Thread: 7saum same load different speeds

Hey everyone, recently bought a 7saum that is well known on the forum, copied same load exactly, 168 bergers, 63.6gr rl26, ADG brass, 210 primers and same seating depth. That load was doing 2900fps in 20” barrel but the loads I have done I was getting an average of 2810 fps.

What would cause such a big difference in speed when using the same load as the rifle was already shooting?

Cheers

Try drying out your powder

Altitude ??? Temperature??? Chronograph itself???

Different chronograph is the most likely culprit


Verify zero range then drop at distance, you will know your answer within two shots at 800 yards

Was 15degrees while shooting so not cold, I used a Garmin chronograph and previous load was used with a Garmin aswell

Shoot it at distance, you will get an immediate answer.

You need to do that anyway with a new setup before you can turn your attention to harvesting animals.

have you pulled one off the older loads and compared what your scales say that load is? maybe a difference in powder weight with a different set of scales?

Originally Posted by JMJW

Hey everyone, recently bought a 7saum that is well known on the forum, copied same load exactly, 168 bergers, 63.6gr rl26, ADG brass, 210 primers and same seating depth. That load was doing 2900fps in 20” barrel but the loads I have done I was getting an average of 2810 fps.

What would cause such a big difference in speed when using the same load as the rifle was already shooting?

Cheers

How many shots to get an average?

Powder batch variation ?

Originally Posted by Blackfern

have you pulled one off the older loads and compared what your scales say that load is? maybe a difference in powder weight with a different set of scales?

Have you FIRED one of the old loads in same chronicgraph set up???

Originally Posted by McNotty

How many shots to get an average?

15 shots

Perhaps the scales weighing the powder are slightly different in calibration?

Originally Posted by JMJW

15 shots

Decent amount. Old owner could’ve used a smaller sample size and got a higher average.

Originally Posted by Micky Duck

Have you FIRED one of the old loads in same chronicgraph set up???

Nah don’t have previous owners loads.

Originally Posted by 7mmsaum

Shoot it at distance, you will get an immediate answer.

You need to do that anyway with a new setup before you can turn your attention to harvesting animals.

Yeah definitely will be shooting at range, I’m completely fine with the speed just curious as to the big difference