RPM Test; a tale of three twists, Chapter 2

[leftiye]

"If all of our knowledge about cast bullets were just based on "lab" testing we would be pretty ignorant. I guess that could be said about a lot of knowledge gained by mankind." Larry Gibson

Larry, my point exactly as concerns your recurring taunt that we don't bother you unless we are members of the "I have a test club". Whazza diff?

[runfiverun]

providing an opposing observation, or fact is the better way to state
an opinion.
and i believe sundogs observation was a very good way to state his opinion.
he was stating where his info came from and what it was.
i have seen others do this during this CONVERSATION.
all that has been asked is what are your observations and what are they based on?
simple enough.

[onceabull]

45 2.1: Get to Quigley,shoot all the smokeless you want, show everyone up...One thing to remember though, the results get posted on the internet... Onceabull

[waksupi]

attacking an observation and a valid point is out of line..
you guys are attacking larry with things he hasnot even tested yet.
and he is telling you where his tests are pointing, then y'all tell him he is wrong.
before he can even get to that point of his test.
if [when] he gets to the point of failure [accuracy change] be it 20" or whatever
i am sure he will say so, if it dont happen, i am sure he will say that also.

amazing what you can observe from typewritten letters about a persons character.
there are quite a few people on this forum i would go fishin with,and a few i would
take fishin.

Ditto

[Larry Gibson]

"If all of our knowledge about cast bullets were just based on "lab" testing we would be pretty ignorant. I guess that could be said about a lot of knowledge gained by mankind." Larry Gibson

Larry, my point exactly as concerns your recurring taunt that we don't bother you unless we are members of the "I have a test club". Whazza diff?

Conducting a test where parameters are narrowed down to isolate the specific issue and accurate measurements are taken in a scientific manner. Sterile type laboratory conditions are not necessary as long as the conduct of the test is consistant. This gives measured results of what did occur instead of postulations on what might or might not occur. That's the "diff".

Larry Gibson

[Larry Gibson]

Leftiye

If you don't like what I post why don't you just show us some tests of your own. All you do is just ask questions not related to the test results I posted. If you really want to be a dog in this hunt lets see some of your work.

45 21.1s comments to sundog were out of line.

Larry Gibson

Larry, that too just sounds like more of the same. Answer the question for a change. If everything that challenges your favored line is irrelevant, then discussing anything with you is a waste of time. Mouthwash!

My post was in response to; "Larry, Sounds like more of the same to me." which was your last post before the one you quote. There is no question in your post, it is a statement. I answered with a statement. If you are going to interject kindly keep track of the conversation, it avoids confusion.

Larry Gibson

[45 2.1]

45 2.1: Get to Quigley,shoot all the smokeless you want, show everyone up...One thing to remember though, the results get posted on the internet... Onceabull

Only if I get to meet and shoot with you. You will be attending.?

[leftiye]

Leftiye

If you don't like what I post why don't you just show us some tests of your own. All you do is just ask questions not related to the test results I posted. If you really want to be a dog in this hunt lets see some of your work.

45 21.1s comments to sundog were out of line.

Larry Gibson

Larry, that too just sounds like more of the same. Answer the question for a change. If everything that challenges your favored line is irrelevant, then discussing anything with you is a waste of time. Mouthwash! Leftiye

My post was in response to; "Larry, Sounds like more of the same to me." which was your last post before the one you quote. There is no question in your post, it is a statement. I answered with a statement. If you are going to interject kindly keep track of the conversation, it avoids confusion.

Larry Gibson

Larry, Just more of the same! Who cares?

[leftiye]

Quote:
Originally Posted by leftiye
"If all of our knowledge about cast bullets were just based on "lab" testing we would be pretty ignorant. I guess that could be said about a lot of knowledge gained by mankind." Larry Gibson

Larry, my point exactly as concerns your recurring taunt that we don't bother you unless we are members of the "I have a test club". Whazza diff? Leftiye

Conducting a test where parameters are narrowed down to isolate the specific issue and accurate measurements are taken in a scientific manner. Sterile type laboratory conditions are not necessary as long as the conduct of the test is consistant. This gives measured results of what did occur instead of postulations on what might or might not occur. That's the "diff".

Larry Gibson

You're right larry, but as usual, that wasn't the issue. My point was that the logic you use to negate laboratory conditions is the same as mine when saying that I don't need to have (not necessary) a test to ask a question that challenges your position. If a question is asked, it deserves an answer, not some crap about "I've got a test, do you? Followed of course by not addressing the theoretical question. My problem isn't with tests, nor facts: It's with your argumentation style (you offer oatmeal instead of answers). All of this is a waste of time, Larry.

[Larry Gibson]

Leftiye

Yes it is a waste of time. Do you know the "diff" between ignorance and stupid?

You do not ask questions, you make statements. I answer questions that are asked. If you do not like the answer that does not mean I did not answer. Those who criticise what I am saying, doing and testing should come up with some sort of facts to back up their criticism. That is how it is done, not by whining about non-answers because they don't agree with you. It is not for me to answer every little whim someone thinks of. If they do not think the results of the test are correct or my interpretaion is correct then it is up to them to prove otherwise. Because you or they don't think so does not make it right, it needs to be proved by you or them.

I am attempting to enlighten your ignorance. However if want to continue to be like a bugger on my finger I can't wipe off that's ok also. If you want a straight answer then ask a straight and direct question. However when you tell me "don't tell me this either" or some such nonsense then it is obvious all you want is agreement. If you don't like my answers that's ok but quit whining that I don't answer when in fact I do and everyone sees it. It's only making you look other than ignorant. Ask the question; I will answer the question. That should be simple enough to understand.

Larry Gibson

[leftiye]

More oatmeal. Don't denigrate, and insult me about this Larry - get on with developing a style involving answering questions directed at you, and one which doesn't involve fallacies, and Prove it with your actions.

[Larry Gibson]

Leftiye

Why don't you take your football and go home. You need to let it be. You piss and moan saying I don't answer the question. I tell you to ask a question and I'll answer it; you only come back with your usual crap.

BTW; just who the hell do you think you are to tell anyone to; "get on with developing a style involving answering questions directed at you".

I think, at least, you have proven yourself not to be ignorant.

Larry Gibson

[Bass Ackward]

So..., what I'm pondering is if HV can be ACCURATE, how's come all these folks are 'stuck' in the rut? After all, this is about accuracy. Isn't it?

Loads that are not CONSISTENTLY accurate, are not accurate.

Corky,

Many reasons.

1. Most benchrest rifles are retired when the throats are worn which is about 1000 rounds. Does the owner want to spend half the guns life developing a load? Or developing a load that may increase throat erosion that may decrease the count to say 700 rounds? (See 4, below)

2. Look at the case capacities these guys are using. If lino is good to 42,000 psi, then the teeny, tiny case capacity (less heat and throat errosion) is going to make this fail at a much lower velocity than with say an 06 at 42,000.

3. How long are the barrels that are used in competition? My most consistent HV load would be 2280 fps out of a 20" barrel.

4. While HV is accurate, it isn't accurate at the way you must play the game to compete. Comps are shot in a timed fashion with warming shots permitted. This creates heat and puts a tremendous strain on lube that lowers overall performance capability. (actually increases throat erosion too) And if you have no guarantee of what the temperature range may be the day of the comp, then you can be screwed again. So a slower load that is less fussy would be the only option for this game.

Your second point is correct. Same for a gun. But the need for accuracy is still defined by the game. Groundhogs at 400 yards that require one or two shots every half hour set a more generous cooling time for that game.

[Larry Gibson]

Bass

I ran the test you suggested today. I was only able to shoot one 10 shot group at each range. As you know this can give some results that may not be linear. Better would be shooting 3 or 5 groups at each range and working off an “average” group size simply be cause at one range you may shoot the smallest group and at another range you may shoot the largest group. However the use of 10 shot groups does tend to give closer results than 5 shot groups.

I used the 10” twist rifle which is a sporter with a 10X scope on it. The bullets were 311291s cast of linotype. They weighed 171 grains fully dressed. They were sized .309 and lubed with Javelina. Cases were fire formed/prepped cases used with that rifle before. They were NS’d with a Redding Bushing die. Primers were WLRs and powder was H4895. All loads were thrown. A Dacron filler was used in each load. Two loads were tested; 28 gr H4895 at 136,000 RPM and 38 gr H4895 at 179,000 RPM. The test was conducted at Tacoma Rifle and Revolver Club. The benches there are very solid concrete. Targets were fired with each load at 50, 100 and 200 yards. One ten shot group of each load was fired at each range then the barrel was cleaned. Two sighter/fouler shots were then fired before the next two 10 shot groups were fired at the next range.

I did get caught with 2 flinches during the testing. A guy showed up with a .300 RUM with a muzzle brake and set up 2 benches down from me. I’ll point out the flinched shots. He caught me on the 50 yard string of the 28 gr load (3rd shot low to the right) and on the 6th shot (out to the right) of the 200 yard 28 gr load. I also called the high 12 o’clock shot on the 100 yard test of the 28 gr load.

The first picture shows all three of the 28 gr load tests. Note the 4 sighter shots. Nine of the 10 shots (minus the called shot) went into .7” at 50 yards. The nine good shots of the 100 yard test went into 1.3”. At 200 yards the 9 good shots went into 2.5 “. As a side note after all the testing was complete I had 5 sighters left. They were the 28 gr load. I fired them at 200 yards and they went into 2.75” so I think that is a pretty god indicator the load is capable of 2.5-3” groups at 200 yards.

The 28 gr load at 136,000 RPM produced linear size groups at 50, 100 and 200 yards (.7, 1.3 and 2.5”).

The second picture is of the 50 and 100 yard 38 gr load groups. At 50 yards the group was 2.55”. At 100 yards the group was 4.7”. Now that gives us an indication that the 38 gr load is also producing linear groups. However, when we see the 200 yard target (3rd picture) we see the devil has popped up. That group is a 14.5” one and is not linear progressively to the 50 and 100 yard groups. To be linear the 200 yard group should have been around 8 - 10 “.

In case you didn't notice the 38 gr load at 200 yards was 10.25" larger (12" larger not counting the called shot) than the 28 gr load. Also note the 28 gr load was as accurate at 200 yards as the 38 gr load was at 50 yards. All in all the 38 gr loads groups at 179,000 RPM do not look all that linear to me.

Larry Gibson

[Bass Ackward]

Larry,

I knew by the detail of the first two paragraphs what the outcome was going to be. Concrete benches? Like that made a difference? Did you eat baked beans before this string too?

All you gotta say was they weren't linear. And or post the targets since you had'em.

Appears that in your case you have RPM syndrome. Good thing you tested for it.

I tried the same load that was linear to 200 on out to 400 yards. (the other hill side) Somewhere between 200 and 400, the load went totally non linear and you could hear weird sounds. Couldn't hold 10 feet. So it appears I have RPM syndrome too. Just at a different range. I am just traveling faster with a better BC to begin with, so I get to go farther before I crap? (Don't let me lose you here) Apparently forward velocity was holding me stable (straight) until I lost enough velocity that a course change was made and the slug went totally unstable.

Now is the course change made out there because RPMS is still spinning about the same and forward momentum is lost enough that RPMs and air then diverts it? I would say here is your RPM effect.

This would explain low velocity and RPM wadcutter failure at 50 yards in addition to HV problems too. It would also explain why slower twist rates give you better accuracy and more distance before wild groups occurred if the slower twist rate was still adequate to produce stable flight. Meaning that 14 twist was the most accurate of your guns even though 14 twist will not stabilize over a 168 grain slug. At some distance farther out, that would flutter and go nonlinear too. Just less RPMs to cause it so velocity held it somewhat linear or straight even if it wasn't MOA.

How much does your 311291 weigh all dressed up anyway?

So ..... (new question) do " ALL " (cast and jacketed) loads go wacko at some magical distance with the key being to get one that doesn't as far out as you want to shoot?

This load heals itself above 80 degrees and does something correctly enough that it does well out to 400 yards. If I hardened it it would be kinda OK now. So if you believed solely in RPMs levels as the cause for inaccuracy directly from the muzzle, that would be incorrect. This load would never be possible. So there is still more going on here than can be defined (or pinpointed) by a single cause. But I would say that the RPM effect happens at any RPM level once velocity is no longer sufficient to provide forward flight.

[felix]

John, what you have just said is what long-lived pitchers (the gun and load) learn early in their career. Those that make it through their 30's (years) not only know what day (ambient conditions) they can perform, but also the capabilities of the hitters in the opposing lineup (the target size). ... felix

[runfiverun]

larry, i should have just mailed you my targets to post.
but you were able to make copies on your own...
bass that part about when it all falls apart is almost the exact same thing i noticed
and posted on one of the other test results pages.

question is now that we know what it does how do we use this?
i mean if i want to shoot 600 yds do i just crank up the vel to 2500 fps and let it
fall into the target?

[Larry Gibson]

Bass

I knew by the detail of the first two paragraphs what the outcome was going to be. Concrete benches? Like that made a difference? Did you eat baked beans before this string too?

I'm not exactly sure what you're trying to say here; I stated the conditions of the test and what occurred. I think you knew what the outcome would be regardless of what I've said, you've seen it too many times yourself. As to the concrete benches, yes they do make a difference. Unless of course someone wants to hypothesize as to the how cast bullets shoot better at HV off the hood of the PU or a card table. I didn't eat baked beans but the concussion from that .300 RUM was nasty enough.

All you gotta say was they weren't linear. And or post the targets since you had'em.

Are you saying I faked this test with targets I had laying around? I "had'em" because I shot them yesterday just as described. If you'd bother to look at the targets and what I wrote you'ld see that only the 38 gr HV load was not linear. The 28 gr load was very much linear. The 38 gr load was not. That was all I gotta say? That was the question wasn't it? You are the one who requested this test saying it would determine if it was RPM or not, aren't you?

Appears that in your case you have RPM syndrome. Good thing you tested for it.

The problem is, even you have "RPM Syndrome".

I tried the same load that was linear to 200 on out to 400 yards. (the other hill side) Somewhere between 200 and 400, the load went totally non linear and you could hear weird sounds. Couldn't hold 10 feet. So it appears I have RPM syndrome too. Just at a different range. I am just traveling faster with a better BC to begin with, so I get to go farther before I crap? (Don't let me lose you here) Apparently forward velocity was holding me stable (straight) until I lost enough velocity that a course change was made and the slug went totally unstable.

You're not going to "lose" me here.

Now is the course change made out there because RPMS is still spinning about the same and forward momentum is lost enough that RPMs and air then diverts it? I would say here is your RPM effect.

We all know the longer the range the greater the effect. Wasn't that your point in asking me to conduct this test? You see you already knew the answer to the question. It is RPM as you've just shown. You got the same effect only at a slightly longer range because you are using the better designed bullet for HV.

BTW; It's not just my RPM effect. It's yours too, along with everyone else.

This would explain low velocity and RPM wadcutter failure at 50 yards in addition to HV problems too. It would also explain why slower twist rates give you better accuracy and more distance before wild groups occurred if the slower twist rate was still adequate to produce stable flight.

Not so. Take standard WCs out of a S&W 6" revolver and they will crap out between 50 and 100 yards. Take the same WCs out of a Colt 6" revolver and they will be accurate past 100 yards. The reason is the S&W has a 18 3/8ths twist and the Colt has a 16" twist. It's the faster twist of the Colt barrel that keeps the WCs stable and more accurate to a longer range.

Meaning that 14 twist was the most accurate of your guns even though 14 twist will not stabilize over a 168 grain slug. At some distance farther out, that would flutter and go nonlinear too. Just less RPMs to cause it so velocity held it somewhat linear or straight even if it wasn't MOA.

All bullets need a certain level of velocity to maintain accuracy and rotational stability over the course of it's maximum distance. How much velocity is dependant on the twist. If the twist is not fast enough the bullet loses rotational stability at reduced velocity.

Actually the 311291s used in the Chapter 2 test weighed 177 grs so if "that 14 twist was the most accurate of your guns even though 14 twist will not stabilize over a 168 grain slug" how do you account for the 14" twist being the most accurate? Since you are guessing "At some distance farther out, that would flutter and go nonlinear too" I shall make a guess that it won't do that out to where it begins to go subsonic. Or perhaps that's not a guess on my part(?).

How much does your 311291 weigh all dressed up anyway?

Bass, if you'd really read my post you'd see what it weighs as the answer is there. Instead of skimming through the post please read it before making assumptions.

So ..... (new question) do " ALL " (cast and jacketed) loads go wacko at some magical distance with the key being to get one that doesn't as far out as you want to shoot?

Would be nice if you'd answer this question in plain English first?

However the answer to your "next" question is "no". "All" bullets do not go wacko at some distance. It depends on the rotational stability and whether the BC of the bullet allows it to maintain sufficient velocity during the course of it's flight if fired at max elevation for maximum range.

That 28 gr load and it's equivalent load in a 10" twist 06 have been shot to 500 yards with complete success. Beyond that the bullet is dropping subsonic which is another story. However out to that time the groups open up in a very linear fashion.

This load heals itself above 80 degrees and does something correctly enough that it does well out to 400 yards. If I hardened it it would be kinda OK now. So if you believed solely in RPMs levels as the cause for inaccuracy directly from the muzzle, that would be incorrect. This load would never be possible. So there is still more going on here than can be defined (or pinpointed) by a single cause. But I would say that the RPM effect happens at any RPM level once velocity is no longer sufficient to provide forward flight.

[B]"[I would say that the RPM effect happens at any RPM level once velocity is no longer sufficient to provide forward flight"

Are you sure you want to stick with that sentence?

Now Bass let me quote your request for this test;

“Larry should use the same top end loads that he did in this test that the slow twist performed better than the fast. Keep this simple. We know that the slower twist is going to shoot these more accurately, he already proved that. Right now we are drawing the conclusion that it is RPMS that is the reason.

If groups are radically bigger with the faster twist rate at 200 than they were at 100, then Larry has proven the RPM theory. If the groups from all twist rates are all linear, then RPMs was NOT the reason for the inaccuracy.

Let's identify the enemy that needs fought.

Added: Really Larry only has to do this with the 10 twist at first. It should be the WORST of the three twist rates. If it is wild, then he has satisfied me and he can continue with the other twists if he wants. If the 10 twist is poor, but still linear, then why waste his time and components? Cause RPMs won't be the problem.”

So are you now reneging on this?

You said; “If groups are radically bigger with the faster twist rate at 200 than they were at 100, then Larry has proven the RPM theory. If the groups from all twist rates are all linear, then RPMs was NOT the reason for the inaccuracy.”

The test does reveal that thr HV load groups are much bigger and non-linear at 200 yards than they were at 100 yards. According to you that then "has proven the RPM theory".

So now that the test reveals an answer you obviously don’t like you come up with other “questions”?

You ask for this test, you set the conditions to this test and you said what it would prove and I agreed to those conditions, what it would prove and would conduct the test. Now that you don’t like it you renege.

I expected better of you Bass.

Larry Gibson

[Bass Ackward]

[QUOTE=runfiverun;338143 question is now that we know what it does how do we use this?
i mean if i want to shoot 600 yds do i just crank up the vel to 2500 fps and let it
fall into the target?[/QUOTE]


Felix,

Never pitched. Mighty nice of you to point that out though clear into page 25 thank you very much.

The issue is the control at and of the release.


Runfiverun,

If you have a bullet hard / strong enough and has a good enough ballistic coefficient that is exactly what you do. Chances are that some of our favorite jacketed loads do exactly the same thing at far longer ranges than we normally shoot. We just never shoot far enough to see it.

Now I understand Veral Smith's recommendation that you need to develop a cast load for the range of interest, then shoot it up close to see how good that is. Forget what it does at 25 or 50. He recommends shooting into a dirt bank where you can call your shots, when they go wild, stop and change something or stop altogether. Then see what it does up close. But if you want a close range load, develop a close range load. Doesn't mean it's going to do squat on out.

[Larry Gibson]

larry, i should have just mailed you my targets to post.
but you were able to make copies on your own...
bass that part about when it all falls apart is almost the exact same thing i noticed
and posted on one of the other test results pages.

question is now that we know what it does how do we use this?
i mean if i want to shoot 600 yds do i just crank up the vel to 2500 fps and let it
fall into the target?

Yup, guess I should of just used the old "M1 pencil" trick, then I could have it any way I want it. Why waste time shooting and conducting tests! Why didn't I think of that!

I guess the real trick to HV loads is to find just that spot (maybe we should only shoot when it's above 80 degrees, eh!) where "velocity is no longer sufficient to provide forward flight" at just exactly where the target is so RPM can't effect the bullet. Then since the bullet is effectively at 0 velocity it can just plop right down on the target! How marvelous......now just how do we do that? Gee then maybe we could recover all our bullets and just shoot them again without recasting! Ya know, this has reall possibilities........

No Runfiverun, I'll just stay in the real world and continue to shoot real bullets. I won't wait for that 'perfect 80+ degree day or wait until the capabilities of the "lineup" fits my load. I'll just keep loading what works and go shooting.

I've about had it with this thread. Think I'll just continue the tests and post the results. I'll let the results speak for themselves and let all the naysayers have their halucinations.

Larry Gibson