Dans Posts

Talk with other Shiloh Sharps shooters.

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semtav
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Re: Dans Posts

Post by semtav »

To minimize the work required to be able to work on load development with newly formed brass I do the following for 40-65 brass.

Measure chamber length to determine trim-to-length.

Back 40-65 FL sizing die out 2 complete revolutions.

Size a piece of brass to see if it will chamber with ease.

If it does back the die out one more time and repeat.

If it does not chamber measure the distance from the end of the barrel to the rim base. One revolution of the die is about 0.069" so turn the die down a bit less than the appropriate amount based on the just performed measurement.

Size the case again to see if it chambers with ease and extracts with ease.

Expand the mouths to bullet diameter and then trim cases to chamber length then chamfer and debur.

The objective is to minimally size your new brass. That way it will not shorten at all if done correctly. And, you can do load development without fire-forming c
semtav
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Re: Dans Posts

Post by semtav »

NMLRA Past Pres. wrote:
Hello: Would someone please explain why wind deflection tables don't seem to include rifling drift?


Kevin,

The reason that wind deflection tables don't include the effects of "bullet drift" on trajectory is because drift is a function of several parameters. It is a function of time-of-flight, which is a function of distance, the bullet's BC and muzzle velocity. The bullet's rate-of-spin also determines the amount of bullet drift; the faster it spins, the more it drifts. Rate-of-spin is, obviously, a function of MV and the barrel's twist-rate. As you can see, adding bullet drift to wind deflection tables would be pretty much a non-starter because a table would necessarily be particular to a specific bullet, MV and twist-rate. Finally, bullet drift is non-linear. It exponentially increases with distance.

That being said, there is some fairly sophisticated exterior ballistics software that can estimate bullet drift. It is not for the faint of heart or anyone that doesn't have a working knowledge of computer programming. Also, one must build a torsional pendulum to measure the bullet's axial and transverse moments of inertia.

A simple way to estimate bullet drift is as follows:

Bullet Drift = 3.4 x Time-of-flight^2

In closing, from a competitive shooting perspective, shimming the rear sight's staff opposite to the barrel's twist direction will mitigate the bullet's drift with a linear approximation that cancels the exponential drift effect. Another way of saying that is to setup one's sights so, if shooting NRA Creedmoor competition, that at 900 yards, in totally calm conditions, one can set their rear sight to mechanical zero and have the shot cut the "X" in the X-ring.
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semtav
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Re: Dans Posts

Post by semtav »

Wiping Test: 45-100 PP Shiloh Sharps

Much has been said and argued with respect to developing a fouling control technique that produces a consistent bore condition between shots. I was just working on organizing past BPCR testing results and came upon a test that was executed back in the Spring of 2008 using a Shiloh Sharps 45-100 Paper-patch rifle in preparation for the Long-range National Championships at Raton. The objective of the test was to determine which of several wiping techniques produced the finest accuracy when shooting patched bullets with no grease cookie.

The experimental setup was as follows:

Test Rifle:
Shiloh Sharps 45-100 sporting a 16-twist Shiloh barrel chambered with special paper-patch reamer (a high fidelity copy of the original Sharps LR match chamber from the 1870's)

Test Ammunition:
Starline 45-100 brass with flash-holes swaged to 0.060" from the normal 0.080"
Federal 150 Match Large Pistol Primers with over-primer paper-wad in primer pocket
100.0 grains of Swiss Fg
0.090" HDPE over-powder wad
Paul Jones Money Paper-patch Bullet cast in 16-1
Bullet patched to beginning of ogive
8 lb tracing paper; wet wrapped and hot plate dried

Wiping Implements:
3/8" flexible Delrin rod with a 45-cal, Tipton Nylon rifle bush screwed into the tip of the rod.
Wiping Solution: 9-to-1 distilled water and NAPA water-soluble cutting oil
Patches: 2.5" round flannel

All test rounds were shot off-the-bench using a quality front rest and rabbit-ear rear bag. The barrel was cooled back to ambient temperature using cold water blown down the bore before the next string of fire. If that wasn't done, the possibility of accumulated barrel heat skewing the test results was not an option this tester wanted to deal with. The cooled barrel's bore was wiped dry and then given the fouling control technique to be used for the next 10-shot string-of-fire commenced.

Three experimental treatments were used to see which wiping technique would produce the best accuracy at 100 yards for 10-shot groups as well as the best MV summary statistics.

Treatment 1:
One damp patch followed by 1 dry patch: Results: 2.1 MOA, MV = 1,311 fps, ES = 15

Treatment 2:
Two damp patches followed by 1 dry patch: Results: 1.1 MOA, MV = 1,332 fps, ES = 9

Treatment 3:
Two damp patches followed by mopping the chamber: Results: 1.6 MOA, MV = 1,325 fps, ES = 32

Treatment 1 had the poorest accuracy and the second best MV statistics. Treatment 2 had the best accuracy and best MV statistics while Treatment 3 had the second best accuracy, but the MV statistics were so bad that from the 1,000-yd line a shooter would be hating the moment if using that fouling control technique. There is no reason, from my experience to ever use Treatment 3 in a match even though the accuracy was OK at 100 yards. Chronographs are great tools to use for load development in my opinion.

As you can see from the results, the difference in bore conditions can have a substantial impact on accuracy as well as muzzle velocity variation even though the exact same load was used and the barrel was cooled between 10-shot strings-of-fire.

It should be said, in closing, that this test was done using paper-patch bullets. Grease-grooved bullets probably would have a different result if one ran a similar test. I've done quite a few such tests with grease-grooved bullets. The best accuracy from those tests was had with 2 wet patches followed by a bore moping. That fouling control technique produced the best accuracy and lowest MV statistics. Several top shooters have reported that same technique produces the best results when shooting grease-grooved bullets in long-range matches.
_________________
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semtav
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Re: Dans Posts

Post by semtav »

Bullet-to-bore Alignment

Greetings Gentlemen,

The topic of bullet-to-bore alignment has been cussed and discussed by a number of marksmen on this forum, who are interested in pushing the accuracy limits of BPCR's and ammo. As I've said on more than one occasion, achieving excellent bullet-to-bore alignment is one of the fundamental qualities upon which match-grade accuracy is built. If the bullet is not properly aligned to the bore, when the bullet bumps-up, the bumped-up portion will no longer be aligned with the non-bumped-up portion. The result of that phenomenon has been seen numerous times when pulling targets in BPCR Target Rifle matches over the years. The evidence of that phenomenon shows-up when bullets that should be stable produce oblong holes in targets. Typically, seating the bullet out further will help as well as shooting a bullet designed for the chamber from which it will be launched.

Years ago the idea of having a conic section instead of a bore-riding section, that matched a rifle's leade angle, germinated while having dinner with some work buddies down in Arlington, TX, back in the Fall of 1998. After a few attempts at "getting it right", one mold maker finally delivered a spectacularly precise mold. The conic section was 0.4580" long. It was 0.3160" at the end of the ogive and finished at 0.3230" before first grease groove. That conic section length is the same as a 1/2 degree leade-angle in a 0.3150l"/0.3230" (bore/groove) 32-cal barrel. The bullet shot very, very well, even when cast in Linotype. I have a picture of a recovered bullet somewhere. If I can find it, I'll post the picture. If one thinks about it, this design concept allows for shooting very hard alloys with no gas-cutting because the front of the chamber is very well sealed. That is not the case with most bullets/chambers. The bullet has an advanced elliptical nose that did not bump-up at all when shot with Linotype or Lyman # 2.

But, making conic sections in molds was a daunting task for mold-makers back then. Given the move to CNC mold making this particular design concept might need to be revisited. So, back in 2003 the idea of stepped driving bands, easy for mold makers to produce, that matched the leade angle came to mind. The design objective was for the leading edges of the stepped driving-bands to acted as a substitute for a conic section. The stepped driving-bands coupled with a tight-fitting bore-riding section work very well to optimize bullet-to-bore alignment for a given chamber front-end. So far, after a few learning-by-doing steps, the goal seems to be accomplished.

To see what this concept looks like; below is the picture of a portion of a 35-40 Maynard round that has been chambered and then extracted. Notice the even engraving on the stepped driving bands.



The bore-riding section was not specified "tight" because this bullet was designed to work with wiping or blow-tubing between shots. The bore-riding section is at bore diameter so there is no engraving on it. For a "wiping only" bullet the bore-riding section would be specified at 0.001" larger in diameter than the largest pin gauge that would fit in the breech just in front of the chamber, not the muzzle.

Here's a picture of the 35-40 Maynard round (necked-down 38-55 case) for your review. In my estimation it is the most efficient cartridge out there that can deliver high performance in silhouette and mid-range matches; given the rifle sports a 10-twist barrel, proper chamber and optimally designed bullet.


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I have no special talent. I am only passionately curious.
Albert Einstein
semtav
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Re: Dans Posts

Post by semtav »

Added thanks to Montana Charlie

Gents,

Here's a bit more detail about some alloys that have been tested for Brinell Hardness stability. The testing started just after returning from Raton 08. Each alloy tested was made from certified lead, tin and Lyman # 2 alloy. Considerable care was taken to make sure the testing was accurate and repeatable. Two other Brinell Hardness testers were used to calibrate the Lee tool that was used for the duration of the testing. All three tested the certified lead at BH 4.5, the tin at BH 5.0 and Lyman # 2 at 15.0. From these initial calibration tests I feel confident that the results I'm reporting are accurate and reflect the BH numbers properly. Some of the published BH numbers for lead-tin alloys is not accurate.

The testing, that lasted one year, was performed as follows:

First test was performed about 1 hour after casting the PP bullets for a given alloy.
For the first 24 hours the sample was tested every 6 hours.
For the next 6 days the alloy was tested every day at around noon.
For the next 51 weeks the alloy was tested every Monday at around noon.

Antimonial alloys tested:
Lyman # 2 (90/5.0/5.0) lead/tin/antimony
95.0 / 2.5 / 2.5
96.0 / 2.0 / 2.0
97.0 / 1.5 / 1.5
97.5 / 1.25 / 1.25
98.0 / 1.0 / 1.0

Lead-tin alloys tested:
20-1 & 16-1

One alloy was made with twice as much tin as antimony to determine what the stability characteristics are. That alloy was 97.0 % lead, 2.0 % tin and 1.0 % antimony. The alloy was very unstable. The takeaway from that alloy is don't mix an alloy with more tin than antimony.

The lead-tin alloys age-softened quickly. The 20-1 was completely age-softened 6 hours after casting and remained at that hardness, 7.8, for over a year. The 16-1 had a BH of 9.8 one hour after casting. At day 4 of the testing the BH was down to 8.2 and has remained at that hardness for over a year.

The 98.0 / 1.0 / 1.0 alloy and 20-1 have the same hardness. The 98.0 / 1.0 / 1.0 alloy took about 12 hours to completely age-harden to a BH of 7.8, the same as 20-1. The 97.5 / 1.25 / 1.25 alloy has the same BH as 16-1 and took 18 hours to completely age harden.

My favorite antimonial alloy is the 97.0 / 1.5 / 1.5, which has a BH of 9.8 and took 18 hours to completely age-harden. It has remained at that hardness for over one year. I have found that this alloy shoots very well in my 8-twist 8mm x 60mm Gredes, 10-twist 35-40 Maynard and in the various 10-twist 38-cals I have. This alloy also works very well for various PP loads.

Here are the mixing recipes:

lead/tin/antimony all by weight

97.0 / 1.5 / 1.5 : 7 parts lead + 3 parts Lyman # 2 : Density = 11.21 gm/cc
97.5 / 1.25 / 1.25 : 3 parts lead + 1 part Lyman # 2 : Density = 11.23 gm/cc
98.0 / 1.0 / 1.0 : 4 parts lead + 1 part Lyman # 2 : Density = 11.25 gm/cc
Density of 20-1 = 11.15 gm/cc
Density of 16-1 = 11.11 gm/cc

95/2.5/2.5 = 13.4 BHN
96/2.0./2.0 = 10.4 BHN
97/1.5/1.5 = 9.8 BHN
(97/1.25/1.25 = (probably) 8.2 BHN)
98/1.0/1.0 = 8.2 BHN (probably should say 7.8 BHN)


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SFogler
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Re: Dans Posts

Post by SFogler »

Semtav,
Thank you for your posts - I have gotten more out of your posts than all the "IMHO" posts combined. I like the "science" approach - gives me a better staring point and food for thought for my own shooting techniques. Please continue with whatever you want to post - it's all good.
art ruggiero
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Re: Dans Posts

Post by art ruggiero »

these are priceless, please don't delete art
semtav
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Re: Dans Posts

Post by semtav »

SFogler wrote:Semtav,
Thank you for your posts - I have gotten more out of your posts than all the "IMHO" posts combined. I like the "science" approach - gives me a better staring point and food for thought for my own shooting techniques. Please continue with whatever you want to post - it's all good.
SF.
Just so you know those are Dan Theodore's posts I saved over the years. Not mine.
Brian
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Re: Dans Posts

Post by Laowho »

Being new to BPCR I've pretty much defaulted over and over to reading and re-reading every bit of what I could find from DanT, even where it came to inferring what his subsequent Greek transpositions were saying. Figure in about a year I'll be able to really understand maybe half of what you've provided here. Thanks.
"Show the slightest preference for this or that, and heaven and earth become infinitely far apart."
Is it any accident that "Statute of Limitations" and "S**t Out of Luck" share the same acronym? I think not (therefore I am).
montana charlie
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Re: Dans Posts

Post by montana charlie »

This thread is intended to be a collection of information from the late Dan Theodore.
If what you have to contribute is about 'what you think of him', rather than 'what he said to you', I suggest you put it in a different thread.
Retired...twice. Now, raisin' cows and livin' on borrowed time...
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Re: Dans Posts

Post by Lumpy Grits »

Semtav-THANK YOU :!:
Hope we can get this thread 'pinned' when everything is up.
Respectfully,
Gary
"Hav'n you along, is like loose'n two good men"
John Boy
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Re: Dans Posts

Post by John Boy »

Technical Information link at bprc.net with many of Dan's writeups ...
http://www.bpcr.net/site_docs-results_s ... mation.htm
Regards
John
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Re: Dans Posts

Post by Lumpy Grits »

THANKS John Boy :!:
Gary
"Hav'n you along, is like loose'n two good men"
Kurt
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Re: Dans Posts

Post by Kurt »

Brian.

Here is one of Dans PM's to me I can post that is not rough :D
I might dig out some more that I have on external storage from a earlier time.

Sent: Fri Apr 03, 2009 12:14 pm
From: Anonymous
To: Kurt




Kurt wrote:
Good morning Dan.

I just been reading your reply on Ricks Ponderings?
I'm glad that your starting to see the light on my posts I have made here in the past starting from Nov.2002 when I first joined this Shiloh Site regarding the free bored chambers and using proper bullets patched to groove diameter and when you were just starting to make your long elliptical radius bullet designs using a harder alloy to support that long nose.

The first cartridge rifle I developed a match load for was a 45-90 Pedersoli with a 0.150" long, 0.460" diameter freebore. That rifle was used to shoot PP'ed bullets at the 2004 World Creedmoor Championships. The rifle/load combination worked very well, but the recoil was bad. It was a John Bodine rolling-block. I had bee loading and shooting a Pedersoli-Gibbs LR muzzleloader for a year or so previously as my first experimentation with PP'ing.

On these two subjects you gave me a lot of rhubarb's in the past even on the old BPCR site when I was using a different handle :lol: .

Humm...don't remember that, but I do remember posting that quite a few top shooters had tried knurled bullets and couldn't get them to shoot as well as regular GG bullets or the GG'less bullets several of us were shooting back then.

Keith Howell used a chamber back in the 90's with a 15 or 18 degree lead to a 3 degree lead with good results also for the .44 but I'm not sure if he ever did that for the .45.
But I'm glad your posting what your finding for the hard alloy and using Antimony in the mix.
And you will also find that a alloy as #2 will shoot great with a GG or PP if it is at groove diameter or just a little over..

So far I've found that too hard of an alloy will produce flyers in the current freebore PP chambered rifle. I did some testing last month with various, stabile lead/tin/antimony mixes as hard as Lyman # 2 at 15.4 BHN. The groups got better as the alloy got softer. An alloy with a BHN of 9.8 shot the best. As I've said there is a lot of misinformation about how hard lead-tin alloys are. An alloy that has a BHN of 9.8 is much harder than even 10-1. But, here's the really odd finding from back in 2004. The Pedersoli referenced above liked 50-1 the best. I tried numerous lead-tin and lead-tin-antimony alloys, but 50-1 out-shot all of them.

Keep up posting your findings it will help a lot of new and some of the older shooters from getting discouraged shooting these black powder rifles I been enjoying for 52 years now.

I just got a reamer ground fron using two chamber casts from two original Sharps rifles, one a 74 and the other was a #3 Creedmoor and the lead was a measured 5 degrees on both chambers.
I haven't decided yet if I will use that reamer for the new Shiloh or re barrel a 85 action yet.

Let me know how the rifle works out.

Kurt
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Kurt
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Re: Dans Posts

Post by Kurt »

Well that didn't come out right. His reply was in bolt letters answering me.
Oh well.

Kurt
The reason a dog has so many friends is because he wags his tail instead of his tongue.

"Socialism is a philosophy of failure, the creed of ignorance, and the gospel of envy, its inherent virtue is the equal sharing of misery"Winston Churchill
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