Slow barrel with 4064?

[D_Lamz]

Went testing my new build by Chad Dixon this past weekend. Measured my velocities with a ProChrono and it seems my numbers are slow. These were the first shots with this barrel, total so far is about 43. Would more rounds that make a difference? Accuracy was good, just wondering about the velocity.
55 Degrees F
7ft of altitude

specs:
Rem 700
22in Bartlein 1/11.25
.308 win

Hornady brass
168gr Hornady BTHP
winchester primers
IMR 4064

OAL 2.800 to ogive ~2.04

42.8gr: avg 2530fps
43.1gr: avg 2545fps
43.4gr: avg 2566fps (ejector marks)

 

[lte82]

43gr of 4064 with the 168's gives me ~2650 fps with a 26" barrel that has around 300-400 rounds through it. Yours should speed up a little as it breaks in, and considering it's a 22 not a 26, ~2540 doesn't sound way out of line.

Nice looking stick by the way.

 

[Hunt]

I just had mine re-barreled by LRI as well with a Krieger 20" 1/11 twist with the Win. Sniper reamer. I was shooting:

178 AMAX
Win. brass
CCI 200
43.1 gr IMR4064

My avg velocity was 2435 fps which seemed low to me as well. This was with about 100 rounds down the tube. I'm hoping to speed it up with some Varget and see where that will get me.

 

[RobertB]

That sounds a little slow, but if accuracy is good and your not needing to shoot real far it wont hurt too bad. Hopefully more rounds will get you some more speed.

Nice rifle and good luck, let us know if she gets faster. Thats a good bbl

 

[D_Lamz]

Hopefully I'll get time to shoot this weekend and post more results.

 

[Dan Newberry]

Sometimes the chronograph is just not right... shooting at long range and plotting trajectory will reveal and apparent velocity much higher than the chronograph says.

 

[JMGlasgow]

Velocity calculations can be done with the Shooter app. Select your zero and plot the come ups for at least 3 distances. Assuming all the information about your lad is correct. Garbage in, garbage out.

 

[Dusty]

He chambered a .308 bartlein bbl for me, with his sniper chamber. Using the same laid I used in my rem. 5r I was shooting about 50 fps. slower with my custom built rifle. I wonder if it could be a loose chamber? The necks on my fired brass are running .345.

 

[bruddah]

Sometimes the chronograph is just not right... shooting at long range and plotting trajectory will reveal and apparent velocity much higher than the chronograph says.

I have seen this 1st hand when shooting ARs out to 800+ yards. Velocity seemed to be about 100 fps faster than we had measured.

 

[sib1948]

My load for my DTA 22" 308 barrel with 168 & 175gr. SMK BTHP at 2000 ft altitude and 60-70 degrees is 42.8gr of IMR4064 with Fed Match primers and once fired Fed brass. 1/3rd MOA is my best group at 100 yards. Was logging 2650 fps on my ProChronograph.

 

[D_Lamz]

******UPDATE******
Went testing again this past weekend and it seems my velocities are getting better as I shoot more. Weird? I also noticed that either I need to practice more or be more stringent when reloading by looking at some of my groups. For example when doing OCW I felt like there's no pattern with each set of groups, some with weird fliers. I also noticed when I did a string there was a higher velocity than doing round robin. (I did a string after my OCW)


82 Degrees F
7ft of altitude

42.2gr: avg 2541fps
42.5gr: avg 2560fps
42.8gr: avg 2572fps
43.1gr: avg 2587fps
**43.1gr 3 round string** avg 2609fps
43.4gr: avg 2618fps
**43.4gr 3 round string** avg 2666fps

Note how different the 43.4gr groups are

Factory FGMM 168gr 5 round string avg: 2548fps