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Okay, needless to say I'm a believer but what surprises me are those that don't think enough data is available to make a conclusion. Granted it may be from several sources but in it's entirety it, to me anyway, is absolute proof.

Here is what I propose:
Let’s come up with a test that will put this one to bed once and for all.
I will do all the shooting on one end but to be a good test I need to have at least 2 others doing the same exact test.
I will turn bullets from the rod I make Bridger bullets from but will change the nose shape only to a round nose vs. a flat nose. Same bullet same weight only the nose is different.

I need two volunteers to help with this. I will provide bullets and make up a data report form to track the results. We will need to use either the same collection box and method or one that is constructed and assembled the same. I can build the box and then send it on to the next shooter with a detailed instruction sheet on setup and use. This will remove the variable of having a different setup.

My thinking is that the needed information is:

Impact velocity
Distance traveled straight
Distance traveled before tumbling
Distance traveled after tumbling
Twist
Bullet weight
Bullet shape

I would also like to be able to have some sort of category for displacement but don't yet know how to quantify that any ideas?

If I missed anything let me know?

This may be something that can be published if there is any interest but there was a very good article in African Hunter a few months back on this very issue so there may not be a need in the publisher’s eyes.

In any event, a test like this, although not a simple thing to but together should be proof to all but the diehards that will never change their minds unless they witness it. In fact I would like to have one shooter be a non believer or at the very least undecided. We can go so far as to have witnesses verify the results.

Well let it rip (no pun intended Ron). I'll do all the loading or you can do it yourself (preferred so there are different people doing this) It will take some time to complete all this but in the end it will be worth it.

John
 
Posts: 855 | Location: Belgrade, Montana | Registered: 06 October 2000Reply With Quote
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If you really want to do this right, I'll volunteer to do the statistics.

Brent


When there is lead in the air, there is hope in my heart -- MWH ~1996
 
Posts: 2257 | Location: Where I've bought resident tags:MN, WI, IL, MI, KS, GA, AZ, IA | Registered: 30 January 2002Reply With Quote
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Brent. I want to do it right and have enough controls that the doubters can't find flaws in the method. If you want to do the SA great. It should be someone other than me as I have a financial insentive here.

quote:
If you really want to do this right, I'll volunteer to do the statistics.
 
Posts: 855 | Location: Belgrade, Montana | Registered: 06 October 2000Reply With Quote
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No problem, but the experiment will need to be well designed before it starts.

I'd be happy to do it using lead bullets because I don't shoot anything else and can easily make fn and rn bullets that are otherwise identical.

When you get the people together, let me know and I'll put together the design.

I think somethings like distance traveled after tumbling will be a hard thing to measure objectively since the point where tumbling starts is not easily identified.

Also think about the issue of weight. If you cut the nose off a RN bullet to make a FN bullet, you loose weight. Of course weight adds to penetration but it also cancels velocity, so adjust accordingly.

The media may interact with the results (ie, FN penetration in one media may exceed RN but may be less than RN penetration in a different media. (Broadhead arrows in sand vs bullets, and broadhead arrows in bone vs. bullets is an example of this sort of interaction).

Anyway, work out the details and I'll run the math. I have zero fiscal interest in this since I don't shoot copper of any sort, and don't sell bullets (at prices that mortals can afford).

Brent

REAL bullets Smiler!


When there is lead in the air, there is hope in my heart -- MWH ~1996
 
Posts: 2257 | Location: Where I've bought resident tags:MN, WI, IL, MI, KS, GA, AZ, IA | Registered: 30 January 2002Reply With Quote
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Brent no cutting off the nose to get a FN. I'll simply change the program to turn a RN instead of the FN. Weight can then be held constant with the only change being the nose shape.

I'll PM you once I get he methodology figured a bit more and then every one can comment. Hopefully it will be a useful endeavor.

Measurement will not be as simple as it sounds but if we keep the methodology the same form test to test and person to person we should be able to eliminate or at least reduce it to an insignificant amount.

John
 
Posts: 855 | Location: Belgrade, Montana | Registered: 06 October 2000Reply With Quote
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I would love to see such a test. Due to my biased view on this topic, probably others should be assigned to gathering the data.
 
Posts: 18352 | Location: Salt Lake City, Utah USA | Registered: 20 April 2002Reply With Quote
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quote:
I would love to see such a test. Due to my biased view on this topic, probably others should be assigned to gathering the data.



I agree 500Grains, I'm biased as well but I don't think that should disqualify you as a data collector. I'm certainly biased but now it's time to proove the theory that FNs are better solids.

If you want to help out I'm all in favor of it.

John
 
Posts: 855 | Location: Belgrade, Montana | Registered: 06 October 2000Reply With Quote
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I could possibly pitch in and help, but not until September (all my stuff is in moving containers until the end of August). Could possibly even meet halfway to pick-up the "box".

If nothing else, I am totally unbiased. Smiler

Cheers,
Canuck



 
Posts: 7123 | Location: The Rock (southern V.I.) | Registered: 27 February 2001Reply With Quote
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That would be great Canuck. This whole thing will take some time to put together and build. Anyone else want to pitch in.
 
Posts: 855 | Location: Belgrade, Montana | Registered: 06 October 2000Reply With Quote
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John,
Let'er rip!
Very interesting. I am totally biased toward Flat Nose solids also.

What calibers and weights might you be planning to test?

If I may be of assistance I can certainly be objective enough to follow your cook book.

BTW, in 5 gallon buckets of water laid end to end on the ground, as well as in the Iron Buffalo guts of alternating plywood and water:

Flat Noses go 3 times as far as Round Noses before tumbling, or keyholing.

Flat Noses do not lose stability until they are greatly slowed down.

Round Noses lose stability at higher speeds so can penetrate farther after keyholing, but it is likely to be veering off course.

Hence the total penetration in Iron Buffalo guts is about 2 to 1 in favor of the "FN" (FP) over the RN.

Just my observations.

You are making a lot of sense to me. thumb
 
Posts: 28032 | Location: KY | Registered: 09 December 2001Reply With Quote
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Gentlemen,

I'm guilty of not following the current trends and topics quite often, but I thought the Flat Nose, Trunicated Nose, Round Nose - Penetration issues were solved in the late 70s thru early 80s. Many were shooting hard cast large bore blackpowder/muzzleloader bullets w/ round or trunicated noses for elk. Field results were terrible as these bullet suffered poor penetration. If I'm not mistaken, engineers for T/C discovered that the poor penetration was due to instability of the bullet upon impact causing it to veer, tumble etc. They determined that the best way to increase stability was to give the bullet a broad meplat which corrected the problem.

Not trying to be a smart ass, just thought that having a wide meplat to improve penetration on a non-expanding bullet was old news and common knowledge.

Gary
 
Posts: 1190 | Registered: 11 April 2004Reply With Quote
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quote:
Originally posted by GaryVA:
If I'm not mistaken, engineers for T/C discovered that the poor penetration was due to instability of the bullet upon impact causing it to veer, tumble etc. They determined that the best way to increase stability was to give the bullet a broad meplat which corrected the problem.

Not trying to be a smart ass, just thought that having a wide meplat to improve penetration on a non-expanding bullet was old news and common knowledge.

Not necessarily a broad meplat, but a design for generating the cavitation bubble for straight line penetration stability.
I wonder why rifle bullet manufacturer needed so much time to introduce bullets following this concept. May be there was no convincing theory for that phenomenon.
 
Posts: 279 | Location: Europe, Eifel hills | Registered: 12 January 2004Reply With Quote
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Norbert,

I agree not necessarily a broad meplat. I was speaking in the context of a RN and trunicated design that suffered from instability upon impact due to its design. Based on that design, using an ever increasing meplat will decrease the front to rear disparity and increase stability which in effect produces a desired cavitation. But if you continue to increase meplat size on that design beyond this point of reaching stabilization...you'll begin to negate the effect. I'm sure there are many superior designs to a RN or trunicated nose other than merely wacking off the end of the bullet flat like t/c did.

Gary
 
Posts: 1190 | Registered: 11 April 2004Reply With Quote
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When pushing pipe underground, you never put on a rounded or pointed end cap. The square open end of the pipe packs with dirt for a few inches and then gives you a flat point 'projectile' that proceeds through the soil with minimal deflection. Hard cast, flat nosed bullets work great in big bore handguns too. I can't see the concept not working in rifles - it just happens at higher speeds. But, I'd love to hear the results of such testing!


==============================
"I'd love to be the one to disappoint you when I don't fall down" --Fred Durst
 
Posts: 759 | Location: St Cloud, MN | Registered: 17 January 2005Reply With Quote
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I have a 45/70 double rifle I could shoot in your test. thumb Big Grin
Dean
 
Posts: 1057 | Location: adirondacks,NY ,USA | Registered: 30 December 2001Reply With Quote
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I gave this a bit of thought last night and I think I need to test a few calibers at 4 or 5 velocities.

My thoughts are to run velocities at 1600, 1900, 2100, 2400, and 2600. To do this I will need cartridges capable of these velocities and each tester needs to verify velocity with a chronograph (not from the book).

Calibers will be:

.375
.416
.458
.474
.510

With the 474 and .510s the 2600 fps load will be eliminated for practicality reasons.

Loads will be fired into the as yet undecided collection box and distances measured. Digital photographs should be taken as a visual record. I think is will be best for me to make one box and then ship it to the other testers. This will eliminate any differences in the box. Due to this I will need to make the box easy to assemble and disassemble for shipping. The iron buffalo is looking like a good platform.

I've been playing with an idea to measure upset within the box. It would require sealing the box on all 6 sides, filing with the media (not decided yet) and sealing. A section can be left to the open air for pressure release but then we can put a pressure gage at a suitable location and read the peak pressure within the box.

It would be very useful to get a pressure over time curve here but I'm not sure of the extra work and expense. To acquire a suitable gage and monitoring device that will withstand the shock and be accurate enough to measure the very short time intervals that would be needed may proove impossible.

I’m still working on that one.

What do you guys think?
 
Posts: 855 | Location: Belgrade, Montana | Registered: 06 October 2000Reply With Quote
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Why worry about tumbling at all? If it happens and the bullet still passes through, so much the better. So just measure penetration and forget about the rest. If you were to pick another variable to add to the equation, measuring deviation from the line of impact might be easier and more important - that is what is the angle between the bullet's path in the media and it's path prior to the media.

Personally, I shoot into my oiled sawdust box, but I'm interested in recovering undamaged bullets, and not mimicking buffalo guts.

Brent


When there is lead in the air, there is hope in my heart -- MWH ~1996
 
Posts: 2257 | Location: Where I've bought resident tags:MN, WI, IL, MI, KS, GA, AZ, IA | Registered: 30 January 2002Reply With Quote
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quote:
Originally posted by Brent:
Why worry about tumbling at all? If it happens and the bullet still passes through, so much the better. So just measure penetration and forget about the rest. If you were to pick another variable to add to the equation, measuring deviation from the line of impact might be easier and more important - that is what is the angle between the bullet's path in the media and it's path prior to the media.

Personally, I shoot into my oiled sawdust box, but I'm interested in recovering undamaged bullets, and not mimicking buffalo guts.

Brent


Sorry Brent, but that is just dumb ... on many counts.thumbdown

And finally, why would you just want to recover undamaged bullets, is this your method of slugging a bore? bewildered

I would just just use a kinetic bullet puller to recover an undamaged bullet, or better yet, never load it at all. Just pick up a new box of component bullets, and remove one from the box with thumb and index finger.

Then you could carry it around in your pocket and admire it now and then, like Chief Lone Watie and his piece of Hard Rock Candy. roflmao
 
Posts: 28032 | Location: KY | Registered: 09 December 2001Reply With Quote
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quote:
Originally posted by RIP:
...like Chief Lone Watie and his piece of Hard Rock Candy. roflmao


There you go with the movie references again -- don't make me post more quotes!
 
Posts: 8773 | Location: Republic of Texas | Registered: 24 April 2004Reply With Quote
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HI John,
Great idea but I think that Ron has solved the situation. The testing would be great fun and practical but the one that drives me is the 45/70 and handguns out penetrating the big bores.
If you get a chance and are making some of your 540 grain .475's I would like to buy some. I want to line up the heavy 5 gallon pails end to end and shoot them at 1500, 2100 and 2400 fps with the video camera running and show what an apples to apples comparrison is.
Take good care see you in Nov,
Dave
 
Posts: 1247 | Location: Sechelt B.C. | Registered: 22 May 2002Reply With Quote
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Whats the point in this, either a RN or a FP has more than enough penitration and some to spare....Both, contrary to some beliefs, travel in a straight direction 99% of the time, many folks are still applying knowledge from what they read that applied to bullets of yesteryear with concern to RN bullets...Woodleighs,and most any monolithic RN is a worthy bullet, but no RN kills as well as a FN IMO...

The best thing about a FP is it kills better by doing more internal damage and it cuts a cleaner entrance wound that lets air in the body cavity and blood out...

All that said, These days I only use Flat nose solids from GS Customs, Northfork and Bridger and I have used them all on a lot of Buffalo ..So do I like FN solids better than RN solids? yes I do, much better.........As far as penitration, either suits me fine, I have never had a modern solid fail to penitrate and when one does, closer investigation usually comes up with a good reason for the failure.


Ray Atkinson
Atkinson Hunting Adventures
10 Ward Lane,
Filer, Idaho, 83328
208-731-4120

rayatkinsonhunting@gmail.com
 
Posts: 42321 | Location: Twin Falls, Idaho | Registered: 04 June 2000Reply With Quote
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quote:
Originally posted by 470 Mbogo:
... but the one that drives me is the 45/70 and handguns out penetrating the big bores.

Dave


Dave, don't take those Linebaugh tests too seriously. He also found that the 25-20 and the 9.3 x 62 have equal penetration. The fault lies in his wet newspaper media which is unreliable, inconsistent, and often produces results which are the inverse of what is observed in the field.
 
Posts: 18352 | Location: Salt Lake City, Utah USA | Registered: 20 April 2002Reply With Quote
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yeah Ripster. I imagine it seem dumb to you. Your ignorance shines out like a million candle beacon.

Rest in peace brother. Nothing going on here that you could grasp anyway.

Brent

PS. In your copious spare time you might look up Dr. FW Mann's book, `The Bullet's Flight from Powder to Target"


When there is lead in the air, there is hope in my heart -- MWH ~1996
 
Posts: 2257 | Location: Where I've bought resident tags:MN, WI, IL, MI, KS, GA, AZ, IA | Registered: 30 January 2002Reply With Quote
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I think tumbling makes all the difference in the world, in game such as elephant or Buffalo when a bullet tumbles it loses all its penetration and normally will angle off in the wrong direction...Most of the problem elephant kills I have seen were the results of poor shooting first and tumbling bullets probably second. Straight line penetration is the one most important aspect of a dangerous game bullet IMO....When that bullet tumbles, penetration stops very shortly thereafter.


Ray Atkinson
Atkinson Hunting Adventures
10 Ward Lane,
Filer, Idaho, 83328
208-731-4120

rayatkinsonhunting@gmail.com
 
Posts: 42321 | Location: Twin Falls, Idaho | Registered: 04 June 2000Reply With Quote
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So, Ray, measuring penetration, or angle of deviation would be a good indication of tumbling no?

Brent


When there is lead in the air, there is hope in my heart -- MWH ~1996
 
Posts: 2257 | Location: Where I've bought resident tags:MN, WI, IL, MI, KS, GA, AZ, IA | Registered: 30 January 2002Reply With Quote
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I don't agree. I've recently experienced bullets tumbling on impact, yet penetrating one helluva long ways. The problem was that the tumbling caused the bullet to veer off its intended path and did not strike vitals flush. I had some tracking to do as a result.

MHO...tumbling is a big deal, whether it causes less penetration or not. I do not want unpredictable penetration, in terms of either distance or direction, if it can be avoided.

Canuck



 
Posts: 7123 | Location: The Rock (southern V.I.) | Registered: 27 February 2001Reply With Quote
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Canuck,
I imagine you were disagreeing with me. So, how do you determine the exact point at which a bullet begins to tumble?

if tumbling causes inconsistent penetration or deflection those can easily be captured in any reasonable analysis, but finding the point at which a bullet starts to tumble is not simple.

I have a .38-55 that appears to tip bullets at 200 yds. I think the tipping starts somewhere between 100 and 200 yds but not exactly sure where or when. This could be construed as the onset of tumbling, but measuring quantitatively is not reasonably possible.

Brent


When there is lead in the air, there is hope in my heart -- MWH ~1996
 
Posts: 2257 | Location: Where I've bought resident tags:MN, WI, IL, MI, KS, GA, AZ, IA | Registered: 30 January 2002Reply With Quote
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hijack

Guys, the intent of this post was to offer to find a way to put the FN vs. RN argument to rest. I feel we need to find a way to determine if/when a bullet starts to tumble and /or veer off course. How we accomplish this is still open to suggestion but that I want to record it is not. I feel it's a vital part of the test.

If one bullet penetrates really deeply but angles off after an inch or two IMO this is not nearly as good as a bullet that doesn't penetrate as far but stays on course.

This need to be a scientific test for it to have any validity and emotional arguments about if it matters should be saved until after the data is collected. JMO
 
Posts: 855 | Location: Belgrade, Montana | Registered: 06 October 2000Reply With Quote
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Fritz,

If the bullet box is 12 inches x 12 inches, and the shots are into the center of the 12x12 square, and the shots are parallel with the longitudinal axis of the box then any bullet which exits the side of the box has veered off centerline by more than 6 inches and can be put into the 'sidewinder' category.
 
Posts: 18352 | Location: Salt Lake City, Utah USA | Registered: 20 April 2002Reply With Quote
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Fritz, if you can provide the data, I'll give you the scientific (statistical) analysis. If the numbers are bogus, the analysis will be too, but just give me the numbers. You guys can argue about the rest. It's a pretty simple thing to do the stats. Taking the measurements may be very difficult, but I'll let you guys figure that out.

Brent


When there is lead in the air, there is hope in my heart -- MWH ~1996
 
Posts: 2257 | Location: Where I've bought resident tags:MN, WI, IL, MI, KS, GA, AZ, IA | Registered: 30 January 2002Reply With Quote
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quote:
I imagine you were disagreeing with me. So, how do you determine the exact point at which a bullet begins to tumble?


Sorry about the hijack Fritz, but I'm gonna answer this one last question from Brent.

The bullets that I was referring to, tumbled on impact. Either way, however, tumbling before or after impact is not good, as the direction of travel while penetrating the target is not predictable.

Cheers,
Canuck



 
Posts: 7123 | Location: The Rock (southern V.I.) | Registered: 27 February 2001Reply With Quote
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Canuck, how do you know that the tumbling started then and not 20 ft in front of the animal (hit a limb perhaps or just bad ballistics), or 6" into the animal when it hits a bone just exactly wrong, etc.?

I got no problem with tumbling being bad or whatever. I just want to know how you are going to measure it with accuracy and confidence. For this test, it's important that the numbers be correct, and the tumbling numbers will be very hard to get right in my opinion - that's why I would settle for angle and penetration alone.

Brent


When there is lead in the air, there is hope in my heart -- MWH ~1996
 
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Canuck, how do you know that the tumbling started then and not 20 ft in front of the animal (hit a limb perhaps or just bad ballistics), or 6" into the animal when it hits a bone just exactly wrong, etc.?


I doubt it started tumbling before the animal. The shots were in open terrain, so deflection is not at all likely. And during load development I didn not notice any keyholing and accuracy was pretty good (0.8" groups in both rifles).

Expert opinion of the manufacturer is that the bullet tumbled on impact. I have no reason to disagree.

Cheers,
Canuck



 
Posts: 7123 | Location: The Rock (southern V.I.) | Registered: 27 February 2001Reply With Quote
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Okay, so for this test, measure the tumbling from point of impact (assumed start of tumbling action), and then deviation from line of sight, ie. angle of departure from initial line of the shot). If that's what you want to use, fine with me. Start shooting.

Brent


When there is lead in the air, there is hope in my heart -- MWH ~1996
 
Posts: 2257 | Location: Where I've bought resident tags:MN, WI, IL, MI, KS, GA, AZ, IA | Registered: 30 January 2002Reply With Quote
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500Grains, totally agree with you. I think that is exactly how I'm going to do it.

I do think however that I want to recover the bullets that sidewind to determine the distance they traveled. To that end I'm thinking of wooden baffles like RIP has on the Iron Buffalo every 1.5-2". These will be 18" sq but will have a 6" dia circle drawn in the center. Any bullet that moves outside the circle will be classified as having veered off. With this method I should still be able to collect the bullets unless they go astray to the extreem.

I think the 6" bull is a good size. In truth I feel that a good bullet should do better than that. This however is a compromise I can live with.

John
 
Posts: 855 | Location: Belgrade, Montana | Registered: 06 October 2000Reply With Quote
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Another issue to decide for a bullet test is how far from the muzzle you place the bullet box. Bullets can take 15 to 75 yards to stabilize. Prior to stabilization, they have increased yaw which can cause them to veer off path. This may be the fault of the twist rate or too much velocity, not necessarily a bullet design flaw. So a fair test of bullet design would probably put the bullet box 25 yards out and use a fast twist barrel to minimize yaw.

However, if you want to know what will happen if you try to stop an elephant charge at 10 feet, better to put the bullet box 10 feet from the muzzle.

Also, rather than replicating the bullet box several places around the continent, why not just build one good box in Montana, and invite folks with the appropriate rifles and loads to show up on specified weekends. You could have several witnesses who could verify the accuracy of the data collected.

In addition to RN vs FN brass solids, I would suggest a "control group" which would be Woodleigh FMJ solids. So for each caliber and velocity, there would actually be 3 types of bullets fired. One of the statisticians among us can specify how many bullets per type and velocity level need to be fired to give meaningful results. I am thinking at last 5?? That makes the testing very laborious, but the article that comes out of this would be fairly definitive, especially if the standard deviations are kept down.
 
Posts: 18352 | Location: Salt Lake City, Utah USA | Registered: 20 April 2002Reply With Quote
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quote:
Another issue to decide for a bullet test is how far from the muzzle you place the bullet box. Bullets can take 15 to 75 yards to stabilize. Prior to stabilization, they have increased yaw which can cause them to veer off path. This may be the fault of the twist rate or too much velocity, not necessarily a bullet design flaw. So a fair test of bullet design would probably put the bullet box 25 yards out and use a fast twist barrel to minimize yaw.

However, if you want to know what will happen if you try to stop an elephant charge at 10 feet, better to put the bullet box 10 feet from the muzzle.

Also, rather than replicating the bullet box several places around the continent, why not just build one good box in Montana, and invite folks with the appropriate rifles and loads to show up on specified weekends. You could have several witnesses who could verify the accuracy of the data collected.

In addition to RN vs FN brass solids, I would suggest a "control group" which would be Woodleigh FMJ solids. So for each caliber and velocity, there would actually be 3 types of bullets fired. One of the statisticians among us can specify how many bullets per type and velocity level need to be fired to give meaningful results. I am thinking at last 5?? That makes the testing very laborious, but the article that comes out of this would be fairly definitive, especially if the standard deviations are kept down.


Excellent point. I am thinking of making this a more inclusive test. I think that with out a conventional bullet control group the test has no reference point. So I will be adding "solids" form other manufacturers. GS, Northfork, Woodleigh, Barnes and whatever other traditional solids I can locate.

As far as the range it may be necessary to shoot at 3 or 4 distances from muzzle to target. How does 10 feet, 20 yards, 50 yards and 100 yards sound?

The magnitude of this is growing exponentially as time passes. I do what to have good fair test or it all has no meaning. This will take some doing but in the end it should be a fairly comprehensive set of data.

I like your idea of people coming to Montana to shoot the test but I am concerned that I don't have much of a population to draw from. Anyone willing to make the trip or who is in the area. This way the testing can be done with the same rifles and I can then load all the bullets. There will be no cost to the testers except getting here. Unfortunately I don’t know of any “nuts†like me that would enjoy a couple full days of range shooting these cannons.

John
 
Posts: 855 | Location: Belgrade, Montana | Registered: 06 October 2000Reply With Quote
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quote:
Unfortunately I don’t know of any “nuts†like me that would enjoy a couple full days of range shooting these cannons.


Oh, I think you do. Smiler

If you are just looking for some "strong shoulders and weak minds", maybe Dave E. and I can figure out a way for both of us to get down there for a weekend, with airmiles or something. Its worth looking into, anyway.

It about a 7 hour drive from here, near as I can figure. Dave would have to fly....what's your closest airport?

Cheers,
Canuck



 
Posts: 7123 | Location: The Rock (southern V.I.) | Registered: 27 February 2001Reply With Quote
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John,
As self-appointed statistician on this venture, you don't really need to use any conventional bullets as a control per se. Though comparisons may serve other purposes.

The larger problem, statistically, is computing an adequate sample size. For that, I need three things from you. One of which may require some preliminary trials.

I need to know the variance of these measures (e.g., penetration). To do that, a sample of say 10 shots may give us a handle on what sort of shot to shot variation there is in penetration. Hopefully, it will be small. Variances are unlikely to be significantly different among bullet types (with some caveats to the more gymanstic tumbling bullets).

Second, I need to know how small a difference you wish to be able to detect. In other words, what is the meaningfully smallest difference for which it makes sense to say two bullets' penetrations are different?

Third, what is the level of confidence you wish to achieve when drawing your conclusions. Do you want 95% certainty, 90%, 50%? You make the call.

If you want 100% certainty, or if you want to detect ANY nonzero difference between the two bullet types, you will need an infinite sample size. So, consider what you feel is realistically meaningful and we can go from there.

Brent


When there is lead in the air, there is hope in my heart -- MWH ~1996
 
Posts: 2257 | Location: Where I've bought resident tags:MN, WI, IL, MI, KS, GA, AZ, IA | Registered: 30 January 2002Reply With Quote
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Canuck That's a hell of a nice offer and I will certainly take you and Dave up on it. Nearest airport is Bozeman (BZN). It's about 3 miles from the shop.

Brent, good questions and points. I think you are right about getting a base line for 10 -20 identical shots is necessary. Once we have that I think is the time to set the sample size. The smallet the varance the fewer shots are needed and the wider the difference the more shots.

That said I would think , and hope, that 10 -20 shots will tell the story for each bullet velocity and distance of impact.

Start doing the math and for each bullet there will be 200-400 shots per bullet (10 or 20 shots). I'm gonna need some new barrels after this is done.

If we do 6 different bullets, 5 calibers at 5 different velocities each and at 4 different distances from the muzzle with a 10 shot per group sample its going to take a total of 6000 shots and if 3 people do the shooting there will be a total of 18,000 rounds fired. If we do more than one bullet weight its going to get worse. I'm beginning to think this is going to take some time to complete. What the hell did I get myself into. eek2

I think I'm goning to get a pact recoil pad or a couple bags of shot. mgun

John
 
Posts: 855 | Location: Belgrade, Montana | Registered: 06 October 2000Reply With Quote
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