7mm Allen Mag test rifle finished.....
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davewilson
Well-Known Member
someone once said that a picture is worth a thousand words. is there any way i could get you to send me a couple of those?
7Rumloader
Well-Known Member
Eaglet according to what Kirby stated in an earlier post the difference was about .060 I'm not sure if he was measuring base to ogive but I think he was.
ss7mm
Well-Known Member
Eaglet:
The Nosler 160 grain Accubond in the picture has an OAL of: 1.410"
The Wildcat 200 grain ULD RBBT in the picture has an OAL of: 1.612"
The difference in the OAL is .202". You were close.
The Nosler 160 grain Accubond in the picture has an OAL of: 1.410"
The Wildcat 200 grain ULD RBBT in the picture has an OAL of: 1.612"
The difference in the OAL is .202". You were close.
ss7mm
Well-Known Member
Dave Wilson:
Send me an e-mail with some mailing info and I'll get some out to you the first of the week.
Send me an e-mail with some mailing info and I'll get some out to you the first of the week.
7Rumloader
Well-Known Member
SS7mm those are some nice looking bullets. Have you shot any yet?
ss7mm
Well-Known Member
7RUMloader:
I haven't shot any of the 200's yet. I'm waiting on the new rifle for that. I have shot a lot of the 169.5's and find them very accurate, at least in my gun.
The only 7mm I have on hand now probably wouldn't digest the 200 grain Wildcats very well. I do have some loaded up to try in the 7mmWby., but haven't shot them yet. I'm not expecting them to do well in this gun, but you never know what a certain combination will produce.
I'm looking at the 169.5 Wildcats as a great varmint load, that could also be used for deer and antelope, but the real reason for the existence of the new gun is to be able to launch the 200 grain Wildcats and, with a big grin on my face, watch them wreak havoc waaaaaay out there.
The term "Ultimate Killing Machine" came up during a conversation with Richard about the gun and his big 7mm ULD bullets and I believe what he says and I know Kirby puts a lot of stock in Richard and his bullets.
Strange how a specially designed little bullet, that only costs a few cents and a cartridge/case design that also is relatively inexpensive can cause a person to go crazy and spend thousands on a new gun just to shoot that special little bullet.
Insanity sure can be fun!!! /ubbthreads/images/graemlins/grin.gif /ubbthreads/images/graemlins/grin.gif
I haven't shot any of the 200's yet. I'm waiting on the new rifle for that. I have shot a lot of the 169.5's and find them very accurate, at least in my gun.
The only 7mm I have on hand now probably wouldn't digest the 200 grain Wildcats very well. I do have some loaded up to try in the 7mmWby., but haven't shot them yet. I'm not expecting them to do well in this gun, but you never know what a certain combination will produce.
I'm looking at the 169.5 Wildcats as a great varmint load, that could also be used for deer and antelope, but the real reason for the existence of the new gun is to be able to launch the 200 grain Wildcats and, with a big grin on my face, watch them wreak havoc waaaaaay out there.
The term "Ultimate Killing Machine" came up during a conversation with Richard about the gun and his big 7mm ULD bullets and I believe what he says and I know Kirby puts a lot of stock in Richard and his bullets.
Strange how a specially designed little bullet, that only costs a few cents and a cartridge/case design that also is relatively inexpensive can cause a person to go crazy and spend thousands on a new gun just to shoot that special little bullet.
Insanity sure can be fun!!! /ubbthreads/images/graemlins/grin.gif /ubbthreads/images/graemlins/grin.gif
ricka0
Well-Known Member
wc872 burn rate
[ QUOTE ]
<font color="purple"> b1g b0re the H-50 BMG powder works great in my RUM but heats the barrel very fast! The wc872 Kirby is using burns slower than the H-50 BMG and cooler from his testing and mine. </font>
[/ QUOTE ]
There has been a lot of talk about some powders burning hotter than others, but it's all silly talk. The only thing that accelerates a bullet is good old <font color="brown"> PV=nRT </font> from hi-skoul chemistry Ideal Gas Law
Pressure * Volume = n (# of atoms) * R (universal gas constant) * T emperature.
Pressure: [*]Volume is fixed (chamber/barrel) [*]# of atoms fixed (new gas molecules contribute < 1%) [*]R is constant
So there is a direct relationship between temp and pressure. You cannot have lower temp without having lower pressure. Pressure is simply the Force in F=MA or A = F/M (acceleration = Force/mass). Any mathematician worth her salt would tell you what counts in the integral of the pressure curve - which looks like
I show this to rule out a Dirac delta function which could transfer less heat to the barrel while producing higher velocity. Generally Dirac spike conditions (when your engine pings) produce <font color="red"> far less </font> acceleration.
If anyone has any empirical data on barrel temp vs. velocity with different powders I'd like to see it. You can get a lower velocity and a hotter barrel by burning a slow powder (H-50BMG) in a short barrel - where much of the powder burns after the bullet leaves the barrel (and thus contributes only to heating the barrel, not accelerating the bullet) - but in that case you have selected the wrong powder.
[ QUOTE ]
<font color="purple"> The wc872 Kirby is using burns <font color="red"> slower </font> than the H-50 BMG </font>
[/ QUOTE ]
WC872 is 20mm Vulcan ball powder which can be loaded using Hodgdon H870 or AA8700 data. You can get it from Jeff Bartlett for only $40/8 lbs (what a bargain!)
A slower burning powder producing equivalent velocity can ONLY result in a hotter barrel. So you're probably right about your barrel getting hotter, the H50BMG burns slower (and incompletely) producing a slightly hotter barrel - but apparently wrong about the relative rates. Given heat transfer is proportional to Temp/area (which is const) and time - I doubt you could measure the barrel temperature difference (given they produced identical velocities).
Burn Rates: (fastest to slowest)
10 Bullseye (Alliant)
17 Red Dot (Alliant)
122 N120 (Vihtavuori)
123 4227 (IMR)
209 N150 (Vihtavuori)
210 N550 (Vihtavuori)
211 4350 XMR (Accurate)
<font color="red"> 212 4350 (IMR)</font> -------------- // ricka's favorite hunting rifle powder
216 H4350 (Hodgdon)
242 7828 (IMR)
243 H1000 (Hodgdon)
248 Reloader 25 (Alliant)
252 Retumbo (Hodgdon)
<font color="red"> 254 H870 </font> (Hodgdon)-------------- same as wc872
...
<font color="red">259 8700</font> (Accurate)------------- same as wc872
260 24N41 (Vihtavuori)
261 W870 (Winchester)
<font color="purple"> 262 50 BMG </font> (Hodgdon) ----------- reference data 50 BMG
263 H5010 (Hodgdon)
264 PCL 513 (PB Clermont)
265
266 20N29 (Vihtavuori)
see B1g_B0re's powder page for burn rate comparisons.
[ QUOTE ]
<font color="purple"> b1g b0re the H-50 BMG powder works great in my RUM but heats the barrel very fast! The wc872 Kirby is using burns slower than the H-50 BMG and cooler from his testing and mine. </font>
[/ QUOTE ]
There has been a lot of talk about some powders burning hotter than others, but it's all silly talk. The only thing that accelerates a bullet is good old <font color="brown"> PV=nRT </font> from hi-skoul chemistry Ideal Gas Law
Pressure * Volume = n (# of atoms) * R (universal gas constant) * T emperature.
Pressure: [*]Volume is fixed (chamber/barrel) [*]# of atoms fixed (new gas molecules contribute < 1%) [*]R is constant
So there is a direct relationship between temp and pressure. You cannot have lower temp without having lower pressure. Pressure is simply the Force in F=MA or A = F/M (acceleration = Force/mass). Any mathematician worth her salt would tell you what counts in the integral of the pressure curve - which looks like
I show this to rule out a Dirac delta function which could transfer less heat to the barrel while producing higher velocity. Generally Dirac spike conditions (when your engine pings) produce <font color="red"> far less </font> acceleration.
If anyone has any empirical data on barrel temp vs. velocity with different powders I'd like to see it. You can get a lower velocity and a hotter barrel by burning a slow powder (H-50BMG) in a short barrel - where much of the powder burns after the bullet leaves the barrel (and thus contributes only to heating the barrel, not accelerating the bullet) - but in that case you have selected the wrong powder.
[ QUOTE ]
<font color="purple"> The wc872 Kirby is using burns <font color="red"> slower </font> than the H-50 BMG </font>
[/ QUOTE ]
WC872 is 20mm Vulcan ball powder which can be loaded using Hodgdon H870 or AA8700 data. You can get it from Jeff Bartlett for only $40/8 lbs (what a bargain!)
A slower burning powder producing equivalent velocity can ONLY result in a hotter barrel. So you're probably right about your barrel getting hotter, the H50BMG burns slower (and incompletely) producing a slightly hotter barrel - but apparently wrong about the relative rates. Given heat transfer is proportional to Temp/area (which is const) and time - I doubt you could measure the barrel temperature difference (given they produced identical velocities).
Burn Rates: (fastest to slowest)
10 Bullseye (Alliant)
17 Red Dot (Alliant)
122 N120 (Vihtavuori)
123 4227 (IMR)
209 N150 (Vihtavuori)
210 N550 (Vihtavuori)
211 4350 XMR (Accurate)
<font color="red"> 212 4350 (IMR)</font> -------------- // ricka's favorite hunting rifle powder
216 H4350 (Hodgdon)
242 7828 (IMR)
243 H1000 (Hodgdon)
248 Reloader 25 (Alliant)
252 Retumbo (Hodgdon)
<font color="red"> 254 H870 </font> (Hodgdon)-------------- same as wc872
...
<font color="red">259 8700</font> (Accurate)------------- same as wc872
260 24N41 (Vihtavuori)
261 W870 (Winchester)
<font color="purple"> 262 50 BMG </font> (Hodgdon) ----------- reference data 50 BMG
263 H5010 (Hodgdon)
264 PCL 513 (PB Clermont)
265
266 20N29 (Vihtavuori)
see B1g_B0re's powder page for burn rate comparisons.
ss7mm
Well-Known Member
Eaglet:
Here's another view of the Wildcat 200 grain ULD RBBT and the Nosler 160 grain Accubond.
This gives you a view of the comparisons in bearing length, boat tail and ogive, as well as overall length.
Here's another view of the Wildcat 200 grain ULD RBBT and the Nosler 160 grain Accubond.
This gives you a view of the comparisons in bearing length, boat tail and ogive, as well as overall length.
Richard338
Well-Known Member
- Joined
- Aug 22, 2003
- Messages
- 126
Re: wc872 burn rate
Complex high pressure non-equilibrium systems often deviate substantially from ideal gas law behavior.
The book gun propulsion technology (progress in astronautics and aeronautics) discusses propellant additives used to reduce burn temperature. There are also recent studies of additives for prolonging barrel life in artillery. I wouldn't discount outright the possibility of a cooler burning powder based solely on the ideal gas law.
Complex high pressure non-equilibrium systems often deviate substantially from ideal gas law behavior.
The book gun propulsion technology (progress in astronautics and aeronautics) discusses propellant additives used to reduce burn temperature. There are also recent studies of additives for prolonging barrel life in artillery. I wouldn't discount outright the possibility of a cooler burning powder based solely on the ideal gas law.
Ballistic64
Well-Known Member
Re: wc872 burn rate
Not an expert by any means,but your formula is not taking into account the powder burn rates and the area in which they're burned.
Not an expert by any means,but your formula is not taking into account the powder burn rates and the area in which they're burned.
davewilson
Well-Known Member
Re: wc872 burn rate
i think big bore's point was, if it ain't makin as much heat,it ain't makin as much pressure. i worked at NASA a few years and it didn't seem this complicated.
i think big bore's point was, if it ain't makin as much heat,it ain't makin as much pressure. i worked at NASA a few years and it didn't seem this complicated.
