• Chat feature is now enabled for ALL USERS!

9 MM AR

#22
I've been considering picking up a receiver set from NFA. Probably the MP5 mag style. For people running shorter barrels, what kind of velocity do you get?
 
#24
I have a AR9 that ive put 600 or so rounds through and ive yet to have any failure to eject... feed issues or anything... its a quarter circle 10... QC5 lower and side charging upper setup! it takes MP5 mags i absolutely love it! it may be my favorite gun I own. spikes tactical Bolt with spikes tactical heavy 9mm buffer has it running very reliably
 

titanNV

NRA Endowment Member
Administrator
Forum Supporter
#25
I have a AR9 that ive put 600 or so rounds through and ive yet to have any failure to eject... feed issues or anything... its a quarter circle 10... QC5 lower and side charging upper setup! it takes MP5 mags i absolutely love it! it may be my favorite gun I own. spikes tactical Bolt with spikes tactical heavy 9mm buffer has it running very reliably

Carbine or pistol?
 

titanNV

NRA Endowment Member
Administrator
Forum Supporter
#28
If you already have an SBR just build another upper in 9mm
Is this legal?

I was under the impression caliber had to be listed on the tax stamp. I might have to dig it out and see.

Of course, the lower (in my case) is different because the AR9 lower takes glock style mags, but if what you are saying is legal, a 300 BO upper might be in the cards for future build.
 

MAC702

LEGEN...wait for it... DARY!
Forum Supporter
#29
Is this legal?

I was under the impression caliber had to be listed on the tax stamp....
Absolutely legal.

The registered specifics do not matter, as long as it is registered.

My factory Colt M4 SBR is registered as a 14.5" 5.56mm. It usually lives life as a suppressed 10.5" .300 Blackout.
 

titanNV

NRA Endowment Member
Administrator
Forum Supporter
#30
I was also under the impression when I did my tax stamp that your could go longer than the barrel length specified, but not shorter. Is that a fallacy as well? I've always just left it as is.
 

stitch702

Recovering Gunaholic
Forum Supporter
#32
I have wanted to build one, but I already have a Keltec sub 2000 and an Uzi, so Its hard to justify it lol.. I may do one eventually anyway since prices are low.
But you DON'T have an AR-15 chambered in 9mm........there's justification in that!!! Also NFA is having a sale or 9mm ar lowers....
 

stitch702

Recovering Gunaholic
Forum Supporter
#33
I was also under the impression when I did my tax stamp that your could go longer than the barrel length specified, but not shorter. Is that a fallacy as well? I've always just left it as is.
If it's already a registered SBR lower, you can swap whatever upper with whatever barrel length you choose. It is the lower that is the registered SBR, not the upper.
 

titanNV

NRA Endowment Member
Administrator
Forum Supporter
#34
If it's already a registered SBR lower, you can swap whatever upper with whatever barrel length you choose. It is the lower that is the registered SBR, not the upper.
I understand that of course. When it was registered I specifically remember when the gunshop employee asked me if I was sure I wanted to register as 10.5", not shorter, explaining that you could always put a longer barrel on it, just not a shorter one. So I either misunderstood, or he misspoke. Either way, good news. I might get a 300BO upper to run suppressed.

Back to AR9 carbine build, is there anything special with the build other than the mag difference and the barrel difference? BCG?
Do they need special buffers or spring?