Butch Lambert
Active member
So the barrel moves up and down and not side to side? What would cause this other than gravity?
Butch
Butch
Weighed Charges at The Nationals
- Thread starter jackie schmidt
- Start date
JerrySharrett
Senile Member
Strange forces from the DARK SIDE!
J
JohnVm
Guest
I'm thinking curvature of the bore in the barrel added to the shock of high pressure but I am thinking it affects horiz and vert with tune.
Last edited by a moderator:
Butch Lambert
Active member
John,
Most people don't index their barrels.
Butch
Most people don't index their barrels.
Butch
I've been told by some perty smart fellers that the driving force has to do more with action flex and lug slap, mostly the result of bolt slop and the angled sear engagement surfaces.
My own testing includes such simple devices as Skip Otto's penny-on-the-barrel and hanging cups of water on the barrel (The Skipper again)........ these tests show a lot of repeatable barrel vibration without ever firing a shot. I've heard, read and postulated that these vibrations are primarily on the vertical plane.
Gravity droop and the 'garden hose effect' no doubt add to these vibrations but I can't measure these effects.
I own a magnetic barrel tuner and with this and a dial indicator it's pretty easy to see that the barrel DOES droop but....... BTW SS rifle barrels are quite ferrous.
al
JerrySharrett
Senile Member
Bill Myers, noted rimfire shooter, gunsmith, and now action producer, built a mechanism to allow attaching an electronic indicator to the barrel of a rail gun setup. With this measure and hold indicator, he could rotate it about the barrel axis as he fired. What he found out was that a barrel actually moves up and down in a 1 O'clock to 7 O'clock swing. I would bet that a left hand twist barrel would vibrate in an 11 O'clock to 5 O'clock swing.
P
pwolfppc
Guest
Action flex and lug slap on something like a glued in Stolle Panda?? I doubt it.
Yes Toby, the shoots in the group are meaningless. Only two shots matter, those two furthest apart. You don't "calculate" ES, it's and expression of raw data......
now concerning your chart, I'm confused about load 1 so I'll ignore it. (statistical analysis generally allows this
) I'm guessing that it's there because you're still including wind drift on some level? Anyway, I'll ignore it.For pointblank BR the info contained in #2,#3,#4 is completely useless, it can't tell you anything no matter how you parse it. You can "show" it to be useful on a keyboard but real world even 40fps is useless at 100-200 unless you were shooting some infinitely stiff unobtanium barrel.
For longrange group shooting, 600-1000yds, the three groups of numbers are equal TO ME
To you, load #3 is the obvious winner. #2 and #3 are equal until you start adding in goofy stuff like wind cycles and such. I say "goofy" because these things (as you stipulated) are irrelevant the the binding stricture which is "the usefulness of SD as applied to vertical dispersion on target."
This illustrates well how our viewpoints differ, good question.
In the interest of clarifying communication, why the 4s and 5s and hard-to-locate 6 in load #3? Why not just do
3350
3350
3350
3350
3350
3350
3350
3350
3350
3360
I just don't see it I guess....... unless it's the typical "baffle with BS" technique. Math and engineering types are trained from infancy to over-complicate descriptions..... were you just wasting my energy or is there a reason?
obfuscation bothers me.
al
T
tobybradshaw
Guest
now concerning your chart, I'm confused about load 1 so I'll ignore it. (statistical analysis generally allows this
It's there because you said that, for BR, ES is all that matters. The 1000fps load has the lowest ES, but I doubt that anyone (including you) would prefer it to Loads 2-4. Ergo, even you don't believe that ES is all that matters.
Speak for yourself.
For longrange group shooting, 600-1000yds, the three groups of numbers are equal TO ME
And yet, if you were shooting 5-shot groups, and ES determined vertical dispersion, the 2-group (vertical) agg would be different for each of Loads 2-4 (with 2 being best and 4 being worst). Why is this not of interest to you?
I've never used chronograph data to choose a load, nor have I ever shot at 1000yd. But I don't have a "favorite" without looking at some targets.
To make the mean velocity the same for loads 2-4. Like you, I eschew obfuscation.
Toby Bradshaw
baywingdb@comcast.net
T
tobybradshaw
Guest
Don, a few questions.
1) Are the amplitudes of the vertical and horizontal components correlated? I.e., if you worked to "fix" vertical dispersion would it automatically help (or hurt, or have no effect on) horizontal dispersion?
2) Have you written this up somewhere? I am way behind in my reading.
3) Just out of curiosity, what is the maximum acceleration you observed?
Toby Bradshaw
baywingdb@comcast.net
H
HBC
Guest
Thrown charges vary and it can't be fixed.
Jerry asked me to make a comment here so I will. I am a 1000 yard shooter and have shot in only one 100 BR match and that was with Tom Gilman in the small bunch of shooters in Hot Springs, AR back in 1963.
I have tested powder measures with a wide range of powders, those used in short range BR and those used in long range BR and have tested a number of schemes to get consistent thrown charges. After hundreds of hours spent in testing to achieve consistent thrown charges it appears to me that if one wants consistent charges, he must first screen the powder and then weigh each charge.
I use a simple screening method of one screen which will not pass a normal granule. That single screen will eliminate fines. Once while screening long range powder, a small chip of wood came to the top of the powder. That convinced me that I was not wasting time screening.
For long range BR, my opinion is that weighed charges are a must. For short range BR 300 yard matches, my opinion is that one should definitely weigh each charge. But if I shot short range I would weigh all charges including for 100 and 200 yard matches.
And to top the above statements, all charges would be weighed and loaded at home. I know that opens another can of worms because I know that probably most short range BR shooters adjust loads at the range.
Like Al, I have chronographed 1000's of rounds and with a precision chronograph setup (48 foot screen spacing to get a real velocity resolution of probably slightly below 1 f/s) and I believe for one to truly conduct a test to show with stastically significance results, that weighed charges are superior to thrown charges, would require testing far in excess of rounds fired than any shooter would be willing to foot the bill for in time and money in order to conduct such a test.
OK Jerry, I have made a comment and that will be it. I know you fine folks can figure it out without me.
BR and Long range shooting are sports I dearly love and I continue to work with new ideas (some folks probably think some of my contraptions are a bit odd) and I will be building a rifle for my wife Nancy in comming months--I believe she loves to shoot almost as much as I do. BTW, I am attaching a photo of her first two 1000 yard BR groups fired in her life--shot last month at the IBS 1000 yard Nationals, Pella, Iowa (we were shooting the 6mm 115 grain DTAC not 115 DATC).
Henry
Jerry asked me to make a comment here so I will. I am a 1000 yard shooter and have shot in only one 100 BR match and that was with Tom Gilman in the small bunch of shooters in Hot Springs, AR back in 1963.
I have tested powder measures with a wide range of powders, those used in short range BR and those used in long range BR and have tested a number of schemes to get consistent thrown charges. After hundreds of hours spent in testing to achieve consistent thrown charges it appears to me that if one wants consistent charges, he must first screen the powder and then weigh each charge.
I use a simple screening method of one screen which will not pass a normal granule. That single screen will eliminate fines. Once while screening long range powder, a small chip of wood came to the top of the powder. That convinced me that I was not wasting time screening.
For long range BR, my opinion is that weighed charges are a must. For short range BR 300 yard matches, my opinion is that one should definitely weigh each charge. But if I shot short range I would weigh all charges including for 100 and 200 yard matches.
And to top the above statements, all charges would be weighed and loaded at home. I know that opens another can of worms because I know that probably most short range BR shooters adjust loads at the range.
Like Al, I have chronographed 1000's of rounds and with a precision chronograph setup (48 foot screen spacing to get a real velocity resolution of probably slightly below 1 f/s) and I believe for one to truly conduct a test to show with stastically significance results, that weighed charges are superior to thrown charges, would require testing far in excess of rounds fired than any shooter would be willing to foot the bill for in time and money in order to conduct such a test.
OK Jerry, I have made a comment and that will be it. I know you fine folks can figure it out without me.
BR and Long range shooting are sports I dearly love and I continue to work with new ideas (some folks probably think some of my contraptions are a bit odd) and I will be building a rifle for my wife Nancy in comming months--I believe she loves to shoot almost as much as I do. BTW, I am attaching a photo of her first two 1000 yard BR groups fired in her life--shot last month at the IBS 1000 yard Nationals, Pella, Iowa (we were shooting the 6mm 115 grain DTAC not 115 DATC).
Henry
Attachments
JerrySharrett
Senile Member
It's there because you said that, for BR, ES is all that matters. The 1000fps load has the lowest ES, but I doubt that anyone (including you) would prefer it to Loads 2-4. Ergo, even you don't believe that ES is all that matters.
Speak for yourself.
And yet, if you were shooting 5-shot groups, and ES determined vertical dispersion, the 2-group (vertical) agg would be different for each of Loads 2-4 (with 2 being best and 4 being worst). Why is this not of interest to you?
I've never used chronograph data to choose a load, nor have I ever shot at 1000yd. But I don't have a "favorite" without looking at some targets.
To make the mean velocity the same for loads 2-4. Like you, I eschew obfuscation.
Toby Bradshaw
baywingdb@comcast.net
Again, you're better at making my points than I am, thanks.
al
Now that's good thinkin' right thar! I agree about the clocking changing with twist direction.
al
Jerry,
No, I can't agree. IMO as long as the relative velocity comparison is valid my actual velocity is of little importance. Except that I may quote to someone that I shoot "at 3150" only to find out later that it's not true...... in the mean time my comeups correlate to listed (and HBC figgered) BC's out to 600yds. Here's why I feel that the chrony's are worth using for relative velocity numbers. I have certain loads which repeatedly show low velocity variation..... and weighing charges has got my variation down to what I consider to be well within the resolution capability of my cheapo chrono units. To put it simply, some of my setups will repeatedly, day after day show low numbers and some will be all over as you say. I just can't assign repeated low ES numbers to random chance.
I do have my range wired with 110AC and CAT-5 (or RG-6, disremember) for an Oehler setup, I've got the pix of Henry's setup saved to my hard drive along with all the info he's given me.... I WILL someday have a real chronograph setup
But meantime I shoot over chrony's and feel that I've got them set up such that I'm getting usable info. BTW, an easy trick for the little chronos is to shoot through them sideways, point at a white surface like coroplast or styrofoam board. Seems to lessen variations due to changing lighting.
BTW, I gave up on "summary data" long ago, I only pay attention to ES any more. Of course I do see and feel the obvious patterns, just like looking at groups...... but I don't analyze and quantify it.
I arrive at "mean velocity" by looking at a days shooting and rounding in my head
I just don't CARE if I'm off 5fps........And my sample size is just, "well,there's another day in the notebook..."
LOL
al
opinions vary
This I can say...... I own three Bordens and have friends with two more. These 5 rifles just shoot and tune like..... well like Borden guns
Borden Bumps are designed to combat bolt slap.
al
Boyd Allen
Active member
Don,
What are you doing? Discussions like this are no place for hard data.Still shooting tuners?
Boyd
What are you doing? Discussions like this are no place for hard data.
Still shooting tuners?Boyd
T
tim in tx
Guest
way to go nancy
she shot like a pro, 35th in light gun overall,thats pretty good for the first time out and congrats on your 15th in score yourself mr henry. tim in tx
she shot like a pro, 35th in light gun overall,thats pretty good for the first time out and congrats on your 15th in score yourself mr henry. tim in tx