9mm Non-dedicated Rig

[CrowCommand]

Anyone have any advice for setting up a 9mm upper on a standard lower? Looking at magwell blocks for Glock mags…curious what I should run for BCG and charging handle.

Just bought an unknown upper cheap, has a 16” 1:10 twist. Will most likely chop and put on a pistol lower, potentially with folder.

Main questions are:

- What’s an ideal barrel length for a PCC in 9mm? - What’s the best magwell to retain LRBHO with Glock mags?

Trying to keep lower swappable to 5.56, so maybe folder is not the route. I guess I’d need the magwell to be easily removed, as well.

Thoughts?

[prepare]

The Foxtrot Mike 9 is one of the better options. The upper and lower have unique enhancements including the only reliable last round lock back.

This is the one I got.
https://store.fm-products.com/produc...7-56dca223cf24

[Dasho101]

https://getstern.com/mag-ad9/
https://sylvanarms.com/product/ar-15...version-block/

those are the only two ive ever seen

[CrowCommand]

Appreciate the responses…. The angstadt one was the first I was looking at…onwards.

[26 Inf]

Before I went to dedicated 9mm lowers I used the EndoMags which you inserted into a PMAG.



https://www.meanarms.com/products/detail/endomag-9mm

*No modifications to your 5.56x45 lower receiver! Changing calibers is now simply a complete 9mm upper for your AR platform. No nuts, no bolts, no drilling, no bull.

*Last round bolt-hold open feature, just as an AR-15 should function.

*Built-in ejector designed to perform under intense conditions.

*Convert your 5.56x45 PMAGⓇ to 9mm in seconds, and easily convert back to 5.56 without damaging your PMAGⓇ. No permanent changes to anything!

*Specially formulated polymer.

*This product carries a MEAN Lifetime Warranty! If you have an issue please contact our support department via email at support@meanarms.com. We are here to help!

The only problem that I had was that it required a precise ritual to safely clear the PCC. Because the ejector is attached to the magazine, if you drop the magazine and then lock action to rear very often the round will remain held in place on the breech face by the extractor. A casual look by the shooter or RO will reveal empty mag well and empty chamber but not detect the round on the face of the bolt. If you go action forward hammer down you may get a bang. Of course if you are placing a chamber flag in the PCC and then letting the action go forward, the round wouldn't chamber.

Solution is to lock action open, drop mag, fingerbang the bolt face, mag well and chamber as well as look.

[1168]

- What’s an ideal barrel length for a PCC in 9mm?

1/2” longer than your 5.56 gun, with the same handguard, optic, etc.

[Screwball]

I run the Stern adapter for Glock magazines… mainly because I’m issued a Glock 19. I have another SBRed lower that takes Colt magazines. Between the two… I prefer the Colt version. Easy to pull out but keeps the controls identical to a 5.56mm gun.

If you decide on Colt, follow this to a T.

https://blowback9.wordpress.com/2022...t-mag-adapter/

My current setup with Glock magazines has a 6” barrel and my Dead Air Odessa under the handguard. I have a Angstadt Vanquish 10.5” integral suppressor waiting on me to do the Form 4. I wanted to get the Odessa freed up for other use, especially since I only run that setup suppressed.

My Colt setup is similar to the DOE gun. Mainly just a fun gun, but I’m considering to pick up a 10.5” H&R upper as a spare for when I want a little extra length.

Optimal length… I’ve heard 7” to 8” is best for 9mm when you consider burn rate, accuracy and maneuverability. I know some that like under 6” for use with suppressors… to me, why not just get a Glock? I have a 16” Beretta CX4, which is a great shooting carbine. To me, SBR 9mm AR is funner that a 16”… and what I prefer.

[prepare]

Before I went to dedicated 9mm lowers I used the EndoMags which you inserted into a PMAG.



https://www.meanarms.com/products/detail/endomag-9mm

*No modifications to your 5.56x45 lower receiver! Changing calibers is now simply a complete 9mm upper for your AR platform. No nuts, no bolts, no drilling, no bull.

*Last round bolt-hold open feature, just as an AR-15 should function.

*Built-in ejector designed to perform under intense conditions.

*Convert your 5.56x45 PMAGⓇ to 9mm in seconds, and easily convert back to 5.56 without damaging your PMAGⓇ. No permanent changes to anything!

*Specially formulated polymer.

*This product carries a MEAN Lifetime Warranty! If you have an issue please contact our support department via email at support@meanarms.com. We are here to help!

The only problem that I had was that it required a precise ritual to safely clear the PCC. Because the ejector is attached to the magazine, if you drop the magazine and then lock action to rear very often the round will remain held in place on the breech face by the extractor. A casual look by the shooter or RO will reveal empty mag well and empty chamber but not detect the round on the face of the bolt. If you go action forward hammer down you may get a bang. Of course if you are placing a chamber flag in the PCC and then letting the action go forward, the round wouldn't chamber.

Solution is to lock action open, drop mag, fingerbang the bolt face, mag well and chamber as well as look.

What BCG, buffer and spring did you run?

[One More Time]

My 9mm upper was an 8", I used Endo mags.

I used a KVP BCG with a Rifle (Green) spring.
You pretty much want the reciprocating mass around 21 - 23oz.
I was using a Law folder and had to cut the carrier's internal weight off a bit to fit the adapter for the folder, with an A5H4 buffer I was at 22oz.
Ran like a champ and didn't trash the brass on the way out.
Vltor has dedicated 9mm buffers now up to 10oz I believe.

My 5.56 upper is using an A5 action.
To use The 9mm upper I used a 5/8" nylon spacer for the A5 tube with the A5H4 and green spring.
A regular carbine tube doesn't need a spacer.

[CrowCommand]

Before I went to dedicated 9mm lowers I used the EndoMags which you inserted into a PMAG.



https://www.meanarms.com/products/detail/endomag-9mm

*No modifications to your 5.56x45 lower receiver! Changing calibers is now simply a complete 9mm upper for your AR platform. No nuts, no bolts, no drilling, no bull.

*Last round bolt-hold open feature, just as an AR-15 should function.

*Built-in ejector designed to perform under intense conditions.

*Convert your 5.56x45 PMAGⓇ to 9mm in seconds, and easily convert back to 5.56 without damaging your PMAGⓇ. No permanent changes to anything!

*Specially formulated polymer.

*This product carries a MEAN Lifetime Warranty! If you have an issue please contact our support department via email at support@meanarms.com. We are here to help!

The only problem that I had was that it required a precise ritual to safely clear the PCC. Because the ejector is attached to the magazine, if you drop the magazine and then lock action to rear very often the round will remain held in place on the breech face by the extractor. A casual look by the shooter or RO will reveal empty mag well and empty chamber but not detect the round on the face of the bolt. If you go action forward hammer down you may get a bang. Of course if you are placing a chamber flag in the PCC and then letting the action go forward, the round wouldn't chamber.

Solution is to lock action open, drop mag, fingerbang the bolt face, mag well and chamber as well as look.

This may be the route I go, thank you. Building out as mainly a fun gun, most likely will not be competing with it.

1/2” longer than your 5.56 gun, with the same handguard, optic, etc.

Curious what your reasoning for this is….I would think 9mm wouldn’t need a real long barrel to stabilize.

This will be going on a pistol lower, so I guess my point is that I’d prefer it longer than hand gun barrel length, but shorter than 16”. Leaning 10.5” at the moment.

No suppressors in my state, unfortunately.

Thanks to everyone else too, I will be referencing this thread as I build.