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PostPosted: Thu May 28, 2020 10:48 am 
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Location: Coalmont BC
Article #24 is now online at Hard Air Magazine....

https://hardairmagazine.com/ham-columns ... o-pellets/

It's hard to believe this marks 2 years as Technical Editor.... but I have to admit I am running out of topics!!!!

Bob

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Dominion Marksman Silver Shield - 5890 x 6000 in 1976, and downhill ever since!
Airsonal; Too many! Springers, Pumpers, CO2, but I love my PCPs and developing them!
Proud Member of the 2000+fps Club!


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PostPosted: Thu May 28, 2020 2:07 pm 
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Location: P.G. B.C.
2 years - I thought maybe 1 :lol: - time flies when you are having too much fun.

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PostPosted: Mon Jun 22, 2020 4:01 pm 
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The last article in my series on Ballistics is now online....

https://hardairmagazine.com/ham-columns ... ug-design/

This is the 25th article I have written for H.A.M. and I am going to take a break from having to meet a deadline every month for a while.... When I have an idea for a stand-alone topic, or a short series, I plan to send them to Stephen, it just won't be monthly any more....

Bob

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Dominion Marksman Silver Shield - 5890 x 6000 in 1976, and downhill ever since!
Airsonal; Too many! Springers, Pumpers, CO2, but I love my PCPs and developing them!
Proud Member of the 2000+fps Club!


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PostPosted: Wed Jul 01, 2020 5:18 pm 
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Location: Coalmont BC
Here is an Index on Hard Air Magazine to all my articles:

https://hardairmagazine.com/ham-columns ... -articles/

Bob

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Dominion Marksman Silver Shield - 5890 x 6000 in 1976, and downhill ever since!
Airsonal; Too many! Springers, Pumpers, CO2, but I love my PCPs and developing them!
Proud Member of the 2000+fps Club!


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PostPosted: Wed Jul 01, 2020 5:49 pm 
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Location: Edmonton
Congrats on a great run, Bob. :drinkers:


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PostPosted: Mon Feb 15, 2021 6:37 pm 
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There is a new article on H.A.M.... It deals with work by Miles Morris on possible drag models for typical airgun slugs....

https://hardairmagazine.com/ham-columns ... es-morris/

It is theoretical in nature, but provides some insight into the anomalous results we are seeing compared to the commonly used G1 drag model....

Bob

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Dominion Marksman Silver Shield - 5890 x 6000 in 1976, and downhill ever since!
Airsonal; Too many! Springers, Pumpers, CO2, but I love my PCPs and developing them!
Proud Member of the 2000+fps Club!


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PostPosted: Tue Feb 16, 2021 5:12 pm 
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Tks Bob. It is amazing how little drag there is until you get up into transonic speeds.
We see this with large bore rifle bullet velocity loss once they go sub sonic. Amazing indeed.
Of course, we are using much higher BC bullets as well. The charts shows almost hitting a wall
at SOS speeds.

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PostPosted: Wed Feb 17, 2021 11:48 am 
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Yes, and it makes total sense for a bullet with a flat nose.... they simply aren't designed to minimize shock wave formation.... Once the Meplat is over 50% of the caliber, the overall drag increases quite rapidly, which is something the "McDrag" program I was using didn't show.... Interestingly, all the shapes show quite a similar increase approaching Mach 1.... pretty much a "don't go there" hill to climb.... However, that rapid increase doesn't occur until Mach 0.9, which is just over 1000 fps.... so it does mean we can play with slightly higher velocities than we thought....

Of course all this is at the moment theory.... but it does give us some insight into limited observations regarding what appears to be lower than expected drag with slugs in that 900-1000 fps area that we are seeing.... 8)

Bob

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Dominion Marksman Silver Shield - 5890 x 6000 in 1976, and downhill ever since!
Airsonal; Too many! Springers, Pumpers, CO2, but I love my PCPs and developing them!
Proud Member of the 2000+fps Club!


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PostPosted: Wed Feb 17, 2021 4:40 pm 
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Location: P.G. B.C.
Appears that the higher vel. rifles that run bullet shapes into the low supersonic range, would lose most of that in the first 50yards or so and for range shooting around 100 to 150yards,
the slightly slower bullets, say 900fps to 950fps range would not be far behind. Of course, what shoots well, if the most important.
shooter 1721 u-tuber did some long range testing from an FX with the FX Hybrids. The long range ballistics and remaining velocities & penetration/performance in ballistic gelatin and in
modeling clay in an earlier video were quite impressive, right to 300yards.

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PostPosted: Thu Nov 03, 2022 9:38 am 
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Location: Alberta
Congratulations I did not know we had a author in are group 8)


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PostPosted: Tue Jan 31, 2023 11:37 am 
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I have just published a new article in H.A.M.... I discusses the difference in some of the Drag Models used in airguns, and why we need a new one!....

https://hardairmagazine.com/ham-columns ... rag-model/

Using the G1 model will lead to incorrect trajectory and wind drift predictions for our slugs, which are capable of being used at higher velocities than is optimum for pellets....

Bob

_________________
Dominion Marksman Silver Shield - 5890 x 6000 in 1976, and downhill ever since!
Airsonal; Too many! Springers, Pumpers, CO2, but I love my PCPs and developing them!
Proud Member of the 2000+fps Club!


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PostPosted: Tue Jan 31, 2023 1:42 pm 
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Location: P.G. B.C.
Sub SOSound projectiles certainly add their own 'flavour' to the equation.

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Daryl


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PostPosted: Mon Nov 13, 2023 7:58 pm 
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Location: Dieppe, New Brunswick
Congratulations. I just joined.them.


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