Printable View
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?
How many shots to get an average?Quote:
Originally Posted by JMJW
Powder batch variation ?
Have you FIRED one of the old loads in same chronicgraph set up???Quote:
Originally Posted by Blackfern
15 shotsQuote:
Originally Posted by McNotty
Perhaps the scales weighing the powder are slightly different in calibration?
Decent amount. Old owner could’ve used a smaller sample size and got a higher average.Quote:
Originally Posted by JMJW
Nah don’t have previous owners loads.Quote:
Originally Posted by Micky Duck
Quote:
Originally Posted by 7mmsaum
Yeah definitely will be shooting at range, I’m completely fine with the speed just curious as to the big difference
So in reality....at end of day.....all things considered.....( Dannyb will have guessed by now what my next comment will be) If you didn't have a chronograph you would still be blissfully happy lmfao. Many a good load has been ruined by those infernal machines.... Ducking now as the jandles start being thrown.
I had about a 25fps spread between the 15shots, old owner shot the rifle plenty at long range and had no issues with his speed.Quote:
Originally Posted by McNotty
If you have load running that tight...and it's accurate. Chuck the plurry chronograph away for now and just enjoy load as it is...if shooting out long it's only a couple more clicks on the twiddle n fiddle knobby things.
Are you certain the old owner wasnt stretching the truth buy a few fps to help with a sale ?Quote:
Originally Posted by JMJW
I brought a gun off here recently that was 1.5 pounds heavier than advertised [emoji1787]
Sent from my SM-S936B using Tapatalk
Yeah agreed. Happy with groups and speed. Was just really expecting similar performance for an identical load so was surprised when it was slowerQuote:
Originally Posted by Micky Duck
The old owner is @stagstalkerQuote:
Originally Posted by BRADS
I was lucky enough to buy his Saum build off him.
Timber stocked 75 sacko?Quote:
Originally Posted by BRADS
Sent from my iPhone using Tapatalk
The rifle was mine. I too am pretty curious to know how such a difference would arise. I had it at 2915fps in my ballistic app when I last verified and killed with it at range with this load. Think the lowest I got on my chrony was 2880fps.
Powder batch makes a massive difference I know another loader was using 2225 at 6 grains more than me and the batch I was using to get same speed.
So if your powder batch is different that will make a difference
Sent from my CPH2531 using Tapatalk
He didn’t buy mine[emoji23]Quote:
Originally Posted by Dicko
Sent from my iPhone using Tapatalk
Yeah reloading some more today, and gonna try a different batch and see what happens. Just gonna get the rifle shooting and validate at range for a trip coming up and then can play around with it to get some more speed.Quote:
Originally Posted by 25/08 IMP
The other way is to up your powder charge if no pressure until you get same velocity job done, that's if it's a batch difference that's causing the drop in fps.Quote:
Originally Posted by JMJW
Sent from my CPH2531 using Tapatalk
Rl26 can be like that. I dropped between .5 and 1 gn off memory when I got a different powder lot several years ago. Also barrel condition makes a difference. I recently got a rifle with rounds and load data. Pulled loads and checked against my scales. Also chronographed the loads and they were doing what the previous owner said. I as I was bored took the barrel back to bare metal when I gave it a check over and cleaned it. I lost 60-80fps by doing that. So there must have been a bit of carbon there somewhere. Hard to tell on the bore scope though. Also using possibly a different powder lot. Combine the two and there's my difference. Going to fire a few rounds and recheck speed. Just out of curiosity to see if it comes up. I have no doubt previous owner was correct in the speeds and powder charge. My test proved that before I loaded. Also I used new cases, so shoulder would have been a bit further back, possibly lowering the pressure a bit aswell. Either way I'm happy with the speed etc and can always add a bit of powder next reloading time if I want too. Will be interesting to see what the barrel says after a few rounds and retest.
Sent from my SM-A145F using Tapatalk