New Years presumption....

A

alinwa

oft dis'd member
I'm putting this theory in writing so's NEXT New Year I can see if I still believe it.

:):):):)

The presumption/theory is simple,"THERE IS NO MAGIC POWDER!!!!!"

And with this comes this corollary, "PRESSURE EQUALS VELOCITY!!!"

And the corollary to this corollary, "TUNING IS VELOCITY DRIVEN!!!"

After spending all last year WEIGHING each and every charge. And after putting artificial lighting in my three chronographs for absolutely consistent lighting day-to-day............. I am currently of the opinion that one can often take 2 or 3 or 5 different powders, load them to matched velocities and they'll shoot into nearly the same hole. And they'll all achieve roughly the SAME MAX VELOCITY in the end.

And of course a wicked SLOW powder may well give a slightly different peak velocity than a wicked FAST powder in the same rifle but that the difference is unlikely to be more than 50fps.....total, to case failure. Especially with short barrels. But this is a BURN RATE issue, not a BRAND thing.

That generally primer pockets will fail, ejector marks will appear and brass will begin to tighten up WITHIN 50FPS for each and all of the "appropriate" powders.




I got sucked into this again because of the RL-17 powder. Early this year I was told by no less than three winning competitive shooters that the new RL-17 "gave them around 100fps of free velocity" and it was wonderful and sublime.........

Now I've chased this tiger before, and the loading manuals are replete with "max charges" all at different velocities. In fact most everybody chooses the "highest velocity" powder listed on the page, then a can of the "most accurate" powder and so on when starting out with a cartridge....

and I've been fooled by chronographs and powder throwers.....a LOT.....


But I bought 10lb of RL-17 anyway..... and it's good powder. But is it "BETTER?" And is it "FASTER?" Does it achieve higher velocity or does it burn cleaner? Or dirtier? No, not really. It's Alliant powder. A niche mix, filling what may have been a gap in the "Burn Rate Chart" but nothing revolutionary IMO. It meters nice, better than it's "twin" H4350........

Yes, different lines of powder have different fouling characteristics.

And different powders have different ignition characteristics.

And different powders have different tuning characteristics...

That primers CAN and DO ignite different powders differently...

But MOST OF ALL different powders have different METERING characteristics and that this alone is responsible for a LOT of misconceptions regarding "Max Charge Weight." Regarding maximum achievable velocity alone the various powders are essentially similar.

AND!!! (flame suit ON :D ) that METERING CHARACTERISTICS are in large part responsible for certain powders gaining following among benchresters as "more consistent" and "easier to tune." (I'm 'wayyyy out on a limb here ;) )

Of course this isn't the whole story...... nothing ever is...... but IMO single and double-based smokeless propellants from the various mfgrs can offer "very similar" performance, that it devolves to a "Ford VS Chevy" argument in all but the most extreme accuracy cases.

I HAVE NOT spent much time comparing the VV line of "5" powders. Maybe they do offer a different enough curve so as to appreciably change max vel.

"Pressure Equals Velocity"

?????


Care to speculate with me?


I'll revisit this concept next New Year.

meantime, I'm sure using up a lot of "no good" powder! And getting fine results. WEIGHED charges all.

Get the charge weight UP, find a primer that gets it all BURNING, find the velocity window and enjoy....... primers equate to ES, a LOT!

I have yet to find a powder that's truly temperature stable.

New Year, New Presumption.....


Maybe setting up for a big dish of crow enjoyed with egg..... on the face.


:D


gonna' go down shoot some more....



al
 
Magic Powders

Wicked;

There are some magic powders for some cartridge/bullet combo's. Lil Gun and 35 gr. bullets in a .22 Hornet for one. More V with less P, magic.

Peak pressure does not equal velocity, the area under the pressure vs. time curve equals velocity.

Tuning is still a mystery to me, is it just velocity or is velocity a result of tuning a charge that we see along with smaller groups?

If you take Bullseye or Retumbo and load 6mm PPC to peak pressures your velocity will be much less (way more then 50 fps less) than if you use 133 or 4198 or BLc2, what kind of velocity do you think you could get from Bullseye in a 30 RUM. But you did say short barrels and appropriate powders so when you said wicked fast and wicked slow you meant a little fast and a little slow, right. There I would have to agree with you, for most midsized cartridges there are easily 6 to 10 powders that will get you about the same max velocity.

Are those appropriate dozen powders all equal, not really. Does it matter which you pick, maybe not so much if you weigh your charges. About fouling and temperature sensitivity, I don't know yet.

Primers, still working on that as well. I know that they can make a difference. It is gospel that small pistol primers will shoot smaller groups in .22 Hornet than small rifle. Why, small pockets and flash holes on PPC? Why uniform pockets and flash holes? I think primers are like powders, there is more than a few that can be made to work well. If I was using an appropriate powder and primer and the gun would not shoot, I would look at a lot of things before I started switching primers and powder.

Tim
 
Al,
That's a lot to digest! It may very well take a year for me to figger' out. I have a full plate and a short fork! :D
Best,
Dan Batko

"Where are we going and why am I in this basket/"
 
dtknowles said:
Primers, still working on that as well. I know that they can make a difference. It is gospel that small pistol primers will shoot smaller groups in .22 Hornet than small rifle. Why, small pockets and flash holes on PPC? Why uniform pockets and flash holes? I think primers are like powders, there is more than a few that can be made to work well. If I was using an appropriate powder and primer and the gun would not shoot, I would look at a lot of things before I started switching primers and powder.

Tim
Click to expand...

opinions I've got :D

"It is gospel that small pistol primers will shoot smaller groups in .22 Hornet than small rifle."

I think this is because the case is so small. The primer effect VS powder charge is HUGE and IMO the regular primers actually try to start the bullet. Hornet's cannot be made truly accurate.


"Why, small pockets and flash holes on PPC?"


Two reasons, #1, to lessen the primer effect on the whole charge, and #2 because only small primer brass will withstand the higher pressure required for truly good burn. Change out to a large primer pocket and it won't take the pressure.

"Why uniform pockets and flash holes? "

Again, uniformity, consistency shot-to-shot.

"I think primers are like powders, there is more than a few that can be made to work well."

Generally I agree with this statement, although I've run into several instances where a given primer is NOT capable of good ignition with a given powder. Some, like 800X and Federal 250 primers are mismatched enough that according to the Federal rep I dealt with, you would not find a load listed in any manual..... at least not in the mid-90's.

And one of the little known tricks of tuning accurate rifles is.... when you're in the ballpark PLAY WITH PRIMERS! Primers alone can be responsible for bring ES numbers down by 25-30fps. 5 or 6 inches at a 1K match, a match where he winning GROUPS may well be smaller than that.

"If I was using an appropriate powder and primer and the gun would not shoot, I would look at a lot of things before I started switching primers and powder."

here we have IMO a difference of viewpoint. :)

And the inclarity, the failure, is mine. My post is predicated on the fact that the gun works..... I'm ONLY talking about powder here, and peripherally primers.

thanks for playing! :):)


opinionsby

al
 
FBecigneul said:
I know
I'm not sure
BUT
It seems to me that those who look at velocity and more velocity as the answer to uniformity on the target are looking in the wrong direction.

I think
I know
I'm not sure
BUT
It seems to me stability is key to accuracy.
A given bullet stabilizes at a given velocity and twist and when you deviate from that you become lost. You try more powder, more velocity, more free bore, less freebore, neck tensions are changed.
A jug of powder costs less than a barrel and so they try a different powder. A barrel costs $300.00 plus the stipend to the gunsmith. So, we try powder, bullet, or OAL changes. The loss of accuracy may well be in the barrel. More twist or less twist may be the key to accuracy at a given velocity. Bullet length and weight are also to be considered. I applaud the bullet maker who thinks outside the box and tries different weights in the same length jacket. Okay, back under my rock. Save all this stuff until next New Year. Be happy. Make what you have work.
Click to expand...

So Francis...... I don't know what to say ;)

Are you implying that bunches of competitors are shooting unstable bullets? That we're infested with mismatched twist rates? That looking at twist rates and tweaking with the rate is an accuracy key?



As far as light loading......how many loads do you actually shoot in competition that are light enough to be found in ANY loading manual?

Would you be willing to switch to Norma brass?

:D

Be frank now...... let's talk about low pressure loads......given that we're shooting a stable bullet of course. Do you have some light loads to share that are agging great?

al
 
al sir

even the best bullet can be slightly unstable .the old 162 amaxes are a good example.since spin rate is realitive to forward velocity,there is situations in which the slower velocities just shoot better as i am sure you have seen,the intial thoughts were
"it is just the wind or my gun is slightly out of tune" the newer reasoning behind this the bullet is thought to be spinning too fast for that velocity,it causes a single flyer once in a blue moon but still can shoot well at times and can be very misleading .so i can either slow the bullet spin down by velocity , but tune ,trajectory height and tof is an issue so keep the velocity the same and get a .5 point slower twist in my barrel.in my case i have seen improvemnts from a 6.5-284 in going from 8 twist to 8.5,and a 308 baer with 240s from a 10 twist to a 10.5 twist [@11 twist they tumble ] but no more odd fliers with the faster velocites or should i say the upper load window. tim in tx
 
Alinwa Alinwa Alinwa
"Would you be willing to switch to Norma brass?"

Don't you know that Norma brass is not to be talked about like that?
Waterboy
 
In looking at the issue of tune, we will do well to not forget Varmint Al's computer simulations and what they taught us about the advantages of bullets exiting the muzzle in a given area of the barrel's/rifle's motion. The velocity where this will occur is a result of timing between the motion of the barrel and the velocity of the bullet.

It is possible to attribute accuracy, or lack of it, to a factor that is less important than the one that is actually dominating the situation, like those guys that worry about a tenth of a grain of powder when there is more to be gained by a seating depth adjustment. Many times we are only guessing as to why a load works, or does not.
 
Where I find the confusion comes in is with a really good barrel, seems you can make any mistake and it still wants to give you small groups. Then you screw on and also run barrel and no matter what you do or try, you ain't gonna make it shoot any smaller groups.


I do think that any barrel made to the highest standards is assigned an agg and that barrel will be that agg range no matter what you do.

Then comes powders that do strange things when the temperatures change, things you would not think should happen and you just don't want to discuss in public or to your friends just to avoid the blank stares. Pressure and velocity, who hasn't seen pressures go up and velocity go down? Seems that there is a window that allows the barrel to shoot at a range of velocities and it will still group the same. :confused:
 
Hello

It appears there is a lot of idle time for Al and Francis. Must be the rain in Washington and snow/ cold in Michigan.
If you have access to Quick Load. Look at barrel time.
It would interesting to get Al and Francis together to discuss there theorys.
 
I guess I would take issue

with the statement that all powder can be made to perform in a barrel. I have a 30-284 X 1.650" that while shooting several powders "OK" it realllly came to life when I gave er some 4197 Scott Brigader. No other powder I tried shot nearly as well in it. I can shoot a number of powders in er but she won't shoot the same tiny hole with them that she does with the Brigader. I think it is strictly barrel related.
 
Glad to play along

alinwa said:
opinions I've got :D

"It is gospel that small pistol primers will shoot smaller groups in .22 Hornet than small rifle."

I think this is because the case is so small. The primer effect VS powder charge is HUGE and IMO the regular primers actually try to start the bullet. Hornet's cannot be made truly accurate.


"Why, small pockets and flash holes on PPC?"


Two reasons, #1, to lessen the primer effect on the whole charge, and #2 because only small primer brass will withstand the higher pressure required for truly good burn. Change out to a large primer pocket and it won't take the pressure.


"If I was using an appropriate powder and primer and the gun would not shoot, I would look at a lot of things before I started switching primers and powder."

here we have IMO a difference of viewpoint. :)

And the inclarity, the failure, is mine. My post is predicated on the fact that the gun works..... I'm ONLY talking about powder here, and peripherally primers.

thanks for playing! :):)

al
Click to expand...

I know I snipped out a lot but that just means I agreed with it, no need to repeat. I actually either agree with it all or don't know better yet. The stuff I left I just want to talk somemore about.

With your tack, funny you put this stuff in general section "Firearms topics not related to Benchrest" because it looks to me to be a lot of gospel short range benchrest stuff. By the way I might just convert.

Starting with the bottom and working up, if you will. I know you wanted to talk about powders and I want to wait on that so next "predicated on the fact that the gun works" I assume you mean the gun and current load is pretty good but needs improvement. Can you put a agg. number to that for decent conditions.

Moving up to "here we have IMO a difference of viewpoint. :)" the unclarity is mine, I was not thinking benchrest and a good working gun/load but instead something actually not working.

At top I talked about .22 Hornet and you responded. I through that in because (and you concured, maybe) one of the reasons for small pockets on PPC brass is to match the priming charge to the powder charge, so on the Hornet even a small rifle primer is to hot and with the pressures so low you can get away with the small pistol primer.

Now for the really interesting stuff so I am going to requote "#2 because only small primer brass will withstand the higher pressure required for truly good burn. Change out to a large primer pocket and it won't take the pressure."

So my thick head might be starting to get a message here. I have been told to toss my Norma 6mm PPC brass as weak and useless. I also have been seeing indications that if my powder charges are something that anyone is willing to publish (unitl I read this "Everyone knows you shoot a 65-68 grain boooolllllet and you load 29.7 grains of N133 in a 14 twist barrrreellll to achieve optimum accuracy at 100-200 yards at 3450 feet per second, right????") I guess that I need to crank up my loads my Norma brass is holding up very well just like the Lapua, I'm not at 3450 FPS.


Now to talk about powders and burn rate, well actually not burn rate but powder burn rate sensitivity to combustion pressure. The burn rate sensitivity to combustion pressure is one reason that burn rate charts often have powders out of place. Burn rate is pressure sensitive and not necessarily a smooth function but may have steps or discontinuities and we know that powders have temperature sensitivites and I doubt that anyone has looked at the temperature sensitivities of partially combusted powders high temperatures and pressures like happen in the barrel.

I am going to speculate that 133 finds a pressure "sweet spot" (lower pressure sensitivity at that high pressure) that can be reached with strong guns and brass that makes the hot burn a little more consistent. This only makes sense if most to the powder is burning at the time the pressure is peaking.

Another theory that relies on similar idea is that this same decreased pressure sensitivity at higher pressure allows operating at the higher pressures without stepping over the line that is hard to avoid more sensitive powders. I can really explain why the higher pressures would improve accuracy but maybe someone else could.

Tim
 
dtknowles said:
With your tack, funny you put this stuff in general section "Firearms topics not related to Benchrest" because it looks to me to be a lot of gospel short range benchrest stuff. By the way I might just convert.

Starting with the bottom and working up, if you will. I know you wanted to talk about powders and I want to wait on that so next "predicated on the fact that the gun works" I assume you mean the gun and current load is pretty good but needs improvement. Can you put a agg. number to that for decent conditions.

Moving up to "here we have IMO a difference of viewpoint. :)" the unclarity is mine, I was not thinking benchrest and a good working gun/load but instead something actually not working.

At top I talked about .22 Hornet and you responded. I through that in because (and you concured, maybe) one of the reasons for small pockets on PPC brass is to match the priming charge to the powder charge, so on the Hornet even a small rifle primer is to hot and with the pressures so low you can get away with the small pistol primer.

Now for the really interesting stuff so I am going to requote "#2 because only small primer brass will withstand the higher pressure required for truly good burn. Change out to a large primer pocket and it won't take the pressure."

So my thick head might be starting to get a message here. I have been told to toss my Norma 6mm PPC brass as weak and useless. I also have been seeing indications that if my powder charges are something that anyone is willing to publish (unitl I read this "Everyone knows you shoot a 65-68 grain boooolllllet and you load 29.7 grains of N133 in a 14 twist barrrreellll to achieve optimum accuracy at 100-200 yards at 3450 feet per second, right????") I guess that I need to crank up my loads my Norma brass is holding up very well just like the Lapua, I'm not at 3450 FPS.


Now to talk about powders and burn rate, well actually not burn rate but powder burn rate sensitivity to combustion pressure. The burn rate sensitivity to combustion pressure is one reason that burn rate charts often have powders out of place. Burn rate is pressure sensitive and not necessarily a smooth function but may have steps or discontinuities and we know that powders have temperature sensitivites and I doubt that anyone has looked at the temperature sensitivities of partially combusted powders high temperatures and pressures like happen in the barrel.

I am going to speculate that 133 finds a pressure "sweet spot" (lower pressure sensitivity at that high pressure) that can be reached with strong guns and brass that makes the hot burn a little more consistent. This only makes sense if most to the powder is burning at the time the pressure is peaking.

Another theory that relies on similar idea is that this same decreased pressure sensitivity at higher pressure allows operating at the higher pressures without stepping over the line that is hard to avoid more sensitive powders. I can really explain why the higher pressures would improve accuracy but maybe someone else could.

Tim
Click to expand...


Lot of stuff we agree on here :) BUT.....

even though it's in the general forum (where I wanted it) the point I'm making is more like "apply benchrest procedure to anything and it'll show improved results..." that it's more about techniques than magical powders.

Benchrest rounds aren't magic but they are well balanced, and most of them are set up in such a way that in making the fireformed cases it becomes easy to achieve good fit. Fit is important to accuracy.

When I say "a gun works" that gun may be a BR rifle, a varminter or even a big hunting gun..... but the gun must work! It must be assembled tightly around centerline, using good components and most of all chambered such that you can make well fitted brass.

Generally speaking it is also (IMO! :) ) true that using fast powders and near max loads will give better aggregate results.... tighten everything up. It's an efficiency thing, just like a race car, idling along isn't efficient.

the small primer pocket thing is more a mechanical detail. Given similar casehead construction a small primer leaves more brass around the pocket for support, AND the small flashhole meters less gas into the pocket. (A primary cause of casehead expansion/primer pocket failure IMO)



"Now to talk about powders and burn rate, well actually not burn rate but powder burn rate sensitivity to combustion pressure. The burn rate sensitivity to combustion pressure is one reason that burn rate charts often have powders out of place. Burn rate is pressure sensitive and not necessarily a smooth function but may have steps or discontinuities and we know that powders have temperature sensitivites and I doubt that anyone has looked at the temperature sensitivities of partially combusted powders high temperatures and pressures like happen in the barrel."

you said a mouthful here. I couldn't agree more. Except that a LOT of people have looked at all this. It isn't all speculation.


And lastly:

"Another theory that relies on similar idea is that this same decreased pressure sensitivity at higher pressure allows operating at the higher pressures without stepping over the line that is hard to avoid more sensitive powders. I can really explain why the higher pressures would improve accuracy but maybe someone else could."


I'm in a little different room here. I think that "benchrest powders" are NO MORE INSENSITIVE TO CHANGES..... but that they METER better so people just get used to the charges varying less and assume it's "the powder"..... IMO once you start weighing powders and eliminate the metering step, ALL powders become more similar in this regard. THIS element of powders is essentially the thrust of my OP.

I've got some powders like 4831 that in all of my old notes say "CAREFUL!, may spike pressure on near-max loads!!" but
I recently spent a day with WEIGHED charges of 4831 running very hot and found it tractable and obedient. More like a "more forgiving" powder. :)

I believe that higher pressures are key to accuracy, in part because of the things you listed above. Higher pressure = better (more complete) combustion, better involvement throughout the case.

This is in no way an "explanation"..... I'm a layman, interested in results. Repeatable results.


For instance, regarding this metering thing. I can remember many times loading at my range where I'd be playing around with loads up near the max. "Playing around" by changing seating depth, neck tension etc...... and I'd just leave the stuff set up overnight and get back on it next day.... BAD juju sometimes! Serious over-pressures or changed results.

Confusing.

So a couple years ago I tried something.... at the end of a day METERING (throwing) powder I'd throw 5 charges and weigh them.

Then in the morning, SAME THING :):)

Two things began to become apparent:

#1, metering is an inexact science, loads varied in weight more than expected. :eek:

And #2, The next day I might be throwing a grain OVER the previous day's charge!


I've since taken it this far...... I'll leave a powder measure set up for days and every now and then walk by and throw/weigh 5 charges and write them down.

I've taken it further..... same idea but load and drain the measure each time, go through the throw/dump procedure for 5rds and then throw/weigh 5rds "for effect"

:eek::eek:

the results have been startling!

I CANNOT throw day-to-day, week-to-week, year-to-year. (Altho some powders are certainly easier than others)

I'll never again go to my notes, look up a powder measure setting from 5yrs ago (or 5 DAYS ago) and just go to work.


bottom line is, maybe I suck!, but for me the only way to repeat day to day is using a scale. And for me this means a good scale because I often work very close to "brass wrecking hot." I want my loads to be such that if I want to I can reload the cases many times. I spend DAYS making my cases.

al
 
My take on presumptions

Too much testing can quickly become paralyzing.

I know people that are always 'testing' their BR rigs....to the point of never competing in a tournament...because their stuff isn't "perfect". Whatever "perfect" is. They would learn more competing in one registered match than in 10 days of 'testing'. It's a self defeating scenario.

Once we reach a certain point in whatever we're 'testing', the results become so diluted that it's hard to tell just exactly what 'the best', is. For me, it's better to look at how something trends rather than a specific 'perfect'.


If you believe something works for you, it will. If you don't, it won't.

Just sayin'.......;)
 
At the current level of competition "believing on yourself" or "It ain't the bow, it's the indian" falls right in there with "give Tony Boyer an H&R Topper and he'll beat ya'.."


yeahhhh, good luck wi'dat.






'course, whadda I know :rolleyes:



al
 
Indians and bows, I like that :-0

alinwa said:
Lot of stuff we agree on here :) BUT.....

even though it's in the general forum (where I wanted it) the point I'm making is more like "apply benchrest procedure to anything and it'll show improved results..." that it's more about techniques than magical powders.

Benchrest rounds aren't magic but they are well balanced, and most of them are set up in such a way that in making the fireformed cases it becomes easy to achieve good fit. Fit is important to accuracy.

When I say "a gun works" that gun may be a BR rifle, a varminter or even a big hunting gun..... but the gun must work! It must be assembled tightly around centerline, using good components and most of all chambered such that you can make well fitted brass.

Generally speaking it is also (IMO! :) ) true that using fast powders and near max loads will give better aggregate results.... tighten everything up. It's an efficiency thing, just like a race car, idling along isn't efficient.

the small primer pocket thing is more a mechanical detail. Given similar casehead construction a small primer leaves more brass around the pocket for support, AND the small flashhole meters less gas into the pocket. (A primary cause of casehead expansion/primer pocket failure IMO)

al
Click to expand...

Yeah, I snipped a lot of stuff again.

This Indian and his bow ain't travelling hundreds of miles to pay to get his you know what kicked.

Relating to BR shooting I am not testing anything but myself, no grand experiments or even messing with seating depth. Just trying to get my shooting off a rest technique refined and learning to read very small changes in the wind. I am shooting the smallest groups I have ever shot but I am no where near competitive. I need a better rear bag and better wind flags and of course a better bow. I shot my first comp in 1974 (50 ft. 4 pos. .22 rf.) I love comp shooting when I am competitive (chance to win).

I reload and shoot to relieve the stress of my job that would prefer that I work all day every day, I don't need the stress of long road trips to compete.

We build and test hardware for space flight and a few years ago I ran a small group that did internal ballistics analysis for experimental rocket motors. One of the guys who worked for me had previously done analyis for a biprop liquid fueled cannon (cool). I have also worked with guys who worked with White Sands on the Light Gas Guns that they use to simulate on orbit collisions, one inch steel balls at 10,000 FPS. Google it you will see that 10,000 is not the best either.

Anyway, AL

I hear you saying that build with precision, load with precision and shoot with precision and it does not have to be benchrest, could be varmint or big game, could be 100 yards or 1000 yards.

While short range benchrest does have some magic it is not that it could not be duplicated for other shooting but you can't always get Lapua brass with small pockets and shoot free recoil for all styles of shooting. Like you said for short range BR we set up guns so it is easy to make good fitting brass of the highest quality and design.

I am not ready to throw charges at the range without a scale to check things and I am not on the ragged edge but I might be going there. I understand exactly what you are saying about small primer pockets. I have stored weighed charges in increasing increments that I will test next trip to the range to see if going up will shrink my groups and ruin my Norma brass but I have Lapua brass too :) I was happy with my small groups but now I want a 5 group agg in the 2's

Tim
 
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