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How many rounds per test "lot"Discussion regarding the reloading of ammunition and tuning of loads for accuracy
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calsibley Super Member
Joined: Jan 28, 2005 Posts: 317
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Posted: Fri Jul 29, 2005 1:24 pm Post subject: Re: How many rounds per test "lot" |
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I should have mentioned that I'll check several sources like reloading manuals, websites, even reloaders I know well to select a few powders and bullets to start with. I think this is critical. Some powders and bullets just aren't going to give good results so there's ltitle point in even trying them. I do like the Sierra and Nosler manuals for this reason. They list their most accurate powders found in their testing. It can really save a lot of bench time. Best wishes.
Cal - Montreal
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Handloader Super Member
Joined: Aug 22, 2005 Posts: 1032 Location: Phoenix, Arizona
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Posted: Wed Aug 24, 2005 8:30 pm Post subject: Re: How many rounds per test "lot" |
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Handloading can be done with either accuracy or hunting as a priority and, therefore, the approaches to the best load differ. Since much of our discussion seems game oriented let me describe what works for me.
Given the game sought my first choice is which caliber and which bullet that will do the job at the ranges intended. Once chosen, I now look at the slowest powder that will give the best volumetric filling and the appropriate. I want volumetric filling to be 90% of case capacity or more. Powder selection dictates primer selection*.
At this juncture I will normally have selected at least two powders that will get the job done with the bullet selected. I will then make up three round test loads beginning with bullets seated to magazine max or .20 off the lands. I normally consult all my manuals to get a good starting load and then work up in either half or full grain increments.
Now, off to the range with chronograph in hand to test for accuracy, velocity and SD. Three rounds are enough to establish a base line. Promising loads that meet the velocity criterion are then tested with 7 round groups @ 200 yds with some attention paid to seating depth and primer differences.
I have found that 200 yd testing is far more valid to evaluate a load than at 100yds. Some bullets will stabilize between 100 and 200 yds and that can result in 100 and 200 yd groups being identical size. 7 round groups will give a statistically broad enough basis for load selection. The first load that meets my predetermined hunting velocity goal with acceptable accuracy becomes the Standard Load. After identifying this load, I then will fine tune a load with seating depth trials.
This system usually allows development of acceptable loads within 20 to 30 rounds.
*Changing primers changes pressure often as much as 10,000psi! Changing pressure will also affect group size. That said, there are specific primers designed to ignite certain powders that may cause pressure increases/decreases relative to other primers.
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LittleMagnum Member
Joined: Jul 05, 2005 Posts: 105 Location: Vermont
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Posted: Thu Aug 25, 2005 7:35 am Post subject: Re: How many rounds per test "lot" |
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I start out rough and load 4 to 5 round recipe batches, in .5 powder increments, up to book max charge. OL is .15 off the lands. Look at the group size's, if one group looks good. I load 10 round of that recipe ( for 3 3-shot groups and the extra round for known pulled flyer if it happens).
If nothing looks good, onto new bullet or powder or primer. If the gun is a real shooter with most loads then I extend the range to 200 yards and pick the best recipe, then back it up with 3 more groups. Once happy I load up a 50 to 100 round batch.
Best advice I give is in note taking!......I like 3-ring hole binder white plain paper, with sticker dot's on them for targets or use a hole punch on your favorite tragets, keep thease in a 3-ring binder with load data written on each target. This way you can compare group sizes at a glance, all your load data for the that gun is in one spot. It's easy to notice things like see how it shoots better or worse as the gun gets fouled. See where the first shot from a clean barrel always goes. I call that stuff good data. Plus if you sell the gun to a friend, you can give him the reloading target data for that gun all in a handy 3-ring binder book. Every gun I reload for has it's own 3 ring binder, with notes and targets.
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Chuckhunter Rookie Member
Joined: Feb 01, 2005 Posts: 11 Location: Pocono Mtns., Pennsylvania
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Posted: Thu Aug 25, 2005 12:59 pm Post subject: Re: How many rounds per test "lot" |
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Dallen, I load at the range and shoot over a chronograph. My main concern is to get all the verticle dispersion out. Shots, left and right are usually a weather report. Once verticle is gone and I'm satisfied with the velocity, I tweak the seating depth and pehaps play with a few different primers. Whichever combo, gives me the lowest E.S. and S.D's and still meets my criteria for accuracy, thats the load I'll settle on. By using this method, my loads become boringly consistant and that's exactly what I want.
_________________ Think one Hole! |
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Coyote_Hunter_ Member
Joined: Mar 05, 2005 Posts: 208 Location: Franktown, CO
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Posted: Fri Aug 26, 2005 8:54 pm Post subject: Re: How many rounds per test "lot" |
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It used to be that I would pick a bullet, primer and powder, and then choose a starting load and 'max' load based on as many data sources as I could find that had similar (not exact) loads. Then, using 0.5g increments, I would build 5 loads at each powder charge, shoot each load over th echronograph and record velocity and point of impact. At home the velocity ahd group size numbers would get plugged into a spreadsheet that calculates Extreme Spread, Standard Deviation and Average Velocity. I would analyze the results and come up with a load. Then I would build more of that load and go back to the range to check it.
Over time I got wise and stopped building 5 loads at each powder level. I would build at least 4 and sometimes 5 for the middle loads, but taper off to 2 or 3 loads at the ends.
Nowadays I am using more powders and spend more time experimenting. I start out by building ONE load at each powder charge and record the data. Often I will do more than one powder and take them all to the range the same day. What I am looking for is differences in point of impact between shots as well as velocity for each powder. Once this data is analyzed I will select a powder and build more loads using the taper method described above - where the low and high-end loads are more for sanity checks and the center loads are where I expect to end up. (An usually do end up.)
For a given powder I generally consume about 35 bullets with the taper method and another 8-10 on the first loads.
_________________ Coyote Hunter
NRA, GOA, DAD |
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POP!! Member
Joined: Dec 02, 2005 Posts: 269 Location: Cheyenne, Wy
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Posted: Tue Dec 20, 2005 9:01 am Post subject: Re: How many rounds per test "lot" |
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Always 4. 3 shot group and one verifier if something looks weird. Now after I feel I have a good load re-verifications begin at various ranges.
_________________ FOTIS |
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BigBlue Super Member
Joined: Jan 16, 2006 Posts: 1108 Location: Lehigh Township, Pennsylvania
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Posted: Fri Jan 20, 2006 9:51 pm Post subject: Re: How many rounds per test "lot" |
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Writing it down is a lot harder for me than just doing it.
I usually start with a bullet I want to use. Then I pick the 3-5 best powders from a velocity and volume standpoint. I prefer to use the bullet manufacturers load data to pick the powders. I do reference others however. To start, I load 3 bullets for each powder at different powder and pressure levels and shoot them to check for pressure concerns. Once I've established safe load levels for those chosen powders, I then load 7 of each. I use one as a fouling shot, and it leaves me 2 different 3 shot groups. I also clean the bore between types of powder to give each an equal footing. I then pick the powder that gave the best accuarcy. It's at this point that I might play with that chosen load for COL and varied amounts of powder. In my experience, I've found that the type of powder makes more of a difference than the COL or varied amounts of powder, so I save those variables for last.
Don
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