Labradar

[R Stiner]

Adamsgt


The reason for moving my labradar to the front of the mounting plate is to get the labradar closer to the front of bench.
It lets me get the labradar 6"or less from muzzle.
I still like the safety factor of muzzle past front edge of bench. especially when using a muzzle brake.

Russ

 

[alinwa]

" I can actually show you in real time how much velocity a SINGLE KERNEL of various powders is worth "

Al........were you going to post some data about this ..................????

bill

No Bill, I'm not.

 

[mturner]

Single Kernel

" I can actually show you in real time how much velocity a SINGLE KERNEL of various powders is worth "

Al........were you going to post some data about this ..................????

bill

Bill,

While I haven't done the testing that Al has done, I can tell you that there would be a lot of difference in velocity per kernel for various powders based on kernel size. But to put a range to it, you could probably see anywhere from 2 to 10 fps per kernel. I wouldn't be surprised if Al has seen even more. I'm basing this information on velocity per tenth of a grain, which can be anywhere from 10 - 30 fps. The weight of a single kernel goes from .01gr to .05gr for typical extruded powders. The weight per kernel can be lower than or higher than this by going to extremes like fine ball powder to 50 BMG powder. This is the quick explanation. It would take Al some serious time to give the long version.

I can tell you without any hesitation that extreme spreads in the 50-70 fps range are very common from thrown charges. This kind of velocity spread can and does cause vertical even in a load that is in tune, simply because the velocities get outside of the tune window. I actually like to tune with a small variation in my powder charges that equals around 30 fps extreme spread, then weigh charges to get the extreme spread to 10 fps or less. Trying to find a tune with extreme spreads under 10 fps can be deceiving. They just go in the same hole even if they leave with the barrel in the middle of it's vertical swing. You'll think your in tune, then eventually a shot will go high or low.

Michael

 

[B.Larson]

Single kernal velocity effects

Bill,

While I haven't done the testing that Al has done, I can tell you that there would be a lot of difference in velocity per kernel for various powders based on kernel size. But to put a range to it, you could probably see anywhere from 2 to 10 fps per kernel. I wouldn't be surprised if Al has seen even more. I'm basing this information on velocity per tenth of a grain, which can be anywhere from 10 - 30 fps. The weight of a single kernel goes from .01gr to .05gr for typical extruded powders. The weight per kernel can be lower than or higher than this by going to extremes like fine ball powder to 50 BMG powder. This is the quick explanation. It would take Al some serious time to give the long version.

I can tell you without any hesitation that extreme spreads in the 50-70 fps range are very common from thrown charges. This kind of velocity spread can and does cause vertical even in a load that is in tune, simply because the velocities get outside of the tune window. I actually like to tune with a small variation in my powder charges that equals around 30 fps extreme spread, then weigh charges to get the extreme spread to 10 fps or less. Trying to find a tune with extreme spreads under 10 fps can be deceiving. They just go in the same hole even if they leave with the barrel in the middle of it's vertical swing. You'll think your in tune, then eventually a shot will go high or low.

Michael

alinwa said...... " I can actually show you in real time how much velocity a SINGLE KERNEL of various powders is worth "

Thanks Mike for your answer......... 2-10 ft/sec spread per kernel.......I`m weighing powder on an A&D FX 120i scale...... would have to rule out most fine ball powders..... in this testing...and with stick...esp. shortcut.... the variance in kernel length would make it a complex test..... to get accurate data what would a guy do..... measure the length of the individual grains of powder....????....Owning 3 chronographs an Ohler 35p,magneto speed and MX2..... there are a lot of factors in measuring bullet speed esp. in relation to single kernel velocity .....it would be a very factor related test ,regimented dependent on barrel temp,barrel cleanliness,and chrono accuracy to name a few...
chronograph readings are notoriously fickle in their readings from one day to the next.....
bill larson

 

[mturner]

Math

alinwa said...... " I can actually show you in real time how much velocity a SINGLE KERNEL of various powders is worth "

Thanks Mike for your answer......... 2-10 ft/sec spread per kernel.......I`m weighing powder on an A&D FX 120i scale...... would have to rule out most fine ball powders..... in this testing...and with stick...esp. shortcut.... the variance in kernel length would make it a complex test..... to get accurate data what would a guy do..... measure the length of the individual grains of powder....????....Owning 3 chronographs an Ohler 35p,magneto speed and MX2..... there are a lot of factors in measuring bullet speed esp. in relation to single kernel velocity .....it would be a very factor related test ,regimented dependent on barrel temp,barrel cleanliness,and chrono accuracy to name a few...
chronograph readings are notoriously fickle in their readings from one day to the next.....
bill larson

Bill,

The best way to run the test is to use simple match. Once you have a velocity increase per grain, or per tenth of a grain, you can weigh the kernels and divide it to see how many kernels are in a grain, then divide the velocity by the number of kernels. You have to keep in mind that the more a case is necked down, the more velocity you get by going up a tenth of a grain. Also the faster the powder the more velocity for a tenth of a grain. An example of a powder and a cartridge that would give a lot of velocity increase per kernel would be IMR4198 in a 22PPC. Using a common powder to BR, N133, the 6PPC gets around 20 fps per tenth of a grain, where the 22PPC closer to 25 fps, and the 30-30 closer to 10 fps.

The main thing to keep in mind is that this is just information that is somewhat useless. Knowing the exact velocity per kernel doesn't help with accuracy, it's just a number. Weighing powder charges closely is what keeps these velocity spreads down, not knowing the velocity per kernel.

There are about four things that determine velocity spread. Amount of powder, primer consistency, bullet seating depth consistency, and neck tension consistency. If I get all of these thing as close as I can, I have seen the 30-30 get down to 2 fps extreme spread for five shots. Since the PPC is necked down more, a person would be doing very well to get velocity spreads down to 5 fps.

Michael

 

[adamsgt]

Bill,
There are about four things that determine velocity spread. Amount of powder, primer consistency, bullet seating depth consistency, and neck tension consistency. If I get all of these thing as close as I can, I have seen the 30-30 get down to 2 fps extreme spread for five shots. Since the PPC is necked down more, a person would be doing very well to get velocity spreads down to 5 fps.

Michael

To start with, there's not much we can do about primer consistency from one primer to the next. Amount of powder can be controlled by weighing. I don't think I've checked my seating depth once I've set my seating die. Better start doing that. Neck tension involves a number of variables on it's own. Uniform neck brass thickness, consistent neck brass hardness and consistent surface on the inside of the neck. The first and third variables can be addressed during brass prep and the second by annealing.

What have I missed?

 

[B.Larson]

Single kernal velocity spreads

Bill,

The best way to run the test is to use simple match. Once you have a velocity increase per grain, or per tenth of a grain, you can weigh the kernels and divide it to see how many kernels are in a grain, then divide the velocity by the number of kernels. You have to keep in mind that the more a case is necked down, the more velocity you get by going up a tenth of a grain. Also the faster the powder the more velocity for a tenth of a grain. An example of a powder and a cartridge that would give a lot of velocity increase per kernel would be IMR4198 in a 22PPC. Using a common powder to BR, N133, the 6PPC gets around 20 fps per tenth of a grain, where the 22PPC closer to 25 fps, and the 30-30 closer to 10 fps.

The main thing to keep in mind is that this is just information that is somewhat useless. Knowing the exact velocity per kernel doesn't help with accuracy, it's just a number. Weighing powder charges closely is what keeps these velocity spreads down, not knowing the velocity per kernel.

There are about four things that determine velocity spread. Amount of powder, primer consistency, bullet seating depth consistency, and neck tension consistency. If I get all of these thing as close as I can, I have seen the 30-30 get down to 2 fps extreme spread for five shots. Since the PPC is necked down more, a person would be doing very well to get velocity spreads down to 5 fps.

Michael

Mike,....Thank you for a thoughtful answer..... I couldn't agree more......"The main thing to keep in mind is that this is just information that is somewhat useless.".... I believe any time you get below 10 ft/sec.E.S.... you are doing very well.
bill

 

[mturner]

Not Much

What have I missed?

Jerry,

There are very limited options on primers, but here are some. Use a milder primer, like the Russian primers. Weigh primers (I don't, too much trouble). Some used to test lots of primers by chronographing BB's propelled by only a primer. They find the most consistent lots and brands this way.

I did look for an old thread where I compared Federal and Wolf primers by weighing the primer mixture variation. This was done by weighing the whole primer, then removing the anvil and priming mixture, then reweighing the cup and anvil without the priming mixture. The variation on the Wolf primers was less by a little. It seems like the greatest amount of priming mixture variation was around .07 gr. That's enough to at least make you want to weigh them. That's a very powerful mixture. Probably equaling 2 or 3 tenths of a grain of powder.

If I find the thread, I will post the link.

Michael

 

[CMaier]

mike...
you are aware there is a sealant above the priming compound ?
how does one account for variation in sealant weight ?
i do not see how primer weight can be used because of the sealant.

Jerry,

There are very limited options on primers, but here are some. Use a milder primer, like the Russian primers. Weigh primers (I don't, too much trouble). Some used to test lots of primers by chronographing BB's propelled by only a primer. They find the most consistent lots and brands this way.

I did look for an old thread where I compared Federal and Wolf primers by weighing the primer mixture variation. This was done by weighing the whole primer, then removing the anvil and priming mixture, then reweighing the cup and anvil without the priming mixture. The variation on the Wolf primers was less by a little. It seems like the greatest amount of priming mixture variation was around .07 gr. That's enough to at least make you want to weigh them. That's a very powerful mixture. Probably equaling 2 or 3 tenths of a grain of powder.

If I find the thread, I will post the link.

Michael

 

[mturner]

Sealant

I have seen a red sealant on Federal primers, but the ones I took apart were of an older lot that didn't seem to have a sealant. The Wolf primers didn't seem to have it either. Any primer that clearly has a sealant would invalidate weighing. The BB testing is valid, but again a lot of work. Chronographing with different primers may be the best way after the other variables are addressed.

When testing at Raton, I seemed to have the velocity variation issues resolved. None of the 6PPC's had low ES's.

Michael

 

[adamsgt]

When testing at Raton, I seemed to have the velocity variation issues resolved. None of the 6PPC's had low ES's.

Michael

I haven't shot at Raton for over a year and a half due to medical issues but I seem to remember Durward Wofford was stubbornly shooting .30 for group. I wonder if he's still doing that. I bought 1K of his .30 bullets from him for my 30BR and they do very well.

 

[mturner]

30br

I haven't shot at Raton for over a year and a half due to medical issues but I seem to remember Durward Wofford was stubbornly shooting .30 for group. I wonder if he's still doing that. I bought 1K of his .30 bullets from him for my 30BR and they do very well.

Jerry,

Durward has pretty much gone back to strictly shooting his 6PPC's. He found the 30BR accurate with a .170" 200 yard group at Raton. He found it easier to stay in tune. But I believe that overall, while his experience was good, I believe during the process of taming the beast, he actually was able to improve his PPC performance. If things aren't quite right in the way of front and rear bags, a 30 will let you know. Get a 30 to shoot, and a PPC can get easier. At the time he switched to the 30, he was shooting the PPC as well, and it seemed that he was shooting the 30 better. Now he shoots his 6PPC the best he ever has. I also noticed that his performance improved drastically when he started shooting a Scoville stock.

Michael

 

[Bro.D]

30 BR for group

Here is my evaluation based on that year of shooting a 30 for group. The 30 BR will shoot with the PPC. In my opinion accuracy is not the issue; the issue comes in when you are trying to shoot fast because a condition dictates it and you are fiddling with gun/bag alignment issues because of increased recoil. This is especially true in the LV/sporter category. When I was in more of a trigger pull and had a bit more time to realign my gun in the bags I did just fine. It was when the conditions got a bit switchy that my aggs suffered. Possibly a more accomplished shooter could have kept up. In the HV category there is much less issue with recoil issues.
Mike is right in that learning how to shoot a 30 BR for group made my 6ppc shooting better. Probably the biggest lesson learned is how my shoulder receives the gun under recoil. If I did not have my shoulder aligned well the recoil of the 30 would put my crosshairs all over the map when returned to my front stop. I could be as much as 3-4" away from the mothball. Learning how to 'receive' the butt into my shoulder really helped this issue. This is what made my ppc shooting better.
That whole year I shot the 30 BR I was using a Kelbly Klub stock in lv and hv wt. A Scoville, Leonard, or Scarbrough stock may improve recoil issue but have not tried it. In the future I do plan to shoot the 30 BR for group but it will most likely only be in my rail gun. Durward

 

[R.G. Robinett]

To start with, there's not much we can do about primer consistency from one primer to the next. Amount of powder can be controlled by weighing. I don't think I've checked my seating depth once I've set my seating die. Better start doing that. Neck tension involves a number of variables on it's own. Uniform neck brass thickness, consistent neck brass hardness and consistent surface on the inside of the neck. The first and third variables can be addressed during brass prep and the second by annealing.

What have I missed?

Case capacity. RG

 

[mturner]

Bullet Variation

Case capacity. RG

Bullet variations in weight, diameter, and ogive length would effect velocity, but Randy, your bullets don't have those variations.

Michael

 

[R.G. Robinett]

Bullet variations in weight, diameter, and ogive length would effect velocity, but Randy, your bullets don't have those variations.

Michael

I hope not - but reality always steps in - nothing is perfect. When weighing charges to the kernel, or, 1/100th of a grain, in order to obtain consistent velocity, do you not have to use cases of identical capacity/volume? RG

 

[jackie schmidt]

I hope not - but reality always steps in - nothing is perfect. When weighing charges to the kernel, or, 1/100th of a grain, in order to obtain consistent velocity, do you not have to use cases of identical capacity/volume? RG

Randy, I guess the only way short of CCing each case to determine the actual internal volume is the old sorting them by weight. I just made up 100 new 30BR cases, and I started with 200. I trimmed a tad off all 200 to get them the same length, and started weighing on my Denver Electronics scale.

I got as much as 2 grains difference between the heaviest and the lightest. I was able to get 100 within .2 grn.

I think Jerry Hensler did some testing with a 6PPC years ago to see just how much cases could vary before the load was affected from shot to shot. If memory serves, he determined that as long as you kept them within .6 grn, there was no issue.

I'm not sure if anybody else has any hard data on it. Heck, I'm not even sure if weighing cases that are dimensionally identical on the outside is even that good of a way to sort them.

In his Book "The Ultimate In Rifle Accuracy", Glenn Newick had a little quip about a young shooter he observed tossing cases down range. Upon inquiring, the kid said, "that shot didn't go into the group". Glenn told him that if he kept that up, at the end of the day, he wouldn't have any cases left.

 

[Andy Cross]

Case Capacity

As one who's measured velocities from a home range setting for many years (I currently own 4 Chrony's, an Oehler 43 and the Labradar) I will state as repeatable provable fact that the only way you'll ever get truly low ES numbers is with weighed charges. Weighed on a scale capable of resolving single kernels of powder.

I can actually show you in real time how much velocity a SINGLE KERNEL of various powders is worth

It would be interesting to conduct tests to find out how much a couple of tenths in a cases water capacity alters pressures and therefore velocities.

 

[alinwa]

For myself, I tried all this stuff. I've still got the box of stuff used to measure case capacity. I've still got stuff from my primer killing and dissecting daze, I've tried everything listed here and 10 more in my quest for low ES but FOR ME

the answer lies in the use of a good scale.


period.


I still mark cases, occasionally. I file rims, have 7 colors Sharpies, I still set aside and mark "flier cases" automatically but FOR ME,

It's the weighing down to the kernel that gets me low ES. Consistently on cases from PPC/BR to X47L to .308-based to -06-based and clear up to (and lately a lot of) 338 Lapua, 338-378 and blown out 338 RUM's........

It just WORKS, then you can work on the pesky details like sorting stuff and refining stuff.


To The Kernel


works


try it







Don't trust the innernet, specifically don't trust alinwa..... just TRY IT!

 

[jackie schmidt]

It would be interesting to conduct tests to find out how much a couple of tenths in a cases water capacity alters pressures and therefore velocities.

Andy, I am sure Jerry Hensler did all of this about 10-15 years ago, using the Ohler Chronograph with the pressure testing feature, recording quite a bit of info. It's somewhere in the archives of this Forum, I just can't remember all of the details.

Maybe Jerry will chime in.