Land to groove ratio

Several years ago a very well known Benchrest Shhoter and I sat down with my Oehler Chronograph and tested velocities of different bullets. This was when the "double radius" bullet craze had first hit. We had Fowlers, Bart's Ultras, Bruno Double 00's and a few others.

Typically the Fowlers had about a .0004 gas ring. The body, which was relative straight, would measure .2431

None of the double radius bullets measured over .2430 on the body, and that dove off pretty quick below that.

The Fowlers would shoot on average 100 FPS faster than the bullets with less bearing surface and longer ogives with exactly the same powder charge.

Just an observation. It really didn't mean much in the grand scheme of things.
 
alinwa said: "Frankly, the barrel's role (rifling and diameter, erosion/cleanliness/age) in pressure is very minimal IME."


I couldn't disagree more......

take 6 different guns........
shoot 5 rounds in each gun... same load...
some will show pressure problems....... some will not......
we are dealing with friction here :

if a barrel is smaller in diameter it would take more force to get bullet down tube
ruff throat= more pressure
copper fouled barrel=more pressure

Right here is the BEST validation of my position.........

Generally speaking I WILL DISAGREE with Blarson.

I care not "what would show" and "we are dealing with" and "would take more"

I deal with science, experimental evidence and generally believe the findings of accredited experts (Harold Vaughn agrees with me. P.O.Ackley, Homer Culver, Elmer Keith, Col Charles Askins.....guys who ACTUALLY DO/DID THE WORK.....agree with me)



(BTW, I HAVE "taken 6 different guns" etc etc etc......in fact I've logged thousands of rounds from dozens of guns and more dozens of barrels....I've tested head-to-head many barrels/guns/combinations. Not "try".... not "would" ....not "we are dealing with".... but I'VE DONE IT. And my findings AGREE with Rinker and McCoy and Marx etc etc etc. My actual tests AGREE with the science involved, they AGREE with sound engineering principles)



And to alla' you'se reading this. Please DO NOT believe me nor anyone else spouting opinion on the innernet, go TRY THIS STUFF!


Then please share your findings with us.
 
Here is the real problem.
You do not have a clue how construct
the "same load".

It requires among other things PRECISE powder measurement,
and you have shown you do not know how.

... same load...
 
OK, so why do two rifles, with the same length barrel, have different pressure characteristics. I'm not arguing...just don't know why.

Same everything else except the rifle....which has the same length barrel.
 
OK, so why do two rifles, with the same length barrel, have different pressure characteristics. I'm not arguing...just don't know why.

Same everything else except the rifle....which has the same length barrel.


The barrel with the highest pressure needs more pressure to get the bullet moving and keeping it moving which could be caused by any of the following.


Surface finish of the barrel it's self
Powder following
Copper following
Cross sectional area of one barrel is smaller
One may have more free bore
Leed angle difference
 
Appreciated for sure but I was asking alinwa to explain in a bit more detail what he's saying....as I think it's different than what you're saying.
 
Like everybody else, I useta' just BELIEVE this stuff....

"ever'body knows" that;


-firecracking/erosion causes pressure.
-copper fouling causes pressure.
-changing from a .237 to a .236 causes pressure.
-powder fouling causes pressure.
-moly decreases friction which lowers pressure
-"rough throat" causes pressure.
-tighter twist causes pressure.

etc etc.....and IT'S ALL SPECULATION!

It gets parroted year after year, over and over until we all "know it"......but it's crap.

Careful head-to-head testing shows it to be untrue. I, and others, have tested each of these items and found them to be not true. It's like "everybody knows that bullets go to sleep and some guns shoot better with distance...." But I've got an Oehler43 and $1000.00 cash that says IT'S CRAP! ;) (my friend with the Oehler43 just gifted it back to me (THANK YOU EDDIE!!!) and now I can shoot groups over two targets. My "$1000.00 and I'll buy your plane ticket, 2:1 odds" offer is back up.)


We all "knew" 20yrs ago that moly and "Danzak" and other "lubricants" lowered the pressure and velocity of a load. The corollary of course is that all the "firecracking/fouling/rough throat" stuff INCREASED pressure thereby raising velocity.

Harold Vaughn told me one time that the whole concept of "moly being more slippery and thereby dropping velocity" was not only flawed, but in his words "impossible." So, he TESTED IT and came up with a scientifically valid reason why typical moly'd loads lost a little velocity. He came up with a reason that WITH NO OTHER CHANGE except changing to moly'd bullets, velocity dropped. His testing was backwards validated over the last 10yrs as folks have begun meloniting bores..........a process which is extremely polarizing and weirdly enough just as many people say it DROPS velocity as say it INCREASES velocity. ;)

Yup, two people in the same room at the same time, one will say "velocity decrease" and the other will say "velocity increase."

Search the innertube to see both sides..... here's a thread from right here, 6yrs ago. http://benchrest.com/showthread.php?71954-Melonite-Barrel-Treatment

SCIENCE sez it INCREASES velocity, meloniting.......

But it's kinda' hard to test without REALLY GOOD velocity control.

In actuality it generally comes down to the specificity of the testing regimen. GOOD testing yields GOOD repeatable results. And the major impediment to GOOD testing is isolation of variables. I tried for years to achieve low ES "just because" I wanted to see if it was possible. I sorted and measured and weighed and bell-curved myself blue and pretty much came to the conclusion that getting low ES consistently was a pipe dream. WAAYYY to many variables and worst of all, some, like primer brisance and variable bore condition through a string are just about un-fixable.

Then there's all the grunting and whining about "how do you even measure it accurately ennyways??"

So, long story short I met this guy who actually showed ES under 10fps.

No BS

No whining

No issues A'tall, just long shot strings with very little variation.

WHAT th'?

So he tole me.

And I bought a scale.

Now I'm a guy who before all this happened I SOLVED the measuring problem by testing. And by improvising back-checks. I don't trust measuring ANYTHING, I like to gauge and compare against either a standard or multiple shots of the same thing..... And I don't trust the standards :)

So I check back.

For instance I tagged three similar chronographs one-behind-the-other to see how much they "varied" (while knowing full well they couldn't vary much) as well as using an Oehler 43. I can go down right now and shoot a bullet over three Chrony's, through the Oehler 43 and read the same shot with a LabRadar. 5 distinct and separate measures on the same shot. And I can know from experience that at least the Oehler and the three Chrony's are very repeatable. The LabRadar is still fairly new to me.

So ennyways, I bought a scale.

And now getting low ES and repeatable testable results is dead easy.......alla' that "how am I gonna' control this" stuff just becomes negligible when ONE CHANGE just wipes 90% of it out. The only thing I can remember being as big an eye opener in my shooting was when I first started shooting real BR gear. I remember having every excuse for fliers.....I'm ashamed to say I even "called fliers"...... and then I had someone build me a real gun. I found out what a PPC or a BR can do. And within that subset of "accurate rifles" I found out about "EASY, accurate rifles." I had a couple 22BR barrels, a 6PPC barrel and two 6BR's that would absolutely shoot dots part of the time before I got my first "easy" one, a Borden that couldn't hardly be forced to shoot bad....and this all with thrown charges. My typical ES with PPC/BR chamberings, thrown charges, is 45-80fps variance depending on the day.

But it doesn't matter, a good gun will compensate. The short-range 30's will too....

And then I got into longer range stuff.

IME it's kinda' hard to compensate beyond 500yds....some do, I ain't arguing with anyone's results, but I went another way. I went in search of consistent velocity and low ES.

And I found it.

IME, weighing powder charges right down to the kernel will eliminate 90% of all the variations but MORE IMPORTANTLY it allows one to actually TEST for things like copper fouling, powder fouling, bore treatments etc. It's pretty easy to see a 30fps change when your innate ES is 5fps, and MORE IMPORTANTLY the ES repeats day after day. But it's impossible to find these variations with thrown charges which vary by 50fps any given day and 100fps day-to-day.

And the really weird thing to me is......a buncha' folks in this thread will ARGUE about those ES figures when they've never tested it! I love to hear stuff like Jackie's testing of bullets over the chrono......I'll submit my opinion that the difference in velocity had to do with initial startup pressures (ie ogive/leade match, seat depth differences changing case capacity, etc) and not due to changes in bore friction from diameter/bearing surface differences. But that's my opinion. The big thing is, HE TESTED IT! And he found one bullet to be faster....awesome!

Testing is hard, and it takes time (years) to form opinions. Some dude says "I'd like to see data" simply doesn't understand what that means. I've got a stack of notebooks a foot high, thousands of rounds, hundreds of loads and combinations. "DATA??" this ain't like in the movies...... but ANY DAY OF THE WEEK, any time, anywhere I can easily show the effects between KERNELS of powder.

And so can anyone here, in the comfort of their own environment if they'll just take the time to DO IT as opposed to perpetuating myths.

Beg, Buy, Borrow or Steal a good scale.

Modify a chronograph by giving it an artificial source of illumination and

SHOOT!

Taking good notes.

BTW "good notes" IMO is absolutely NOT buying into some guys ideal of the perfect spreadsheet and filling in the blanks. It's NOT filling out a bunch of useless "dope" in a "Sniper's Data Log"....... it's just writin' stuff down. $.27 ringbinders bought 50 at a time at the Fall Back To School Sale are your friend. Don't THINK, don't COLLATE, don't itemize/organize/columnize/graph anything just WRITE STUFF DOWN. You've got hundreds of sheets, just date a page and scribble everything pertinent down. Turn the page, shoot some more, do it again. As the questions pop up, you write down the answers.

I've been hanging around this board of Wilbur's off and on for over 20yrs. I've watched a lot of myths die. I've seen a lot of folks mad when "secrets" have been revealed and I've got to meet some wonderful people who've tested stuff in ways I'd have never dreamt of (Skip Otto anyone? Dan Hackett? Charles Ellertson and his barrel-stretching buddies? Henry Childs? Yes, even Harold Vaughn came on a few times back in the day.......and I'm leaving a bunch out, some on purpose ;) ) but what I've learned is, "ain't NUTTIN means NUTTIN until it's tested!"

Examples?? Let's just start with reloading rules, tips and tricks. How many reloading manuals will tell you "adjust the seating depth but BE CAREFUL NOT TO TOUCH THE LANDS BECAUSE PRESSURE WILL SPIKE!! SOMETIMES DANGEROUSLY!!" and how many people reading this right now just "know" that setting your case down to touch the shell-holder and then giving it enough to produce a "cam-over" is (good/best/necessary/useful etc) and that "spinning the case a quarter turn three times while sizing/seating will straighten" and "straighter presses make straighter ammo" and on and on and on........and then Neil Jones pioneered the concept of fitted dies (apologies to Palmisano/Pindell) and The Skipper comes out with something called "Skip's die shims" and ever'body sez "that'll never work!" And crooked ammo just becomes a thing of the past....for some people.

While others still argue on the innertube that "Redding dies are better than them cheapo RCBS dies"


What I'm saying Wilbur is that just a few years ago I had "fast barrels and slow barrels" that I thought were identical but in many cases they were not. What I'm saying is that IME the variations come from the work that's been done on the barrel. The reason I'm currently so hot about my (Gordie's) chambering method is that for the first time in my life I can actually make chambers the same! In the past I've had many barrels chambered with the same reamer where the chambers vary by 3-4 thou in diameter. It's simple fact that if you set up a barrel between centers and run a reamer into a bore that wanders away from center that chamber will be bigger. Also (and I'm wayyy out on a limb here....) the throats will act differently, the ramp-up pressures may be different at least until the burrs are worn away. I'm not sure what all goes on but in my opinion the change occurs from the ogive back....it's not a function of barrel fit/finish. Right now, today I can make one chamber the same size as the next. Same throat, burr-free and same capacity all-round. And this ability, coupled with carefully monitoring charges has so far eliminated "fast" and "slow" barrels....

Time will tell and I'm happy to be corrected, but at this point I BELIEVE that fast and slow barrels aren't random. I currently believe they're built.
 
All these different numbers we agonize over;

"I believe it is the wind, I really do".
-P Wolfe

CCBW remembers when P Wolfe pulled in and parked a little pull-behind he had just bought that had the dump valve open. Parked it close behind the firing line. Sat it there for the 3-4 days. Everyone smelled the stench. Finallly someone saw the source.

Turns out it wasn't the wind.

Now then, if we can just make all our variables constant.

.
 
There he is again, making those claims.
PRECISE WEIGHING OF POWDER is the clue.

NO WAY.ask any br shooter.
lol
very nice al
 
I would love to get my hands on some of that high priced, highly accurate testing equipment used by those who have all the answers.

Francis all you need is a wet finger. Wet your trigger finger and hold it to the wind. That bullet WILL NOT go out of the group while that wet trigger finger is reading the wind. Then, take that reading, enter it in Microsoft Excel, and.......

..
 
a) NO ONE CLAIMED TO HAVE ALL THE ANSWERS.
(TYPICAL REPLY FROM THOSE NOT WILLING TO LEARN)
b)https://www.amazon.com/FX-120i-Precision-Balance-0-001-shield/dp/B00GP0IMPO
OR BETTER
c) current oehler 43 is a 83
http://www.oehler-research.com/custom/system83.php

just cough up the cash, buy some note books and get to work.

" I DO NOT HAVE IT, I CANT AFFORD IT, SO IT IS NOT TRUE"

next

I would love to get my hands on some of that high priced, highly accurate testing equipment used by those who have all the answers.
 
I learn really slow.....

I held onto that belief in "fast" and "slow" barrels for so long that I one time spent a bunch of time and money making a really good barrel just a little worse....

I had a "fast" 6X47L barrel that was finished out wikkid long, like 30". Shot like a house afire but was really long, so long it was kinda hard to reach out and catch the cleaning patches. And I was in one of my sporadic (over 30yrs! LOL) tuner phases which, if I added one, would make it even longer.

But FAST! like 150fps over and above, at least in my mind.

So what the hey? why not bring her back a few inches and just fix everything at once? A fast barrel like this I'd only lose a few fps....

So cool to be able to just do it myownself ennyways....

So I did.

And it's just another barrel.

I mean nothing bad, it still shoots just as good, logically.......my notes say so.........but the "magic" is gone along with all that free velocity.

Which brings us to the REAL problem. I STILL WANT TO BELIEVE IN MAGIC!!!

LOL

But it's gettin' beat out of me.

Slowly

al
 
Doesn't every serious shooter know that a shorter barrel, shooting it's classic powder for that chambering, will produce less velocity than when it was longer? Most times many fps per inch of barrel loss.


.
 
I'm a slow learner but not confused.
awnilA
said myths are just that, myths. He said to go out there and shoot and test and report back to him on this internet. He said tests and facts and figures are flawed but still report back to him. To my way of thinking this is how myths are hatched. I can't be trusted.

reiaMC
Said
surface ratio...area of the land/area of the groove
Usefulness....I have no idea

So now we are expected to ascribe to the beliefs and writings of one who has no idea. No thank you.

This very good and well intentioned thread has gone down a slippery slope.

I do believe Jerry Sharrett who told me to hold my wet trigger finger in the wind and that I won't have any shot go out of the group while doing this. Hell, I couldn't even shoot and had a one inch penalty because I didn't finish my group. I'm a slow learner.

And to Bill Larson
I am not going to come back to this thread ever again.
Oh, one more myth/story but true......Ken Hottenstein won Super Shoot going on one belief. When at the lower end of Kelbly's you find yourself between the kitchen door and the outhouse. Only shoot when the wind has a pleasant aroma.

keeps it from getting deleted LOL

:)
 
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