I have a 9mm upper. I’m trying to piece one together on AIM, or Palmetto. I never made a 9mm AR.
I’m looking at these parts to get started:
79$ barrel - https://www.aimsurplus.com/products/foxtrot-mike-9-9in-9mm-nitride-barrel
109 bolt - https://www.aimsurplus.com/products/kaw-valley-precision-blow-back-9mm-ar-bcg
If I were to buy these two things, would the rest of the parts I need just be regular AR parts to get this thing made?
Not quite. You will need a dedicated lower or a magwell block (Hahn). These come in a variety of flavors, but mostly Glock and Colt.
You need a muzzle device that 9mm fits through. The threading on that barrel makes this simple because most devices in that threading are made for 9mm.
You need to take up some space in the receiver extension (buffer tube). Most go with a longer, heavier 9mm buffer, but some get away with a carbine buffer and a spacer or stack of quarters.
Some triggers don’t work with some bolts, and/or cannot handle the stress of blowback PCCs. I’ve found that with modern ramped bolts and dedicated buffers most triggers work properly.
1168 is correct, you need to use a longer buffer but you really should use a dedicated pistol buffer. Solid steel pistol buffers weigh 6-6.5 oz, quite a bit heavier than a carbine buffer.
Andy
I use the 10 oz. KAK extended extra heavy buffer and prefer the recoil impulse with the heavier buffer.
I used an 8" PSA upper and barrel.
If I was to do it again I would go with a CMMG RDB barrel and bolt set.
I used the KVP BCG, about 1500 rounds with no issues.
Also used a KVP linear comp.
For the lower I used an Aero with a CMC PCC trigger, carbine extension with a green spring and an A5H4 buffer with a Law folder.
Vltor now has dedicated PCC buffers to 9.6 oz. https://www.vltor.com/shop/ar/buffer-components/vltor-a5-buffers-stainless/
I used Endo mag inserts and some old Pmag bodies, had three that didn’t give me any problems.
Last version of it had a 9" handguard and a KVP XL linear comp.
Unfortunately I’m in the middle of moving, and spending money. Then I’ll be saving money, but traveling longer. The 9mm lower options are so disappointing in terms of the price. I’m not a fan of the 9mm cartridge, but it’s the only ammo I see coming back to normal price. That’s why I want to build one. I already have a 556 pistol build it’s awesome to have for inside the home or what not. My 9mm build will be on the back burner for some time.
Then again I found this: https://www.midwayusa.com/product/1019567735?pid=900392