapping parts at the range, the snow is still pretty deep to loose things in.Not wanting to ramp the 9MM BC at this time either unless absolutely necessary for reliable performance. Cheers. G2.
Hi, thanks for the advice guys, recieived my Colt 9MM hammer and fitted it, it works fine I had tried a regular 5.56 hammer before with 9MM bolt and found that it would jam when cocking, trapping the BC to the rear, not allowing the hammer to continue rearwards to engage the sear and lock back and the hammer not allowing the bolt to travel forward again without having to disassemble it, the BC in a rearwards position would not allow the weapon to be seperated either, I would have to drive the hammer pin out and allow everything to pop loose to allow the BC to come forward and seperate the upper and lower halves, so a 9MM hammer certainly works and prevents this.
I was thinking that after dry fire testing that the 9MM hammer will work with a 5.56 upper, the only difference could be a slightly faster ignition time or lighter strike as there is less mass in the hammer than regular AR hammers. I used some Prussian blue to mark the strike on the hammer from the 9MM firing pin usig the 5.56 upper and found it was roughly in the meatier part of the hammer strike face, so hammer strike location seems fine not to high or low. I think it will work, just wanted to know who has tried it as I will be taking my 9MM to the range w/ a 5.56 M4 upper.Hate swapping parts at the range, the snow is still pretty deep to loose things in.Not wanting to ramp the 9MM BC at this time either unless absolutely necessary for reliable performance. Cheers. G2.
