M*CARBO Brotherhood

9mm AR issues at the range

Okay, I went to the range Monday to enjoy some Veteran Freedom firepower display, Ia lso went with a coworker who is a Vet with limited shooting experience. I let him shoot my AR-15 in 9mm, when he calls me over saying he can’t get a round to chamber, mind you this is the first time this rifle is being shot, and

Upon further examination…

If you guessed broken shell, you would be right. I watched a video on shell extraction from Midway USA and am currently soaking the brass in Kroil before I go to extract it. Has this ever happened to you. (FYI the red round is a snap cap used for images)

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I was wondering bout the snap cap lol. damn on a new case? what ammo brand and lot? yep its happened to me, a couple of times when i first started reloading and on occasion now.
the sell broke shell extractors. makes it a simple removal. problem being, they dont make one for 9mm. that ive found. I made my own, but its involved, but before that, depending on how bad the case is jammed,#1 I have used a tap 3/8 tap it into the brass case being careful, insert a bolt, then use a wooden dowel knock it out from the barrel end,
#2 stainless 7.62 bore brush if its not jammed in too hard twist the brush into the casing and pull. got about a 50/50 shot with that.
hone/polish the chamber after removal barrel is not broken in so its a tad tight probably.

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The video shows Larry Potterfield using an oversized bore brush and forcing it into the cartridge. When I think of it now this was a box of commercial reloaded ammo I picked up a while back.

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yep. that works. think its 308 brush for 9mm. on bad ones, usually over pressured loads,
i had to do the tap trick, but last one was on a 22/250 that he loaded way to hot.made it more of a pain in the but it was in a bolt action Remington 700. case puller i had then wouldn’t work on that chamber.space constraint.

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lot of times with reloads, its someone that has used the case one time to many loading hot loads, and they got to thin…cases stretch.
not tellin you whats what, but i would break than ammo down to components. and reload it. checking the cases as i go.
i dont use anyone’s reloads. except my own.that way, if something happens its on me…

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Some what related but about 15 years ago when I was still collecting a civilian Uncle Sugar pay check I was qualifying with my Glock 22 shooting factory fresh government issued 40 S&W Federal Hydro Shok ammo and I had a head case separation in the chamber. Did a New York reload and went for my back up gun. We had to send the barrel in to our service’s armory and they said the case looked to be a 9mm round in the box of 40s. WTH??? Never thought the factory could do something like that.
Tom

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Tell me about the build.
Buffer weight/ length
Spring details
BCG
Barrel
It is very possible that an incorrect recoil balance caused this, blowback ar carbines and pistols need some pretty specific components to operate reliably.
Not enough ass and the BCG takes off way to soon/fast, before the pressure drops enough to extract reliably.
Something to consider.
I’ve built 3 blowbacks in the last year, touchie little buggers.

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Albrosmith, this gun is built off of New Frontier Armory (NFA) Lower, and an Anderson upper (this was changed to a New Frontier side charging upper post incident to make it all NFA). Barrel is 16 inch NFA, Buffer is stock M4 with a spacer by NFA. BCG is also NFA.

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It could use a heavier buffer, that should slow down extraction marginally allowing chamber pressures to drop a bit more.

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See your new post, what a coincidence, just had the zombie killers out last weekend!
On 9mm I think you would need a 7.5 oz buffer, .on my .40’s I run 10 oz. That stock one is way tooooo light.
Also, loose the spacer, KVP (among others) makes pistol caliber length buffers (4-1/8") Solid stainless in 7-1/2 oz and tungsten 10 oz. Also, the BCG should have the weighted plug in it (look in the butt end, filled or hollow?). For 9mm I would start with a sprinco red spring, start with a Sprinco orange or 308 extra power in the 40’s.
Also, when you are working up a good recoil balance, load 1 or 2 rounds only several times before you fill up a mag. There is a magic balance that can happen where the BCG travels back just far enough to pickup the next round without resetting the disconnect in these rigs, resulting in really cool multi round bursts impressing your friends but unfortunately attracting unwanted attention from the LEO’s
One last thing, Mill spec FCG is also a good idea, the bolt speed these things generate will blow right by the disconnectors in some “High quality” and “Super Smooth” FCG’s, again resulting in full fun mode and the above mentioned unwanted attention. Anti rotation pins are also a good idea, a lot more load wearing on those trigger pins then a typical AR.
Enjoy!

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The zombi killers


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@Squidder_K I was digging around and have an extra red spring and 7.5 buffer, just for the data I would like to loan it to you to see how it works in your 9mm platform. If you are game, pm me your address.

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