Best barrel length for 9mm sbr?

[Maverick1911]

I can't imagine this hasn't been addressed at some point but I a new to the sbr world....all my stuff is 16 inches or better. So, if I am building a 9mm ar that I eventually would like to run suppressed, is there an optimal barrel length? Loss of accuracy differences? And what barrel makers are the get to go with without ruining the bank?

 

[338Shooter]

5" TROS 3 lug barrel.

 

[CAR-AR-M16]

I can't imagine this hasn't been addressed at some point but I a new to the sbr world....all my stuff is 16 inches or better. So, if I am building a 9mm ar that I eventually would like to run suppressed, is there an optimal barrel length? Loss of accuracy differences? And what barrel makers are the get to go with without ruining the bank?

Barrel length effects velocity, not accuracy.

5" TROS 3 lug barrel.

Can't go wrong with one of those. I had one that was accidentally shipped to me. I was a nice guy and called them up and they sent me a prepaid shipping label with the right guys address.

 

[Gabriel42]

Sorry for the hijack but this thread got me curious. I promise I will begin doing my own research shortly but is there an reliable setup that I could run with an existing SBR'd AR lower that will accept Glock magazines? Assuming an adapter is needed. Thanks.

 

[Nimaro]

Sorry for the hijack but this thread got me curious. I promise I will begin doing my own research shortly but is there an reliable setup that I could run with an existing SBR'd AR lower that will accept Glock magazines? Assuming an adapter is needed. Thanks.

the OPs thread piqued my interest as well and I was curious about the same setup Gabriel mentioned. Are there any complete 9mm upppers in a 5-7 inch length that are a must have?

 

[Maverick1911]

5" TROS 3 lug barrel.

I was looking at Tros but read a few reviews on their accuracy being all over the place....I have no personal experience with them but would be interested in hearing how you like yours? It says it is for colt style magazines....will it not work with other mags/uppers?

 

[338Shooter]

I wouldn't fiddle with a 9mm AR that isn't the Colt pattern. You'll always be able to get parts for a colt pattern gun.

I have shot mine at steel out to 200 yards. Did fine with open sights. It's the only part I kept from my 9mm AR when I parted it out. Sitting in the safe waiting to be used again one day. Or auctioned off to the highest bidder I suppose.

 

[pritch]

I'm just wrapping up a DI AR build with a lower from Double Diamond Law Enforcement that is designed to take Glock mags. While the product is stellar, dealing with the company has been a nightmare! If you want one of their lowers, buy it from Riflegear.com, NOT DDLES directly! The upper can QC barrels, so I can swap out the 16" barrel for one with an integral suppressor or a short one if I go the SBR route.

(Pic not mine!)

[Broken External Image]

 

[leemozoid]

Lone Wolf also makes a Glock magazine compatible 9mm lower.

I have a 5" TROS 3 lug upper. Unfortunately I only have 1/2x28 threaded cans. Anyone make a 3 lug to direct thread adapter? Title II arms advertises one but they seem in a perpetual state of out-of-stock.

 

[sethk]

Check this out for velocity info at various barrel lengths:

http://www.ballisticsbytheinch.com/9luger.html

On average, the biggest drops in fps per inch of barrel lost are from 13" to 12" and 9" to 8" inch and then then after 7 inches the loss climbs increasingly (though 5" is a relative sweet spot).

Here's what you loose in fps for each length compared to a 17" barrel:

16": -14.2
15": -16.3
14": -13.2
13": -18.4
12": -44.5
11": -51.4
10": -62.4
9": -64.3
8": -80.9
7": -96.8
6": -125.3
5": -151.2
4": -210.7
3": -279.5
2": -365.1

I suppose the length isn't so important if you plan on shooting subsonics. (?)