Pressure rule...

[Larry Gibson]

Mr. Gibson,

I have been searching thru those links you offered & not found something that I was looking for, in them.

Are these COWW + 2% tin, & Lyman#2 alloys 30XCB boolits being used for these tests you have done to check for accuracy at 2890-2910fps being water dropped or heat quenched in any manner, or just coming out of the mold with no more heat treatment(air cooled)?

The testing of the RPM Threshold has taken place over quite a few years. Numerous rifles have been involved, numerous cast bullet designs involved and several different alloys (COWWs, COWWs + tin, #2 alloy, linotype and #1 alloy [a quadranary alloy (copper added)]. Hundreds of different loads have been shot for accuracy at 50 to 300 yard primarily. Thousands of rounds have been tested for accuracy, chronographed and pressure measured. A lot of time, components and money have gone into the testing. The RPM Threshold theory has been documented and proven. It has also been proven the RPM Threshold is not a limit and can, in fact, be lowered or raised but it is still always there.

With regards to the topic of this thread it has also been proven, not only by myself but numerous others now, we can shoot cast bullets accurately well above the "limits" set by the mentioned formula. In doing that the formula is proven incorrect. The formula was developed based on assumptions that weren't correct (the alloy fails under acceleration at a certain level of chamber pressure....this is partially correct BTW) and without the understanding of what actually caused the inaccuracy at a certain level of velocity (centrifugal force of too much RPM was the actual reason).

As to the alloys; Initially both air cooled and water quenched (out of the mould) bullets of COWWs, COWWs + tin, linotype and #1 alloy were tested in 10, 12 & 14" twist barrels chambered in .308W, Some were also tested in 10" twist 30-06s and 10, 11 and 12" twist 30-30s. As testing progressed over a few years and hundreds if not thousands of rounds it was found that #2 alloy WQ'd out of the mould giving a BHN of 22 - 24 gave the most consistent accuracy over a broad spectrum of velocity from 1700 fps up to 2700 + fps. #2 alloy proved especially accurate at higher velocity in the 14" twist 308W with the 311466 and the 30 XCB bullets. With the building of my own 16" twist 30x60 XCB WQ'd #2 alloy proved to be best upwards of 3100 fps in not only my own 16" twist rifle but also in other 17 and 18" twist rifles. Recently a member here has had a 30x57 built with 15" twist and is getting excellent accuracy at HV with the #2 alloyed 30 XCB bullet.

Further heat treating has proven not necessary as the WQ'd #2 alloy holds up to the pressure and acceleration to those velocities. The limiting factor appears to be the inability of keeping the GCs on as when the bullet sheds the GC at such velocity the accuracy is lost with that bullet. Somewhere in those threads mentioned I discuss this and post results.

[OS OK]

OS OK

No apology necessary. Glad what I assumed was what you meant was correct. Happy to have provided the correct answer.

Again...thank you very much & I do appreciate 'all posts' made by you.
I realize that every time you open your mouth here on this CB site that one of the 'DETRACTORS' will almost immediately chime in and challenge your 'EMPIRICAL DATA'...please remember this> ''I am not one of your 'detractors', never have been nor ever will be."

charlie irby

[Larry Gibson]

OS OK

Never considered you a "detractor" in the least. You've always asked good, thoughtful and pertinent questions and have also added much to many discussions. I just didn't quite understand specifically what you referred to in your question....probably my bad. No problem here.

[Larry Gibson]

Traffer

Let me answer your question;

One perhaps very stupid question...There are several people who are now using powder coated then sized cast bullets for somewhat higher speed and longer range rifle shooting. Are there any general rules of thumb concerning the shift from using lubed bullets to grooveless PC'ed bullets for rifle shooting? Is there any parallel to paper patching?

I do not PC myself. However, I have ran numerous tests on various PC'd bullets of pistol and rifle calibers of many different types of PC. The velocities have ranged from 400 fps upwards of 2800+ fps. Measured pressures have ranged from less than 9,000 psi to 40,000+ psi. I do wish to thank all those who have sent me pullets to test.

To be honest I have not seen anything about PC that makes me want to give up lubed grooves or even to PC any bullets myself. Some of the supposed benefits such as "they shoot cleaner" and "there is less smoke" mean little to me. I clean my guns regularly anyway and I really haven't found the smoke to be an issue as I no longer shoot indoors.

I have found in some gins many PC'd bullets leave a PC fouling that after a few rounds detracts from accuracy, sometimes severely. I have also found some PCs will lead the bores severely in some guns but not others. The cure for both is to lube the bullets with a normal bullet lube such as LLA, BAC or 2500+.....but if doing that then why PC?

I have run a side by side test with a fellow who said PCing the bullets was a lot quicker than sizing and lubing. Turned out I sized and lubed more than twice as many bullets in the same time he could PC them. Some say PC bullets are more user friendly in progressive presses than lubed bullets but since I don't use bullet feeders in either of my Dillon's I've not found any difference.

As to accuracy I've also not found any increase in accuracy. Some PC'd bullets shoot as well as identical lubed bullets but I've not found any PC'd bullets that will shoot more accurately than the identical lubed bullet. As to getting higher velocity with accuracy I have not seen that whatsoever with PB'd or GC bullets either in rifles or handguns. I don't shoot GC'd bullets sans a GC so I don't know about those. Also it is claimed PC'd bullets give higher velocity with less pressure than their lubed counter parts. I have velocity and pressure tested a lot of PC'd bullets comparing them in identical loads with their lubed counterpart bullets. I've not measured any increase in velocity or lessoning of pressure contributable to PC vs lubed bullets in any test.

As to precision accuracy such as in long range shooting or CBA matches, again, I've not seen any benefit of a PC'd bullet improving accuracy in either venue. No one is using PC'd bullets in CBA matches and I'm sure if PC'd bullets were more accurate those boys would be using them. I've also seen several so called "long range accuracy" video's posted on Utube in which PC'd bullets were used. Shooting numerous rounds at a large target (most often a large steel gong) at long range and finally hitting it or coming close and claiming "accuracy" does not fit my definition of accuracy. That's simply long range "blastin'" to me.......

I do keep track of what the boys on the PC forum are doing as I'm always interesting in things that actually improve my shooting. So far I've not seen anything about PCing bullets to warrant my doing it. No problem with those who are PCing bullets, I wish them success and who knows.....perhaps they may actually improve things. Unfortunately, so far it just appears to be a passing fad.......

Paper patching is a whole nuther ball game and can be quite beneficial.....but also can be quite frustrating........

[JBinMN]

Mr Gibson,

Thanks for your informative reply.


I realize that you have gone over much of this in those other links you referenced & I am still going thru them gathering info.
As I do go thru them I have questions & rather than bringing some of those topics back to life so to speak, I am trying to ask questions here for all the folks who read will get more info & not just myself, so your cooperation in helping everyone get clear & learn here is appreciated.

I am not trying to argue on the behalf of Fryxell, or Lee, or anyone else, but am asking so that it will help me gather more info to make better decisions in the future. You are here & Fryxell & Lee don't seem to be available here, to answer such questions, so you are the one to ask the way I look at things. It is only with your cooperation that any questions will be answered, so you "rule the roost" on this it seems.


BTW, I am only familiar with Fryxells info & not Lees info, so I have not reference Lee up to this point, but I will place the name in parenthesis next to Fryxell if they both came up with such proposals about what is a "minimum" pressure formula for good obturation( 1440 x BHN) and the "maximums" for certain types of firearms & conditions like is listed on the lasc castboolits page I referenced(sourced) earlier in this topic as shown below:

Approximate "Maximum" Chamber Pressure For Lead Alloys (PSI)

Plumbers lead, stick on WW 13,000 - (Black Powder Only)

Wheel weights / clip-on 25,000 - Non-Magnum handgunloads, Rifles to 1,900 fps


Lyman # 2 (alloy varies in Lyman cast bullet books) 35,000 - Magnum handgun & rifles to 2,000 fps


Quench-cast WW (dropped from mould into cool water) 48,000 - Magnum handgun & rifles to 2,200 fps


Oven heat treated WW 55,000 - Jacketed velocities in handguns and rifles with quality bore & balanced load

I have another question about the comparisons between your testing & the differences of your testing vs what I think was the Fryxell(Lee) proposals for their results & info.

The question is, since you used a GC for your testing & it appears that Fryxell(Lee) may have not used a GC, and just used "plain based"(PB) boolits for their testing & their resulting info is based on what happens with a PB boolit & not a GCed one; is it not possible that not only they came up with their info from their results that apply to PB & not GCed boolits, but you came up with your info from your results & your info applies as well, but to GC boolits & not plain based, so thus is correlated to theirs but for the difference in how the base of the boolits are exposed to the effects of firing?

What I am trying to say with that question as long as it is... is that if two identical rifles, with the same components put together to make the rounds, with the only difference being that one rifle & round has a boolit without a GC & is PB, and the other does have a GC to protect the boolits base, would the results of both rifles being fired, demonstrate your proposal about pressure & velocity? Or is it possible that the one with the GC would demonstrate your proposal & the PB one would demonstrate the Fryxell(Lee) proposal on the pressure & velocity?

{ I believe I just asked the same type question in two different ways intentionally, in order to try to get an answer that pertains to the question with out regard to the external ballistics of what happens after the boolits leave the muzzle GC or PB... }

I understand about the RPMs having an effect on the projectile. I understand that it starts from the time that the projectile leaves the chamber & enters the rifling until it is spent & can have an effect on the projectile "after" it leaves the muzzle. I am just trying to get to where the similarities or differences between your results & the Fryxell(Lee) results while it is "in the rifle", and not addressing what happens after the projectile leaves the muzzle right now.

I will address the RPM effect & any questions about that part of the testing once I have covered the questions about the similarities & differences between your test results & findings & the other results & findings.

All with your cooperation of course.


I am trying to ask questions that will shed light on "why" you would come up with different results than the others if you were using the same conditions factors & components to do the testing. IF the second set of testing does not contain the same components to form the test, then it is entirely likely that the 2nd test results will be different. \

I think we are all aware of the fact that changing components can change results in just the production of a round & when it is fired, to include the type of projectile, cast or jacketed. We know that a cast lead(alloy) boolit can & usually will give a different result than a full jacketed one, when fired, as well as we know that using a different powder or a different primer can change results, and this includes using a Gas Check(GC) will generally have a different effect than a plain base(PB) one, depending on circumstances.

So, what I am getting to here, is proposing that if you are using something different than what Fryxell(Lee) used in coming up with their info, like using a GC instead of a PB boolit, then perhaps their info is correct for PB boolits & not GCd boolits. Then likewise, your info from your testing may show that a GC'd boolit can do what the PB boolit can not.

Since the bases are either protected by GC or not, I think that will have an effect on the results, not just in the Internal ballistic sense, but even on to the External ballistic sense out to the target since there is a difference in the base of the boolits & how they can react to the gasses formed when the round is fired.

If all the components and firearms in the testing are identical, with the exception of whether or not the base is protected by a GC or not, it would not surprise me in the least that the results & info gathered between the two would be different & those folks doing the testing can come up with different info from one another, since they are not duplicating one anothers testing.

Last questions in a long post...

Do you not think that that by adding a GC to the testing would have an effect on what results you might get regarding testing pressure & velocity as compared to a PB one?

And follow-up question....

Do you not think it is possible that the "formula" of one or the other may work with PB boolits & not GC boolits, or the other way around GC vs PB & thus either one may be proven as true & parallel depending on whether a GC is used or not to test?

I would appreciate any response to these questions that increases knowledge. I hope that you will find the time to answer them, as they seem quite reasonable to ask. At least, to me they are reasonable questions.

Thank for your time.


---------------

P.S. - To all... - I did not proofread this post for any errors in syntax, spelling, etc.., but am just going to leave it as is, since I think it should get thru as written even if it has some errors. Or, I will address any errors if it is pointed out as important to be changed.

-----------
ETA - I am returning to add that I have Not Yet finished reading All of the links provided earlier & perhaps such questions I asked are contained in those topics. Up to this point I have not yet seen these questions come up, & that is why I asked about them. I also understand that the questions above may seem to be just repetitions of the same thoughts to form such questions & in a way they are, but I wanted to be sure that the info I may get from the answers will establish how I form any other questions in the future regarding similarities & differences in testing & the hypothesis formed from such testing. < Man o man is that a "mouthful" to digest... Hell this whole post might seem that way to some... haha

[Larry Gibson]

JBinMN

" I am not trying to argue on the behalf of Fryxell, or Lee, or anyone else, but am asking so that it will help me gather more info to make better decisions in the future. You are here & Fryxell & Lee don't seem to be available here, to answer such questions, so you are the one to ask the way I look at things. It is only with your cooperation that any questions will be answered, so you "rule the roost" on this it seems.

BTW, I am only familiar with Fryxells info & not Lees info, so I have not reference Lee up to this point, but I will place the name in parenthesis next to Fryxell if they both came up with such proposals about what is a "minimum" pressure formula for good obturation( 1440 x BHN) and the "maximums" for certain types of firearms & conditions like is listed on the lasc castboolits page I referenced(sourced) earlier in this topic as shown below:"

Let me address both Fryxell and Lee's "formulas". Fryxell does not differentiate nor mention any perceived or tested difference between a PB or GC'd bullet. However, his discussion, in the referenced sites you list, focusses on what appear to be revolver bullets. His conclusions appear to be based on testing mostly conducted by others of revolver cast bullets at revolver level velocities and pressures. His formula does not state any distinction between PB and GC'd cast bullets yet his cited premise of the various psi levels for different alloys takes us well up into the realm where only GC'd bullets are used (Lyman # 2 (alloy varies in Lyman cast bullet books) 35,000 - Magnum handgun & rifles to 2,000 fps & Quench-cast WW (dropped from mould into cool water) 48,000 - Magnum handgun & rifles to 2,200 fps). Thus based on Fryxell's writings most assume, such as the OP, that the formula covers both PB and GC cast bullets.

Fryxell also, as is common, misuses the word "obturation" in meaning the bullet is expanding or upsetting to "seal the bore". That is not a correct definition. If you look up obturation/obturate in the dictionary you will find so. In the "Firearms Encyclopedia" published by Harper and Row for Outdoor Life the definition of obturation refers to the expanding case in the chamber to seal off the rearward movement of the expanding gas back into the action. Back in the day it was thought that "bumping up" (the bullet upsetting and expanding to engage the rifling) was needed but we now know that is not needed and is, in fact, a hindrance to best accuracy. We now size our cast bullets to the throat (revolver or rifle) which is most often equal to or larger than the groove diameter of the barrel. The cast bullet then, when fired, does not "obturate" to seal anything but is instead swaged down into the barrel. Fryxell even mentions harder cast bullets do not "obturate" Testing has also confirmed lubed cast bullets are swaged down smaller by the layer of lube between the alloy bullet and the steel barrel. The steel does not size to fit the bullet and the lube acts hydraulically and does not compress. Thus the bullet actually gets swaged down to a diameter less than groove and bore diameter.

As mentioned, Fryxell's conclusions seemed based on revolver bullet examples with nothing mentioned about tests conducted with GC'd rifle bullets at higher pressures. Note in the use of any revolver the barrel twist and potential velocity level never takes the RPM of any cast bullet above the RPM threshold level (between 120,000 to 140,000 RPM with lubed ternary or binary cast bullets, GC'd or not). Also most PB'd cast bullets shot in rifles seldom get into much less exceed the range of the RPM Threshold.

In Lee's "Modern Reloading", 2nd edition, Lee friend "John" uses an 2 groove Springfield (obviously a M1903A3 30-06) as an example with linotype bullets. Lee also does not differentiate nor mention whether PB'd or GC'd cast bullets but we can assume, since Lee makes GC'd 150 gr 30 cal moulds, that the bullets were GC'd. In that example Lee states the "compressive strength" of the linotype bullet fails at 26,326 psi. Yet consider how many thousands of "Keith" 44 Magnum loads have been shot with a COWW cast 421429 air cooled with a BHN of 11 - 13 over 21/22 gr of 2400. That load with a supposed "softer' alloy bullet shoots superbly out of a revolver at 33,000 - 35,000 psi. How is that and just what happened to the basic thesis of both Fryxell and Lee's formula where the Keith bullet should have failed at 25,000 psi......?

" I have another question about the comparisons between your testing & the differences of your testing vs what I think was the Fryxell(Lee) proposals for their results & info.

The question is, since you used a GC for your testing & it appears that Fryxell(Lee) may have not used a GC, and just used "plain based"(PB) boolits for their testing & their resulting info is based on what happens with a PB boolit & not a GCed one; is it not possible that not only they came up with their info from their results that apply to PB & not GCed boolits, but you came up with your info from your results & your info applies as well, but to GC boolits & not plain based, so thus is correlated to theirs but for the difference in how the base of the boolits are exposed to the effects of firing?"

Actual pressure and velocity testing of the same bullet GC'd and non GC'd have confirmed the use of the GC vs no GC (or a GC vs PB bullet of the same design, weight alloy, etc.) makes little or no difference in velocity or pressure. Any difference between them is within the test to test variation ES. However, to give Fryxell his due a softer alloyed bullet smaller than the throat that is GC'd does not expand in the throat as much as a PB similar bullet would. That is why softer alloyed cast bullets that are GC'd can be driven to higher velocity and pressure with accuracy in revolvers, particularly in the magnum revolver/cartridges.

"What I am trying to say with that question as long as it is... is that if two identical rifles, with the same components put together to make the rounds, with the only difference being that one rifle & round has a boolit without a GC & is PB, and the other does have a GC to protect the boolits base, would the results of both rifles being fired, demonstrate your proposal about pressure & velocity? Or is it possible that the one with the GC would demonstrate your proposal & the PB one would demonstrate the Fryxell(Lee) proposal on the pressure & velocity?"

First of all let me say that the concept put forth that for a test to be valid you must have " two identical rifles" is false. Also much ado is given, mostly by nay sayers, that a blind test is needed, is also false. Even with a single rifle the data of velocity, pressure and accuracy will vary from test to test with the same ammunition. Given 2 identical rifles, if that is even possible, the data from each will also vary not only from each other but from test to test of the same ammunition also. Thus we use "comparative analysis" to evaluate the results from 2 different rifles. For example we see this all the time with any test such as a comparison of accuracy of one rifle to another. Or the comparison of accuracy of one load to another.

The answer to your question can be answered if we look only at the internal ballistics of a GC vs PB pressure velocity test. Probably not going to see much difference in the internal ballistic measurement of pressure and the exit velocity. However, during the external ballistic phase (flight of the bullet) and damage done to either bullet will result in deviation from the flight path. How much deviation depends on the amount of damage (imbalance) and the RPM. Odds are the higher the pressure, the higher the velocity and the higher the RPM are that the PB bullet will not fare well down range. Thorough testing has proven PB bullets, even pretty hard cast ones, begin to lose accuracy above 1500 - 1600 fps.

"{ I believe I just asked the same type question in two different ways intentionally, in order to try to get an answer that pertains to the question with out regard to the external ballistics of what happens after the boolits leave the muzzle GC or PB... }"

Yes you have.

" I understand about the RPMs having an effect on the projectile. I understand that it starts from the time that the projectile leaves the chamber & enters the rifling until it is spent & can have an effect on the projectile "after" it leaves the muzzle. I am just trying to get to where the similarities or differences between your results & the Fryxell(Lee) results while it is "in the rifle", and not addressing what happens after the projectile leaves the muzzle right now."

The difference is their assumption the "obturation" point (Fryxell) or the "compressive strength" (Lee) of the alloyed cast bullet is based on the pressure constant for pure lead used in the formula. It would probably work to a degree if our cast bullets were pure lead. They are not though, especially the ternary alloyed ones which have a much different figure depending on the composition of the ternary alloy used. Lee attempts to correct that through the use of BHN but Fryxell apparently, based on the formula used, doesn't. The real problem with both of is the failure to comprehend that the lubed cast bullet when inside the bore is already swaged down and confined by the barrel and the layer of lube. It does not "obturate" . Softer alloyed bullets can collapse into the lube grooves if the lube dissipates. The nose of long nose bearing bullets with small percentage of drive band bearing surface and also bend to one side into the grooves. We know this from inspecting recovered bullets. Perhaps none of those were known to either Fryxell or Lee when they postulated the formula?

" I am trying to ask questions that will shed light on "why" you would come up with different results than the others if you were using the same conditions factors & components to do the testing. IF the second set of testing does not contain the same components to form the test, then it is entirely likely that the 2nd test results will be different."

Read Fryxell closely on this matter and he does not quote much of his own results from his own testing. He puts forth his own concepts based on published information in other sources and results others have gotten from their tests....with different firearms BTW.

Lee uses an example of a test with the 2 groove Springfield. A simple enough test that I have suggest numerous times to loacate the RPM Threshold for a given powder and cast bullet. Exactly what Lees "John" found when he conducted that test was....the RPM Threshold of that load. Unaware of the adverse effect that the RPM/centrifugal force was having Lee drew the wrong conclusion based on the velocity where accuracy deteriorated. He assumed it was due to pressure. It was not.

My results have been consistent through a wide range of tests using multiple rifles, multiple caliber/cartridges, multiple cast bullet designs and multiple loads over 12+ years. While the "numbers/data" may not have been exactly the same the end result was always the same.

I think we are all aware of the fact that changing components can change results in just the production of a round & when it is fired, to include the type of projectile, cast or jacketed. We know that a cast lead(alloy) boolit can & usually will give a different result than a full jacketed one, when fired, as well as we know that using a different powder or a different primer can change results, and this includes using a Gas Check(GC) will generally have a different effect than a plain base(PB) one, depending on circumstances.

Don't get too hung up on that premise. The result, whether different or not, will depend on the question we seek the answer of.

So, what I am getting to here, is proposing that if you are using something different than what Fryxell(Lee) used in coming up with their info, like using a GC instead of a PB boolit, then perhaps their info is correct for PB boolits & not GCd boolits. Then likewise, your info from your testing may show that a GC'd boolit can do what the PB boolit can not.

Again, neither Fryxell nor Lee differentiate between PB or GC'd bullets in their formula. Ergo most everyone who buys into the formula doesn't either. The formula makes a blanket assumption that "cast bullets" fail at a certain level of pressure. I have given results of both PB and GC'd bullets that prove that assumption incorrect as sometimes they do fail due to pressure but other times they don't. Thus the blanket premise of the formula is incorrect.

Since the bases are either protected by GC or not, I think that will have an effect on the results, not just in the Internal ballistic sense, but even on to the External ballistic sense out to the target since there is a difference in the base of the boolits & how they can react to the gasses formed when the round is fired.

I do believe you are correct as factual testing has proven. However, both bullets are quite accurate at various pressure levels that exceed the levels the formula predicts they should fail at..

If all the components and firearms in the testing are identical, with the exception of whether or not the base is protected by a GC or not, it would not surprise me in the least that the results & info gathered between the two would be different & those folks doing the testing can come up with different info from one another, since they are not duplicating one anothers testing.

Probably correct, as already discussed, if you are looking at raw data.....the numbers will be different. Again, though, if using comparative analysis the results will, most likely, be the same and a correct conclusion can be deduced from those results.

Do you not think that that by adding a GC to the testing would have an effect on what results you might get regarding testing pressure & velocity as compared to a PB one?

Already asked and answered.

Do you not think it is possible that the "formula" of one or the other may work with PB boolits & not GC boolits, or the other way around GC vs PB & thus either one may be proven as true & parallel depending on whether a GC is used or not to test?

Of course that is possible, but no matter how you state it or defend them neither Fryxell or Lee made the distinction between the two bullets for use in their formula. They both state "cast bullets". Neither has come forward to clarify their meaning or the context of PB vs GC cast bullets in their formula. Ergo we must take them at their word that "cast bullets" means just that; cast bullets. And even if they did make a distinction then the problem arrises of the examples of both PB and GC'd cast bullets defying the formula.


Note; let me add my intent here is not to cast dispersion on either Fryxell or Lee. Heck, I studied and believed both before I discovered otherwise. Both are well learned gentlemen who have added a lot ot our cast bullet endeavor. Both came up with their conclusions and "formula" well before the RPM Threshold was fully realized. Neither of them had, at the time they published their formula, access to the information/data/proof I found during the last 10 - 12+ years of testing and research. It is entirely probable neither even considered the RPM or effect of centrifugal force. Like all of us (yes that includes me) their foundation of knowledge was developed and learned based on the previous writings and theories of others. Again, I am not trying to discredit them at all, just saying we learn from mistakes and new found knowledge.

[JBinMN]

Much Thanks!, Mr. Gibson, for your informative & for me, anyway, relatively easy to understand explanations & answers to my questions!


I will continue to go thru the links you provided & re-think things after that & absorbing the post you just offered and what I can gather from my reading of those topics.

It is very likely that doing so will give me more questions to ask & I will try to use more brevity in doing so. I just want to try to make sure what I am asking is understood, as I have seen that in some cases, even in this topic, that sometimes if the question, or questions, are put in a certain way, they can be misunderstood for exactly what is being asked..

I will mention here that, IMO, not too many folks are even concerned with such things being discussed here & do not feel like they should take the time to read & understand what is being discussed, since they just want to make up some rounds & shoot them.

I think there is a large group who seeks to cast & handload those projectiles & just want to know how/what to do to make them work. Not thinking about the "details" that make shooting those rounds "do what they do".

There also seems to be a smaller segment of that group who wish to know more & try to understand more of the "intricacies" of what happens from , as said, Muzzle to Target". Even after that though, the interest of knowing more wanes.

Then, there is an even smaller group from oput of the former group, who are interested in all of that & even into the Internal ballistics & what results might be happening Externally, based on what is happening from the "Chamber to the Muzzle" with those Internal Ballistics, even before the projectile gets to the, "Muzzle to Target." stage(s). I think I am of this latter group, along with some others who show interest.

Discussions such as these & some discussion that were referred to, earlier thru links, enter into that smaller groups interests, & of those who wish to follow & know such things, while the majority of handloaders/reloaders & shooters don't care much about such info. It is very interesting as fara s I am concerned, & learning more, IMO, is fascinating to this smaller group, who wish to get down & know the "nitty gritty" of how things work from beginning to end.( I.E. - Chamber to Target, rather than "Muzzle to Target.")

Thanks again! for taking the time to answer the questions I asked & hopefully you will be able to do the same as others may ask questions & when/if I have more to ask about such things.

All in the interest of sharing knowledge.

[JBinMN]

Still reading, I have not forgotten this subject.


I do have a life away from reading stuff like this, believe it or not.


I am wondering though... No one else has questions, or comments?

[kokomokid]

Still reading Larry Gibsons older post and trying to decide what kind of barrel I could buy that would be suitable for both 30xcb cast bullet and light palma jacket bullet. I was thinking 12 or 13 twist with three lands and grooves at 28 to 30 inches in medium palma weight. Maybe Larry will comment on what he would order??

[Larry Gibson]

Go with a 14" twist. It will fully stabilize the Palma bullets and 168 MKs. I also will stabilize, even at "normal" cast bullet velocities most cast bullets many think it won't. A have thoroughly tested 170 - 200 gr cast bullets in my 27.5" Palma .308W with 14" twist and got excellent results.

[kokomokid]

Go with a 14" twist. It will fully stabilize the Palma bullets and 168 MKs. I also will stabilize, even at "normal" cast bullet velocities most cast bullets many think it won't. A have thoroughly tested 170 - 200 gr cast bullets in my 27.5" Palma .308W with 14" twist and got excellent results.

Thank you Larry. Would the three land and groove rifling be a good choice for the bullet mix?

[Larry Gibson]

Three lands a grooves would be excellent. That's what the Broughton barrel is on my 30x60.

[Traffer]

Traffer

Let me answer your question;

One perhaps very stupid question...There are several people who are now using powder coated then sized cast bullets for somewhat higher speed and longer range rifle shooting. Are there any general rules of thumb concerning the shift from using lubed bullets to grooveless PC'ed bullets for rifle shooting? Is there any parallel to paper patching?

I do not PC myself. However, I have ran numerous tests on various PC'd bullets of pistol and rifle calibers of many different types of PC. The velocities have ranged from 400 fps upwards of 2800+ fps. Measured pressures have ranged from less than 9,000 psi to 40,000+ psi. I do wish to thank all those who have sent me pullets to test.

To be honest I have not seen anything about PC that makes me want to give up lubed grooves or even to PC any bullets myself. Some of the supposed benefits such as "they shoot cleaner" and "there is less smoke" mean little to me. I clean my guns regularly anyway and I really haven't found the smoke to be an issue as I no longer shoot indoors.

I have found in some gins many PC'd bullets leave a PC fouling that after a few rounds detracts from accuracy, sometimes severely. I have also found some PCs will lead the bores severely in some guns but not others. The cure for both is to lube the bullets with a normal bullet lube such as LLA, BAC or 2500+.....but if doing that then why PC?

I have run a side by side test with a fellow who said PCing the bullets was a lot quicker than sizing and lubing. Turned out I sized and lubed more than twice as many bullets in the same time he could PC them. Some say PC bullets are more user friendly in progressive presses than lubed bullets but since I don't use bullet feeders in either of my Dillon's I've not found any difference.

As to accuracy I've also not found any increase in accuracy. Some PC'd bullets shoot as well as identical lubed bullets but I've not found any PC'd bullets that will shoot more accurately than the identical lubed bullet. As to getting higher velocity with accuracy I have not seen that whatsoever with PB'd or GC bullets either in rifles or handguns. I don't shoot GC'd bullets sans a GC so I don't know about those. Also it is claimed PC'd bullets give higher velocity with less pressure than their lubed counter parts. I have velocity and pressure tested a lot of PC'd bullets comparing them in identical loads with their lubed counterpart bullets. I've not measured any increase in velocity or lessoning of pressure contributable to PC vs lubed bullets in any test.

As to precision accuracy such as in long range shooting or CBA matches, again, I've not seen any benefit of a PC'd bullet improving accuracy in either venue. No one is using PC'd bullets in CBA matches and I'm sure if PC'd bullets were more accurate those boys would be using them. I've also seen several so called "long range accuracy" video's posted on Utube in which PC'd bullets were used. Shooting numerous rounds at a large target (most often a large steel gong) at long range and finally hitting it or coming close and claiming "accuracy" does not fit my definition of accuracy. That's simply long range "blastin'" to me.......

I do keep track of what the boys on the PC forum are doing as I'm always interesting in things that actually improve my shooting. So far I've not seen anything about PCing bullets to warrant my doing it. No problem with those who are PCing bullets, I wish them success and who knows.....perhaps they may actually improve things. Unfortunately, so far it just appears to be a passing fad.......

Paper patching is a whole nuther ball game and can be quite beneficial.....but also can be quite frustrating........

My particular interest is in 22lr, Perhaps the only bullet that is still manufactured exclusively in lead with lube. I believe without a doubt that eventually 22lr will shift to powder coated bullets. No need for grease, grooves or knurling With the additional other benefits, it is just a matter of when the manufacturers will figure out a process to produce them in the same quantity as their process allows them to make with the current knurled greased bullets. But the process is unique to 22 rimfire so likely no one else in the world is interested in it except me.

[JBinMN]

While I am still going thru the topics referenced above about RPMs , etc.. I have already found I have some questions about pressures, as well as RPMs, but will wait until I am finished reading to ask them.

I would say that when/if anyone else takes the time to read thru them, I would venture to say that the ones who are detracting from the info trying to be shared are not helping me with maintaining a good grasp/comprehension thru "continuity". It , to me, is not unlike trying to have a conversation & someone keeps interjecting or interupting the conversation so that it is hard to keep ones thoughts in line. Perhaps that is "just me", but I find myself only reading so much & then having to stop & try to get my mind back on the main subjects being covered. making my progress a bit slower than I had hoped, and I am still on the first of 4.


It reminds me of the saying used in one of the posts, "Endeavor to persevere" & that is what I am trying to do when reading some of these posts in those topics.



ETA/P.S. - I might add that I am trying to focus on "pressure" in those topics & not RPMs right now & that seems to be making things just a bit more difficult as well.
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For a bit of a chuckle... The saying also reminds me of the quotes by Lone Watie in the movie, "The Outlaw Josie Wales" where he says:

I wore this frock coat in Washington, before the war. We wore them because we belonged to the five civilized tribes. We dressed ourselves up like Abraham Lincoln. We only got to see the Secretary of the Interior, and he said: "Boy! You boys sure look civilized.!" he congratulated us and gave us medals for looking so civilized. We told him about how our land had been stolen and our people were dying. When we finished he shook our hands and said, "endeavor to persevere!" They stood us in a line: John Jumper, Chili McIntosh, Buffalo Hump, Jim Buckmark, and me — I am Lone Watie. They took our pictures. And the newspapers said, "Indians vow to endeavor to persevere."

We thought about it for a long time, "Endeavor to persevere." And when we had thought about it long enough, we declared war on the Union.

I didn't surrender neither. But they took my horse and made him surrender...Now he's pullin' a wagon up in Kansas.

One has to laugh a bit on occasion to break of the monotony of some things, like reading interupted conversations.