Integral 9mm AR

Mousehouse · Post by **Mousehouse** » Sat Apr 12, 2008 11:12 pm

Has anyone built one? If so, what length barrel did you use and what type of baffles?

I thought about using a 7.5" barrel and porting it similar to what the MP5SD. Would porting it down each side of the barrel be better?

Ideas or suggestions?

Mousehouse · Post by **Mousehouse** » Sat Apr 19, 2008 11:03 pm

I figured someone would reply to this.

This is what I am thinking.

One is to build it similar to the MP5SD and drill several holes right after the chamber in 2 or 3 different rows.

The other is similar to what most do on integral MKI, II & III barrels. Drill a couple of rows down the length of the barrel to vent the gas.

I don't know which method would be best. Any ideas?

What size should I make the ID of the baffles for 9mm projectiles?

David Hineline · Post by **David Hineline** » Sun Apr 20, 2008 12:27 am

The downfall of the MP5-SD is that the resulting power level of the bullet is 380 acp. Why port your barrel rather than just shoot 147gr bullets?

Your gun won't even have enough power to push over an IPSC popper target.

Illuminated_one · Post by **Illuminated_one** » Sun Apr 20, 2008 10:51 am

Silencer Research tested 3 different integral 9mms. The quietest was the SRT upper, and it used some porting in the barrel, but not enough to noticeably reduce the velocity. It was considerably quieter than the other two.

Mousehouse · Post by **Mousehouse** » Sun Apr 20, 2008 1:06 pm

I am mainly building this rifle to shoot and to be semi quiet.

Mtdew · Post by **Mtdew** » Sun Apr 20, 2008 8:22 pm

If you dont want to run 147gr, just port it like the SD

However use less ports so you dont drop the velocity as low as the SD. Keep drilling untill you hit 1050fps. Also keep the ports away from aluminum (use a carbon steel or SS "blast shield) if your using a Al tube

Mousehouse · Post by **Mousehouse** » Sun Apr 20, 2008 9:43 pm

I plan on using all stainless. It will weigh more but it should take a lot of abuse.

#93 · Post by **#93** » Mon Apr 21, 2008 1:05 pm

Mtdew wrote:If you dont want to run 147gr, just port it like the SD

However use less ports so you dont drop the velocity as low as the SD. Keep drilling untill you hit 1050fps. Also keep the ports away from aluminum (use a carbon steel or SS "blast shield) if your using a Al tube

Uh-ooo The Camp 45 I just built is a ported integral unit with an aluminum tube. It is thick in the area of the primary expansion chamber something like .80 and I have 1/4 inch hardware cloth rolled up around the barrel. Have you seen aluminum tubes damaged from being in the ported expansion chamber?

HandyMan · Post by **HandyMan** » Mon Apr 21, 2008 4:15 pm

Just a WAG, but I would think your safe with the hardware cloth. It would diffuse the gas from the ports.

wolf · Post by **wolf** » Mon Apr 21, 2008 5:37 pm

#93 wrote:
Mtdew wrote:If you dont want to run 147gr, just port it like the SD

However use less ports so you dont drop the velocity as low as the SD. Keep drilling untill you hit 1050fps. Also keep the ports away from aluminum (use a carbon steel or SS "blast shield) if your using a Al tube
Uh-ooo The Camp 45 I just built is a ported integral unit with an aluminum tube. It is thick in the area of the primary expansion chamber something like .80 and I have 1/4 inch hardware cloth rolled up around the barrel. Have you seen aluminum tubes damaged from being in the ported expansion chamber?

After some use ,take a look for gas cutting where the ports are
If none your safe if any ,you can put in a tight fitting piece of SS tube into the main alu tube where the gas jets hits the tube

but i think the cloth is doing the job ,,but it dosnt hurt to take alook ,,it might not to

#93 · Post by **#93** » Mon Apr 21, 2008 10:19 pm

I permanently attached the tube to the barrel so I did not have to register it as an SBR. I can not get in there to take a look. The ID of the tube is 1.5 so hopefully with the hardware cloth and the distance I will be OK. With the price of 45 I will not be shooting it as much as I would like anyhow.

Mtdew · Post by **Mtdew** » Mon Apr 21, 2008 10:28 pm

#93 wrote:
Mtdew wrote:If you dont want to run 147gr, just port it like the SD

However use less ports so you dont drop the velocity as low as the SD. Keep drilling untill you hit 1050fps. Also keep the ports away from aluminum (use a carbon steel or SS "blast shield) if your using a Al tube
Uh-ooo The Camp 45 I just built is a ported integral unit with an aluminum tube. It is thick in the area of the primary expansion chamber something like .80 and I have 1/4 inch hardware cloth rolled up around the barrel. Have you seen aluminum tubes damaged from being in the ported expansion chamber?

you will be fine. Your ports are so far from the chamber it's not a issue.

It's only a issue when you are trying to port the velocity out of 9mm (like the SD) and the ports start just past the chamber

see the previous thread on integral AR's
viewtopic.php?p=159721&highlight=#159721

BigDave@SMDW,LLC wrote:What is your outer tube made from? Aluminium will melt from the jot jets of gas coming out of the barrel ports..... Ask me how I know. You will need to put something in between the tube and the porting if you dont want to burn holes in your registerd tube.....if it is made of aluminium.......good luck in your idea, this is how we find out if a design will work, through experimentation and with people trying things.

David

BigDave@SMDW,LLC wrote:The diffiuser is only needed if your ports are within about 5 inches of the chamber, after that there isnt enough burning propellant to melt the tubing, my port that melted the aluminium tubing was about 1.5 inches in front of the chamber and it burned through the tubing in a couple of hundred rounds of semi auto fire. Use any kind of baffles at the front you want after the end of the barrel and with that much volume, you should be fine..... 2 1/4" tubing will make a really fat can wit ha lot of volume, we all know, volume is your friend

Dave

#93 · Post by **#93** » Tue Apr 22, 2008 12:21 am

Thanks Mtdew - I feel better now.

Mousehouse · Post by **Mousehouse** » Mon May 19, 2008 6:56 pm

If I build the expansion chamber separate and use a thread on suppressor would that require 2 stamps?

I thought about using a 5.5 or 6.5 inch barrel. Bore holes in the barrel, install end caps to seal the chamber. That way I can use the can on other hosts.

hmorphone · Post by **hmorphone** » Tue May 20, 2008 4:30 am

I believe that would definitely be a two stamp project.

braxton357 · Post by **braxton357** » Tue Oct 14, 2008 6:04 pm

Any updates?

Mousehouse · Post by **Mousehouse** » Tue Oct 21, 2008 8:34 pm

No update. I am having a hard time using my current barrel. I don't want to port it and I can't find a barrel like I want. I might order a blank and go from there.

I just finished a 22 integral for one of my AR's. It works well and plan on using the same design on the 9mm.

jmorris · Post by **jmorris** » Wed Oct 22, 2008 8:23 am

I built mine out of 1.75â€

Deathray · Post by **Deathray** » Wed Oct 22, 2008 8:28 am

Mousehouse wrote: I just finished a 22 integral for one of my AR's. It works well and plan on using the same design on the 9mm.

For those of us mulling over which design to go with, could you please share some details on the design? Integrals are something I have not seen much in the way of tech threads on here. I'd love to see the guts of one if to satisfy curiosity more than anything. Obviously if it's a proprietary setup, I completely understand not wanting to show it off to competitors.

Integral 9mm AR

Integral 9mm AR

Why use porting