Fast Barrel on my Cooper?

[8andbait]

Is it possible for barrels of the same length to be 100-150 fps faster than each other?

According to drop data out to 400 yards my 6.5 creedmoor is at 2840 fps when it should be 2710 according to Hornady Data.

Factory Hornady 140 gr AMAX.

zeroed at 200
300 yards is up 2.0 MOA
400 yards is up 4.5 MOA

supposed to be
300 yards up 2.5
400 yars up 5.25

According to this my velocity is 2840

Any thoughts? 130 fps more out of the same length barrel seems extreme.

Not complaing, very happy if it's true.

thanks, gary

 

[elkaholic]

Is it possible for barrels of the same length to be 100-150 fps faster than each other?

According to drop data out to 400 yards my 6.5 creedmoor is at 2840 fps when it should be 2710 according to Hornady Data.

Factory Hornady 140 gr AMAX.

zeroed at 200
300 yards is up 2.0 MOA
400 yards is up 4.5 MOA

supposed to be
300 yards up 2.5
400 yars up 5.25

According to this my velocity is 2840

Any thoughts? 130 fps more out of the same length barrel seems extreme.

Not complaing, very happy if it's true.

thanks, gary

It's not impossible but highly unlikely if you are talking same barrel length. More than likely, there is some combination of input error such as zero, scope height, etc. which is affecting your drop numbers.....Rich

 

[rscott5028]

it's not just the barrel length that matters if comparing to published load data

diferences in chamber+brass+temp+altitude+powder lot+twist rate and/or chrony error can all cancel or stack up to easily 150+/- fps

in fact, it doesn't look like you're using a chrony
rather, it appears you're calculating mv off of come-ups vs POI

so, now you've got possible error in published scope adjustment per click vs actual, plus sampling error from group sizes, variable MV SD/ES, and published vs confirmed BC

you're actually not doing bad

just keep shooting without making changes and make sure everything is consistent before you adjust

-- richard

 

[8andbait]

cool, thanks

I really do need a chronograph.
Also need somewhere I can shoot longer than 400 yards.

I have done alot of calculations and zeroing. The current combination seems to be working very well together and faster than anticipated which for me is just fine

we will see what the future brings.

thanks, gary