I bought some Hornady "American Gunner" ammunition in 308.
They claim 2700 fps from a 24" test barrel.
On my rifle, when tested with a MagnetoSpeed chronograph, I only saw 2520 fps (give or take 15 over a number of shots).
I have a 1 in 10 twist, 24" barrel - so was expecting to be near factory figures...
Is this just manufacturers claims or am I likely to see much difference on a hot day etc?
Weather conditions impact on muzzle velocity?
Moderator: dromia
Forum rules
All handloading data posted on Full-Bore UK from 23/2/2021 must reference the published pressure tested data it was sourced from, posts without such verification will be removed.
Any existing data without such a reference should be treated as suspect and not used.
Use reloading information posted here at your own risk. This forum (http://www.full-bore.co.uk) is not responsible for any property damage or personal injury as a consequence of using reloading data posted here, the information is individual members findings and observations only. Always verify the load data and be absolutely sure your firearm can handle the load, especially older ones. If in doubt start low and work your way up.
All handloading data posted on Full-Bore UK from 23/2/2021 must reference the published pressure tested data it was sourced from, posts without such verification will be removed.
Any existing data without such a reference should be treated as suspect and not used.
Use reloading information posted here at your own risk. This forum (http://www.full-bore.co.uk) is not responsible for any property damage or personal injury as a consequence of using reloading data posted here, the information is individual members findings and observations only. Always verify the load data and be absolutely sure your firearm can handle the load, especially older ones. If in doubt start low and work your way up.
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IainWR
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Re: Weather conditions impact on muzzle velocity?
Calibration on your chrono?
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Mikaveli
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Re: Weather conditions impact on muzzle velocity?
Ha ha - I only chrono'd to calibrate my calculations...IainWR wrote:Calibration on your chrono?
Now I have to chrono a chrono?
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ukrifleman
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Re: Weather conditions impact on muzzle velocity?
Altitude, ambient temperature, barometric pressure and the fact you are not using the same test barrel, will all have an effect on muzzle velocity.
Factor in any variance in your chrono and you would be very fortunate to replicate the test load velocity.
Hold a few rounds back from your batch and test fire them on a warm sunny day and see the difference!
How many people actually get the published MPG out of a gallon of fuel as advertised by vehicle manufacturers?
ukrifleman
Factor in any variance in your chrono and you would be very fortunate to replicate the test load velocity.
Hold a few rounds back from your batch and test fire them on a warm sunny day and see the difference!
How many people actually get the published MPG out of a gallon of fuel as advertised by vehicle manufacturers?
ukrifleman
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