Tag: velocity

September 29, 2022 – ‘Tacticool’ Thursday

September 29, 2022 /

Rolling around to another Thursday, today I am going to finish off the conversation that I started last week on the ballistics of my reloads for .357 magnum. This was my first trip to the range with my chronograph. Look at all the junk I have to take, I am thinking of getting a larger range bag since mine is chronically full.

Since I provided the raw data last week, I am going to skip entering it this week. But, below I am going to provide the calculations from that data. What I can tell from the data is that charge weight makes very little difference in velocity unless it is the highest charge,

I think that it is worth pointing out a couple of things. Given the choice of charges and based on this data, I would choose the smallest load of 5.8 grains just based on performance. This actually ignores one variable that I didn’t test and that is accuracy. It is possible that one of the four charges is more accurate than the other three. The truth is, that would be the true choice. So, I will have to test that in the future.

5.8gr5.9gr6.0gr6.2gr6.3gr
Velocity9499329259431055
3 sigma327284161131168
Energy316305300312391

What I didn’t get was close to the published velocity. The data suggested that I should get 1050-1150 fps. It could be because I substituted components. I really don’t think so, but it is possible.

Now, theirs was measured on a 10″ barrel. However, I had a 16″ barrel and would expect to get similar to better velocity. To show what a difference barrel length makes, I also shot some factory .38 special on my range trip.

2″16″
17841031
27511094
37731131
47881131
57621154
67831159
77621143
87781143
97761113
Average7731122
3 sigma35117
Energy172363

What is the difference between .357 magnum and .38 special besides case length? It is pressure of cartridge during ignition 35,000 vs. 17,000 psi respectively. What I didn’t say with this data is the bullet is slightly lighter at 130 grains. Granted, this is a lighter bullet but the equalizer number is the energy.

Looking at the energy of 363 ft*lbs for .38 special versus 391 ft*lbs for .357 magnum I would deem this load as inadequate. Energy and velocity are not everything there is something to be said for accuracy as well. At least on the surface, I am definitely not getting the full potential of .357 magnum with this load combination.

If you remember a pound of powder is 7000 grains. And if I loaded 100 rounds averaging about 6 grains each for 600 grains I still have 90% of a pound left. It is good enough to make plinking rounds but given the choice, I would look for another powder.

End Your Programming Routine: I have done this exercise with several different powders and bullet weights. So, expect more of this in the future. Given our current state of reloading component shortages, it is unlikely that I am going to readily find a replacement to try any time soon. Of course, I am going to focus on what I currently have to get the most information on what I have on hand. I found the process enlightening, I hope that you did.

September 22, 2022 – ‘Tacticool’ Thursday

September 22, 2022 /

If you listened to my podcast on Monday, then you got a sneak preview to what I was going to talk about today. After all of these years, I am finally getting around to testing some of my reloads. I needed/wanted some validation data before I resumed doing any further reloading.

Now, I don’t know if you have been aware of what has been going on the last couple of years but in case you have been in a hole, reloading components are really hard to find. Fortunately for me, I loaded this ammunition in 2017. The challenging part is that replacing it is going to be challenging with the lack of components. Listening to Gun Talk the other day, I heard that some powders won’t even be made for another year. Good luck finding primers too. Fortunately, I have some of both.

What was my setup? Well, here is my source for my loads, the Hodgdon website.

My starting point is the second line, but I included the first line for comparison. I can’t possibly inform all the nuances of reloading today but you should know pushing a lead bullet too fast can cause barrel fouling. I interchange bullets sort of willy-nilly as long as we are talking about the same type bullet construction. My rule is as long as the weight is the same and it is copper jacketed, it should be safe to load with published data. If using lead bullets, make sure you are not using jacketed load data to start with until you have some idea of what you are doing.

Not everything is perfect. The cases I used were mixed head stamp instead of Winchester, the bullet I used was a Speer 158gr hollow point instead of a Hornady XTP (also a jacketed hollow point) but the powder was Hodgdon Universal and the primers were Winchester.

I have another secret, I also mix and match primer brands with starting point loads. This is not an endorsed reloading best practice. You can find tables ranking primer ignition and granted, I am not an expert but we are in a time when you have to work with what you can get. My best guess is that you might effect accuracy or not be able to duplicate published data but I really have my doubts that changing primer brands is actually dangerous.

The way I initially choose my starting point loads was to cross compare powders that work across multiple cartridges. I also look at multiple sources, availability and so on and pick a direction. I literally wrote down a list of powders that would work and went to the store to see what they had. Lest you think that you can buy this stuff online – you can. But it has to ship under a specific HazMat banner so it costs quite a bit more for small quantities. Purchasing local is almost always the best deal, but again this is a matter of getting it or not.

I load 100 cartridges at a time. So in this case, I loaded 20 – 5.8 grains, 20 – 5.9 grains, 20 – 6.0 grains, 20 – 6.2 grains and 20 – 6.3 grains. I fired all of them and measured the velocity. I am working on my 1000 round trigger job concept and my rifle is not even sighted in so I just shot for velocity measurement.

There are two other variables to consider. One is the barrel length. Mine was fired out of a Rossi 92, 16 inch barrel. In theory, this should give the highest possible velocity compared to a shorter barrel. You can see the published load used a ten inch barrel. The other is the outside temperature. This day was a smoky 80 degrees. In theory, the warmer the outside temperature, the more velocity you are going to get. It has to do with the theory of reaction, gas/pressure etc. You don’t want any more science today.

Without further adieu, here is the raw data.

Since I have given you all of the tools to calculate the results, you can go ahead of me if you like. I am going to save the analysis for next week and I will let you in on a secret, I am withholding some information that will be helpful on my overall prognosis. Nevertheless, what is presented is the basic starting point looking at the data.

You did listen to my podcast on Monday didn’t you? You will see that I have some values highlighted in red Those to me are the outliers. You will also notice that I have some blanks, those were the results of missing the chronograph. Since you listened, you know my theory and how I am going to handle them next week. I will give you this week to catch up and listen to the podcast.

End Your Programming Routine: This is the culmination of years of kind of stumbling around in the dark. My next planned range trip I have a very similar exercise planned with a different powder. As a scientist, I can only make educated decisions with data. I don’t know how far I can actually take this given today’s shortages but I will probably have enough data to decide to keep looking at components or work on dialing the current ones in.

August 18, 2022 – ‘Tacticool’ Thursday

August 18, 2022 /

We finally get to the whole reason for doing weeks of testing today. My initial question was what difference does the pellet weight make in energy. Or said differently, what pellet would be best to eliminated pests. Is a heavier or lighter pellet better? My opinion is that the highest energy pellet is the best. To calculate that, I need to know the velocity of the different weight pellets.

On the left is the Crossman Powershot 5.4 grain and on the right is the Gamo Rocket 9.6 grain. You might recall to date, all testing has been done with various models of the Gamo 7.54 grain pellet. An interesting anecdote about the Powershot is that I was reading reviews about it and apparently can penetrate 16 gauge steel in the right circumstances. I bought it because it was light, for comparison purposes.

5.4gr Muzzle5.4gr 30′7.54gr Muzzle7.54gr 30′9.6gr Muzzle9.6gr 30′
1006879942849864797
1028884946853855777
1028901966866855785
1005904959859857798
1040875953855847795
1007880952870848784
1049913973852840793
1039885947853852787
1027895951868840786
1036903966858844791
1026.5 +/-46.9891.9 +/- 38.9964.6 +/- 19.5857.3 +/- 22.2850 +/- 23.4789.3 +/- 20
All values in fps

Why do I keep measuring velocities at two different distances? I am hoping to get enough data that I can calculate (or guess) velocity at distance and have an educated guess at performance with one measurement. Using formulas I have discussed in the past, here are the results in energy at target distance.

5.4gr 30′7.54gr 30′9.6gr 30′
9.5 12.313.2
All values in ft*lbs

From the data, it would appear that my hypothesis is correct for my assumption. The 9.6 grain pellet has the most energy at target range. Therefore, this would be the most effective pellet for pest control.

I want to point out that energy should not be the sole determining factor in selection of ammunition. Barrel rate of twist can only stabilize projections within a certain weight range. That really translates to accuracy and consistency. There are additional considerations for wind drift as well. The lighter the pellet, the more likely wind is going to effect point of impact as well. That variable is more difficult to test, but it is a known fact. Finally, depending on the distance of the target and the overall velocity, pellets drop based on the rate of gravity, so the slower the pellet the more drop at distance making aiming (and accuracy) more difficult.

End Your Programming Routine: I hope that you have enjoyed my mini-series on pellet ballistics. I have learned a lot as well as re-awakening some long dormant brain cells on math. I will be back from time to time with this line of writing because I have thoroughly enjoyed the process and I have the tools to do it now. I have one more test in this line to complete but it is going to take a bit of effort to finish. For now, I am coming back with something different next week.