Tag: BB

October 26, 2023 – How Many Pumps for Accuracy

October 26, 2023 /

Hopefully, my zeal for experimentation and data translates into interest. I know that not everybody is like me. But, I get excited when people are excited about what they are doing. It really doesn’t matter what the topic is, I find it fascinating when people are into their thing. I may not want to do it, but I enjoy the enthusiasm.

The truth is, I wrote the article “I Hate Pumping” a few weeks ago prematurely. It was always my plan to test accuracy of BBs based on the number of pumps. I should have written after I collected all of the data first but I was in a little bit of a funk. I was getting ready to hunting and was suffering a little bit of brain fatigue. I needed something on the spot and I didn’t have time to do all the work.

My creativity seems to go in spurts. Right now, I am flush with ideas and time is getting a little less constraining. Now that the sun is going down with some evening left, I have time to read, think and tinker in the evening whereas in the summer it seems like it is go until you drop. I have several weeks of topics (that I think are good) in the queue. So, I want to close the loop on this testing for you.

Let me start with what I was trying to accomplish. Using the Crossman 1000 and shooting BBs, what does the number of pumps do to velocity? I did a series on pellets many months ago but I wanted to use BB’s this time because my preferred rifle, the Crossman Optimus only shoots pellets and I have a whole bunch of BBs. After understanding the pump to energy curve and knowing how many pumps would be adequate energy to dispatch pests, I wondered if this was even an accurate platform with BBs.

I found out that pumping the maximum twelve pumps is a chore but it was also pretty wild after the initial five attempts. To boil it all down, is it even worth it to shoot BBs? Looking at the picture, I think that you can see nine pumps is a significant improvement in accuracy over 12, it looks like seven is slightly better, five looks pretty dialed in and three starts to wander again.

This is good news. If the results would have all been like twelve pumps, I would have given up. Five is also a far cry from twelve pumps in the effort department. Looking at the energy data, I am not sure the energy is adequate for pests at five pumps, but that is OK, BBs are far cheaper to shoot if we are just talking about practice and trigger control and I have a lot of them around. The most important thing for practice is that it will hit where you aim.

Of course, now I will not leave things here. I am going to try a new series with my son’s Crossman 760. I did a baseline test months ago with pellets and found that rifle to be vastly inferior to the potential velocity. Ten pumps (the max) was equal to about four pumps on the Crossman 1000. What I am now trying to establish is that is it the velocity that stabilized the BB or is it rifle specific?

That being said, expect another one of these with a new set of data. This time, I promise that I will wait until I have everything completed. But like I said above, I need to do a better job closing the loop with subjects that I introduce. Maybe I should introduce a new category like ‘Results’ to share my conclusion. That will keep me more honest when using it and then I can write the post in a more scientific fashion. I will think on that.

End Your Programming Routine: Based on my results, BBs can be accurate without needing Popeye’s arms. That being said, not all tools are best suited for every job. Where I have settled is that I should be able to adequately shoot BBs with five pumps for practice. Stayed tuned for another analysis on potentially why five pumps is the best.

October 12, 2023 – I Hate Pumping

October 12, 2023 /

Every since I purchased my Crossman Optimus spring piston, air rifle my Crossman 1000 has sat in the corner. I don’t think that there is anything wrong with it but that it is a variable pump rifle. That means to get the same performance (actually less than) from the 1000 to the Optimus, it takes twelve pumps. I know that I am aging, but this wears you me as well as it takes a long time for a follow up shot.

I continue to collect pellet ballistic data, looking for that magic combination of energy between velocity and weight. The other day, I was thinking, I should do some work with the Crossman 1000 because it also shoots BBs. Maybe I can practice even cheaper? Maybe I can burn up those BBs I loaded on day one and haven’t shot since I went to pellets with the Optimus?

I am not going to bore you with more numbers. I find it interesting and maybe if you really want, e-mail me for the results. But, one of my going in theories was that BBs would not be accurate. As I was trying to measure velocities across that 1 1/2″ window, I was struggling. I shot probably 30 shots to get ten measurements. When you have to pump the rifle 12 times with increasing force, it really gets to be a chore.

The scope that comes with the rifle is cheap and barely useable. I do not recommend the Crossman 4×15 that you can purchase for $20. Since mine came with the rifle, I will use it for now until I get fed up with it. The point of that is that it is not easy (or clear) to see through it well. But, from what I could see, it looked like was shooting all over the place. Hence, why it took me so many shots to get measurements.

All of these shots were from a rest with 12 pumps at 10 yards. The ones in the red represent the first 5 shots whereas everything else happened afterwards. It is no wonder I struggled to get measurements with the chronograph.

I started out with a whole series of velocity/energy measurements with BBs and pumps just like I did with pellets. This time I went 3, 5, 7, 9 and 12 pumps. Skipping all of those other intervals saved my arms a lot of movement and I didn’t really care to get that much data. I am pretty sure the velocity curve follows the one that I previously calculated for pellets. The other thing that I did differently was measure the velocity at the target (10 yards). The reason I did that was because I am trying to determine how effective this rifle with BBs really for pest elimination.

I already know that 8 ft/lbs at the muzzle is lethal on pests. The last thing I want is an ineffective tool. After I got all of my measurements, the next thing that I wanted to determine was how accurate is this rifle with BBs anyway. So, I just started shooting at targets. At first, my groupings were pretty tight, then things started to go a little wonky.

By the time I got through my planned magazine, I was struggling to pump the rifle even on the first stroke. After I ran my magazine dry, I tried another test. I simply cocked the bolt and pulled the trigger. Low and behold, it fired. Then I did it again and it fired again. I did it a third time and it was just the thud of the spring.

So, it appears that twelve pumps puts more air in the chamber than is used to drive the BB. This is the cause of the increasing difficulty to charge the rifle after firing. I believe that it is also the cause of increasing inaccuracy. I really don’t know where the line is between expected results and chaos, but I would say five shots is a safe bet since that is where I got my best groups.

I am going to continue this test with other pumps groups. The reason being is that I am trying to determine if it is even worth training marksmanship with this rifle and BBs. Ideally, I would like to know this rifle well enough that I could say, this is where I train and this is where I could use it if need be. After all, an inaccurate rifle is pretty much useless. You don’t do anything for marksmanship or pest elimination and you might shoot something that is not intended.

End Your Programming Routine: The big drawback is the multiple pumps. I am hoping that my data says that 3 pumps is adequate. This would relegate the Crossman 1000 to mostly just target shooting, but it would be worth it for the practice. If the accuracy proves to be a problem, then it may relegate the rifle to the garage sale pile.