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MH64
11-22-07, 15:43
OK, am looking to build a 9mm upper and am not wanting to put it on a dedicated 9mm lower. So what do I need to do to get the 9mm to work on a 5.56 lower?

Don't know anything about magblocks so what do you guys recommend and why? And whats up with top-load v bottom-load mag blocks?

I have a spare Colt M16/SP1 upper (no barrel), Colt 9mm bolt/buffer and 9mm port cover. So figure the minimum to get will be 9mm barrel and magblock.
What else?

Buck
11-22-07, 18:43
Given the parts that you already have and your requirements, I would suggest the following. It should be just the thing for killing cans and jack rabbits.

I believe the best mag block is the HANN top load

You will need to change to a 9mm hammer, but it will work with your 5.56 upper too

A 9mm M4 style barrel from RRA should also suit your needs.

From Brownells

100-000-920
Hann Precision Top-Loading 9mm Conversion Block $140

739-000-015
Brownells AR 9mm Hammer $16


From Rock River Arms

9MM0201ASY 9mm Chrome Moly Barrel Assembly, 16-Inch CAR
With bayonet lug, threaded, 1/2-36 thread. $185

Just my .02

TacDoc
11-23-07, 06:31
I'm researching the 9mm AR possibilities also. As I understand, if you ramp the 9mm bolt you can use ANY trigger in your lower receiver. 9mm hammers are single stage only. This modification to the bolt lets you use a 2 stage FCG like the RRA.

ADCO list this in their shop services for $35.

LukeMacGillie
11-23-07, 06:35
Given the parts that you already have and your requirements, I would suggest the following. It should be just the thing for killing cans and jack rabbits.

I believe the best mag block is the HANN top load

You will need to change to a 9mm hammer, but it will work with your 5.56 upper too

A 9mm M4 style barrel from RRA should also suit your needs.

From Brownells

100-000-920
Hann Precision Top-Loading 9mm Conversion Block $140

739-000-015
Brownells AR 9mm Hammer $16


From Rock River Arms

9MM0201ASY 9mm Chrome Moly Barrel Assembly, 16-Inch CAR
With bayonet lug, threaded, 1/2-36 thread. $185

Just my .02

Why does he need to change to a "9mm" hammer, Do you need a special hammer to make 9mm go boom;)

Buck
11-23-07, 11:30
Why does he need to change to a "9mm" hammer, Do you need a special hammer to make 9mm go boom;)

Actually yes you do...

A semi auto carrier and a semi auto hammer will not work. If you wanted to I guess you could buy a full auto m16 bolt carrier and a full auto m16 hammer and put them in your semi carbine and brave the BATFE, that would work, or you can simply use a semi auto 9mm hammer...

LukeMacGillie
11-23-07, 12:18
Actually yes you do...

A semi auto carrier and a semi auto hammer will not work. If you wanted to I guess you could buy a full auto m16 bolt carrier and a full auto m16 hammer and put them in your semi carbine and brave the BATFE, that would work, or you can simply use a semi auto 9mm hammer...

Is there a special 9mm Semi Only Bolt?

SuicideHz
11-23-07, 12:35
Actually yes you do...

A semi auto carrier and a semi auto hammer will not work. If you wanted to I guess you could buy a full auto m16 bolt carrier and a full auto m16 hammer and put them in your semi carbine and brave the BATFE, that would work, or you can simply use a semi auto 9mm hammer...


Nothing wrong with the bolt carrier being a FA bolt carrier.

I don't know why you are insisting on the FA hammer.

I am using a 2-stage RRA NM with my Colt bolt and it works fine. I had it ramped though.



IMHO you ought to send your bolt in to ADCO and have it ramped and at the same time order a barrel from him and let him ship it all back together.

Use whatever trigger you want at that point. It leaves you room to upgrade your 5.56 setup in the future.

Buck
11-23-07, 13:30
Nothing wrong with the bolt carrier being a FA bolt carrier.

I don't know why you are insisting on the FA hammer.

I am using a 2-stage RRA NM with my Colt bolt and it works fine. I had it ramped though.



IMHO you ought to send your bolt in to ADCO and have it ramped and at the same time order a barrel from him and let him ship it all back together.

Use whatever trigger you want at that point. It leaves you room to upgrade your 5.56 setup in the future.

Im not insisting on anything... I simply answered the question...

My suggestion was to purchase a $16 9mm hammer from Brownells that is designed to work in the Colt 9mm AR platform... It will function with a standard semi carrier and will also function with a standard 5.56 upper...

If you want to suggest that someone use a modified bolt from ADCO firearms, thats fine too... It just costs more...

Ramp 9mm Bolt: Modify bolt for use with standard hammer $35.00

Just my.02

Buck

SuicideHz
11-23-07, 13:35
I addressed the price difference without spelling it out.

$35 ramping ($19 more than new hammer) = freedom to use whatever trigger later on and not have to get ramping done THEN when he'd rather not give up a working 9mm carbine. I say get it out of the way now, all of it.

That's all. That and he won't have a $16 hammer sitting around if he upgrades later...

BigTinVA
11-23-07, 15:30
If a 9mm hammer is used, is ramping the bolt still necessary? I have read that the 9mm AR's are particularly hard on hammer pins and can elongate the holes in the lower receiver, is this due to the hammer style used or non-ramped bolts, just the nature of the beast or what? Thanks for any input and sorry if I am taking this thread off topic.

SuicideHz
11-23-07, 15:38
I do know that you can use KNS anti rotational pins to prevent this problem and IIRC, it only happens when going FA or bumping...

MH64
11-23-07, 21:38
OK let me see if I got this right.

A Hahn top load block
Ramped 9mm bolt
Std AR 5.56 semi hammer