borbal

As promised, we have made a short YouTube video explaining how to measure usable case capacity. https://youtu.be/o3eJxKXqmn8 As you will see, it is a very simple process and is really no more difficult that measuring case capacity to the case mouth...

BlueBoy69 said; "...it's, as previously mentioned, calculating the volume taken up by the rear of the projectile. Not everyone's a mathematician/engineer/scientist." I think you are thinking about it the wrong way - certainly the wrong way up. I will post a link to a video on the easy way to do it.

Thanks BlueBoy69, I appreciate your comments. I will have another think about that word 'usable'. QL has a library of every bullet ever made and every case ever made and so can calculate the usable case capacity given the COAL. But then, you pay £150 to save you that bother. Harmut Broemel also did all the drawings for all the cartridges and chambers listed by CIP, and so he recycled that work for another market. Good for him. The P-Max simulator is free at the point of use but for that, you need to do the easy task of measuring the usable case capacity of your particular cartridge. This is actually superior as it is an actual measurement, not an estimate. Anyhow, thanks again for looking at the P-Max external ballistics simulator. Geoffrey Kolbe

Hello BlueBoy69 Yeah, the problem is that there is not room for the word 'Usable' in front of 'Case capacity'. However, it is explained in the manual (linked to in the explanation text under the data entry form) that by 'case capacity' what is required is the measured capacity behind the loaded bullet. And then there is that little asterisk after " case capacity* ", which if you look to the bottom of the page explains that you need the measured capacity behind the loaded bullet. I guess people will get used to what 'case capacity' means in the P-Max simulator. I do provide a list of 'usable' case capacities so that people can get a ballpark feel of how the cartridge will perform, also linked to in the explanation text under the data entry form. But you are encouraged to measure the case capacity behind the loaded bullet yourself as that is ultimately the best data of all. Anyhow, apart from that, did you find the simulator easy to use? Any other comments about using it? Thanks Geoffrey

Hello BlueBoy69 Well, the data you put into the P-Max simulator was not the same as for QuickLOAD ..... The P-Max simulator required the measured case capacity behind the loaded bullet, in other words the "usable case capacity", which QL says is 42.7 grains of water. So the entered case capacity in P-Max should be 42.7 grains of water, not 48 as you entered. Try that and see what you get... Thanks Geoffrey

Thanks GT3_richy It would be helpful if you could say what your load, case capacity, bullet weight, barrel length was, and what your measured MV was Thanks Geoffrey

Many of you many have used my online external ballistics software at http://www.geoffrey-kolbe.com/external_ballistics.htm The eventual goal was, '...a collection of ballistics programs will enable the estimation of all the ballistic information needed from "click" to "thump"...' and I have been putting the last brick in place with an internal ballistics simulator. It is similar to QuickLOAD, which has been around for over 20 years, and the new GRT software which saw the light of day last year, in that it is a numerical simulation using closed bomb data to generate models of powder energy and burning rates. The virtual charge of powder is then 'ignited' and progress of what happens next is determined by the physics. It is purely a numerical simulation and there are no assumptions about peak pressures or muzzle velocities. Unlike these two programs, The BBT "P-Max" simulator can be accessed online using any device with a browser. It does not have to be downloaded onto a device with an operating system for which the program was written. One thing the P-Max simulator does have in common with QuickLOAD and GRT is that it needs a large library of powder types to be really useful. But that is not easy as powder companies are very reluctant to part with their powder data - particularly US powder companies. The reason is that they do not want to fall foul of the anti-terrorist legislation and so will not release information which might be potentially useful to enemies of the United States. Well, it is early days and so far, I only have the data for the Chemie Swiss "RS" range of powders and a couple of Vihtavouri powders. But it is a start. Anyhow, you can access the simulator at http://www.bbt.scot/ballistics/pressure.htm I would be interested to know what you think about it. Is it easy and intuitive to use? Does it give results which are reasonable compared to your experience? One thing you should watch out for is that the case capacities required are the case capacities behind the loaded bullet, NOT the case capacities to the mouth of the case. Thanks Geoffrey Kolbe

Many of you many have used my online external ballistics software at http://www.geoffrey-kolbe.com/external_ballistics.htm The eventual goal was, '...a collection of ballistics programs will enable the estimation of all the ballistic information needed from "click" to "thump"...' and I have been putting the last brick in place with an internal ballistics simulator. It is similar to QuickLOAD, which has been around for over 20 years, and the new GRT software which saw the light of day last year, in that it is a numerical simulation using closed bomb data to generate models of powder energy and burning rates. The virtual charge of powder is then 'ignited' and progress of what happens next is determined by the physics. It is purely a numerical simulation and there are no assumptions about peak pressures or muzzle velocities. Unlike these two programs, The BBT "P-Max" simulator can be accessed online using any device with a browser. It does not have to be downloaded onto a device with an operating system for which the program was written. One thing the P-Max simulator does have in common with QuickLOAD and GRT is that it needs a large library of powder types to be really useful. But that is not easy as powder companies are very reluctant to part with their powder data - particularly US powder companies. The reason is that they do not want to fall foul of the anti-terrorist legislation and so will not release information which might be potentially useful to enemies of the United States. Well, it is early days and so far, I only have the data for the Chemie Swiss "RS" range of powders and a couple of Vihtavouri powders. But it is a start. Anyhow, you can access the simulator at http://www.bbt.scot/ballistics/pressure.htm I would be interested to know what you think about it. Is it easy and intuitive to use? Does it give results which are reasonable compared to your experience? One thing you should watch out for is that the case capacities required are the case capacities behind the loaded bullet, NOT the case capacities to the mouth of the case. Thanks Geoffrey Kolbe

I lived briefly in the United States, but found that the culture there is actually very conformist - and that was California! There are rules, and if you break the rules, you pay the penalty. If you do not have all the pieces of paper in place, you do not pass 'go'. In the UK, by contrast, there is a grey fuzzy area between the black and the white, some room for negotiation, some recognition that it is the principle that is important rather than the details. So I came back to the UK. That said, I live in an area of the Scottish Borders that is very remote, despite it being a mile from the border with England. There is no mobile phone reception. The skies are some of the darkest in the UK. If I want to go outside my back door and shoot off some piece of ordnance, there is no-one near enough to complain.

Why are you wanting a set of headspace gauges?

I recall David Little of Kynoch telling me how to anneal cases. You pick up the case, turn the front of the case in the flame of the torch until the back of the case is getting too hot to hold, put the case down and pick up the next case.....

I had a search on this site for the new 'free' internal ballistics software available from GRT Tools, but there seems to be only one mention. I wondered if anybody had tried it and how it rated against QuickLoad? If there was an online internal ballistics program, accessible by anybody with a browser, free to use, would this be useful to people?