13.7

[Odinz7]

Contemplating getting a 13.7 BA barrel

Was wondering if anyone has experience with these and pin and welding them to 16 legal?

Gonna get a dead air keymo brake for it (read they work) If anyone has experience here?

also Bexar arms did a great chart for what Muzzle Devices work for 13.7 to 16 lengths.

Based on this sheet my ideas will work but Wanted to see if any first hand experience from anyone. Thank you!


Bexar arms write up: https://docs.google.com/spreadsheets...Tig/edit#gid=0

[secondwind]

I've done a couple with a Noveske KX3, they worked great

[beanz2]

Contemplating getting a 13.7 BA barrel

Was wondering if anyone has experience with these and pin and welding them to 16 legal?

Gonna get a dead air keymo brake for it (read they work) If anyone has experience here?

also Bexar arms did a great chart for what Muzzle Devices work for 13.7 to 16 lengths.

Based on this sheet my ideas will work but Wanted to see if any first hand experience from anyone. Thank you!


Bexar arms write up: https://docs.google.com/spreadsheets...Tig/edit#gid=0

I had a Dead Air DA101 muzzle brake on a 12.5 Ballistic Advantage barrel. I guess it worked, but I didn't have any comparison with another device on the barrel. The biggest negative about the DA101 is that it is very heavy. I used it mostly for a suppressor mount.

Later I changed for a Precision Armament Hypertap brake. It was much lighter and the muzzle rise was perceptibly reduced over the Dead Air DA101 (on the 6x scope I was using.) I lost the Key-Mount compatibility, but to those in California, that probably should not matter.

[Odinz7]

I had a Dead Air DA101 muzzle brake on a 12.5 Ballistic Advantage barrel. I guess it worked, but I didn't have any comparison with another device on the barrel. The biggest negative about the DA101 is that it is very heavy. I used it mostly for a suppressor mount.

Later I changed for a Precision Armament Hypertap brake. It was much lighter and the muzzle rise was perceptibly reduced over the Dead Air DA101 (on the 6x scope I was using.) I lost the Key-Mount compatibility, but to those in California, that probably should not matter.

That is true. I liked the idea of the keymo attachment, in case I ever get the opportunity to move from this dreadful place.

[beanz2]

That is true. I liked the idea of the keymo attachment, in case I ever get the opportunity to move from this dreadful place.

Once I wrote to Precision Armament to see if they can license and incorporate Key-Mount into the Hypertap and they replied, "Stay tuned." So I have some hope there. The Hypertap may not have the length you need if you want to pin and weld however.

Removing a pinned and welded device is not usually very hard, but there is a fair chance you may damage the muzzle device.

[Rukus]

I’ve used the BE Meyers 249f. It worked well. They are discontinued afaik, but there is at least one company I’ve seen that makes a clone with the same dimensions.

[Capybara]

Just a non-AR fanatic guy and reloader here but wouldn't reducing the actual length of the rifling and barrel itself and making up the difference with the muzzle device potentially degrade ballistic performance? Less rifling and not sure of the difference between barrel affect versus muzzle device affect on ballistics?

I've seen a lot of CGers do this when trying to build a replica of various ARs like the XM177, etc. Do people mainly buy sub 16" barrels in Commifornia just for looks or is there some added benefit that I, not being an AR fanatic, just an AR owner and casual shooter don't understand?

Enlighten me please!

[DrewTheBrave]

Just a non-AR fanatic guy and reloader here but wouldn't reducing the actual length of the rifling and barrel itself and making up the difference with the muzzle device potentially degrade ballistic performance? Less rifling and not sure of the difference between barrel affect versus muzzle device affect on ballistics?

I've seen a lot of CGers do this when trying to build a replica of various ARs like the XM177, etc. Do people mainly buy sub 16" barrels in Commifornia just for looks or is there some added benefit that I, not being an AR fanatic, just an AR owner and casual shooter don't understand?

Enlighten me please!

There is a compromise here, with the goal of finding the shortest barrel configuration with the desired muzzle device to be legal for use as a rifle. Yes, a 16" barrel without a muzzle device would give you a little bit extra velocity, but muzzle devices offer performance benefits that many of us are willing to give up some velocity to obtain.

Some people have specific muzzle devices that they prefer, and will choose the shortest barrel they can find that will still meet the 16" legal minimum once it is permanently attached.

I went with a Wilson Combat 14.7" barrel because it was on sale, and their muzzle brake is designed specifically to exceed 16" when installed. It also gave me the option to use a blast diverter for when I don't want a shockwave to blast my range neighbors or my shooting buddies (like my spotter when hunting).

https://shopwilsoncombat.com/BLAST-DIVERTER-RAPID-THREAD-MUZZLE-BRAKE/productinfo/SP-RTMBBD/

I have long rifles for precision shooting, and short AR pistols for close range use. But many of us want a "goldilocks" gun that does everything well, and are willing to make some compromises to find that perfect balance of size & performance. 13-15" pinned & welded barrels are a great way to find that sweet spot.

[Capybara]

Thanks Drew. Good explanation. I've seen it for years here but this post by the OP just triggered the question, "Why"? Makes sense.

[ar15barrels]

Contemplating getting a 13.7 BA barrel

Was wondering if anyone has experience with these and pin and welding them to 16 legal?

Gonna get a dead air keymo brake for it (read they work) If anyone has experience here?

also Bexar arms did a great chart for what Muzzle Devices work for 13.7 to 16 lengths.

Based on this sheet my ideas will work but Wanted to see if any first hand experience from anyone. Thank you!


Bexar arms write up: https://docs.google.com/spreadsheets...Tig/edit#gid=0

I have perm attached a LOT of 13.7" barrels but also had a LOT of people show up that were not accounting for the length of the barrel's threads being inside their muzzle device when they did the math in their head without subtracting the 5/8" of thread length.

You need a 3" of muzzle device and shims/washers to get a 13.7" barrel to 16.1".

That spreadsheet linked above does not take into account muzzle devices with a counterbore and the effect on how many threads will be engaged between the muzzle device and the barrel.
I do not advise going to less than 7 threads of engagement (1/4") as less than that is not a really good thread junction to hold a muzzle device let alone a suppressor.
The surefire muzzle devices listed are missing 1/8" of threads at the rear so when you add the necessary spacers to get a 2.7" muzzle device on a 13.7" barrel to be over 16", you have something like 3-5 28tpi threads engaged.
So while the theoretical math used in the spreadsheet above seems to work, in reality, many are not a good idea for actual use.
You are FAR better going to a 13.9" barrel and not running any extra spacers to just get over 16".
Then you get 10+ threads of engagement and no worries about baffle strikes or muzzle devices coming off the end of the barrel and flying downrange.

[sigstroker]

That is true. I liked the idea of the keymo attachment, in case I ever get the opportunity to move from this dreadful place.

Be sure to use shims instead of a crush washer, to assure concentricity for when you put a can on it later. It won't be easy to swap those out if it's pinned and welded.