6 arc barrel starting to speed up

270quest

WKR
Joined
Jan 31, 2017
Messages
1,020
Location
Boise, Idaho
Rifle - Howa Mini 20” CF barrel, suppressed.
Load - 105 Berger hybrid, h4895, was averaging around 2725-30.

In the fall, I put around 100 rounds thru this rifle. I last used it in November and put it away. Took it out today for the first time and shot 25 rounds through it with the exact same load. Perfect conditions - overcast no sun about 70° same chronograph as last year. For those 25 shots I averaged 2790 ft./s. Most shots fell between 2780, and 2810. Meaning the barrel sped up around 50 to 60 ft./s from the last time I used it.

Gun was still sited in where I left it about 1.2 to 1.3 MOA for 10 shots at 100 yards. The SWFA 3-9x had not moved.

Going to take it out again in another week and shoot the gong at distance and verify velocities but if I’m pushing 2800 ft./s from a 105 grain hybrid that’s gonna kill a lot of critters away out there with basically no recoil! Especially at 5-7000k feet elevation.
 
A bit of copper in the bore lubricates it so you get a bit more speed.
Also the same load in fired brass is a little bit faster than new brass, probably a combination of the two, and is totally expected.
 
Yup expected if it was a new barrel.
I’ve had some speed up & level off around 100 -125 rnds. Others went closer to 200 to level off.
 
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