Someone shot, consistently, at over half a mile 905yds with a pcp
- Thread starter Windmeister
- Start date
FANTASTIC!....Do we know if the shooter can provide us more information?...To start with, that is one powerful gun, it has the fpe of a .380 pistol...
Note: I wish I had more experience with airguns past 150-200 yards but I don't...
Of particular interest is the propellant used, BAR pressure & volume or air per shot and I am very interested in the scope...If the zero was set at let's say 400 yards, the drop at 900 would be 1050 inches! (88 feet)...With a Zero set at 800 yards it would drop 19 feet (228 inches) unless the ballistic program I am using is wrong.
Let's then assume that the gun is zeroed at 900 yards and we give the bullet a very generous .500 BC even though I don't believe it has over .250)...By comparison, a MatchKing Sierra boat tail (very aerodynamic) similar bullet has about a .370 BC....Then: AT WHAT BORE ANGLE was that gun shooting and what was the scope height in order for the shooter to be able to see the target?
We hear the gun rapport 900 yards away and then we see the pellet hitting the metal plate 2 seconds later...The camera and mic are at the target.
This is an open terrain where conditions (wind) are prevalent...Hopefully Physicists and Mathematicians around this forum can provide us some more precise ballistics (in simple words please- don't post many pages of graphs and tables).
Regards,
AZ
Note: I wish I had more experience with airguns past 150-200 yards but I don't...
Of particular interest is the propellant used, BAR pressure & volume or air per shot and I am very interested in the scope...If the zero was set at let's say 400 yards, the drop at 900 would be 1050 inches! (88 feet)...With a Zero set at 800 yards it would drop 19 feet (228 inches) unless the ballistic program I am using is wrong.
Let's then assume that the gun is zeroed at 900 yards and we give the bullet a very generous .500 BC even though I don't believe it has over .250)...By comparison, a MatchKing Sierra boat tail (very aerodynamic) similar bullet has about a .370 BC....Then: AT WHAT BORE ANGLE was that gun shooting and what was the scope height in order for the shooter to be able to see the target?
We hear the gun rapport 900 yards away and then we see the pellet hitting the metal plate 2 seconds later...The camera and mic are at the target.
This is an open terrain where conditions (wind) are prevalent...Hopefully Physicists and Mathematicians around this forum can provide us some more precise ballistics (in simple words please- don't post many pages of graphs and tables).
Regards,
AZ
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Simplified possible description;
Given 1000 fps mv for 92 gr as stated for 204 fpe . Approx G1 shape bullet.
Shot to 905 yards.
Time for sound at say 1120 fps = 2.424 sec to reach target vicinity (depends on temp ).
Time difference between rifle shot and bullet strike = 1.63 sec approx ( my repeated timing) forgetting the few yards between target and camera.
Therefore actual bullet flight time = 4.054 sec.
A ballistic coefficient of 0.1667 would match that ToF at NTP and would seem to be quite reasonable for a lead bullet of that profile etc..
Velocity at impact approx 495 fps for 50 fpe KE and would seem quite enough to mushroom those bullets like the pic shows.
From a 100 yards zero the sight would need 251 MOA elevation which is 4.18 degrees
Bullet drift in a 5 mph wind across the entire range would be just under 10 ft.
One of those 300 MOA scope adjustable mounts, or my Optimizer could shoe it in.
There, taking the not so subtle hint, I've left out most of the interesting stuff in deference to simplicity but there's enough there to check it out and make corrections as one may please if interested. ………… Kind regards, Harry.
Given 1000 fps mv for 92 gr as stated for 204 fpe . Approx G1 shape bullet.
Shot to 905 yards.
Time for sound at say 1120 fps = 2.424 sec to reach target vicinity (depends on temp ).
Time difference between rifle shot and bullet strike = 1.63 sec approx ( my repeated timing) forgetting the few yards between target and camera.
Therefore actual bullet flight time = 4.054 sec.
A ballistic coefficient of 0.1667 would match that ToF at NTP and would seem to be quite reasonable for a lead bullet of that profile etc..
Velocity at impact approx 495 fps for 50 fpe KE and would seem quite enough to mushroom those bullets like the pic shows.
From a 100 yards zero the sight would need 251 MOA elevation which is 4.18 degrees
Bullet drift in a 5 mph wind across the entire range would be just under 10 ft.
One of those 300 MOA scope adjustable mounts, or my Optimizer could shoe it in.
There, taking the not so subtle hint, I've left out most of the interesting stuff in deference to simplicity but there's enough there to check it out and make corrections as one may please if interested. ………… Kind regards, Harry.
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I asked about BC if his
.257 bullet. He said he shot it over 2 chrony's at 50yds. And worked out the BC too 0.320
.257 bullet. He said he shot it over 2 chrony's at 50yds. And worked out the BC too 0.320
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To learn more about this you can go to the GTA forum or the Talon forum. Look up "rifle50". He has several threads started over there, especially GTA, where he describes what he has and how he's doing it. Very interesting reads.
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"from a 100 yards zero the sight would need 251 MOA elevation which is 4.18 degrees"
Bullet drift in a 5 mph wind across the entire range would be just under 10 ft.
One of those 300 MOA scope adjustable mounts, or my Optimizer could shoe it in.
Thank you Harry...Fair enough, this does it for my question about the scope....
By any chance do you know if he is using air? (I assume he is) and if shooting at 200-230 BAR, what volume of air per shot?...I am just trying to figure out the internals (Transfer ports, etc.) in order to shoot that 92 gr. bullet at 1,000 ft./sec.
Best regards,
AZ
Bullet drift in a 5 mph wind across the entire range would be just under 10 ft.
One of those 300 MOA scope adjustable mounts, or my Optimizer could shoe it in.
Thank you Harry...Fair enough, this does it for my question about the scope....
By any chance do you know if he is using air? (I assume he is) and if shooting at 200-230 BAR, what volume of air per shot?...I am just trying to figure out the internals (Transfer ports, etc.) in order to shoot that 92 gr. bullet at 1,000 ft./sec.
Best regards,
AZ
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He is shooting air. There is no transfer port. It is a .257 condor. The valve is in the tank and the tank is located at the back of the gun and also acts as the butt stock. It is an inline direct to the pellet system. These guns in stock form will fire .25 cal pellets well over 1000fps.
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"These guns in stock form will fire .25 cal pellets well over 1000 fps."
Yes I know they shoot .25 cal pellets at 1000 fps...But 92 grain bullets at 1000 fps.?
I am just trying to find out if all these hot rodded guns are using secondary compression devices (Staged Compression) in order to further increase the 200-230 BAR pressure in the air cylinder/chamber (By Hydraulic or spring pistons to further compress the air volume or ?), or is it that they work by mere "Pressure Duration" meaning let's say: 200 -230 BAR Sustained pressure all the way until the bullet leaves the barrel or ?
To me this is a cultural question and kindly ask not to get into complicated matters, I am curious about knowing in simple terms how it is done.
Regards,
AZ
Yes I know they shoot .25 cal pellets at 1000 fps...But 92 grain bullets at 1000 fps.?
I am just trying to find out if all these hot rodded guns are using secondary compression devices (Staged Compression) in order to further increase the 200-230 BAR pressure in the air cylinder/chamber (By Hydraulic or spring pistons to further compress the air volume or ?), or is it that they work by mere "Pressure Duration" meaning let's say: 200 -230 BAR Sustained pressure all the way until the bullet leaves the barrel or ?
To me this is a cultural question and kindly ask not to get into complicated matters, I am curious about knowing in simple terms how it is done.
Regards,
AZ
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Some of the .257's use 4500psi bottles, 3600psi bottles, and some 3000psi bottles. Regardless they use huge reworked valves to flow enough air to push 900-1000fps. Depending on which tank and other variables, these guns can get 3-10 shots on a fill. If you really want details call Randy at R&L airguns. He builds these guns. Doug Noble makes the best valve for these guns to my knowledge. He goes by the screen name Dayotat on the airgun forums. He has built some of the most notable .257's like Cedric's.
A cultural question? There is no "staged compression" these guns operate like the majority of todays PCP guns and operate off of what ever fill pressure and tank volume is used.
A cultural question? There is no "staged compression" these guns operate like the majority of todays PCP guns and operate off of what ever fill pressure and tank volume is used.
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AJ:
Thanks for your reply...
A cultural question?
I am learning and still want to know how it is achieved as questioned in my previous post, thank you for these tips on who to contact...I wish I knew this stuff but I don't...I am into accuracy and have never experimented the mega power, mega velocity fields...My experience with airguns is from many years but goes to one little niche: "competition accuracy" and this is basically .177's and some .22's at competition velocities...While I have a .25 and have shot .30's and .357's, I have not done any experimenting not shot other that standard pellets.
Regards...
AZ
Thanks for your reply...
A cultural question?
I am learning and still want to know how it is achieved as questioned in my previous post, thank you for these tips on who to contact...I wish I knew this stuff but I don't...I am into accuracy and have never experimented the mega power, mega velocity fields...My experience with airguns is from many years but goes to one little niche: "competition accuracy" and this is basically .177's and some .22's at competition velocities...While I have a .25 and have shot .30's and .357's, I have not done any experimenting not shot other that standard pellets.
Regards...
AZ
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I was just trying to answer your question and meant no ill will. Sorry if it came across wrong. I understand your experience is much different and things like this are "new" to you. I highly recommend contacting Randy as I just spoke with him the other day and is a very good man and can help answer what I can not. I have been kicking around buying a .257 condor for a long time. I am just not a big fan of the AF platform and waiting on other options in .257. I have explored building one off a marauder, but the work to make it happen is rather extensive and I will be rather limited with a .257 marauder.
Go to GTA and select PCP forums, then at the top of that page select big bore. Lots of info that might help you out. Try PM-ing rsterne on GTA. He is a wealth of knowledge and is one of the best in regards to big bore builds and overall knowledge.
Hope that helps
Aaron Robnolte
Go to GTA and select PCP forums, then at the top of that page select big bore. Lots of info that might help you out. Try PM-ing rsterne on GTA. He is a wealth of knowledge and is one of the best in regards to big bore builds and overall knowledge.
Hope that helps
Aaron Robnolte
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Good advice from Aaron.
AF rifles are not the only .257's in the running, but right now they are the most talked about. However when you invest $1800 to $2200 dollars for an air rifle, I want something more than Air Force. In no way I'm knocking AF they make a good rifle. I would rather have one from Quackenbush, Extreme Big Bore, etc. I think you get more for the money with these than the AF rifle. When I priced out an AF rifle in .257 from Porter Bullets it was $2150. The one I'm having made is $400 cheaper from of the Extreme Big Bore.
Extreme Big Bore won 1st & 2nd place at the recent Extreme Benchrest in AZ. They were using .308 ca as well as helium. Mike and Chris have some really good ideas for the .308 and now their putting that knowledge towards the .257. Go to the GTA forums on the Big Bore section and look up Whiteout rifle. Interesting read. There are several different threads on this.
Again, I'm not knocking AF rifles. I found a .22 cal AF on line and if I'm not out bidder, it'll be mine.
AF rifles are not the only .257's in the running, but right now they are the most talked about. However when you invest $1800 to $2200 dollars for an air rifle, I want something more than Air Force. In no way I'm knocking AF they make a good rifle. I would rather have one from Quackenbush, Extreme Big Bore, etc. I think you get more for the money with these than the AF rifle. When I priced out an AF rifle in .257 from Porter Bullets it was $2150. The one I'm having made is $400 cheaper from of the Extreme Big Bore.
Extreme Big Bore won 1st & 2nd place at the recent Extreme Benchrest in AZ. They were using .308 ca as well as helium. Mike and Chris have some really good ideas for the .308 and now their putting that knowledge towards the .257. Go to the GTA forums on the Big Bore section and look up Whiteout rifle. Interesting read. There are several different threads on this.
Again, I'm not knocking AF rifles. I found a .22 cal AF on line and if I'm not out bidder, it'll be mine.
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Jim, glad to hear Extreme is building a .257!! I might have to give them a call. I really like their work, but was unaware they were dabbling in the .257? Do you have any preliminary specs on your Extreme .257??
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Brent really doesn't want to make a .257, but after I spoke with Chris from Whiteout fame, Brent agreed to make one. He's working on everything but the barrel now. I have a 9 twist Shilen barrel on order. When I get it, I'll have my gun smith put a target crown on the barrel. This will have an adjustable RVA valve that Chris and Mike designed for their Whiteout. The valve is adjustable from the outside of the rifle.
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I believe the rifle was built by Randy (RL) and Doug (Maddog).. Maybe some other hands in there... Here's a link with story..
http://talonairgun.com/forum/viewtopic.php?f=4&t=33502
http://talonairgun.com/forum/viewtopic.php?f=4&t=33502
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I been talking with him and he sent me a correction for the 50 yards BC at .361
Carl also stated that "past 400 yards that is was more trial by error". BC changed too much and calculations/charts just did not work out at the range.
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