Bullet Prep — Giving You the Long Range Edge
Editors Note: This is the 1st part in a series of articles by Pete Petros in the methodology he uses to prepare his bullets for long-range shooting.
When it comes to precision reloading and shooting, the main goal is to ensure everything from start to finish in the reloading process is close to the same as possible. Most shooters think of this as choosing the best brass for the cartridge, sorting it by weight, and prepping it properly to attain replication in brass properties. Then by carefully weighing each powder charge and seating the bullet to the same depth each time, the finished products will act the same as they are fired through the barrel.
This is very true, and these steps along with many sub-steps in case preparation are critical to attaining the most consistent results out of a load, but let us back up a step.
What is the most important component in a loaded round? Many would argue it is the type of powder and charge being used. Others may say the brass choice or even the primer make the load. The most important component in the mix is definitely what will give the final results, and that is the bullet.
These days there are so many choices in bullet types and style in every caliber to get the job done. Some are known to perform better than others, and certain rifles will shoot certain choices better. In fact, most of the bullets available to the reloader today are all good quality and will get the job done. It is no secret that a high Ballistic Coefficient VLD (Very Low Drag) type bullet will shoot better at long ranges and cut through the wind better. But what can you as the shooter do to make your bullet choice even better?
In the same essence as modifying a stock engine in a car to enhance or increase performance, you can do the same to your choice projectile to squeeze a tad more performance out of it. There are a few steps that can be taken to do this quite simply. Flash back to the beginning of the article. We talked about brass sorting and prep prior to loading. The same goes for your bullet. Through sorting your bullets in the same lot and prepping them, you can tighten your groups dramatically, and make your “close to the same” loads even closer to being identical.
The absolute first step in bullet sorting by some reloaders is to sort the lot by weight. Even in the highest quality bullets you will find a few tenths of a grain spread or more in weights. Through sorting by weight you can split the entire lot up by variation. A simple and affordable scale for this step is the MTM DS-1250 mini digital scale ($36.95). Although any scale type will work for this job.
MTM DS-1250 Mini Scale
The next step taken in bullet sorting is to take the lot of bullets planned on being loaded, and measure them by base to bullet ogive. You will notice that even in the highest quality bullets available there is a variance of a few thousands of an inch or more. Take your lot, and sort them by base to ogive length and group them together.
Base to Ogive Measurement
This can be done in a couple of ways. One of our most recent tools that we have released is the Sinclair Bullet Sorting Stand. This stand comes with a dial indicator with a finger lever to lift the indicator leg up built on a post off a solid trued flat granite block. We offer special bullet comparators just for this tool that sit flat and true on the granite surface. This makes the job of sorting easy and fast, and you can be done in no time.
Sinclair Bullet Sorting Stand with Indicator $79.95 (comparators sold separately)
Another traditional way to measure the bullet ogive to base length is by the use of a caliper with a clamp on comparator body/insert combo. This technique works, but is a bit slower and has a tendency to be a bit more inconsistent than the stand method.
Traditional measurement method with comparator and calipers
The secret to consistency in both of these tools is the most important rule to remember. Basically the softest material in the process is the copper jacket of the bullet being measured. It will give a few thousandths with the more pressure you put onto the base while inserting it into the comparator. What is important and critical to this is to make sure you use the same light but steady pressure on the bullet base while measuring. This is where the bullet Sinclair Bullet Sorting Stand excels. After you lift the indicator stem up, lower it (slowly and steadily) onto the bullet while in the comparator, it will give the same amount of pressure each time. Prior to measuring the bullet, lightly “seat” the bullet ogive into the comparator with your finger to “seat” the ogive, then proceed to measure. Repeat this the same way each time to attain similar results. A good tip from reloaders that have been using the stand is to use the pointed indicator end versus the included flat end. While measuring be sure that the point is centered on the bullet base. The flat end tends to be more inconsistent in measurements.
Lightly seating the ogive into the comparator to ensure consistent measurement.
Once you are set up and ready to sort bullets, take a batch of ten of the bullets randomly out of the un-measured lot. Measure each one as described earlier. Write each measurement down on a piece of masking tape and lay out on a flat surface with the measured bullets on your workbench in order of what you found. When all are measured, repeat the process with the same ten until you see consistency in your recorded test lot. When you achieve the same results during the repeating process, you have a consistent technique, and are ready to sort the entire batch.
With the measurements taken from the ten test bullets find the average of the batch. This is most likely the same or close to the average of the entire box or lot you will be sorting. The average measurement will be your “0” batch. Take one of the average bullets, place it in the stand and zero out the indicator face so it shows “0” when it is being measured. Test it a few times again to make sure that the zero is true and consistent.
The next step is setting up a system of separating the measured bullets. A great way to do this is by using empty bullet boxes, or glad ware containers. Take your chosen containers and mark them with masking tape labeled “0 (average), -.001, -.002….+.001, +.002…and so forth depending on how wide the spread of measurements are. These numbers are the difference in thousandths of an inch, found from the average you found in the test sequence.
Sinclair Bullet Sorting Stand in action with a “zeroed” out average bullet. Note the labeled containers with sorted bullets in background.
Now it is time to measure. Place each bullet in the appropriate container for what you find. Keep these measured batches together, and label them so you remember which batches are which for the next steps in the bullet prep process. (see picture above). Many will leave it here and go ahead with the reloading process. In the next installment of this article, I will outline the next steps that can be taken to maximize these sorted bullets even more for performance. These next steps are meplat trimming and bullet pointing. The final steps in tweaking the ultimate long range bullet, Keep your eyes peeled for the next part of this series in future Reloading Press newsletters!
February 22nd, 2010 at 11:45 am
I want to start sorting my precision bullets, but when I sort by weight, and by base-to-ogive, I would have two sorts. Does one have priority over the other? Or do I have to have a series of weights for each base-to-ogive length; or a series of base-to-ogive lengths for each weight? Sound like a lot of plastic cups, a half acre or so. Help?
February 22nd, 2010 at 11:59 am
When I measure bullets I use 2 comparator bushings for boat tails. One on the stand and one that mounts on the stem of the dial indicator. That way I can measure the true bearing surface of the buttet, the most important dimension, not just the base to ogive length
February 22nd, 2010 at 12:01 pm
Great tips…but I am guessing that meplat trimming will change the weight of the bullet…didn’t we just go in a circle? Should you meplat first then separate by weight?
February 22nd, 2010 at 12:58 pm
Hello,
Thanks for the fantastic article on bullet prepping. Now I get it! I’m fairly new to this process. Now I have a plan thanks to you. I can’t wait for the next edition. I enjoy the loading and subsequent accuracy improvement as much as I do shooting.
Jake Winemiller
Sterling, Nebraska
February 22nd, 2010 at 4:44 pm
Great artical. Getting back to basics. : )
February 23rd, 2010 at 6:51 am
I found I can use my Sinclair concentricity base and comparator with the dial indicator to accomplish this task. I move/remove the case blocks and, viola!, bullet sorting apparatii.
Thanks for the idea!!
February 23rd, 2010 at 10:47 am
Dear Doug,
Yes the trimming will chance the weight of the bullet so meplat uniforming first would make sense before you weigh sort. However, the proper steps are too;
1. Sort your bullets by base to ogive measurement first so you can adjust the meplat uniformer tool to each group so you are taking the same amount off each bullet.
2. (optional) Use Whidden bullet pointing system to point up bullet.
3. Meplat uniform bullets.
4. Sort bullets by weight. (you will probably find that sorting by weight is not really needed after you do this once).This may be a good idea if you are shooting off brand bullets though.
Take care,
Phil H.
February 23rd, 2010 at 10:49 am
Dear Walt,
In our opinion the base to ogive measurement is the most important for 2 reasons;
1. You have to do this if you are meplat uniforming so you are cutting your bullets to the same length.
2. Even if you do NOT meplat uniform you should do this so you can adjust your seating die stem for each group so all your bullets are seated the same distance on or off the lands in your ‘sweet spot”.
I once weigh sorted 1000 Sierra 155 GR Palma bullets 99.9 % were 154.9 to 155 grains on the nose. I had 4 that were 154.8 and 2 that were 156 grains.
Take care,
Phil H.
February 23rd, 2010 at 3:44 pm
Mr. Petros:
I understand and agree with your article but need additional information about each step. When sorted by weight what do I do next? Lets say that a box of 100 – 142 gr. bullets 60 are 142.0, 10 are 140.5, 10 are 141.0, 10 are 141.5 and 10 are 142.5. I now have the results but what do I do? If the remaining preraration steps net a (+-) .5 vertical target strike at 100 yards with the 60- 142.0 grain bullets, what do I do with the remaining bullets? In theroy they will shot higher or lower meaning sight adjustment for each batch of remaining weights.
The same question is for the base to ogive length. What do I do with the various (+-) lengths? Save them up until I have a hundred of each from future purchases, adjust my powder charge? The other item with this measurement is who cares? Does the (+-) .001 length affect the way the powder burns, hence pressure, hence vertical strike differences?
My bullets are set by the seating die off of the ogive and meplat, so when I know the base to ogive length variant what do I do?
To Walt above Phil says “In our opinion the base to ogive measurement is the most important “. Why?
My Sinclair meplat cutter uses the ogive as a reference regardless of the distance to the base. Yes I use the same setting for all the meplat trimming there by yeiding a uniform ogive to meplat dimension for all of the same type of bullets.
Clark
February 23rd, 2010 at 3:46 pm
Charles Koch
Thank you for your response to the article. You have a very valid point, and I am going to explore this even more. As you point out the bearing surface is also a very important (if not the most important)way to separate bullets.
As for a true difference between just ogive to base vs. bearing measurements in performance I would be curious on what I saw across the chronograph between shorter/longer bearing surfaces. With just ogive to base separation, I have personally seen single digit extreme spreads in velocity, but to how much would it improve the spread if I was to sort by bearing surface, I am honestly unsure. Additionally, I have seen less variation in the bearing surface versus the ogive to base measurements in the higher end match bullets.
The ogive to base measurement is giving the reloader more consistency in seating depth and bullet jump. This is the primary focus of the first part of the article. I will talk to some bullet gurus out there to see their take on the bearing surface measurements, and let you all know what I learn from them in the next part of the article.
We appreciate your feedback. Hearing from the shooters out there as yourself
helps us improve our concepts, and ideas here at Sinclair!
Thanks Again!
Pete Petros
February 25th, 2010 at 12:19 pm
Clark
Thanks for your question. I failed to mention some details in the weigh sorting portion of the article, and will add to the next part of it in next month’s Reloading Press.
When I am weigh “sorting” I am looking for a window of allowance in terms of overall bullet weights. I will sort them by tenths, but when finished with my batch, I will take out those below and above the 1% variance of total weight. For instance if I am weighing a 180 grain bullet and find a low range of 179.0 and top end of 181.3 the difference is 2.3 grains or 1.27%.
I will take out those that fall outside the 1% (my set allowed variance) which is 1.8 grains, or .9 grains above or below 180, or roughly 179.1 to 180.9, I will cull out those that fall below 179.1 and above 180.9. This is only usually a few out of a total box. You may set your own rules, maybe you want a set allowance of .5 %, it is up to you. With the culled bullets, I will use those for practice or fouling shots.
The same percentage allowance can be used for varying lengths of bullets you find in ogive to base length sorting. Determine your set allowances and combine batches.
For instance out of 100 bullets if you find the following 10 tot. .498”, 25 tot .499”, 30 tot .500”, 25 tot .501”, and 10 tot .502”. A total of .005” or 1% of total of the mean (average length). Keep the .498”, and .499 “ together, keep the .500”’s together (most of the lot should fall in the mean length), and batch the .501” and .502 together. Some people, including myself will keep all of the same length separate (usually when sorting more than 100 bullets), it is up to you, and your preference. All sorted batches are loaded and shot together, for a consistent load. If you have more length variance cull out those above or below a set percentage and use those for practice or foulers.
As for the importance of base to ogive length, I spoke with Bryan Litz, lead ballistician for Berger Bullets, and author of “Applied Ballistics for Long range Shooting” on this.
He mentioned among other points that “the base to ogive length is mainly a true indicator of if the bullet has been formed correctly, you are actually measuring for constant B.C. from bullet to bullet while sorting this way”. He also said that the variance in base to ogive occurs while the bullet is being formed in the point die. Amounts of lubrication, and if varying pressures are used during the forming process you will see differences. Bullets not formed completely will have large diameter meplats, a shorter ogive, and a long bearing surface, creating a lower B.C.
So in depth the most important reason you sort this way is to combine similarly ballistic coefficient bullets together.
Hope this clears up the question a bit, and if you need more let me know!
Good shooting
Pete Petros
March 21st, 2010 at 5:13 pm
Pete, I have a noticed a great difference in ogive measurement using the hornady lock and load oal length gauge in my MRC .300wsm using Sierra GK 165gr. HPBT bullets I get 2.290″ and when measuring using the Sinclair hex style bullet comparator I get 2.255″.
This is a big difference and which one should I rely on? I have used the hornady (stoney point) for the last five years to work up my loads. I know there has to be a reason but am puzzled.
If the hex style nuts Sinclair sells are throated with reamers what does Hornady use? Just like to clear up a few things. Thank you, Ger