Hello to everyone! I went shooting today with pellets sorted by weight yesterday. I want to thank you guys for your input and comments.
David: I posted two pictures above measuring the head size of pellets that weighed 33.0 gr. and 34.5 gr. with my calipers.They show that despite the weight difference, the head sizes were the same at 6.35mm. I don't have a clue what pellet manufacturers use to lubricate their pellets to keep them from clumping together during the manufacturing process, but I do not like the crappy residue it leaves in the barrel. That buildup of that crud causes accuracy to plummet eventually...which is why I clean all my pellets.
Widget: It was an awful lot to do in one sitting and I probably won't do that many in one day again anytime soon, but I admit that I actually enjoyed it. I put the TV on Turner Classic Movies and weighed pellets and listened to some great old movies while doing it.
Havoc: I am amused because you say that now, but once you see the results you may change your mind about it. Or maybe you could hire someone to weigh some pellets for you?
Mayank and Sirk: I am going to leave it up to you guys to do all the super scientific testing and extrapolate the results. I sincerely hope you will do so just as a thought experiment if nothing else. I am fascinated by your words and understand some of what you say, but unfortunately I am not trained in those disciplines. I am merely an enthusiast that has an insatiable curiosity about all the variables in the equation that is related to this thing called accuracy. I do know that in any equation there must be certain constants as a basis for accurate conclusions, and for extrapolating results to untested areas. What I am endeavouring to do here is find those constants, and in weighing these pellets I have discovered that one of the most important factors in my accuracy tests must be pellets that all weigh the same. If they did not, then all results could be called into question.
So, I went shooting today at my friends backyard at a measured 50 yards, with pellets that were weighed out yesterday...it was about 80 degrees with about 90% humidity and very overcast and drizzling at times. But there was no wind at all...not a breath of air was moving the palm frond tips even. All shots were over my chronograph.
I started out shooting the MKII pellets out of my FX Streamline that were weighed to 33.9 grains. I was immediately dismayed because I got an average velocity of 872 ft/s, and the last time I shot her with unsorted pellets the avg. V was 882 ft/s. Why such a big difference? I removed the stock to make sure the hammer spring nut hadn't moved on me...knowing I had secured it with VibraTite. Since that wasn't the culprit, I sat there wondering if my regulator might have somehow gotten out of whack, and yet knowing that wasn't really a credible possibility either, and I didn't want to take her all apart to check the reg. out in the weather on an inclement day...Then it hit me like a ton of bricks! The last time I shot her was with unsorted pellets and today I was shooting her with pellets sorted according to their weight!
Then I had an idea! I shot some pellets that all weighed 33.0 grains and promptly got an avg. velocity of 882 ft/s! An increase in velocity of 10 ft/s over the 33.9 grain pellets by by just a one grain decrease in weight! So I then shot some pellets that all weighed 34.9 grains and got an avg. velocity of 862 ft/s! A 10 ft/s drop in velocity below the 33.9gr. pellets by just a one grain increase in weight! And I also discovered that MK1 pellets that weigh 33.9 grains shoot an avg. of 7 ft/s slower than the MKII 33.9 grain pellets do! I guess because of the increased drag caused by them having slightly larger skirts?
This discovery is very important to me because I have been struggling desperately to get my two FX rifles to shoot at a constant velocity each time. In the last couple months I have experimented extensively with my Huma regulators' pressure settings and plenum sizes, in an attempt to get them to give me the same results each and every time. I used to weigh pellets but stopped because I had so much trouble with my factory regulators arbitrarily fluctuating up and down, so I figured what was the point and stopped weighing them. But in testing my Huma regulators with my new Huma reg tester I discovered that my Huma regs were giving me a fairly exact pressure for each shot...and thought there couldn't be a great difference in velocity from shot to shot due to hammer spring release velocity. Then I remembered the great disparity in the weight of the pellets in every tin I ever weighed, regardless of manufacturer. The answer was right in front of me!
So I got a new Lyman scale and weighed some MK1 Heavy's, shot them out of my Wildcat and was amazed at how tight the chrono numbers were. At the time I mistakenly thought it was the addition of a heavier brass hammer weight that caused the chrono numbers to tighten up so much, but I now know the only thing the heavier hammer weight does is allow me to use less turns on the spring adjustment nut. The real reason the chrono numbers were so close is because all the pellets I shot over it weighed the same amount. I am such an idiot for not seeing what was right in front of me all along! Of course a tin of pellets with 20 different pellet weights is going to give 20 different velocity readings over the chronograph!
One great benefit to shooting pellets that all weigh the same is NO MORE FLYERS! The ones shot from each batch that weighed the same were going into one hole groups of not more than 3/8" at 50 yards! And that is with me just me putting the crosshairs on a spot, squeezing the trigger, writing down the chrono number on my tablet, and then doing it again and again and again all day. Just absolutely effortless accuracy without even trying!
A second great benefit is my chronograph numbers are super tight now...just the way I thought they should have been all along! From now on before I make an adjustment to one of my regulators, or my hammer spring tension, or any thing else for that matter, I am going to shoot pellets that all weigh the same over my chronograph to establish a baseline for comparison. Then shoot pellets of the same weight after I make the change and compare the results. The bottom line is it was not my regulators nor my hammer spring tension adjustments causing the great disparity in my chrono numbers...it was the great disparity in pellet weights that caused the chrono numbers to be unfairly askew!
These numbers are from shooting the MKII pellets weighed to 33.9 grains out of my Streamline today: 873, 872, 869, 871, 872, 870, 873, 873, 872, 870, 869, 874, 874, 873, 873, 871, 875, 873, 873, 875, 874, 870, 873, 873, 874, 872, 873, 872, 872, 869. Avg=872 ft/s SD=1.6 ft/s ES=6 ft/s.
These numbers are from shooting the MK1 pellets weighed to 33.9 grains out of my Streamline today: 863, 860, 864, 861, 864, 865, 864, 865, 867, 866, 866, 866, 865, 866, 866, 868, 868, 867, 869, 864, 866, 864, 866, 865, 866, 864, 864, 864, 864, 865, 867, 867, 865. Avg=865 ft/s SD=1.8 ft/s ES=9 ft/s.
All pellets tested had been thoroughly cleaned with Acetone before they were weighed, and all pellets were lubed with Napier Power Pellet Lube and gently rolled on an old soft t-shirt to remove any excess. I hope this post is of benefit to some of you guys trying to get the best accuracy out of your rifles, and get more precise results when you make adjustments to your regulators or hammer spring tension. You can only trust the results of your adjustments if the pellets all weigh the same when you shoot them over the chrono. In some cases people may not need to change their regulator or hammer spring tension at all to get better accuracy...they may just need to start shooting pellets that all weigh the same amount!
I only wish there were a way for a pellet manufacturer to have some kind of device in the assembly line that could electronically weigh and sort pellets to within a tenth of a grain, so that I could count on all of the pellets in a tin weighing the same. But until then I am one airgunner that is absolutely going to be sorting all my pellets according to their weights!
AND FINALLY SAY GOODBYE TO THOSE DARN FLYERS! ;-)
All the best, Chuck
