9mm PCC Options

[Funjeff]

How do people have CA legal 8" MPX's?

"Homemade" mag locks

 

[Liensevi]

I’ve got just over 5,000 rounds through my Daniel Defense DD PCC 916 now and it’s been great. Haven’t had a single issue with it so far, it’s been rock solid.

 

[AR15barrels]

How do people have CA legal 8" MPX's?

They are only legal as pistols as an 8" MPX with a stock would be an SBR under both federal and CA laws.
People use intrafamily transfer or LEO friend to get them originally and then PPT when they sell them.

 

[AR15barrels]

"Homemade" mag locks

There is a video floating around showing an MPX lower with a hogue freedom fighter maglock installed.
I'm pretty sure I could do that for people that need it done.

 

[Darqhelmet]

I'm interested in getting into Pistol Caliber Carbines for fun shooting and maybe some competition (IDPA).

I've been looking at the following:

Scorpion EVO
Sig MPX
Springfield Saint Victor
Stribog SP9A3G

I have extra Colt 9mm SMG mags and extra Glock Mags (who doesn't).

Am I missing any? Any recommendations?

No scorpion saint kicks hard or what it is. Sig annoyed me but it was a gen 1, stribog is nice, but I’ve only ever shot a mag so no long term opinion.

Sold the scorpion to many weird things and oob is not unheard of.
Oldest kids took my Saint when we moved and still love it. Sig was nice, but it never did run like the blow backs.

 

[Skilly]

I went a bit of a different path. I purchased the Juggernaut SSE 5.56 and then bought a set of Endomag inserts from Optics Planet - they ship them with no issues. I got a 9mm barrel from Faxom and then a JP Spring and Weight set. If you go this path, keep in mind the way barrel length is measured is different between 223/556 and 9mm. The 9mm barrel is total length, and the 223/556 is measured from the mounting at the receiver.

I like having an AR15 lower that I can swap to other calibers without much issue.

 

[Plenty_Pack_556]

"Homemade" mag locks

Homemade as in

 

[dirty_monkey]

 

[AR15barrels]

If you go this path, keep in mind the way barrel length is measured is different between 223/556 and 9mm. The 9mm barrel is total length, and the 223/556 is measured from the mounting at the receiver.

Wrong on both accounts.
ALL barrels, regardless of gun design, are measured from the breech face to the muzzle.
It just happens that on a rotary locking AR-15 barrel that the breechface is 3/8" forward from the rear end of the barrel whle on a blowback 9mm, the breechface is 1/8" behind the rear end of the barrel.

 

[Skilly]

Wrong on both accounts.
ALL barrels, regardless of gun design, are measured from the breech face to the muzzle.
It just happens that on a rotary locking AR-15 barrel that the breechface is 3/8" forward from the rear end of the barrel whle on a blowback 9mm, the breechface is 1/8" behind the rear end of the barrel.

great explanation, thank you. But not wrong on both counts - you're essentially providing better detail on why they are different.

If I order a 10" 9mm barrel and a 10" 556 barrel, they are going to be about 1" different correct? The confusion is in the replacement. An 9-inch 9mm barrel acts more like an 8" -inch 5.56 barrel when you measure how much stick-out room you have for your handguard.

 

[AR15barrels]

The 9mm barrel is total length, and
the 223/556 is measured from the mounting at the receiver

Both of these in bold are wrong.
ALL barrel lengths are measured from the boltface to the muzzle.
It's clearly explained in the ATF's guide.

In the specific case of a 9mm blowback operation AR barrel length, the breechface is 1/8" behind the actual barrel without any feedramp that sticks back behind the rear face of the barrel.
In the specific case of a 223/5.56 AR barrel, the breechface is 3/8" forward of the rear end of the barrel.

 

[AR15barrels]

If I order a 10" 9mm barrel and a 10" 556 barrel, they are different OAL correct?

Both will be 10" from the breechface to the muzzle.
Overall length of a barrel has nothing to do with the barrel's legal length.
Barrels lengths are described by the legal length, not their overall length because all barrel lengths are measured from the breechface.
If you choose some nonstandard way to measure barrels, you could measure from any point on the barrel you like or even from your couch to the end of the muzzle device, but that's got nothing to do with how barrels are measured in marketing materials or in the CABOF or ATF tech branches.

 

[Joker67]

People with JP5’s are amazing to watch in USPSA. Pricey, but that’s a case of getting what you pay for.

 

[Trapper]

People with JP5’s are amazing to watch in USPSA. Pricey, but that’s a case of getting what you pay for.

They combined AR ergonomics, MP-5 roller lock up, it feeds from.glock mags and has a very effective muzzle brake. Once you're tuned to the correct angle lock piece for your ammo, they are very fast and flat shooting

 

[RustVendor]

People with JP5’s are amazing to watch in USPSA. Pricey, but that’s a case of getting what you pay for.

kinda, they are the best but you can get 90% of the way there for like 2k less.

 

[Skilly]

Both will be 10" from the breechface to the muzzle.
Overall length of a barrel has nothing to do with the barrel's legal length.
Barrels lengths are described by the legal length, not their overall length because all barrel lengths are measured from the breechface.
If you choose some nonstandard way to measure barrels, you could measure from any point on the barrel you like or even from your couch to the end of the muzzle device, but that's got nothing to do with how barrels are measured in marketing materials or in the CABOF or ATF tech branches.

Right you demonstrated that (well). You are muscling through my original point - I get it; the same OAL.

How they are purchased is just length, so in practical terms, if you have a barrel you are swapping out (like I did) and you know what that length was and need it to match, don't pick the same length to replace with a 9mm barrel. It will sit differently in the receiver - replacing a 9" 556 barrel with a 9" 9mm barrel will not give you the same working length. That was really my point.

Marketing materials don't explain this very well, if at all. A 9mm AR barrel is physically shorter on the outside by roughly 1" compared to a 5.56 barrel of the same legal, measured length.

 

[painkiller]

I run a scorpion and have a JP gmr and a the JP5.Scorpion is such a great gun,and once you put a timney trigger in it, the world is limitless.The lone downside is cost of mags, but platform is cheaper than the jp overall.

 

[AR15barrels]

A 9mm AR barrel is physically shorter on the outside by roughly 1" compared to a 5.56 barrel of the same legal, measured length.

9mm barrels have the breechface 1/8" behind the rear face of the barrel while 5.56 barrels have the breechface 3/8" forward of the rear face of the barrel.
The difference between those two is exactly 1/2".

Many barrels are not the actual length they are sold as.
It's common for them to be 1/8" to 3/8" different than they are listed as.
I attribute that to marketing people that don't know how to measure barrel length and simply used a tape measure from one end to the other.
Most 16" barrels are actually more like 16-1/4" out of an abundance of caution.

 

[Skilly]

9mm barrels have the breechface 1/8" behind the rear face of the barrel while 5.56 barrels have the breechface 3/8" forward of the rear face of the barrel.
The difference between those two is exactly 1/2".

Many barrels are not the actual length they are sold as.
It's common for them to be 1/8" to 3/8" different than they are listed as.
I attribute that to marketing people that don't know how to measure barrel length and simply used a tape measure from one end to the other.
Most 16" barrels are actually more like 16-1/4" out of an abundance of caution.

Dead horse beaten. You are missing the point. You almost got it, in your first sentence though, although in the 2 experiences I had the difference was closer to 1" rather than 1/2" - might be marketing people, but they aren't usually making the spec; they are marketing the spec given to them.

Face value, account for a longer noted length in a 9mm if you plan on trying to match a 223/556 barrel you are intending to replace with something of equal length.

 

[AR15barrels]

in the 2 experiences I had the difference was closer to 1" rather than 1/2"

Then the two barrels were not the same legal length.
Someone created 1/2" of error for you to have a 1" difference.