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pdshooter
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FW Mann's bullet diameter theories
Apr 7th, 2015 at 11:11pm
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Finished reading Mann's under-appreciated book on The Bullet's Flight. In it he advocates bore diameter lead bullets as better than groove or groove plus diameter for breach seated oor fixed ammo. Any advocates out there bor bore diameter lead bullets?
  
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shovel80
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Re: FW Mann's bullet diameter theories
Reply #1 - Apr 7th, 2015 at 11:18pm
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I've read mann's Book also, i need to read it again! Great Book!!

Terry
  

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Re: FW Mann's bullet diameter theories
Reply #2 - Apr 8th, 2015 at 6:20am
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Quote:
Finished reading Mann's under-appreciated book on The Bullet's Flight. In it he advocates bore diameter lead bullets as better than groove or groove plus diameter for breach seated oor fixed ammo. Any advocates out there bor bore diameter lead bullets?


Was he referring to black or smokeless in this case?

Rate of twist would be a factor ....
  

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Schuetzendave
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Re: FW Mann's bullet diameter theories
Reply #3 - Apr 8th, 2015 at 10:55am
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I have been extremely successful shooting breech seated bullets that are .002" wider than the groove-to-groove diameter for smokeless powder using 20:1 lead:tin alloys in precision cut rifled RKS choked barrels.

I also use the wider bullets for fixed BPCR shooting as well.

Bullets have to be tight enough to prevent gas cutting around the side of the bullet.

With a good bullet lube, wider bullets will not lead up my barrel. When Mann advocated bullets that were only groove-to-groove diameter it may have been due to the efficiency of the lubes he was using.
« Last Edit: Apr 8th, 2015 at 11:05am by Schuetzendave »  
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MartiniBelgian
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Re: FW Mann's bullet diameter theories
Reply #4 - Apr 8th, 2015 at 1:13pm
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Actually, Mann claimed that pure lead, bore diameter bullets shoot best - just a very small groove-dia part at the rear being enough with smokeless.  Hum...
  
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Re: FW Mann's bullet diameter theories
Reply #5 - Apr 8th, 2015 at 4:04pm
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I have always wanted to try it but a bore diameter mould is hard to come by and I am not into sizing.

JLouis
  

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Re: FW Mann's bullet diameter theories
Reply #6 - Apr 8th, 2015 at 5:07pm
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I have not shot any bore diameter grease groove bullets, but I do shoot a lot of bore diameter paper patched bullets.   

I think that, when using black powder, they are the same as using a grooved diameter grease grooved bullet.  Accuracy is has been very good when you consider the traditional equipment limitations, but I wouldn't bet the farm against some of these guys who are at the top of their game with modern equipment Smiley

Chris.
  
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Re: FW Mann's bullet diameter theories
Reply #7 - Apr 8th, 2015 at 6:25pm
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I've used the Mann bullet (2 diameter) in two different rifles.

1. My 38 cal slug gun. .368 bore x .376 groove. It's 20/1 and uses cross paper patches and I made the bore and groove portions of the bullet, .001 over on the bore and .002 on the groove with the patch material. The base band is .10 long. Over all length of the bullet is 1.035". Bore riding area is .60 lg. Shot with straight BP.

2. My 22 rf, BSed bullet. 30/1, no lube grooves. .56 lg with a .10 lg base band, .001 over groove. The .21 bore ride area is .0005 over bore. Shot smokeless.

Frank
  

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Re: FW Mann's bullet diameter theories
Reply #8 - Apr 8th, 2015 at 7:13pm
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Finished reading Mann's under-appreciated book on The Bullet's Flight.

You did finish the book? 
I got stuck last fall in a cabin with nothing else to do but read that book. No electricity, no internet, no phone, no TV, no nothing, no other books or magazines, not even wood to whittle. and nothing else to read. It rained cats and dogs and it was cold and miserable for several days. So i finished that book, too.
A few random comments: 
1. His experiments were not very organized or useful, many obvious questions were left unanswered, while others were answered ad nauseum. . He tried over and over things that he had proven himself,  such as the effect of bullet base and nose on accuracy, etc. 
2. Some of his experiments are simply imagined out of boredom or misplaced curiosity. He did not have any sort of system to try things, such as various degrees of bullet hardness, or various twist rates, or primer types, or lube types, or anything that a logical organized person with a penchant for experimentation would do. One hundred times i scratched my head asking myself why he did not try things that where screaming to be tried. . 
3. While i was very interested in the subject, and therefore i took the book to the cabin to read, just in case of bad weather, i soon lost enthusiasm. I can easily sum up the content of the book as this: make sure the bases of the bullets are nice and sharp and square, and try bore diameter bullets with black powder (as Mann suggests) and slightly larger than groove for smokeless loads (as H. Pope suggests). 
4. The book was the most tedious and boring piece of writing i have read in the more recent half of my life. It and the rain drove me to sleep every other page. This, while reading on a subject that interests me. 
5. This was easily the worst spent money among all my shooting related expenses.   
6. I will offer the book as a gift to my gunsmith, he deserves a good nap too.
  
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Re: FW Mann's bullet diameter theories
Reply #9 - Apr 8th, 2015 at 7:16pm
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MartiniBelgian wrote on Apr 8th, 2015 at 1:13pm:
Actually, Mann claimed that pure lead, bore diameter bullets shoot best - just a very small groove-dia part at the rear being enough with smokeless.  Hum...

False claim, he made. He tried very little else.
  
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Re: FW Mann's bullet diameter theories
Reply #10 - Apr 8th, 2015 at 7:39pm
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Mann's volume is what it is.  It IS basic research, exhausting sometimes to wade through because he included so much detail.

It is indeed sad that he died before he published more.
  

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Re: FW Mann's bullet diameter theories
Reply #11 - Apr 8th, 2015 at 8:00pm
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There is alot of important information being shared if one has an open mind to accept what is being passed on from his exaustive research. I found the money for the book welll spent in my case. His intent was to find the answers to the questions that he found constantly popping up in his mind in his search for the X Error. He wasn't per say doing research for the whimsy of others.
  

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Re: FW Mann's bullet diameter theories
Reply #12 - Apr 8th, 2015 at 8:53pm
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I've read through it a couple of times as I found it quite interesting.  I originally bought the digital version ( PDF file on a disc ) and then later bought a hard copy with H.M. Pope's handwritten notes in it.   Too bad his handwriting was so messy.  I haven't been able to decipher a lot of his comments Smiley Smiley

Chris.
  
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pdshooter
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Re: FW Mann's bullet diameter theories
Reply #13 - Apr 9th, 2015 at 8:38am
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I, too, read it at my house in the Black Hills with no TV. I found a few things of interest.

1. Imbalanced bullets were the major component of the elusive "x" error. Until we can cast in a vacuum or resort to swaging ,air pockets are going to be there.
2. Cast bullets without a gas check according to Mann should be limited to 1450 fps.
3. In his plank shooting experiments he determined that your bullets have to be closer than a half inch to be deflected by a plank parallel to the bullets path.
4. His experiments weren't broad enoudg to try different lubes. It took him many years to conduct the experiments as it was.
5. The experiments he conducted were done with Mr Leopold and Harry Pope's collaboration so he had two of the best advising him. In fact, Leopold told him to go with smoleless and forget black powder when Dr. Mann was in the middle of his research.
6. If you approach this book in which the spirit of research was conducted, I think you will find it interesting albeit a little tedious at times.
7. I would highly recommend reading it because if you only oick up one thing it will be very useful.

Dennis
  
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Re: FW Mann's bullet diameter theories
Reply #14 - Apr 9th, 2015 at 9:06pm
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Frank

"2. My 22 rf, BSed bullet. 30/1, no lube grooves. .56 lg with a .10 lg base band, .001 over groove. The .21 bore ride area is .0005 over bore. Shot smokeless."

"no lube grooves"  guess I missed something earlier,  how are you lubing them?

  

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