Have you ever wondered if your reloading scale was accurate? If so, you’ve probably wondered how do I really know if my scale is telling me the truth about powder or bullet weight when all I have to use to check and calibrate the device is a small check weight which was made by the lowest bidder, somewhere overseas.
It doesn’t really matter if the scale is analog, like an Ohaus 10-10 beam scale, or if it is digital, like a Frankford Arsenal or a Gempro 250. Basic physics is still being used to derive a result, whether it be purely magnetic-mechanical or the result of a load cell’s capacitance which is then in turn interpreted into a numerical result. Certainly, precision metrology relies on traceability to some known standard. The folks at the flavor lab at Coca-Cola, for instance, aren’t using your average kitchen scale when they are working on a new flavor and need to measure out components.
Of course, we aren’t Coca-Cola, but we still would like to know if our scales tell us what is true. There are a couple of ways one could go about this: paying to send off your scale to be calibrated at a calibration lab, purchasing a quality mass standard and using it for calibration, or working at place with a known good scale and using something of your own, say a bullet, to be measured and then used as your standard. Another manner, and the one I’ve elected to use, is to compare multiple scales using the same samples for measurement and seeing if there is a difference (or not) between them.
I own two different digital scales, the Frankford Arsenal 750 and the Gempro 250. Besides cost, the major difference between the two is in resolution. Put simply, the amount of resolution is the amount of precision that the scale can achieve. This can be deceptive; just because a scale can tell you that a bullet weighs 185.1 grains or 185.09 grains isn’t always significant. For our use of checking powder charge weights, what we really want to know is the measurement of powder to a tenth of a grain, as that is how most reloading manuals are presently written. There are use cases where more precision is necessary for success, such as long range shooting, but for bullseye purposes, we need not be concerned with more than a tenth of a grain; instead, we should instead be concerned with whether the press or technique we use to measure powder is itself consistent, with as little variation as possible.
A brief note on why I have two different electronic scales is in order. I purchased the Frankford Arsenal first in order to get up and running (I had sold my PACT scale I used for shotshell reloading some years ago). I like it fine, but I would prefer something that didn’t utilize batteries and I can keep plugged in, so I picked up the Gempro 250 when it went on sale.
I took 50 projectiles and weighed them across the two scales on the same day and in succession, so as to capture statistically similar conditions for analysis.
What you see here is that there is no significant difference between the two scales. It does appear that the Frankford Arsenal scale tends to weigh items a bit heavier than the Gempro 250, but that’s all you can really tell- and only then by about tenth or two of a grain.
In sum, there really is no difference in these two scales and both will work equally well for measuring reloading powder charges, sorting cases, or sorting bullets. What will be interesting is to run this analysis again, throwing in a mechanical scale into the mix. More to come!
In an email exchange with Dave Salyer regarding handloading for Bullseye, he made mention that when using Nosler JHPs he had found a half inch improvement in group size at 50 yards when using new cases compared to mixed cases. This has me thinking two thoughts: 1) that case tension when new could potentially be a factor in attaining accuracy and 2) that bullet choice should center on a JHP bullet for optimal results.
With Dave’s mention on the brain, I purchased a bunch of different match grade bullets and have been slowly measuring them and sharing the results here. I believe that by measuring them I should be able to tell at least two things: 1) whether or not the bullets were statistically consistent and 2) try to determine if the measurements I found from the Nosler JHP were also present in other makers offerings.
It appears that the Sierra Sports Master, model #8800, exceeds the beloved Nosler JHP in standard deviation (SD) of both weight and length and may be an idea candidate for a 50 yard load. This assumes that a lower SD (in these areas) is conducive to best accuracy.
Measurements taken were weight, length, and diameter (in that order). At first, I was a bit baffled by my measurements- I even got out the micrometer to check, but these bullets, as the specification sheet indicates, do in fact measure .4515″ at the base. There is a slight outward taper below the ogive from .451″ to .4515″ at the base, but it is there.
You won’t believe this, but there were only two different lengths captured in my sample of 50: .536 and .537 inches.
Either I just measured 50 of the most consistent bullets so far, or something was wrong in my measurement process. As near as I can tell, both my technique and equipment is no different than previous studies. These bullets are incredibly consistent in terms of length- a single thousandth of an inch being the only difference between the bullets in the sample.
The probability plot indicates that the sample weights were normally distributed, save for an outlier:
The summary report indicates that the mean and median are the same. The report also indicates that the SD is .18 grains, more than half smaller than the Nosler weights reported back in March. Lastly, I’m pleased to report that the Sierra bullets I measured here are on average 185.09 grains- meaning you actually on average getting what is claimed on the box.
Relationship Between Weight vs Length:
A regression analysis indicates that there is some relationship between weight and length, but that they are not particularly strongly related with one another, as Pearson’s coefficient is a modest 16.91%. This is most likely due to only two lengths to model the evenly distributed weights.
In general, these bullets appear to be well made and arrived in excellent shape. On average, these bullets are slightly overweight. These bullets have had the lowest standard deviation in weight of any bullets measured thus far, and the consistency will not be a detriment. These bullets appear to be constrained in terms of their length, as they have been the most tightly spaced of any measured thus far. Like the Nosler JHP, this tightly controlled length may help keep bullet seating repeatable and crimping consistent. This in turn may explain why these bullets will be excellent performers for 50 yard bullseye shooting.
Mitutoyo Digital Micrometer/GemPro 250 Digital Scale
Terry Labbe is a High Master shooter from Alabama and is the proprietor of Magnus Bullets. He makes his way around the Southeast bullseye scene, shooting lights out wherever he goes. I met him at the 2016 GA State Shoot after calling and placing an order for his #801 (185 GR Button Nose) and #802 (200 GR SWC) cast bullets to be delivered at the shoot. From the phone call I thought he was a affable fellow; meeting him in person did not disappoint.
After playing around with other cast bullet providers, I thought it was incredibly short sighted on my part that I wasn’t supporting a guy one state over who shoots his own product- with excellent results. In my defense, I didn’t know about Magnus until visiting either the bullseye forum or the mailing list, so while I might be late to the party, I did finally arrive! I like supporting folks invested in their business, and the quality of Terry’s bullets speak for themselves.
Measurements taken were weight, length, and diameter (in that order). I found very quickly that I was unable to discern much diameter difference- it’s entirely possible that there is a difference that a micrometer could tell, but the calipers I was using all turned up measurements of .452 inch in diameter.
I had some outliers in my length measurements:
It is entirely possible that the outliers were due to faulty measuring on my part. I did find that, depending on how you rotate the bullet around its axis, you can find yourself coming up with different measurements; you should also be aware that the sprue on the bottom of the bullet can distort the length measurement.
I always choose the longest measurement by turning each bullet a quarter turn and then taking a measurement; whatever is the longest is the one recorded. I did not have to do much rounding up or down- most every measurement was right on or near a graduation. Nevertheless, it is entirely possible I introduced bias, though I took great pains to avoid doing so.
In general, however, the length of the 801s I measured were evenly distributed:
Another view of the same data:
The weight recorded across the sample lot of 100 had a median value of 185.28 grains and a mean value of 185.26 grains. Finally- a manufacturer that actually meets specification instead of hiding material savings in process control!
To be fair to other manufacturers- I’m not making the claim that I can tell the difference between 184.4 grains and 185.5 grains; all I’m saying is that I’d like to get what is listed on the box most of the time.
Lastly, I hope that a pattern is becoming clear about the various manufacturing methods bullet crafters employ- we’ve seen a electroplated bullet, a cup and core bullet, and now cast. Last on the list is the swaged variety- any ideas what that data is going to look like? Stay tuned!
Relationship Between Weight vs Length:
A regression analysis indicates that there is a relationship between weight and length, which is fairly strong, though it would be better if Pearson’s coefficient was 65% or greater, instead of 50.4% that the data supports. That said, if I reran the analysis without the outliers, I’d probably see an increase that might approach 65%.
It’s also important to note that Pearson’s coefficient isn’t the only criteria by which any bullet in particular, and this variety specifically, should be measured or critiqued.
A strong relationship between length and weight, especially when diameter is constrained, is what passes the sniff test here. If there wasn’t such a relationship, you’d naturally wonder what was causing such variation- no such wondering is needed here.
I’ve shot a couple thousand of these and can’t say enough good things about them. Terry has shot 2658 with his lead bullets, so I should think they’d be good enough for anybody!
While bullet technology has advanced, using electroplating as an example, it still stands to reason that a cast bullet, made properly, will get the job done- and in this case, your money is supporting someone who supports the sport- how can you beat that?
Brown & Sharpe Dial Micrometer/Frankford Arsenal DS-750 Scale
When I think about the big bullet companies, I think of metal(s) futures contracts, sales, supply chains and manufacturing- probably in that order. Planning the desires of the company, making those hopes and dreams come true, a way to build what is necessary for them come true… well, it’s enough to boggle the mind. Winchester, or Olin Corporation, is an integrated metals and chemical manufacturer. Did you know they make a lot of chlorine? They also sold their brass business back in 2007.
Nosler is not as large any of the big three, and was founded around the time Hornady and Speer got their start. Nosler is still a family owned and run company in Oregon- I’m not sure if it is 2nd or 3rd generation at this point- and they are well known in the bullseye community for making P/N 44847, a 185 grain jacketed hollow point bullet, that became somewhat famous due to it’s use by the Marine Corps pistol team. Based on this reputation alone, I sought out a couple of boxes and finally sat down to measure a few.
Measurements taken were weight, length, and diameter (in that order). I found very quickly that I was unable to discern any diameter difference- it’s entirely possible that there is a difference that a micrometer could tell, but the calipers I was using all turned up measurements of .451 inch in diameter.
I had some outliers in my length measurements:
Now, it is entirely possible that the outliers were due to faulty measuring on my part. I did find that, depending on how you rotate the bullet around its axis, you can find yourself coming up with different measurements. I always chose the longest by turning each bullet a quarter turn and then taking a measurement; whatever was the longest was the one I recorded. I did not have to do much rounding up or down- most every measurement was right on or near a graduation. Nevertheless, it is entirely possible I introduced bias, though I took great pains to avoid doing so.
That said, this data is not normally distributed (though it is mostly evenly distributed) as I keep measurements to .001″. However, it probably would be normally distributed if I could get repeatable resolution to another significant digit- which would be nice, but also expensive.
The bulk of measurements were from .532 to .533- a very narrow band. I wonder what the specification is for the length of this bullet?
While the P-value in this case is high, it isn’t as high as that of the Speer TMJ 185 Grain bullets I measured previously. That in and of itself is not an indictment on this particular bullet in general, or this lot (KM06F18-1/150513121312) in specific. All this means is that the weight was normally distributed across the sample taken (50).
You’ll note the same trend here was was seen with the Speer before- on average, the bullet you pull out of the box is going to be lighter than 185 grains. Also, in regards to the weight distribution, the Speer had a better standard deviation than the Nosler.
A note of process change: I’ve since moved to my new forever home and sufficiently warmed up the scale and have kept it in a temperature/humidity stable area, which is different than the place in which I made my previous measurements of the Speer TMJ 185. In due course, I’ll run some gage R&R tests to see what variability my equipment (and technique!) may play in my results.
Relationship Between Weight vs Length:
A regression analysis indicates that there is some relationship between weight and length, but that they are not particularly strongly related with one another, as Pearson’s coefficient is a modest 25.5%.
I think if the outliers were taken out, the regression model would still not be as robust a predictor of weight vs. length. I’m at a loss as to why there isn’t a stronger relationship, other than:
Measurement bias in length or weight
Bullet construction properties are not represented well in a regression analysis
Analysis may in fact be correct, and this is the level of quality to be assumed is aimed for
Outliers distorting the data
As more measurements are taken, I’ll be sure to update the results.
In general, these bullets appear to be well made and arrived in excellent shape. On average, these bullets are underweight, though there seems to be a very narrow band(s) of bullet length that is showing up in the data, which may help keep bullet seating repeatable and crimping consistent. This in turn may explain why these bullets are known for their match quality.
Brown & Sharpe Dial Micrometer/Frankford Arsenal DS-750 Scale
At work, I’ve been learning Six Sigma/Lean principles, and thought that my interest in reloading might be a good point where I can delve a little deeper into both what I enjoy intellectually for work and for fun, and, hopefully, learn more about what makes a quality bullet or case. Consequently, I’m documenting my efforts so that others can compare notes, generate discussion, and develop a greater understanding of this facet of reloading.
Having recently taken up bullseye, or precision pistol shooting as the NRA is now deciding to call it, like anyone new to a sport, I dug right in and started studying what has been written about reloading for this particular course of shooting. It’s a well worn field by all accounts, rife with genius and ignorance, but what bothered me most was the complete lack of data regarding what sorts of qualities one should look for in a round of match grade (meaning “target”) ammunition. Surely, I thought, the answer could just as easily be measuring a “known” match grade round and trying to replicate that. SAAMI even has a specification for 45 ACP Match ammunition- so surely there isn’t a mystery here.
Of course, it isn’t that simple. What may shoot well in one pistol may not in another, some powders may “feel” different in regards to recoil (something I don’t believe in at present), component differences between what a factory may use and what you may be able to get, and so forth. Additionally, I don’t have access to an outdoor range or independent testing mechanism like a Ransom Rest, so even if I could take all the measurements I could get my hands on, I couldn’t presently test them in any controlled way. Lastly, even if I could do a double blind controlled study and find a “magic bullet,” there are going to be days when the human factor- the skill necessary to shoot a shot deep into the black- is the limiting condition.
Nevertheless, I decided I’d start measuring bullets and cases and making the results available to all. As I revisit brands/lots, I’ll continue to expand the various data sets that I collect. If variation occurs from established, repeated measurements over time, then it may be a good reason to investigate an alternative supplier.
I recently purchased a couple boxes of Speer’s TMJ 185 gr. bullets (lot D12X, Part #4473) that I plan on using in bullseye tournaments over the course of this year. These bullets are made in the new style- instead of cup and core construction– and are instead electroplated. The accuracy of plated bullets is subject to great debate among the bullseye community, though I’m not aware of which specific brands anyone has found lacking. I can’t remember who commented on The Bullseye Forum that one could probably get away with using rocks as projectiles at the 25 yard line, so I’m guessing the complaints about plated bullets has something to do with the 50 yard performance- but who, when, and evidence of them not performing haven’t been demonstrated to my knowledge with any sort of test results such as with photos, target, and load data to back up the claim that plated bullets don’t work well.
Measurements taken were weight, length, and diameter (in that order). I found very quickly that I was unable to discern any diameter difference- it’s entirely possible that there is a difference that a micrometer could tell, but the calipers I was using all turned up measurements of .451 inch in diameter. This makes a certain sense; the constraint on a bullet isn’t weight or length- we speak about bullets in terms of their caliber, which is what will determine practical weight and length for a given projectile (assuming sufficient rifling and other necessary conditions).
You’ll note that the length of N measured is evenly spaced; I only have resolution to .001 inch. My measurement system is such that if I took a measurement and the needle was between graduations that I made a judgement call; if it was past what I considered a half space, I rounded the size up. If the tick was below the half space, I rounded down. I didn’t have to do that frequently, but I do want it noted.
The data are evenly distributed and have a low standard deviation, however, the data is not normally distributed; as I noted above, the data does have some semblance of continuous measurements, but it was categorized for ease of reporting, as the alternative is to get more resolution, which seems unfruitful.
The data is normally distributed which is indicated from the high P-value (the null hypothesis in this case was that the bullet weight would be normally distributed; thus, the null cannot be rejected). This is also evident from the trend of the samples to tend towards the center, or mean, of the graph. There are a couple of straggler data points on either end, which could be an indicator of either an improper measurement on my part (bias), or that the bullet was in fact the weight recorded.
The weight plot above indicates that, if my scale is to be believed, the majority of bullets are in fact underweight. Interestingly, the standard deviation from the mean is just enough weight to get many samples “over the hump,” assuming that it was a positive value, of course.
Relationship Between Weight vs Length:
A regression analysis indicates a strong relationship between bullet weight and bullet length. Remembering that we are fundamentally constrained by diameter (caliber), one would reasonably conclude that in order to increase weight, one must either use a different material or increase the amount of mass present; which in this case would be length. The model is explained to a high degree of confidence, statistically speaking.
The bullets appear to be very well made and to very tight tolerances, even though in general they are underweight. How they will shoot remains to be seen, but there is nothing in the data to suggest that, if loaded properly and within a narrow velocity tolerance, any particular physical property would present non-nominal performance.
Brown & Sharpe Dial Micrometer/Frankford Arsenal DS-750 Scale
For those unfamiliar, NASA has a non-traditional media program that invites various social media users for a vast multitude of events- rocket launches being the primary interest of many, though there have been other events as well- notably getting to watch a rocket’s “hot” or test fire in the desert of Utah. I applied to view a launch in Virginia thinking I had no chance whatsoever of being selected. I don’t have a high post count here, nor do I engage with social media sites very much. However, the fates went my way and I got invited to be a social media commentator for the first Antares night launch from the Wallops Flight Facility, which is operated by the Goddard Space Flight Center, near the end of October 2014.
The flight from Atlanta to Norfolk takes about 2 hours. I took a night flight into ORF. As the plane began its decent, we turned around and could see the black mass of the ocean on one side and the incredible lighted area of Chesapeake Bay and the Norfolk Naval Station, home to the Atlantic Fleet. I could see the serpentine Chesapeake Bay Bridge, the absence of certain parts indicating which sections were undersea tunnels so that the fleet can come and go as it pleases.
After staying the night in Norfolk, I made the drive up to Wallops from Norfolk using the Bay Bridge. The trip up was uneventful and mainly as expected- the highway along the coastline was dotted with many businesses which had already shuttered as the summer season was over and so, too, were the opportunities to make money from the tourists.
Along the way, I stopped at a Wal-Mart, conveniently placed to take advantage of the coastal traffic, to get some snacks because I wasn’t sure what sorts of provisions would be available for the remainder of the day, and picked up my first bag of Utz Crab Chips, which I found to be quite wonderful.
After arriving at the Wallops Visitor Center, which was to be the waypoint between the tours and activities among the facilities, all of the #NASAsocial invitees gathered together for sign-in and welcoming. Jason Townsend was our lead for the entire event, and was assisted by various team members. After what seemed like a whirlwind of meeting folks and getting somewhat oriented, it was time for the pre-launch meeting and press question and answer session, which was going to be broadcast on NASA TV. Just by the nature of these events, which are not reliant on national news media or other similarly sized and resourced organizations, the crowd was enough to fill the viewing room of the visitor’s center and the show, as they say, got on the road. It was light chatter, with some interesting characters from much larger NASA/Space watching sorts of blogs taking up the first couple of rows- while I did wonder if the folks doing the reporting for their blogs actually made any money at it, I was also simultaneously struck by the vulgarity of such a thought.
After our press briefing, which was close to an hour in length, we all piled up into busses to take a trip out to launch area, which has been photographed by NASA HQ, and you can view the photos here. They are really much better than the photos I collected, though I was pleased with this particular snap:
It was a pretty uneventful showing- the wind was blowing quite a bit and there was a bit of a chill coming in the air. The people we met from Orbital and that were in charge of the Antares launch of the “Orb 3” Mission were polite, cordial, and were somewhat alarmed when I asked whether the reorganization of Alliant Techsystems into the new Orbital Sciences Corporation was going to have any bearing on future launches in terms of cost savings, earnings per share, and other sorts of business metrics. They immediately had one of their very professional PR people come over and speak to me directly, as they probably didn’t want to get off message, in addition to trying to get a handle on who this particular rube was and why was he asking these sorts of questions.
I read the papers and just happened to be well informed, is all. This did eventually lead to a discussion the next day with a rocket motor guy and the history of Thiokol, DuPont reloading powders, and hunting in his home state of Utah. I think we get an idea that these people who are in charge of these various systems of the world at large are somehow separate and distinct from the rest of us; and that just isn’t true. Everyone I met from ATK/Orbital and from NASA were incredibly professional- but also approachable.
After the “close as we can let people who don’t have security clearances get to the launch pad to take photos and ask questions,” we got back onto the busses and headed back to the visitor center to disperse for the evening.
Across the street was a NOAA installation, noted by the large antennas- a favorite view of mine, I have to say!
The stay on Chincoteague was pleasant enough. I ate at Famous Pizza; I skipped the pizza and had a flounder sandwich with cocktail sauce- delish! They had Tool playing in the kitchen, so I knew I was at the right place.
The hotel left a bit to be desired- I couldn’t quite figure out why there were so many black flies swarming about in the room, until I looked it up. How anyone visits such a place as a summer retreat with so many flies is beyond me- I’m used to the low bug count of the Redneck Riviera, I suppose. That is my only complaint, but the place is covered in flies and it is in a marshland, so not sure how germane the comment is.
I got up for the day’s events- it was a real marathon- we basically ran from place to place on the installation to visit the different facilities and hoping to maintain our schedule. I could have spent a week in each department we visited. Instead, #NASASocial only got about an hour or so per place- not including bus transport between different facilities- and it just wasn’t long enough. I only later learned that there were supposed to be 50 attendees, but due to the launch being rescheduled, we only retained 20 or so of the 50 (moved from Fri/Sat to Sun/Mon).
I can’t imagine what it would have been like with a full compliment of NASASocialites. I think our group was just the right size, even though I didn’t mingle with all of them (especially the younger, more boisterous narcissist types- very “me” focused). They have their own sort of way of approaching this world that doesn’t suit me. The older and more settled, professional crowd was more my speed. However, you have to give a bow to the NASA Social HQ people for selecting a very different, diverse, and hodge-podge group of people to attend the launch. There are many different crowds and audiences that could potentially be reached from this social media coverage. For instance, my followers, and who I follow, vary tremendously. From my Twitter amateur radio people, Google + local group and my Facebook friends- everyone from who I’ve taught to who has taught me. It’s a varied audience and I’m sure that everyone else (and even those who were not) who was selected for this event probably had just as many varied audience members, too. It’s quite likely that this is part of the selection criteria to be included in a #NASASocial event in the first place.
Some tour! Our first stop was with the balloon lab. There was discussion about the shortage of helium and that when it gets too expensive, they will/may have to switch back to the more dangerous hydrogen for fuel. The various materials they had on hand to construct the balloons varied in size; the largest the balloonists had built contained the approximate volume of the Astrodome.
The lab itself was full of all sorts of things. Wall racks with giant rolls of Mylar and polyethelene just waiting for use.
Oddly, none of us asked how the balloons are constructed. It’s obviously more involved than giving a 3rd grader a hot glue gun, some popsicle sticks, and yarn. But construction details weren’t mentioned once and I can’t believe it didn’t occur to me to ask.
We took a look through the rest of the, well, I’m calling it balloon factory, and we went past various testing chambers, one of which was an anechoic one, no doubt to test the various electronics packages that fly aboard the different balloons. There are multiple balloon launch sites.
After getting our fill of balloons, we moved to the Sounding Rocket Foundry. I simply can’t do it justice- they perform nearly everything from raw machining to final assembly of these sub-orbital rockets. 2015 was the 70th Anniversary for Wallops, which has launched over 16,000 rockets; the name “Wallops” comes from an early English surgeon who owned much of the land in the region.
The shop checks for rocket deflection, does a BEND test, and has a giant shaker table. Sounding rockets are violent creatures- there is a lot of work that goes into the payloads, of course, but those won’t matter if they can’t get to orbit. Imagine having your tires balanced on your car- that’s, sort of, what these fine folks are basically doing. I did notice the high number of blue lab coats, which I asked about. They are used for ESD protection. Or, if it is chilly in the room.
We also found out that, much like leaving a light on in a theatre to keep the evil in the dark, you don’t use the word “explode,” when you are discussing the combustion forces at work in a rocket motor. You instead say, “it makes fire.”
The last stop of the day before the launch was a tour of the launch command and control. It reminds one of everything we see in the media- the trenches of monitors, people running pre-flight checks, following the step by step guide that takes nearly a day or so to get through. When you are sending a rocket up- you better get everything as right as you can.
I did learn during this part of the tour that the NASA logo was affectionally called “The Meatball.”
After this last jaunt, we headed back to the visitors center, and got geared up for the night launch. Sadly, I missed it, along with everyone else. There was some boat in the downrange launch area that couldn’t be moved out of the area in time to meet the launch window. I couldn’t stay- I headed back to Atlanta on the earliest flight out the next day.
And in maybe some way, I was lucky. The next evening, the rocket had an anomalous event during launch which ended with the rocket’s destruction, along with major damage to the launch pad and associated facilities.
The #NASAsocial people who were able to stay were evacuated away, along with the other VIPs from a launch viewing area around two miles away from the launch pad. Eventually, Orbital decided that there was a defect in the rocket engine itself and have moved away from that supplier to another.
I had a wonderful time, even though I didn’t get to view the launch directly. I would encourage anyone who is interested in NASA and space in general to keep an eye out for a #NASAsocial event near you- it’s worth the trip!