I'm wanting to build a 9mm on an AR platform, something with a ~9" barrel and my tirant 45.

How bad will the gas be in my face if I use a sig brace? It would be blowback operated.

I am running a 5.5" barrel with a Tirant9 and I dont even notice gas to the face. I am running a ST-9X 9mm heavy buffer and wolf high powered spring which helps in lockup time.

Running 5.5" TROS 3-lug, Blitzkrieg hydrolic buffer and JP AR-10 carbine spring. I will have a GA Revo free in the next few weeks, but have shot it with an Octane and Tirant and didn't notice any blowback at all, even with stock at its shortest.

I am using a Gibbz side charge upper so there is no rear hole for the cocking handle which might be helping. Also, if I did notice a little gas suppressed I could switch to an AR-10 rifle spring for a little longer lockup.

AR is very modular with a ton of ways to tweak it to your prefrence.

Also a .45 suppressor should have less back pressure than a 9mm, so you are already on a good path to minimize blowback.

themonk wrote:I am running a 5.5" barrel with a Tirant9 and I dont even notice gas to the face. I am running a ST-9X 9mm heavy buffer and wolf high powered spring which helps in lockup time.

Nice that's the barrel length I'll be working with on my pistol build I'll be using the JP Silent Spring. What handgaurds are you using? I'm looking at the new Midwest industries SP handgaurd.

Killerapplesauce wrote:

themonk wrote:I am running a 5.5" barrel with a Tirant9 and I dont even notice gas to the face. I am running a ST-9X 9mm heavy buffer and wolf high powered spring which helps in lockup time.

Nice that's the barrel length I'll be working with on my pistol build I'll be using the JP Silent Spring. What handgaurds are you using? I'm looking at the new Midwest industries SP handgaurd.

I did a crappy ebay rail for testing but will be swapping it out with a 10" Knights URX 4.

Killerapplesauce wrote:

themonk wrote:I am running a 5.5" barrel with a Tirant9 and I dont even notice gas to the face. I am running a ST-9X 9mm heavy buffer and wolf high powered spring which helps in lockup time.

Nice that's the barrel length I'll be working with on my pistol build I'll be using the JP Silent Spring. What handgaurds are you using? I'm looking at the new Midwest industries SP handgaurd.

Odin Works is a great choice. I went with a 10" hand guard.

I have a 5" barrel on mine with a Octane 45HD I don't notice any blowback with it. It isn't a real AR though, its a Just Right Carbine.

Ya i ended up with the Midwest Industries SP 9.25 inch. My Ti-Rant 9 sticks out about a inch. I really like it and you can take it on and off easy if needed. Those Odin Works hand guards look pretty nice too.

I've heard blowback isn't bad for right handed shooters, but left handed shooters have a much less pleasant time...

I got my Revo 45 in and have had several trips to the range and about 500 rounds through it. Even with rapid fire I never felt like I was getting gasses much, but I'm not sensitive to it. Some ammo blows a lot more smoke out the front (American Eagle) than others, but it still didn't get me. I think Lot of how much gas you get is based upon the build and the can used.

I'm running a standard upper on my 5.5" 9mm ar with a AAC TI rant 9. No issues. I also shoot lefty

BlakeJ wrote:I'm wanting to build a 9mm on an AR platform, something with a ~9" barrel and my tirant 45.

How bad will the gas be in my face if I use a sig brace? It would be blowback operated.

If you are using a Sig Brace on a pistol properly then your face should be nowhere near the pistol.