tweaking loads
- Thread starter adubbert
- Start date
I find that the accuracy loads in the lyman reloading handbook to be a good powder charge to start with, then work up and down from there 1/2gr at a time to find the best load. just load 5 or 6 of each. you can then try different powder and bullets and seating depth, but just change one thing at a time. don,t get in a hurry {it took me two years to get my Uberti fine tuned) and keep a book to write the results in so you don,t forget what has been tried.
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I reload with different powers usually 5-10 rounds with each powder .I usually go up by .2 gr.
allowing barrel cool time between groups.
COL also a factor if you can vary it
bullet weight and manufacter variations
record keeping is a MUST.
ie. a specific load might be great in one rifle...but horrible in diff rifle of same calibre.
allowing barrel cool time between groups.
COL also a factor if you can vary it
bullet weight and manufacter variations
record keeping is a MUST.
ie. a specific load might be great in one rifle...but horrible in diff rifle of same calibre.
.2grain increments but start with all your loads at the lands. When you find a load that groups the way you want it, then play with seating depth .010 off the lands to .020 into the lands in .005 increments (.010 off, .005 off, .000 soft jam, .005 in, .010 in, .015 in, .020 into the lands) and see which tightens up the group. Use a comparator for seating depth as the ogive to tip can vary as much as .010 which can and will vary your actual seating depth into and off the lands.
You can also try .01grain above and below the load you find in the initial load test to further tweak and see if it makes a difference.
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"...the max loads for my rifles..." It's not the max load for your rifle. It's the max load for the cartridge. That'd be in your manual.
Beginning with the starting load given in your manual, load 5 rounds only. Go up by half a grain of powder, loading 5 of each keeping them separate until you get to the max load in your manual.
Then go shooting. Shoot at 100 yards, for group only, slowly and deliberately off a bench.
Change targets between strings of 5 and allow time for the barrel to cool.
Once you've found the most accurate load, you can go back to the previous charge and work up by 1/10ths to the best load.
Fiddling with the seating depth is entirely trial and error. Usually, but not always, the best accuracy comes with the bullet being just off the lands measured in thousands of an inch. Like CyaN1de says, 10 to 20 thou off the lands is usually enough.
Beginning with the starting load given in your manual, load 5 rounds only. Go up by half a grain of powder, loading 5 of each keeping them separate until you get to the max load in your manual.
Then go shooting. Shoot at 100 yards, for group only, slowly and deliberately off a bench.
Change targets between strings of 5 and allow time for the barrel to cool.
Once you've found the most accurate load, you can go back to the previous charge and work up by 1/10ths to the best load.
Fiddling with the seating depth is entirely trial and error. Usually, but not always, the best accuracy comes with the bullet being just off the lands measured in thousands of an inch. Like CyaN1de says, 10 to 20 thou off the lands is usually enough.
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So you've got a safe maximum load. Now you want to find the best accuracy. Let's assume you are loading the rounds from the rifle's magazine. If this is the case there is only so much latitude available for adjusting the seating depth of the bullet, so we should concentrate on tweaking the powder charge first.
You have your maximum load and you have a pretty good idea of how it groups, so now drop 1 full grain of powder and fire a group with that load. If accuracy does not improve, split the difference between these two and load up a half grain below max. If accuracy did improve drop a second grain and see what effect 2 grains below your maximum load has. When you see improvement record it and the load, then adjust up or down another half a grain, then a quarter grain until you find the sweet spot. I do not believe that there is any advantage to going to smaller increments than .2 grs as most powder scales are only accurate to .1 gr, but everyone will have their own opinion about this, and if you want to take it down to .1 or to .05 grs that is up to you.
Assuming you have enough length in your magazine to have the bullet seated long enough to touch the lands, you should determine the maximum load with this COL. The pressure will be higher, so do not assume that your maximum load with a shorter COL is still safe. It might very well be that the best accuracy will be observed with the bullet seated in the lands. The reason for this is because the pressure that begins the bullet's motion is very uniform round to round. Crimping does the similar thing with a shorter COL. The next step is to begin testing groups as the bullet is incrementally seated deeper. You could accomplish this simply by turning in the seater stem a quarter or a half turn for each group.
My own system is to only use bullets with crimping grooves in my hunting rifles and crimp each cartridge. When I load for my target or varmint rifles I seat out until I have firm contact with the lands. I have recorded some very accurate loads using both systems, and it is far less tedious than attempting to find the ultimate accuracy by small adjustments to the COL, only to discover that a change in powder, bullet , or primer lot numbers puts you back to square one.
You have your maximum load and you have a pretty good idea of how it groups, so now drop 1 full grain of powder and fire a group with that load. If accuracy does not improve, split the difference between these two and load up a half grain below max. If accuracy did improve drop a second grain and see what effect 2 grains below your maximum load has. When you see improvement record it and the load, then adjust up or down another half a grain, then a quarter grain until you find the sweet spot. I do not believe that there is any advantage to going to smaller increments than .2 grs as most powder scales are only accurate to .1 gr, but everyone will have their own opinion about this, and if you want to take it down to .1 or to .05 grs that is up to you.
Assuming you have enough length in your magazine to have the bullet seated long enough to touch the lands, you should determine the maximum load with this COL. The pressure will be higher, so do not assume that your maximum load with a shorter COL is still safe. It might very well be that the best accuracy will be observed with the bullet seated in the lands. The reason for this is because the pressure that begins the bullet's motion is very uniform round to round. Crimping does the similar thing with a shorter COL. The next step is to begin testing groups as the bullet is incrementally seated deeper. You could accomplish this simply by turning in the seater stem a quarter or a half turn for each group.
My own system is to only use bullets with crimping grooves in my hunting rifles and crimp each cartridge. When I load for my target or varmint rifles I seat out until I have firm contact with the lands. I have recorded some very accurate loads using both systems, and it is far less tedious than attempting to find the ultimate accuracy by small adjustments to the COL, only to discover that a change in powder, bullet , or primer lot numbers puts you back to square one.
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