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300wm rl26 help with pressure signs
- Thread starter unclefish
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coyotezapper
Well-Known Member
Re: 300WM RL26 help with pressure signs
QL predicts 3009 fps w/ 76.3 grs RL26 25" bbl 63,859 pmax 3.531" oal 97.2% fill
QL predicts 3009 fps w/ 76.3 grs RL26 25" bbl 63,859 pmax 3.531" oal 97.2% fill
Thanks. Now UFish has some MV data to compare his loads to.
Does QuickLoad account for bullets jammed into the lands, and the additional pressure associated with jammed bullets? That would be hard to do, IMO.
I do see that your QL data is based on an OAL 0.045" less than UFish's OAL. Just curious if QL attempts to model bullets jammed versus jumping to the lands. UFish's MV and pressure should be lessened with additional bullet jump to the lands.
Does QuickLoad account for bullets jammed into the lands, and the additional pressure associated with jammed bullets? That would be hard to do, IMO.
I do see that your QL data is based on an OAL 0.045" less than UFish's OAL. Just curious if QL attempts to model bullets jammed versus jumping to the lands. UFish's MV and pressure should be lessened with additional bullet jump to the lands.
I loaded some more up and pUT them .050 off lands. I will try to shoot tonight . Also I talked to barnes and they said find a similar bullet with rl26 data and start at low end . Give it a try tonight or tomorrow. I have a magneto speed just need to sit down and figure that out to. When I get 5 minutes.
Well just got home . I sunk the bullet in to .050 off the lands. The belt didn't even move at 71 gr or 72 gr. @73 gr it made my calipers read .001 more. Figured out that magnetospred pretty sweet. Besides they give u a square tube that don't fit in to a 30 cal hole.
Barnes 200 gr lrx with rl26 300wm 25" barrel
71gr =2845max 2804 min 2825 average fps
72gr=2871max 2861min 2864 average fps
And yes this load was dead on 2 touching 1.was 1/2 inch away 100yrds
73gr= 2918max 2898min 2906 average fps
My friend says put the gun in the case and bring it to colorado.
But of coarse I cant do that . For some reason I think I can always make it better right.. he told me I was nuts if I change anything. I told him you are always telling me about trigger time. He put his head down for a second and then says well maybe a couple more times here. But don't touch anything.
Barnes 200 gr lrx with rl26 300wm 25" barrel
71gr =2845max 2804 min 2825 average fps
72gr=2871max 2861min 2864 average fps
And yes this load was dead on 2 touching 1.was 1/2 inch away 100yrds
73gr= 2918max 2898min 2906 average fps
My friend says put the gun in the case and bring it to colorado.
But of coarse I cant do that . For some reason I think I can always make it better right.. he told me I was nuts if I change anything. I told him you are always telling me about trigger time. He put his head down for a second and then says well maybe a couple more times here. But don't touch anything.
MagnumManiac
Well-Known Member
If you BELIEVE this, then go right ahead.
I no longer use case expansion as a way to determine pressure, I bought a pressure trace, it TELLS me what pressures I'm running, and has proven that case expansion has NO correlation to pressure, whatsoever, hard brass may not expand until 70, 000psi is reached, or more.
Read Denton's articles, what he says is FACT.
Cheers.
coyotezapper
Well-Known Member
QL has many ways of altering load specs but I don't think it has one for jamming bullets. For example you can change the temperature and it will show you how sensitive your powder is. ( I don't use this as I test it myself )
The .045" was to get him to .050" jump where I have found is a good starting place for "X" bullets. Seating depth is a big thing in QL as it predicts pressure based on available powder space. I use QL to help choose a powder, for example I ran RL26 with a 175 LRAB in my 7SAUM and it shows it to be the ideal powder for this combo - 3000 fps easily at a safe pressure. My current powder H4831 I am getting just under 2900 fps.
coyotezapper
Well-Known Member
IMO your 1 grain increments are a little large. I would have used .5 grain increments. It looks like you have a nice flat spot in your velocity at 72 grains. I would load 6 each of 71.8, 71.9, 72, 72.1 and 72.2 and test again. The thing to look for here is vertical along with velocity. Find where your velocity is the same or close to it between each different load and this will be your powder node. Load to the middle of the node and fine tune with seating depth in .003" increments if needed. Barnes "X" usually need very little tuning once you find the powder node. If you have time load higher in .5 grain increments. At 2871 fps you are only around 54K PMAX, a long ways away from 64K. Your numbers are real close to QL numbers so you should be able to go to their max at 75.8 grains - 3006 fps. Remember pressure = velocity. Once you get to 3000 fps you will be at max pressure even if you are below the 75.8 grains. Keep us informed of your progress and especially your hunt details.
If you BELIEVE this, then go right ahead.
I no longer use case expansion as a way to determine pressure, I bought a pressure trace, it TELLS me what pressures I'm running, and has proven that case expansion has NO correlation to pressure, whatsoever, hard brass may not expand until 70, 000psi is reached, or more.
Read Denton's articles, what he says is FACT.
Cheers.
What I believe, and have demonstrated for many years, is that I can measure belt and case head expansion of 0.0005" with dial calipers graduated to 0.001". If you had measured case head expansion for any length of time, you would have arrived at the same conclusion. And that's why I corrected your errant statement on the need for a 0.0001" blade micrometer.
Never said a pressure trace wouldn't be a better way to identify pressure. Neither did you, until now.
I also believe I won't damage any modern rifle if my belt or case head expansion is held to less than 0.0005" expansion on the original shot fired on the virgin brass cases. And that I'll always identify pressure with this method, before the one you recommend: stiff bolt lift.
Stiff bolt lift will be reached at different pressures with different actions, more so than the variability of brass case head / belt expansion. So why you recommend stiff bolt lift, preferentially to belt / case head measurements is a mystery to yourself. Some custom actions won't exhibit stiff bolt lift until pressures are way higher than stiff bolt lift occurs with a Remington 700 or Win M70. The brass used to manufacture casings, although not identical between manufacturers, is still more consistent (with less variability) than the spectrum of actions manufactured and sold.
Brass case expansion to the point of failure is the safety relief valve on overpressured cartridges. When the pressure gets too high, the pressure will be released at the case head/primer, before the steel action lets loose (on the majority reloading errors and overloads). Measuring case head expansion or belt expansion allows one to measure and detect overpressure way before the safety relief valve opens.
If you or Denton disagree with these FACTS, it's a free country and everyone is allowed to be wrong.
If you want to claim pressure trace is better than measuring belt / case head expansion, I would hope you're correct, based on the cost of pressure trace.
When you claim one needs a 0.0001" calibrated measuring instrument to measure 0.0005" belt / case head expansion, you're wrong.
...it TELLS me what pressures I'm running, and has proven that case expansion has NO correlation to pressure, whatsoever,...
You can't be serious. How do you expect to be taken seriously, when you claim case expansion has no correlation to pressure?
Could you then continue, and explain which mechanism causes case expansion? Force is required to deform brass. What do you, Denton and pressure trace believe is the source of the force responsible for the deformation/expansion of cartridge case heads?
I think I understand what you're trying to communicate, but this statement is just as wrong as your claim that a measuring device calibrated to 0.0001" is required to measure a difference of 0.0005".
MagnumManiac
Well-Known Member
As I stated, if you believe that a set of springy calipers are accurate to read .0005", then go right ahead and do it that way. I will GUARANTEE that if I measured those same cases with my blade MICROMETER, it would read EXACTLY what your belts measure. Why you need the accuracy of .0001", is so you can read to EXACTLY 1 10, 000th of an inch, you simply cannot do that with calipers. PERIOD.
I have measured case head expansion for many years, no where, anywhere, in no manual does it state to use calipers of any type to measure case head expansion. I am a machinist, I would never use calipers to read ANYTHING once it had been turned/milled to size, inside/outside mics that read to .0001" are mandatory. Calipers only ever get used for ROUGH measurements, because they are inaccurate by nature.
Getting to brass expansion, .0005" is a generic measurement that equates back to the days of copper crusher testing, as brass is harder than copper, the deformation of brass is less, it was guesstimated to be less than the amount of expansion it took to expand a primer pocket for 3 firings before case hardening proved that no more expansion took place. It has no exact correlation to the pressure the cartridge is producing, because brass hardness varies, soft brass, such as Federal, will deform at much lower pressure than harder brass like Winchester.
I concede that brass deformation can be used to ascertain safe loading techniques, but it does NOT tell you what pressure you are running, neither does the chrony reading. All it tells you is the brass is expanding at those pressure levels.
New brass often expands twice as much, or more, as once fired brass, is this excessive according to your calipers?
BTW, new unfired brass should NEVER be used for case head expansion measurements due to the very fact that it always expands far more than once fired brass, and brass should only be used for case head expansion for a maximum of 3 firings.
If this is not what you wish to hear, then it's too bad that you can't learn the correct methods, telling me I'm incorrect doesn't change the facts that YOUR methods go against everything ever written on the subject.
As I stated, if you believe that a set of springy calipers are accurate to read .0005", then go right ahead and do it that way. I will GUARANTEE that if I measured those same cases with my blade MICROMETER, it would read EXACTLY what your belts measure. Why you need the accuracy of .0001", is so you can read to EXACTLY 1 10, 000th of an inch, you simply cannot do that with calipers. PERIOD.
I have measured case head expansion for many years, no where, anywhere, in no manual does it state to use calipers of any type to measure case head expansion. I am a machinist, I would never use calipers to read ANYTHING once it had been turned/milled to size, inside/outside mics that read to .0001" are mandatory. Calipers only ever get used for ROUGH measurements, because they are inaccurate by nature.
Getting to brass expansion, .0005" is a generic measurement that equates back to the days of copper crusher testing, as brass is harder than copper, the deformation of brass is less, it was guesstimated to be less than the amount of expansion it took to expand a primer pocket for 3 firings before case hardening proved that no more expansion took place. It has no exact correlation to the pressure the cartridge is producing, because brass hardness varies, soft brass, such as Federal, will deform at much lower pressure than harder brass like Winchester.
I concede that brass deformation can be used to ascertain safe loading techniques, but it does NOT tell you what pressure you are running, neither does the chrony reading. All it tells you is the brass is expanding at those pressure levels.
New brass often expands twice as much, or more, as once fired brass, is this excessive according to your calipers?
BTW, new unfired brass should NEVER be used for case head expansion measurements due to the very fact that it always expands far more than once fired brass, and brass should only be used for case head expansion for a maximum of 3 firings.
If this is not what you wish to hear, then it's too bad that you can't learn the correct methods, telling me I'm incorrect doesn't change the facts that YOUR methods go against everything ever written on the subject.
We don't need to measure to 0.0001" case head expansion in order to identify excess pressure. So I don't need a 0.0001" scaled measuring device. If you think a 0.0001" scaled device is required to measure changes exceeding 0.0005", you must be selling measuring devices.
"...in no manual does it state to use calipers of any type to measure case head expansion." That statement doesn't mean anything. You advocate stiff bolt lift as a superior means of elevated pressure identification. I'm not aware of any manual that instructs to measure the force required to lift the bolt off a fired cartridge either.
No reloading manual tells us to exceed their published maximum load. Yet how many exceed those published maximum loads? No reloading manual tells us to change any of the components in their publish load recipes. Yet how many change out primers or casings?
I have no idea why you're focusing on the importance of knowing exact pressure values in psi. I never claimed cartridge belt/head expansion measurements can provide one with the numeric value of that fired cartridge's pressure. I never claimed a chronographed MV can be used to identify a numeric value of pressure. And I never stated I was measuring case belt/head expansion in an effort to obtain a numeric value for the magnitude of the pressure. We don't need a numeric pressure value to identify powder loads that expand case belts/heads. We can identify pressures that reach levels sufficient to expand case belts/heads by taking a simple measurement of case belt/head expansion. That's all I'm doing. Nothing magical. And it's all that's necessary to identify pressures that will render brass casings useless thru repetitive firings at those powder charges.
You recommend stiff bolt lift for high pressure identification. Does stiff bolt lift provide an "exact correlation to the pressure the cartridge is producing"? Obviously not. That doesn't mean that stiff bolt lift doesn't provide notice that the pressures may be excessive in a rifle.
You were wrong on two counts.
1) You wrongly stated "case expansion has no correlation to pressure, whatsoever."
2) You stated "You cannot measure case head expansion ACCURATELY with calipers. You can ONLY measure case head expansion with a blade type micrometer that reads to .0001" accuracy." Nowhere in this Thread did anyone identify the need to measure to 0.0001" - other than you. I confidently measure distances greater or equal to 0.0005" with my 0.001" calipers all the time. Others do also when +/-0.0001" is close enough. Even +/- 0.0002" is good enough.
For all your focus and effort stressing that "You can ONLY measure case head expansion with a blade type micrometer that reads to .0001" accuracy." you then state that case head expansion is "not a good way to gauge pressure". So really, how important can it be to use a measuring instrument with 0.0001" markings to measure case head expansion to 0.0001" for purposes of identifying pressure? That's too funny.
All the OP desired was help with cartridge pressure signs. He wasn't striving to become a machinist or identify pressure levels to a numeric value +/- 50psi. He received help, and all ended well, partly by measuring case belt expansion with his unsuitable 0.001" Mitutoyo caliper. He's not even a machinist. And I'm comforted knowing others can also measure what needs measured with a set of quality 0.001" calipers.
