Chopping a barrel

[LowSpeed_HighDrag]

Trying to make a solid, suppressed only upper. Sending a 6920 OEM2 to ADCO to have it chopped at 11.5". I think that the smaller gas port will be beneficial in suppressed shooting. My worry is that a government profile barrel couldnt be chopped and threaded at 11.5 due to the 203 notch.... Anyone know about this?

[MegademiC]

Trying to make a solid, suppressed only upper. Sending a 6920 OEM2 to ADCO to have it chopped at 11.5". I think that the smaller gas port will be beneficial in suppressed shooting. My worry is that a government profile barrel couldnt be chopped and threaded at 11.5 due to the 203 notch.... Anyone know about this?

I had one done, the threads are in the notch, which is larger than 1/2” diameter. It works.

[tango-papa]

I had one done, the threads are in the notch, which is larger than 1/2” diameter. It works.

Curious - leaving gas port as is?

tp

[Todd.K]

I want to say somewhere almost 11" will put the threads in the notch with a full shoulder behind it.

The dwell time 11.5" fans like over 10.5" does not apply to dedicated suppressed. The can adds more than enough dwell time for either, so it comes down to handguard length and looks.

[Clint]

The dwell time 11.5" fans like over 10.5" does not apply to dedicated suppressed. The can adds more than enough dwell time for either, so it comes down to handguard length and looks.

Do you consider the 10.5" to be a better choice than 11.5" for dedicated suppressed use?

Trying to make a solid, suppressed only upper. Sending a 6920 OEM2 to ADCO to have it chopped at 11.5". I think that the smaller gas port will be beneficial in suppressed shooting. My worry is that a government profile barrel couldnt be chopped and threaded at 11.5 due to the 203 notch.... Anyone know about this?

You can only get about 11.25" barrel length before the shoulder gets into the taper down for the notch.

A good option may be to chop to 10.5" which removes the whole notch and thread 5/8-24 if the suppressor mount has that option.

[MQ105]

5/8-24 has advantages if, as Clint stated, your mount allows. You can tell Adco to put the shoulder where the barrel begins to taper rather than specifying a specific length. I have a DD barrel that was done this way and it's about 11.2" and runs great suppressed. .067 port.

[MegademiC]

Curious - leaving gas port as is?

tp

Yes.
It was a stag upper I no longer had a use for, so I chopped it to 11.5” for a pistol build for an iron sighted range gun.

Gp measures .075” with calipers (I know it’s not proper, hence the call-out on method).

Clint’s post reminded me- I think there was a slight convex taper to the shoulder which would make up about .25”. I wasn’t worried as I’m running an a2 with a crush washer.

The gun has an h buffer and shoots very smooth. No suppressor, so it seems .075 would be a little over gassed for a dedicated silenced upper, but I’ll let others provide more detail on that.

This might sound like some hall of shame stuff, but it’s a junk range gun I’m just playing around with just to see how it works and how I like the length.

[SeriousStudent]

Out of pure idle curiosity, why wouldn't you just buy one of these?

http://sionicsweaponsystems.com/stor...gas-block.html

http://sionicsweaponsystems.com/stor...-stripped.html

[titsonritz]

Out of pure idle curiosity, why wouldn't you just buy one of these?

http://sionicsweaponsystems.com/stor...gas-block.html

http://sionicsweaponsystems.com/stor...-stripped.html

I was actually wondering the same thing.

[Todd.K]

Do you consider the 10.5" to be a better choice than 11.5" for dedicated suppressed use?

...thread 5/8-24 if the suppressor mount has that option.

I prefer the shorter length myself.

Great tip on threading 5/8-24 if possible. I have made a few custom barrels for myself with 5/8-24 threads.

For anyone wondering, a 14.5-16 carbine barrel with a spec gas port is just right for a suppressed only barrel when cut down.