Load Development
We wrote this article to see if we can open up some postings from some of the blog readers out there. If you would like to offer your two cents on how you go about developing a load, please feel free to post them on the blog for others to read. We are sure everyone will appreciate looking at other shooters approach to fine tuning a load.
Each handloader has different goals in mind for load development. Many shooters are trying to achieve the best accuracy they can regardless of velocity and the type of bullet they shoot. Other shooters, especially long-range shooters, may have a muzzle velocity number as a goal but more importantly a resulting terminal velocity which will determine the amount of wind drift they experience down range. These shooters are also concerned about bullet stabilization at long range. Usually benchrest, varmint, or prone long-range target shooters, will be highly aware of the external ballistics of their bullet with respect to what is happening down range. A silhouette shooter (IHMSA type) will demand accuracy but also be mindful of terminal energy at the target for knocking over the heavier ram silhouettes. Other handloaders, such as hunters, may be trying to reach a muzzle velocity or terminal velocity value for a particular type of hunting bullet so the bullet penetrates and expands properly on impact. Regardless, accuracy always remains a goal for most load development processes.
Regardless of the type of shooting you do, it is important to establish a goal for your load development. The goal may be pure accuracy, muzzle velocity, terminal velocity, or some combination of the above. If you are trying to develop an accurate load for 1000 yard shooting, it is not important how well the load groups at 100 yards but how well it groups at longer distances or how it bucks the wind. If you are a traditional benchrest shooter who shoots 100 yards and 200 yards, it is important to test your loads at 200 yards as well as 100 yards. You may find that one load will group better at 100 yards and another load groups at 200 yards. You might want to test various loads in windy conditions because one load may experience less wind drift than another.
When developing loads, we try to test basic loads in predominately calm weather and at temperatures close to the temperature range we will be using the final product in. If there is wind, try to shoot in a consistent crosswind if possible and by all means use flags if you have them. Watch changing light conditions as it can create vertical stringing that may mislead your interpretation of your groups. Change one variable at a time. If you want to try a different primer, then keep everything else the same. Same goes with bullet type, weights, seating depth, cases, powder type, charge, etc. It is much easier to see the results if you only change one thing. Start with 3 to 5 shot groups at shorter distances to see if a change you made looks positive or negative. Start with a quality bullet first, try a recommended powder out of your reloading manual, then experiment with different charges, different seating depths, primers, other powders, and lastly change the brass manufacturer or lot if you feel it will be beneficial.
Invest in a decent chronograph. It doesn’t have to have all the bells and whistles, just the basics. A chronograph is an invaluable tool for use during load development. Knowing the muzzle velocity will allow you to predict wind drift down range, bullet drop, and terminal velocity. Standard deviation is a good indicator of consistent performance but not always a true indicator of a load’s ability to group well. The chronograph can also be used to identify performance changes when switching to a new lot of powder, primers, bullets, or even cases.
While developing a load, recordkeeping is extremely important. Keep good records on firearms, components, seating depths, weights, powder measure settings, weather conditions (especially temperature and humidity), velocities, etc. Buy a logbook or create your own, but keep track of the data. It will serve you better than your memory regarding components you have tried when you come back to that particular firearm a year later.
As we stated earlier, the purpose of this article was to get readers to post some of their thoughts on load development and share them with other viewers. We encourage you to post any specific things you do that helps you in load development.
July 15th, 2009 at 1:13 pm
Please explain about the light and how it affects POA in relation to POI and under what conditions, and how to correct for it.. Thanks, JKBIII
July 15th, 2009 at 3:56 pm
I’m reloading my 223 with 23.3 grs of reloader 7.using the 53 gr Sierra Match King .I’m getting dime size groups at 100yds.Under 2 inches at 200yds and under 4 inches at 300yds.My rifle is a Kimber 84m.Any one got a better load?
July 15th, 2009 at 7:49 pm
For me load development is more than half the fun of the sport. My first venture into serious load development began with a 17 Mach IV that had an extra-long neck. This was not by choice- the chamber reamer was incorrect and it was not identified until we bought and used a Sinclair Chamber length gauge during our first round of load development for this cartridge.
The request also noted the needs to determine your ultimate goal. Our primary goal was precision (group size) because we wanted to use these for small varmints. Of course we also wanted the highest velocities we could get with acceptable precision.
(NOTE: Precision is the size of the group. Accuracy is the position of the group over the intended target. Accuracy is adjusted with sights and sighting, precision is how the firearm and a specific load behaves and can not be ‘adjusted’)
We choose bullets based on the purported terminal ballistics and available weights available. We choose powders based on recommendations from established load manuals and publications. For the 17Mach IV’s Todd Kindler (Woodchuck Den / Small Caliber News) provide tremendous assistance. Primers were chosen through testing during the development process. Velocity Standard Deviation and Extreme Spread were used as measures of uniformity in loading and powder performance, but surprisingly did not correlate to accuracy as strongly as I expected.
My quality background taught me that 30 piece (shot) samples give the highest confidence ratings for measurements. Since that was not practical we dropped to the next accepted sample size level of 7 shots per sample.
Sets of 7 rounds were made for each set of variables. The variables were:
1) Case Manufacturer (using fire-formed cases)
2) Bullet type – by each manufacturer
3) Primer type for each manufacturer (std vs match…)
4) Powder charge starting with the lowest recommended load with each set increasing by .2 grains each set (please remember this is a small capacity cartridge) for each powder type considered
5) Seating depth beginning with .020 off the lands and reducing to .005 off the lands.
Velocity and precision data was carefully collected for each trial, along with temperature, humidity and barometric pressure. (Barometric pressure did not turn out to be a significant influence – temperature did, humidity also did but to a much lesser degree). I transferred all of my data into an MS Excel workbook to keep track of the load details and results and conduct analysis. RCBS.Load seems like it could do the job, but I apparently am not smart enough to use the Construct User Load Data feature, in spite of hours (days?) trying. I do use the Target Tool feature for my group analysis and archiving.
We learned a lot:
* We learned to record and control the length of time between shots which turned out to be significant with a hot barrel acting differently than a cool barrel. Since this resulted in hundreds of shots (THE FUN PART!!!!)
*We learned to standardize our cleaning frequency (after each 7 shot group) and used fire-forming loads as fouling shots.
* We learned that different brass really is different – IE – Lapua brass shot differently than Remington brass with the exact same primer/powder/bullet combinations. Different loads had to be developed for each brand of case because the case capacity (and weight) varied noticeably between them. This caused us to modify our goal to also develop loads for each brand of case so they would have similar points of impact. The Lapua was by far the best and we worked up loads for the Remington brass that came as close as possible to the Point of Impact the Lapua produced – although slightly less precise.
* We learned that we had to know everything about the rifle that will be shooting the rounds under development. Finding the long neck in our chambers changed a lot about our loads and resulted in having to form cases from .222 instead of 221 Fireball and scrapping hundreds of fire-formed cases.
* We learned the value of the Sinclair bullet and case comparator in determining where each potential bullet needed to seated to control the distance off the lands. The bullet and case comparators are indispensable tools that provide the only reliable way to assure precision in case forming/resizing and bullet seating.
* We learned that the fire-forming groups of the long-neck brass were almost as accurate as the best loads we later developed, which happened to use the same powder and primer but the lowest charge.
* We learned that a good neck turner and 1/2 length resizing cut groups in half. A good neck turner meant consistency within .0005. we also learned that measuring neck thickness needed to be done on a tool with a pilot to get the effective neck thickness and not the thickness in one small spot. We like the Sinclair Case Neck Sorting Tool with the solid mandrel and no longer use our micrometer style gauges.
* We learned that most scales are not reliable enough for small calibers like the 17 Mach IV. Until we bought the Acculab Scale we were unknowingly being confused because of powder and case weight variation. Even our .223 loads improved once we started doing development using the Acculab. Once developed we were able to use, my favorite, an electronic metering scale like the Lyman DPS or a quality thrower for high volume reloading like the 223’s for our ARs.
*We learned we have a lot to learn……………
We still use the same 5 variables and 7 shot sample sizes when developing loads for our other rifles, excluding semi-autos. However, for Semi-Autos seating depth is based on a maximum length for the magazine and .010 increments down to slightly under (.030) the minimum of the recommended COAL from the reloading manual.
Our must have measuring tools for every caliber now includes:
Sinclair Chamber Length Gauge
Sinclair Cartridge Comparator
Sinclair Bullet Comparator
Sinclair Case Neck Sorting tool with an indicator that reads in .0001″ increments
Acculab Scale that reads to 2 decimal places so we can believe the tenth reading -
I apologize for going on for so long, but this is why I love this sport.
July 16th, 2009 at 8:46 pm
One of my best tools for load development is an Excel workbook which lets me both keep records and do data sorts on load results. I have taken to calculating the load’s MOA so that I can compare loads that were shoot at all distances from 100 -300 yards. Further, I log group sizes of the complete group, e.g., 5 shots and then those groups where one is called out, e.g., best 4/5. I log both into the sheet so that they both can contribute to the accuracy data and all groups are recorded and kept individually so that I can later examine the group behavior. This approach has taken time to refine, but not pays analytical dividends, especially in the winter time when I can do a lot more data analysis. I developed this because I work with at least 5 different calibers continually. Can’t stress enough keeping notes and records right down to the 3 ring binder I take to the range so I can record group sizes and load data while the barrel is cooling.
July 17th, 2009 at 7:27 am
Thanks Again for the GREAT!!! info..
You all have helped me become a better reloader and a better shooter…
I love this sport.. Thanks Again..