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View Full Version : Explain this, oh sages.



fourarmed
02-06-2006, 01:01 PM
Been helping a cousin with his .45-110 Sharps replica. Yesterday I shot 25.0/XMP-5744/457125. I shot 10 with a tuft of dacron and 10 without. There were a couple of surprising results. One was that both loads averaged within 5 fps of each other at 1100 fps. The big surprise was that the extreme spread of speeds WITH DACRON was 161 fps, and WITHOUT DACRON was 28 fps. The group for the latter was 2" at 70 yds., and for the former it was around 5". I found this so surprising that I now wonder if it is possible that I got the two mixed up, but I am sure that I did not.

StarMetal
02-06-2006, 05:06 PM
August

Well Sir, you are wrong on some things:

2) Using fillers/wads in uncompressed loads is inviting disaster. You may end up with a severly damaged chamber or barrel as the result of this practice. Accurate arms clearly cautions against this practice.

Wrong, that is absolutely not true. Not only I but lots of members here have an enormous amount of experience in use of fillers. I'll grant you that the IMPROPER use of fillers can invite disasters.

3) Dacron is made from petroleum and, therefore, a propellent of sorts. At least it's flamable. The dacron was adding to the combustion mix in your cartridges and affecting the velocity.

Wrong. In fact it doesn't burn. For one the exposure to the powder heat and flame is so sort it never burns. This is a proven fact by myself and other posters that use Dacron and find it laying on the ground often not even charred. If you're concerned about it adding energy to the powder use Kapok, I can assure you that's not a petroleum product.

4) Hopefully your data will lead you to deleting this practice from your loading procedures.

Hopefully you'll read all the our forum topics on this subject and see you're loading procedures aren't all that they could be.

Joe

swheeler
02-06-2006, 05:40 PM
Fourarmed; I have found that some propellants in certain cartridges do not benefit from dacron filler, for me they are 5744 and 4759 in all bottleneck cases that I have tried them in. When I used them extreme spreads increased and in most cases acccuracy decreased. I have shot xmp5744 in the 300 Remington Ultramag with low ext spreads and excellent accuracy with no filler, kinda like dropping an alkaseltzer in a coke bottle. I do use fillers in lots of loads with great success, when used correctly I have no worries of ringed chambers or anything else .

44man
02-06-2006, 06:11 PM
Joe is absolutely correct. So is swheeler. Some loads and powders do not benefit from fillers. I do have some luck with 4759 in my 45-70 revolver but can't say if they are more accurate with or without it.

Wayne Smith
02-07-2006, 08:16 AM
I do remember reading - I read so much I'm not sure where, but I think Mike Venturino - that the relationship between velocity SD and group size is far from linear and possibly inverted, as you found. The whole point of the discussion was that velocity SD is an over rated statistic and quite possibly meaningless in terms of accuracy.

BruceB
02-07-2006, 08:57 AM
Morning, gents....actually evening to us night-shift fellers. I hoisted well
over a thousand tons of ORE tonight, which should bring our company a good half-million dollars or so at today's comfortable gold price ($570/oz, more or less).



I'll also weigh in on the side of those who use fiber fillers.

I use a lot of dacron; in fact. the large majority of my rifle loads use the stuff. This usage spans a wide range of cartridges, from 6.5x54 Mannlicher to the .45-70 and .416 Rigby. The type I use is the stuff that comes in a large loose clump. not the quilting batts.

I have proven to my own satisfaction that in many applications (not all, by any means) my ammo is more uniform and shoots better when using dacron fill.

As Joe stated, the dacron is not consumed in firing the round. My benchrest is usually littered with bits of the fiber after firing into any sort of breeze, and I've seen tufts wafting down the firing line from other folks' rifles.

In spite of what the 'common wisdom' might say, I have also found that in many loads with supposedly "position-insensitive" powders such as 2400 and 5744, the uniformity and performance is improved with a loose dacron tuft to hold the powder to the rear of the case. My proof is provided by the chronograph, which plainly shows slightly-elevated velocities (and hence pressure) along with smaller extreme spreads and standard deviations. More telling yet, is that accuracy is also improved in many examples, and sometimes dramatically so.

In fairness, this doesn't always happen, and occasionally I see WORSE performance with dacron fill.

The above statements are based on hundreds of occasions where I loaded test lots of identical rounds, except that one lot would have dacron, and the other lot no dacron. Fired on the same day in the same conditions, I have amassed enough experience to confidently make these claims for my methods, my guns, etc etc.

As ever, individual experiences can vary considerably. Anyway, I'll be putting dacron in cases for a long time to come. It's a very useful component on my bench. I have never encountered the least sign of trouble or unexplained pressure jumps in many thousands of rounds fired with dacron, nor have my rifles been harmed in any way.

felix
02-07-2006, 09:58 AM
Wayne, the ES statistic is more important for accuracy where 5 shot groups are concerned, and most especially for over a long distances. The SD is important for an ammo maker providing a whole production run, i.e., something where something is going to be insured. ... felix

carpetman
02-07-2006, 11:30 AM
BruceB---I know it would vary greatly,but about how much gold would typically be in a ton of ore?

7br
02-07-2006, 11:58 AM
My brother in law is an obsessive engineer. He has started reloading. As I told my sister, this is the perfect hobby for him. He has about a billion factors to deal to track and analyze.

Somewhere it has stuck in my head that barrel harmonics can really wreak havoc with groups even if you have a very low std deviation or ES. Basically, the end of the barrel is going to be a node. If your bullet gets to the end of the barrel when it is at the max amplitude of the wave, you are screwed no matter how consistant your velocity.

One of the NRA hi power rifle publications suggested loading 20 rounds ammo and increase each charge .1 grain. As can be imagined, the impacts tend to rise with each increasing charge. What is interesting is that you can get several clusters where 4 or 5 rounds will impact within a very small distance. Center your charge on the cluster and see how the load performs. Course, this might have little to nothing to do will barrel harmonics and just the burn curve of the powder.

Hey, there is an idea. Maybe the filler is raising pressure enough to make the burn curve a little steeper. Inconsistant neck tension would have a more pronounced effect on a steeper curve??? How consistant is the oal of the cartridges and of the cases?

felix
02-07-2006, 12:14 PM
Mark, it is the other way around. You want the boolit to exit the barrel when the barrel is at its quietest. That would not be at a node, but exactly in between two nodes. At the top of the positive (or negative) hump where directions are being changed. You want as low as frequency as is possible, which is another factor. ... felix

44man
02-07-2006, 12:49 PM
I found a way to eliminate barrel vibrations. I have the wife hang on the muzzle.

7br
02-07-2006, 01:28 PM
Mark, it is the other way around. You want the boolit to exit the barrel when the barrel is at its quietest. That would not be at a node, but exactly in between two nodes. At the top of the positive (or negative) hump where directions are being changed. You want as low as frequency as is possible, which is another factor. ... felix

Absolutely correct. My physics class was many moons ago and I can't seem to put my finger on the all of the formula and phrases. What I should have said was the muzzle would be an anti node and the chamber end would be a node. There may be one or more nodes along the barrel at the wavelength of the soundwave. Now if I could put my hands on the speed of sound in steel, I could start to make some calculations.

fourarmed
02-07-2006, 01:31 PM
Just to make sure my original post was clear, let me reiterate. I got the smallest extreme spread and the smallest group with the load that had NO dacron holding the powder in place.

The .45-110 case is almost 3" long. The Lyman 457125 boolit probably takes up a half-inch of that or a little more. The powder charge doesn't take up much more than that. There's a big cavern in there.

StarMetal
02-07-2006, 01:47 PM
This is the formula equation for the speed of sound throuh bulk material basically structural steel. I had to copy a pic of it to put it down right here. Just click on the pic and it will come up clear.

7br
02-07-2006, 02:39 PM
Did you weigh the dacron? Most of the space taken up by the dacron should be air. I would think it would be easy to have quite a variation in the mass of the dacron and a corresponding variation in the usable case volume.

StarMetal
02-07-2006, 02:47 PM
7br

We're talking about a very very very light mass here. Dacron is very light material. I doubt the effect of varying dacron mass would even be noticeable.

You lost me on that the only space Dacron should occuply is the air space. What other space is there? There's powder space, taken up by the powder, bullet space, taken up by the bullet, then air space, taken up by the dacron should one use it.

fourarm

It's not 100 percent written in stone that a filler works with EVERY type of powder out there. With the majority the SD and ES are better. The powder that you uses happens to not be one it works good with. Apparently too you didn't need a filler with it.



Joe

fourarmed
02-07-2006, 02:52 PM
Mark, I was using about a square inch of quilt batting - about 2 grains. The way I cut it by area produces quite a uniform weight. As you say, there is a huge amount of air in the case. The chamber ringing issue aside, it is hard to understand why uniformity in the powder location doesn't lead to uniform pressures in this case. I suppose primer action could have an affect. I was using Federal Large Rifle.

On the other hand, loading is nothing if not empirical. What works, works.

7br
02-07-2006, 03:01 PM
Joe
I was trying to say if you double the amount of dacron, you have reduced the amount of case volume by a corresponding amount.

StarMetal
02-07-2006, 04:14 PM
No, all you done then is increased the density of the dacron.

Joe

BeeMan
02-07-2006, 05:20 PM
On the other hand, loading is nothing if not empirical. What works, works.

A couple favorite sayings:

In theory, there is no difference between theory and practice. In practice, there is.

In God we trust, all others bring data.

BeeMan

fourarmed
02-07-2006, 07:01 PM
Thanks BeeMan. Here are a couple more in a similar vein:

If reproducibility may be a problem, conduct the test only once.

If a straight line fit is required, obtain only two data points.


Which reminds me of this corollary to Murphy's Law:

The most expensive component in the circuit will always fail in time to save the fuse.

Larry Gibson
02-07-2006, 08:17 PM
fourarmed

Like BruceB, StarMetal and others I use a lot of dacron in my loads. I mostly use it as a filler, not as a wad. However, I have used dacron as a wad and filler in the 45-70 and a 45-90 with 5744 and got no noticeable improvement of the ES or accuracy with the 45-70. I never got worse results either. The ES and accuracy was improved with the dacron wad in the 45-90. I was using a Rapine 460500 and the bullet in both. Let me say this about the literally thousands of cast bullet loads with and without dacron I have chronographed (been using them since the mid '70s); most often there is little increase in the average velocity of loads with the same powder charge when a dacron wad is used. It is the uniformity caused by better ignition, i.e. a lesser ES, of the load with dacron that improves accuracy.

You state in your initial post;

"I shot 10 with a tuft of dacron and 10 without. There were a couple of surprising results. One was that both loads averaged within 5 fps of each other at 1100 fps. The big surprise was that the extreme spread of speeds WITH DACRON was 161 fps, and WITHOUT DACRON was 28 fps. The group for the latter was 2" at 70 yds., and for the former it was around 5".

Let me ask a few questions then I will explain why I ask the questions.

Did you test the load with dacron first?
Was the barrel clean when you started shooting the first load?
What type of bullet lube were you using?
What was the temperature when you were shooting?
Did you clean the barrel between groups or shoot it dirty for the second test?
How much time was there between the testing of the two loads?
Was it the first two or three shots of the string with dacron that caused the high ES?

I ask these questions because you say you "shot 10 with a tuft of dacron and 10 without". I infer from this you shot the load with dacron first. You make no mention of whether the barrel was clean or not or if you shot any foulers to season the bore. It is my observation that a 10 shot string with cast bullets out of a clean barrel will always exhibit a higher ES and larger group than a 10 shot string out of a fouled or seasoned bore. It takes two or three shots for the lube and residue to properly foul or season the bore.

There is one caveat though. The residue of some lubes can get quite hard when the barrel sits after one string and you will get a higher ES and flyers until the barrel and residue warms up, usually within two or three shots. Thus you can get practically the same results from either cause. I have shot a lot of 5744 and have had results the same as yours (with other powders also) but it was from one of the two reasons listed. Not to say what you describe as the cause simply being the use of the dacron can’t happen but I’ve never seen it. I would suspect another reason than just the difference of the dacron wad.

Larry Gibson

PS; before I get called on it let me say I have had some rifle load combinations that will put the first several shots from a clean bore into the same group at 100 yards. However, in each of these cases the first two or three shots are still outside the normal ES of and Idententical load through the seasoned or fouled bore. They may shoot good at 100 yards but the higher ES really shows at 200 yards. Those who are limited to 100 yards or less may not find that important.

fourarmed
02-07-2006, 09:00 PM
Did you test the load with dacron first? Yes!

Was the barrel clean when you started shooting the first load? I can't say for certain. Not my rifle. I fired one round of another load to see if rifle and chrono were functioning. (Rifle had been back to gunsmith for the umpteenth time.)

What type of bullet lube were you using? Felix on one side and BW/Alox on the other. (Ran out of BW/A and refilled with FWFL from big batch.)

What was the temperature when you were shooting? Around 40.

Did you clean the barrel between groups or shoot it dirty for the second test? The latter.

How much time was there between the testing of the two loads? Fired continuously.

Was it the first two or three shots of the string with dacron that caused the high ES? I didn't notice that.

fourarmed
02-07-2006, 11:22 PM
Had to leave before I could do anything but answer Larry's questions. That gives me some food for thought. The 457125 carries a lot of lube, and this was the first time I have used it. For such preliminary testing, I didn't go to a great deal of trouble equalizing potential confounds.

BruceB
02-08-2006, 12:58 AM
BruceB---I know it would vary greatly,but about how much gold would typically be in a ton of ore?


Well, it's a bit off topic, but it won't be the first time.

Our cut-off grade, the point at which the gold content doesn't make the stuff worth processing, is about 0.35 ounces of gold per ton of muck. Right now, we seem to be averaging about 0.60 to something over one ounce per ton. I have seen reports of "high-grade" areas producing six or seven ounces per ton of rock, but that's not too common.

The last reported quote I saw for "cash cost of production" was around $230 per ounce, which means over $300 profit for every ounce coming out of the mine, with today's gold prices. If things are proceeding reasonably well, we can hoist about 250 tons per hour. The conveyances which bring muck to the surface are called "skips", and most "skipping" (hoisting of muck) is done on night shift. Of course, we also have to hoist waste rock just to get it out of the way of the underground workings. There's no profit in waste rock.

We often stockpile muck which falls slightly below the cut-off grade, and add it to the high-grade going to the mill so that the limited gold content is still recovered.

This company has fifty square miles of property at this site, and based on what we know is here in the very FIRST square mile we've explored (and not completely explored, at that), they predict twenty years of mine life. It's a long-term proposition, I'd say.

BTW, our gold is CAST into ingots at the mine refinery....haven't tried making boolits from it yet (Take THAT, Lone Ranger, you two-bit silver-bullet piker....)

Roudy
02-08-2006, 01:35 AM
Starmetal....If you increase the amount of dacron in the load doesn't that decrease the amount of air in the load? Therefore the total mass inside the case is larger (but not by much) since dacron has more mass than air.

BTW the reason for free floating a barrel is to let the barrel vibrate consistently (harmonics) without being influenced by random contact with the stock.

7br...if your brother-in-law hasn't seen this article called "How Bullets Fly" http://www.nennstiel-ruprecht.de/bullfly/ you might want to introduce him to it. Will keep a good engineer busy for months!

Larry Gibson
02-08-2006, 03:37 PM
fourarmed

Got to agree with you on the "potential confounds"! Shooting another (unkown?) round prior to the test, not fouling the bore with the type of load used prior to test and using two different types of lube (maybe 3 considering the first shot) without cleaning between strings sure could "confound" things.

However, from your answer "Did you test the load with dacron first? Yes!" I would venture it took two maybe three shots to properly foul the bore. I'd say that's more than likely where the higher ES came from.

Would be interesting if you could run the test again just for S&Gs. Load 13 rounds with the dacron and 10 without using the same lube on all the bullets. Shoot the first 3 extra shots with dacron to foul the bore and ensure the chronograph is lined up. Then shoot the remaining 10 with dacron for the test. 5744 burns pretty hot so give it one minute or so between shots. Let the rifle cool before shooting the 10 shots without dacron. Again give it a minute or so between shots. When done with the second string take a look at the first shots velocity. If it is either the high or low velocity for the string delete it and compute the ES for the remaining 9 shots.

Also if that first shot without dacron is the high or low velocity of the string it is telling you that the lube residue in the barrel is hardening up as the barrel cools. Might not mean much for normal plinking or shooting but if it causes inaccuracy then it isn't good in a hunting situation.

Larry Gibson

fourarmed
02-08-2006, 04:53 PM
Thanks Larry, and let me say it's good to see your handle on the board. Hadn't heard much from you since the Shooters days.

I will be trying more of that load as soon as I get more of the boolits cast. It shows much more promise than the 3 different 405 grainers I tried in the rifle.

I use two Lyman lubrisizers, a 35 year-old 450 and a new 4500. The new one has never had anything in it but FWFL from the big pour, but the old one has had BW/chassis grease, the NRA lube, LBT Blue, and now FWFL in it. Takes a long time to clear the old stuff. On the other hand, after a few rounds, it's going to be thoroughly mixed in the bore.

I will attempt to control conditions better next time, as the results were just too surprising to be entirely due to the presence or absence of dacron, in my experience. Everybody else's too, apparently.

Joe Bob
02-10-2006, 02:42 AM
Fourarmed...
I have been following this thread and have come up with what just might be the problem. First, let me say that I haven't a damn clue as to what you and all the other fellows are talking about and have never in my life loaded with Dacron, youron, myron, theiron, or enron. Here's what I think, anyway...You might count the number of threads in the Dacron tuft, then count each grain of powder that goes into the shell casing. Add those two and multiply by the ballistic coeffecient of the bullet you're gonna load and divide the answer by the number of times you've been laid during the vernal equiox. Now, if you come up with a number (any number), that's good. If you don't come up with a number, that's bad. Go out and shoot what prints the smallest group at the higest safe velocity. If I can be of further assistance, please, don't hesitate to let me know......That'll be five dollars, please
Joe Bob

fourarmed
02-10-2006, 01:11 PM
Well, OK, just as long as it's SCIENTIFIC!

carpetman
02-10-2006, 02:44 PM
BruceB---Thanks for the information about gold and mining. I know nothing about it and find it interesting. The only mine I have been in is Carlsbad Caverns in New Mexico. They use to mine guano or whatever it is that they call bat****. Tons of the stuff was shipped by rail to California to develop their citrus trees. You mentioned the ore going to the mill. How far away is the mill and how is it shipped there? What process does the mill do to extract it? None of this is off topic. With the braintrust on this board---a more practical solution might be devised so that gold bullets might become economical. Would make a heck of a rabbit bullet. We are all aware they love karats.