ANOTHER subsonic question?
- Thread starter KeithR41
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Re: ANOTHER subsonic question?
The Hodgdon website shows 13.3 gr of trailboss in the 30-06 with 150 gr NBT producing 1061 fps (max is 19 @ 1477).
You didn't specify caliber so I can't get closer.
If it's a 308, I'd try 10gr through the Chrony (make sure it gets out the bbl!)
The Hodgdon website shows 13.3 gr of trailboss in the 30-06 with 150 gr NBT producing 1061 fps (max is 19 @ 1477).
You didn't specify caliber so I can't get closer.
If it's a 308, I'd try 10gr through the Chrony (make sure it gets out the bbl!)
Re: ANOTHER subsonic question?
Just take 180gr data and load it. The RN's are more stable at subsonic speeds because they're shorter and the CP and CG are arranged properly. You might be keyholing them if it's a 10, 11 or 12t barrel.
Take the can off to test for keyholing first, shoot them close at 25y or so to make sure they're not wobbly right off the bat and will cause baffle strikes.
If you're having stability problems seat them backwards in the case, they will more than likely stabilize.
Just take 180gr data and load it. The RN's are more stable at subsonic speeds because they're shorter and the CP and CG are arranged properly. You might be keyholing them if it's a 10, 11 or 12t barrel.
Take the can off to test for keyholing first, shoot them close at 25y or so to make sure they're not wobbly right off the bat and will cause baffle strikes.
If you're having stability problems seat them backwards in the case, they will more than likely stabilize.
Re: ANOTHER subsonic question?
I have a .308 PSS, stock Remington barrel, cut to 18in. I've got two box's of Hornady 180gr SP on order but I want to demo my can for the LT. of my team on Monday. I was hoping I could put something useable together just for that day.
Here's my first loads:
10.5gr Trailboss / 10.3 and 10gr of Trailboss also.
FED GMM brass
CCI LR primer
Hornady 180gr SP (Obviously)
Keith
I have a .308 PSS, stock Remington barrel, cut to 18in. I've got two box's of Hornady 180gr SP on order but I want to demo my can for the LT. of my team on Monday. I was hoping I could put something useable together just for that day.
Here's my first loads:
10.5gr Trailboss / 10.3 and 10gr of Trailboss also.
FED GMM brass
CCI LR primer
Hornady 180gr SP (Obviously)
Keith
Re: ANOTHER subsonic question?
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: KeithR41</div><div class="ubbcode-body">I have a .308 PSS, stock Remington barrel, cut to 18in. I've got two box's of Hornady 180gr SP on order but I want to demo my can for the LT. of my team on Monday. I was hoping I could put something useable together just for that day.
Here's my first loads:
10.5gr Trailboss / 10.3 and 10gr of Trailboss also.
FED GMM brass
CCI LR primer
Hornady 180gr SP (Obviously)
Keith
</div></div>
That will probably shoot just fine. I don't know if it's going to be subsonic for sure, but that seems right around where most people are shooting the 180's and a 308.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: KeithR41</div><div class="ubbcode-body">I have a .308 PSS, stock Remington barrel, cut to 18in. I've got two box's of Hornady 180gr SP on order but I want to demo my can for the LT. of my team on Monday. I was hoping I could put something useable together just for that day.
Here's my first loads:
10.5gr Trailboss / 10.3 and 10gr of Trailboss also.
FED GMM brass
CCI LR primer
Hornady 180gr SP (Obviously)
Keith
</div></div>
That will probably shoot just fine. I don't know if it's going to be subsonic for sure, but that seems right around where most people are shooting the 180's and a 308.
Re: ANOTHER subsonic question?
I've had excellent results With two loads, first was 9.4 gr of trailboss under a Hornady 150spt, and my favorite was a 220 gr Hornady RN on top of 10.5 gr of Clays. both are very quiet, the latter has shown great accuracy (about 1.75-2 MOA) out to 300yds, though you cant do much with it at that range. But it has proven quite deadly at 150 -200 yds. I've shot a couple animals that didn't even flinch or know they were hit, they simply stood there until they expired. Both loads were using brass with a 0.135 flash hole, neck sized and seated to cover the cannelure.
I've had excellent results With two loads, first was 9.4 gr of trailboss under a Hornady 150spt, and my favorite was a 220 gr Hornady RN on top of 10.5 gr of Clays. both are very quiet, the latter has shown great accuracy (about 1.75-2 MOA) out to 300yds, though you cant do much with it at that range. But it has proven quite deadly at 150 -200 yds. I've shot a couple animals that didn't even flinch or know they were hit, they simply stood there until they expired. Both loads were using brass with a 0.135 flash hole, neck sized and seated to cover the cannelure.
Re: ANOTHER subsonic question?
The accuracy on my load was dismal. I did seat the bullet to cover the canelluer, which is alot shorter than my standard 168mk load. Now that I've got it SS I'll work on the accuracy issue. I've read somewhere that a suppressor with add 30-50 fps to a load but I did not see a noticable difference with it on. Has anybody noticed this?
Keith
The accuracy on my load was dismal. I did seat the bullet to cover the canelluer, which is alot shorter than my standard 168mk load. Now that I've got it SS I'll work on the accuracy issue. I've read somewhere that a suppressor with add 30-50 fps to a load but I did not see a noticable difference with it on. Has anybody noticed this?
Keith
Re: ANOTHER subsonic question?
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: KeithR41</div><div class="ubbcode-body">The accuracy on my load was dismal. I did seat the bullet to cover the canelluer, which is alot shorter than my standard 168mk load. Now that I've got it SS I'll work on the accuracy issue. I've read somewhere that a suppressor with add 30-50 fps to a load but I did not see a noticable difference with it on. Has anybody noticed this?
Keith </div></div>
Very minmal, maybe less than 30-50fps. I have noticed that altitude has a very big impact on sound signature. the speed of sound can vary with atomspheric conditions, and/or elevation.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: KeithR41</div><div class="ubbcode-body">The accuracy on my load was dismal. I did seat the bullet to cover the canelluer, which is alot shorter than my standard 168mk load. Now that I've got it SS I'll work on the accuracy issue. I've read somewhere that a suppressor with add 30-50 fps to a load but I did not see a noticable difference with it on. Has anybody noticed this?
Keith </div></div>
Very minmal, maybe less than 30-50fps. I have noticed that altitude has a very big impact on sound signature. the speed of sound can vary with atomspheric conditions, and/or elevation.
Re: ANOTHER subsonic question?
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: coldboremiracle</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: KeithR41</div><div class="ubbcode-body">The accuracy on my load was dismal. I did seat the bullet to cover the canelluer, which is alot shorter than my standard 168mk load. Now that I've got it SS I'll work on the accuracy issue. I've read somewhere that a suppressor with add 30-50 fps to a load but I did not see a noticable difference with it on. Has anybody noticed this?
Keith </div></div>
Very minmal, maybe less than 30-50fps. I have noticed that altitude has a very big impact on sound signature. the speed of sound can vary with atomspheric conditions, and/or elevation. </div></div>
It varies significantly more with pressure (hence altitude) than the moisture in the air and temp. Pressure is #1, then temp is a reasonable second, a distant 3rd factor is humidity.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: coldboremiracle</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: KeithR41</div><div class="ubbcode-body">The accuracy on my load was dismal. I did seat the bullet to cover the canelluer, which is alot shorter than my standard 168mk load. Now that I've got it SS I'll work on the accuracy issue. I've read somewhere that a suppressor with add 30-50 fps to a load but I did not see a noticable difference with it on. Has anybody noticed this?
Keith </div></div>
Very minmal, maybe less than 30-50fps. I have noticed that altitude has a very big impact on sound signature. the speed of sound can vary with atomspheric conditions, and/or elevation. </div></div>
It varies significantly more with pressure (hence altitude) than the moisture in the air and temp. Pressure is #1, then temp is a reasonable second, a distant 3rd factor is humidity.
Re: ANOTHER subsonic question?
<span style="font-style: italic">Air density</span> varies with pressure, temperature, and humidity.
However,
<span style="font-style: italic">The speed of sound</span> varies only with temperature.
-Bryan
<span style="font-style: italic">Air density</span> varies with pressure, temperature, and humidity.
However,
<span style="font-style: italic">The speed of sound</span> varies only with temperature.
-Bryan
Re: ANOTHER subsonic question?
Actually, the speed of sound does change slightly with humidity. Humidity affects density, and the speed of longitudinal waves in a medium is affected by density.
Here's a calculator which will let one calculate how much:
http://www.sengpielaudio.com/calculator-airpressure.htm
Actually, the speed of sound does change slightly with humidity. Humidity affects density, and the speed of longitudinal waves in a medium is affected by density.
Here's a calculator which will let one calculate how much:
http://www.sengpielaudio.com/calculator-airpressure.htm
Re: ANOTHER subsonic question?
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Bryan Litz</div><div class="ubbcode-body"><span style="font-style: italic">Air density</span> varies with pressure, temperature, and humidity.
However,
<span style="font-style: italic">The speed of sound</span> varies only with temperature.
-Bryan </div></div>
c=sqrt(K/rho)
c = speed of sound
K = bulk modulus
rho = density
Which means that the speed of sound varies with density, which varies with pressure, temp and humidity.
Can you explain how your statement works?
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Bryan Litz</div><div class="ubbcode-body"><span style="font-style: italic">Air density</span> varies with pressure, temperature, and humidity.
However,
<span style="font-style: italic">The speed of sound</span> varies only with temperature.
-Bryan </div></div>
c=sqrt(K/rho)
c = speed of sound
K = bulk modulus
rho = density
Which means that the speed of sound varies with density, which varies with pressure, temp and humidity.
Can you explain how your statement works?
Re: ANOTHER subsonic question?
Look in the reference linked below, at the section marked "Details - Speed in Ideal Gases and in Air".
Note the formula. Speed is proportional to the pressure, but inversely proportional to the density. Since density in an ideal gas is a function of the pressure, those two cancel out, leaving only the temperature, and, to a minor extent I noted above, the moisture content.
http://en.wikipedia.org/wiki/Speed_of_sound#Details
Look in the reference linked below, at the section marked "Details - Speed in Ideal Gases and in Air".
Note the formula. Speed is proportional to the pressure, but inversely proportional to the density. Since density in an ideal gas is a function of the pressure, those two cancel out, leaving only the temperature, and, to a minor extent I noted above, the moisture content.
http://en.wikipedia.org/wiki/Speed_of_sound#Details
Re: ANOTHER subsonic question?
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Lindy</div><div class="ubbcode-body">Look in the reference linked below, at the section marked "Details - Speed in Ideal Gases and in Air".
Note the formula. Speed is proportional to the pressure, but inversely proportional to the density. Since density in an ideal gas is a function of the pressure, those two cancel out, leaving only the temperature, and, to a minor extent I noted above, the moisture content.
http://en.wikipedia.org/wiki/Speed_of_sound#Details
</div></div>
Got it, thanks.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Lindy</div><div class="ubbcode-body">Look in the reference linked below, at the section marked "Details - Speed in Ideal Gases and in Air".
Note the formula. Speed is proportional to the pressure, but inversely proportional to the density. Since density in an ideal gas is a function of the pressure, those two cancel out, leaving only the temperature, and, to a minor extent I noted above, the moisture content.
http://en.wikipedia.org/wiki/Speed_of_sound#Details
</div></div>
Got it, thanks.
Re: ANOTHER subsonic question?
http://en.wikipedia.org/wiki/Speed_of_sound
bohem,
According to the information linked above, I think what it comes down to is that your equation is general, meaning it applies to all matter. For example you can use it to find the speed of sound in nitrogen, helium, steel, water, etc.
The simple relation that I was referring to only includes temperature:
a = 331 + .6*T
where:
a is the speed of sound in m/s
T is the temp in degrees Celsius
This relation holds for common air (I think it uses the ideal gas law to simplify), so it's a special case of your general formula.
In conclusion we're both right... I think...
-Bryan
http://en.wikipedia.org/wiki/Speed_of_sound
bohem,
According to the information linked above, I think what it comes down to is that your equation is general, meaning it applies to all matter. For example you can use it to find the speed of sound in nitrogen, helium, steel, water, etc.
The simple relation that I was referring to only includes temperature:
a = 331 + .6*T
where:
a is the speed of sound in m/s
T is the temp in degrees Celsius
This relation holds for common air (I think it uses the ideal gas law to simplify), so it's a special case of your general formula.
In conclusion we're both right... I think...
-Bryan
Re: ANOTHER subsonic question?
I just saw Lindy's reply; a better explanation than mine.
Seems we're all on the same page now.
Thanks,
-Bryan
I just saw Lindy's reply; a better explanation than mine.
Seems we're all on the same page now.
Thanks,
-Bryan
Re: ANOTHER subsonic question?
Thanks for coming back to that Brian, Lindy's reply was coming from the same page I had been using but I missed the ideal air simplification.
Thanks for coming back to that Brian, Lindy's reply was coming from the same page I had been using but I missed the ideal air simplification.
Re: ANOTHER subsonic question?
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: KeithR41</div><div class="ubbcode-body">I have a .308 PSS, stock Remington barrel, cut to 18in. I've got two box's of Hornady 180gr SP on order but I want to demo my can for the LT. of my team on Monday. I was hoping I could put something useable together just for that day.
Here's my first loads:
10.5gr Trailboss / 10.3 and 10gr of Trailboss also.
FED GMM brass
CCI LR primer
Hornady 180gr SP (Obviously)
Keith
</div></div>
Keith,
IIRC, the PSS has a 12-twist barrel. You probably will not have much luck with 180's out of a 12-twist (though some people here have). I never have gotten them (RN or BTSP) to stabilize through any 12-twist I've ever tried. I have had excellent results with Berry's 150 gr plated Flat Nose 30-30 bullets though. I'm using 6.8 gr of Hodgdon Titegroup in LC89 Match brass (weighed to 1 gr extreme spread) lit by a Fed 215M magnum primer. COL is 2.635 and I put a moderate crimp on them with a Lee Factory Crimp Die. They give me 1033 fps avg and <1.5 (many times <1)moa accuracy. 9.2 gr of Trailboss gets me the same velocity but isn't as accurate (~3 to 4 moa) in my rifle. This is through a 17 inch Remmy SPS Tactical 12-twist. Velocities given are with the suppressor on. As usual, start higher and work down to make sure you don't stick one in the bore.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: KeithR41</div><div class="ubbcode-body">I have a .308 PSS, stock Remington barrel, cut to 18in. I've got two box's of Hornady 180gr SP on order but I want to demo my can for the LT. of my team on Monday. I was hoping I could put something useable together just for that day.
Here's my first loads:
10.5gr Trailboss / 10.3 and 10gr of Trailboss also.
FED GMM brass
CCI LR primer
Hornady 180gr SP (Obviously)
Keith
</div></div>
Keith,
IIRC, the PSS has a 12-twist barrel. You probably will not have much luck with 180's out of a 12-twist (though some people here have). I never have gotten them (RN or BTSP) to stabilize through any 12-twist I've ever tried. I have had excellent results with Berry's 150 gr plated Flat Nose 30-30 bullets though. I'm using 6.8 gr of Hodgdon Titegroup in LC89 Match brass (weighed to 1 gr extreme spread) lit by a Fed 215M magnum primer. COL is 2.635 and I put a moderate crimp on them with a Lee Factory Crimp Die. They give me 1033 fps avg and <1.5 (many times <1)moa accuracy. 9.2 gr of Trailboss gets me the same velocity but isn't as accurate (~3 to 4 moa) in my rifle. This is through a 17 inch Remmy SPS Tactical 12-twist. Velocities given are with the suppressor on. As usual, start higher and work down to make sure you don't stick one in the bore.
Re: ANOTHER subsonic question?
My 180gr RN got in. I switched brass to my normal Fed match stuff I use. Didn't feel like dulling my trimmer with the Hornady TAP stuff. Anyway, the same 10.3gr of Trailboss with the 180gr RN was almost 200fps faster than the same load in the Hornady brass and 180gr SP. 1120 FPS.
I tried 10gr of TB, that load wasn't SS either, avg. out to 1097fps. There must be less case volume in the Fed brass compared to the Hornady, creating more pressure?
Anyway, my PSS is able to stabilize both 180gr RN and SP just fine. Haven't had a problem with either of them.
Now I'll try 9.8, 9.6, etc. until I get back to SS velocity.
The accuracy was quite noticably better with the Fed brass and RN bullets than the previous load. I don't know if that is because they are supersonic or if it's the components?
Keith
My 180gr RN got in. I switched brass to my normal Fed match stuff I use. Didn't feel like dulling my trimmer with the Hornady TAP stuff. Anyway, the same 10.3gr of Trailboss with the 180gr RN was almost 200fps faster than the same load in the Hornady brass and 180gr SP. 1120 FPS.
I tried 10gr of TB, that load wasn't SS either, avg. out to 1097fps. There must be less case volume in the Fed brass compared to the Hornady, creating more pressure?
Anyway, my PSS is able to stabilize both 180gr RN and SP just fine. Haven't had a problem with either of them.
Now I'll try 9.8, 9.6, etc. until I get back to SS velocity.
The accuracy was quite noticably better with the Fed brass and RN bullets than the previous load. I don't know if that is because they are supersonic or if it's the components?
Keith
Re: ANOTHER subsonic question?
Coldboremiracle, what twist are you using? Did you moly coat those yourself, and how much difference did that make?
Coldboremiracle, what twist are you using? Did you moly coat those yourself, and how much difference did that make?
Re: ANOTHER subsonic question?
I'm using a 10 twist, which I didn't think would be enough, but it seems to work just fine. I also tried 220smk's, they worked too.
I did moly coat those bullets, with moly powder I got from Lyman, I just toss a box of bullets into a 1 lb Hodgdon powder can, sprinkle in a little moly, and put the whole thing in my case tumbler for about twenty minutes. works great. as far as a difference, I haven't noticed much, maybe an average 15-20 fps, I just like to think that it reduces barrel wear and cleaning needs. BTW, I've been using the same bag of moly for about 4 years, and its not even halfway gone yet.
I'm using a 10 twist, which I didn't think would be enough, but it seems to work just fine. I also tried 220smk's, they worked too.
I did moly coat those bullets, with moly powder I got from Lyman, I just toss a box of bullets into a 1 lb Hodgdon powder can, sprinkle in a little moly, and put the whole thing in my case tumbler for about twenty minutes. works great. as far as a difference, I haven't noticed much, maybe an average 15-20 fps, I just like to think that it reduces barrel wear and cleaning needs. BTW, I've been using the same bag of moly for about 4 years, and its not even halfway gone yet.
Re: ANOTHER subsonic question?
I would suggest a tour over to:
http://www.guns.connect.fi/gow/QA.html
And give it a read. If you have the capability I would suggest downloading the entire site before it is pulled from internet by the Finnish gov't. There is tons of good poop here on quiet loads and how to achieve it.
One guy has done it and was able to download the pics and everything. Takes more savvy with computers than I have.
As a result of this page I built a 358 Winchester with 26" barrel for launching 222 gr. flat nose lead bullets at 1100. With no can it sounds like a 22. Used a Pacnor barrel with 14 twist (which will stabilize up to 300 Grain bullets)
This 222 gr. load shoots around 1.7" at 50 yards.
Col Fackler of the Army Wound Ballistic Lab/ IWBA told me this bullet at 800 fps will give through and through on the biggest guy walking so I figure launch at 1100 I will still have it at 100 yards.
Next game play is to get a 300 grain mold and launch at same velocity.
I haven't done that much work with jacketed bullets but a 308 with cast bullets does not give peak accuracy with 10 inch twist but gives excellent accuracy with slower turns like 13 twist but you are limited to bullet weight which is about 170 grains to stabilize it.
With my 222 grain flat nose cast bullets I achieved through and through on 4X4 pine at 25 yards. I got through and through on 2X4 at 100 yards. Did not try the 4X4 but suspect it would too.
Name of the game is bullet stability. If you are not cutting round holes at 1000 inches it is not going to stabilize. But then again if you have the accuracy you don't necessarily need to achieve stabilization if you are hitting where you are aiming.
The Marine Corps Rifle Team has won and placed in lots of 1000 yard matches using 168s and bullets showing yaw on the target but they figured if the accuracy did not deteriorrate when it went subsonic no problem. You don't get points for round holes at 1000 yards only for the score.
If I had the money I would pay the difference and get a 30" barrel from Pacnor for this project.
I would suggest a tour over to:
http://www.guns.connect.fi/gow/QA.html
And give it a read. If you have the capability I would suggest downloading the entire site before it is pulled from internet by the Finnish gov't. There is tons of good poop here on quiet loads and how to achieve it.
One guy has done it and was able to download the pics and everything. Takes more savvy with computers than I have.
As a result of this page I built a 358 Winchester with 26" barrel for launching 222 gr. flat nose lead bullets at 1100. With no can it sounds like a 22. Used a Pacnor barrel with 14 twist (which will stabilize up to 300 Grain bullets)
This 222 gr. load shoots around 1.7" at 50 yards.
Col Fackler of the Army Wound Ballistic Lab/ IWBA told me this bullet at 800 fps will give through and through on the biggest guy walking so I figure launch at 1100 I will still have it at 100 yards.
Next game play is to get a 300 grain mold and launch at same velocity.
I haven't done that much work with jacketed bullets but a 308 with cast bullets does not give peak accuracy with 10 inch twist but gives excellent accuracy with slower turns like 13 twist but you are limited to bullet weight which is about 170 grains to stabilize it.
With my 222 grain flat nose cast bullets I achieved through and through on 4X4 pine at 25 yards. I got through and through on 2X4 at 100 yards. Did not try the 4X4 but suspect it would too.
Name of the game is bullet stability. If you are not cutting round holes at 1000 inches it is not going to stabilize. But then again if you have the accuracy you don't necessarily need to achieve stabilization if you are hitting where you are aiming.
The Marine Corps Rifle Team has won and placed in lots of 1000 yard matches using 168s and bullets showing yaw on the target but they figured if the accuracy did not deteriorrate when it went subsonic no problem. You don't get points for round holes at 1000 yards only for the score.
If I had the money I would pay the difference and get a 30" barrel from Pacnor for this project.
