My first AR pistol build. Any suggestion or comments appreciated.

[heavygunner8]

Hey,

This is my first AR pistol build, so I don't have much experience. From lurking a bit on the forums, I've come to conclude that the following parts are considered higher end quality. The purpose of this pistol is for both home defense and range shooting. Here is my list so far:

1. KAC SR-15 E3 11.5" complete upper (https://www.brownells.com/rifle-part...prod98040.aspx)
2. BCM LPK with no grip or trigger (will get a magpul grip)
3. geissele trigger SSA-E
4. Aero precision stripped lower receiver
5. Vltor A5 pistol buffer kit (A5H2 buffer weight)
6. SBM4 pistol brace
7. Aimpoint T-2 RDS

Without considering suppressor, mounted light, or angled foregrip, I think i'm just under $3000 spent. Not including work bench, vise, various tools...etc for general AR-15 building. I know this is a lot to spent, but I want high end quality parts that will last me a life time.

[Hulkstr8]

Is this your first AR build?

I personally would swap the Geissele SSA-E to a SD-C or a regular SSA for defensive ARs.

I would get a Mega Arms gator lower. I love Aero and have a bunch of their lowers, but Mega is nicer.

Otherwise it looks cool. Idk about throwing a KAC upper on a franken lower, but KAC makes nice stuff.

I would put a Law Tactical folder on it.

Also, I would just see if a local gunsmith would just let you use their tools for a few bucks.

[heavygunner8]

Is this your first AR build?

I personally would swap the Geissele SSA-E to a SD-C or a regular SSA for defensive ARs.

I would get a Mega Arms gator lower. I love Aero and have a bunch of their lowers, but Mega is nicer.

Otherwise it looks cool. Idk about throwing a KAC upper on a franken lower, but KAC makes nice stuff.

I would put a Law Tactical folder on it.

Also, I would just see if a local gunsmith would just let you use their tools for a few bucks.

Buying tools, as I plan on building more ar in the future. I already bought an aero lower, I got it for 50 bucks on a sale, so I gotta use it lol. Are there any drawbacks to having KAC upper on a Franken lower? The parts I’m putting in the lower are all high quality parts though.

[Hulkstr8]

No I wouldn't forsee any issues with using the KAC upper -it'll be nice.

I bought a shit ton of tools I thought I needed to build ARs and I end up using only a handful. Punch set. Delrin tipped hammer. Roll pin pusher (although it mars my finish every time I use it even with tape around it). Vise. Reaction block. Reaction Rod. That's all I really need, but I have more.

[wigbones]

It does seem odd to throw a $1700 KAC upper on a $50 Aero lower. While It would work, I would personally spend the extra on a KAC lower. Your parts list is all high end but then you go cheap on the lower. Either way you should have a nice setup.

[heavygunner8]

It does seem odd to throw a $1700 KAC upper on a $50 Aero lower. While It would work, I would personally spend the extra on a KAC lower. Your parts list is all high end but then you go cheap on the lower. Either way you should have a nice setup.

I thought Aero Precision was a good quality lower receiver? It's just a stripped lower, standard 7075 aluminum with smooth finishes, they usually go for around 80 - 100$. I just got a good deal at 50.

Edit: I might pick up the mega arms stripped lower and save the aero precision for another build.

[wigbones]

I'm not saying there's anything wrong with Aero Precision. In fact I've built out a couple Aero lowers and they are very good for the money. Call it OCD or whatever, I just personally wouldn't pair one with a complete KAC upper.

[MistWolf]

Based on my experience-
- Hold off on getting a free float tube. Short barrels don't flex as much long barrels. I've been shooting shorties for some time with a Magpul Slimline handguard all the way out to three hundred yards. I have yet said to myself "I need a free float tube".
- Gas port diameter is critical. Too large and recoil is sharp. Too small and it won't lock back. The window between is small on a short barrel.
- Plan on a suppressor. Suppressors make shorties better.
- I don't think an SSA-E will give you any advantage on a shorty. I think a standard trigger with a smooth pull would be better.
- Good call using the Aimpoint T2 (the Scalar Works mount is awesome), quality LPK, A5 and SB4. I used the brace they made for the Galil ACE.
GB003_zpsodotziid.jpg
- Shorties place high demands on extractors and springs. Don't skimp. I recommend the Colt spring. IG recommends the Sprinco spring.
- Don't even bother with a brake or a compensator. If you don't get a suppressor, contact Clint. He has a nifty muzzle device for shorties.
- If you need an adjustable gas block, the SLR works great and they have excellent customer service.
- Keep a spare BCG and springs on hand.

[Iraqgunz]

You can start by posting in the correct area.

[hdrolling]

I thought Aero Precision was a good quality lower receiver? It's just a stripped lower, standard 7075 aluminum with smooth finishes, they usually go for around 80 - 100$. I just got a good deal at 50.

Edit: I might pick up the mega arms stripped lower and save the aero precision for another build.

Aero works fine, but not top of the line and closer to budget a part. Why wouldn't you want a Knights lower? I would also recommend skipping the SSA-E and using an SSA unless you plan to do some precision shooting with your pistol?

Also I didn't see an end plate in your parts list, you might want a QD end plate of some sort. The BCM LPK doesn't come with one and I didn't see it mentioned when I looked up the VLTOR pistol tube kit.
I've used the BCM and Noveske QD end plates and their pretty much the same.

My pistol also has the BCM LPK, great kit and everything fits and works the first time. I also have the SBM4, works and looks great but in warmer weather it softens up and moves a slight amount.

300 1 by hd_rolling, on Flickr
300 2 by hd_rolling, on Flickr