Chrono Results: 12.5 Triarc vs 14.5 DD with Federal 55gr Gameking (T223E)

[Jdfd556]

I went out with a friend and got some chrono data on my Triarc 12.5 Barrel and his 14.5 DD midlength barrel.

Temp: 72 degrees
Humidity: 40.63%
Barometric Pressure: 29.99 bar pressure (in HG)
Elevation: 30' above sea level
Ammo: Federal TRU 55gr Gameking
Chronograph: Magnetospeed Sporter

10 shot averages
12.5: 2920 fps
14.5: 2942 fps

Both guns had SF RC suppressors on them (12.5 had a RC2, 14.5 original RC1). We then plugged our data into Strelok Pro and confirmed the zero at 100 yds then the MRAD holds at 200, 300, 400, and 500 yards. Our holds were spot on to 500, and that 22 fps difference resulted in only a .1 mil difference at 500 yds. I held 3.5 mils, he held 3.4. We will get more data on different ammo types (Fed XM193 and BH 77TMK or MK 262 mod 1) and different barrels of the same length (2 12.5 LMT's 14.5 KAC, another 14.5 (URGI barrel), . If those results are similar using these 3 ammo types and 6 barrels (3 for each length), the 14.5 will not be a length I will buy in the future. For 5.56, it will either be a 12.5" or 16," especially since I am moving to DT suppressors to save some weight on the end of the gun.

I hope this helps anyone who was looking for this sort of data/informal write up and I will post more chrono results here hopefully soon.

 

[Molon]

Now do an apples to apples comparison. Compare your 12.5" TRIARC barrel to a 14.5" barrel that also has single edge polygonal rifling like the TRIARC barrel does, both without suppressors.



The type of rifling found on the TRIARC Track 2.0 barrel is rather unique for AR-15 barrels. The rifling is known as single edge polygonal rifling (SEPR). The patent for this type of rifling (as well as a patent for machinery used to manufacture this rifling) is held by F.J. Feddersen. With single edge polygonal rifling, one side of the land has a traditional squared edge, while the other side of the land has a polygonal edge.

The F.J Feddersen patent for SEPR states that this type of rifling produces less bullet deformation than traditional rifling. F.J. Feddersen also claims that this rifling significantly reduces escaping gases and loss of gas pressures.

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