Washington Objective: Non-SBA AR-9/EPC 9mm pistol for home defense

[Member 34319]

Every choice is a compromise. I'd only use a pistol if I couldn't reach my carbine first. Punching holes in paper tends to make one over confident. Nobody knows just exactly how a home invasion is going to go down but I'd bet my lilly white bubblegum I wont be standing in my hallway with safety glasses, earmuffs, and adjusting my stance while my heart is pumping piss. It will be terrifying and traumatic, that much I'm certain.
I'm not the only one in the house. My wife and 12 year old son better be able to defend the home and themselves in my absence and they stand a much better chance with a carbine than a handgun or shotgun. The latter two would definitely end up in misplaced shots or worse. 9mm is a better than average cartridge for a pistol and doubly so for a carbine. There are loads of good defensive rounds to choose from, practice AMMO is relatively cheap, recoil is not intimidating, and most of all because 9mm is the number one choice of professional action movie directors.
Next there's the matter of indoor shooting without a suppressor. .22LR isn't fun without hearing protection, I don't have an NFA stamp but if I did I would still choose 9mm and 6-8" barrel would be the ticket. In fact I tried to get an 8" upper but for some odd reason they seem scarce. Maybe the 11" drops a decibel.
If I accidentally shoulder my buffer tube defending my family, we all live, and the feds come for me, I'll face the music.

All very good points.

I met a lady that bought a little PC Charger from Ruger and only put a laser on it. Her thinking was pistols are too much recoil and holding it forward was difficult. She was much better at holding the little Charger with two hands down by her hip in a relaxed way and using the laser as an aiming device. Others laughed until she put 9/10 in the A from 25 yards.

 

[FnM]

Sprinco offers various strength springs for carbine length tubes. I'm running their regular strength these days with a 10oz buffer for ~23.9oz total reciprocal mass. (Note, in post below I tested and ran for a time their heaviest. Saw no difference when switching to the lighter spring in terms of bolt bounce so went lighter)

I recommend you turn right around on that Aero bcg and buy something else. (https://www.northwestfirearms.com/threads/wtf-happened-here-pew-go-boom.396062/).

The list of Aero compatible drop in triggers is in my post above, though I found success with a Triggertech AR9 trigger.

You want to shoot for 21-25oz total reciprocal mass. So bust out the scale and measure away to determine buffer weight.

Also, this works as advertised and is a worthwhile addition to a build: https://maconarmory.com/product/aero-epc-mag-catch-upgrade/

Thank you for that. It's the second time I've heard that. I already ordered the lighter spring but hadn't considered the bolt. Here's some secondhand data I found regarding Colt's original data.

Lots of 9mm AR information - AR15.COM

Firearm Discussion and Resources from AR-15, AK-47, Handguns and more! Buy, Sell, and Trade your Firearms and Gear.

www.ar15.com

The author is also favoring a 10oz. buffer and the lighter spring. Aero's bolt is reportedly 14.7oz but that too is secondhand data. The only problem I foresee is if I'm unable to get a retailer to ship parts when this bill passes. Provisions within the bill restricts the importation of any parts for AR's.

 

[Hueco]

Thank you for that. It's the second time I've heard that. I already ordered the lighter spring but hadn't considered the bolt. Here's some secondhand data I found regarding Colt's original data.

Lots of 9mm AR information - AR15.COM

Firearm Discussion and Resources from AR-15, AK-47, Handguns and more! Buy, Sell, and Trade your Firearms and Gear.

www.ar15.com

The author is also favoring a 10oz. buffer and the lighter spring. Aero's bolt is reportedly 14.7oz but that too is secondhand data. The only problem I foresee is if I'm unable to get a retailer to ship parts when this bill passes. Provisions within the bill restricts the importation of any parts for AR's.

Yea, my total reciprocal mass range comes from colt's OG designs (with some wiggle room on both ends because who really knows with all the gazillion parts now out there).

I compare Aero with a FailZero bcg here:
https://www.northwestfirearms.com/threads/wtf-happened-here-pew-go-boom.396062/post-3190835

I may have had one (or a lower) that was out of spec, but feature for feature Aero just seems to be on the low end. Still…I'd have used it if it worked and I wish you luck with your build.

 

[FnM]

Yea, my total reciprocal mass range comes from colt's OG designs (with some wiggle room on both ends because who really knows with all the gazillion parts now out there).

I compare Aero with a FailZero bcg here:
https://www.northwestfirearms.com/threads/wtf-happened-here-pew-go-boom.396062/post-3190835

I may have had one (or a lower) that was out of spec, but feature for feature Aero just seems to be on the low end. Still…I'd have used it if it worked and I wish you luck with your build.

I must have missed your final results and parts list. Did you have success or have to abandon the build?

 

[Hueco]

I must have missed your final results and parts list. Did you have success or have to abandon the build?

Success. I'm a stubborn SOB. Long and short is, if you use all Aero recommended parts or Aero branded parts and it still don't work, they'll ask you to send it to them and they'll make it right - whatever that may be.

My annoyance with them is in their not releasing any spec numbers so that people can measure and determine themselves if something is out of spec or tolerance stacked with something else.

In all likelihood, I have an out of spec lower which led to the BCG riding on top of the hammer's reset point causing the hammer to follow the bolt home, setting off the next round - and thus the cycle continued until the mag ran out or the lighter strike failed to detonate the primer.

I could have sent it back to Aero but was stubborn in wanting to learn more about the platform. From an assembly perspective, it's an easy build.

My final parts ended up being the FailZero BCG, a 10oz extended length buffer, carbine length spring, and triggertech AR9 drop in trigger.

Only thing you can do, since official dimensions don't exist, is assemble and function check it. Do safety checks with snap caps then spend the first few mags loaded 1~5 rounds until you're satisfied it's working as designed.

 

[FnM]

After rereading everything and getting my aero bolt… I'm suspecting the problem may be your aftermarket drop in trigger Both the author of the AR-15.com article an Aero issue warning of trigger reset malfunctions when using other than a milspec or standard FCG.