From: none@none.com99   
      
   On 5/18/2025 10:05 AM, Jim Wilkins wrote:   
   > BP wrote in message news:100d0r8$12ddo$1@dont-email.me...   
   >   
   > Jim Wilkins  wrote:   
   >>   
   >> Around the time of the US Civil War military barrels were rolled out from   
   >> short thick blanks over a mandrel, then drilled to size, rifled and   
   >> straightened by expert hands.   
   >   
   > At least superficially the DOM process could combine drilling, rifling   
   > and straightening steps into one, or at worst two, using nearly identical   
   > machinery. What am I missing? Is the problem a too-small final ID?   
   >   
   > It does occur to me that the pull strength of the internal mandrel grows   
   > as the square of the diameter, while the pull force likely grows linearly   
   > with the circumference. I suppose that would set a lower bore limit....   
   >   
   > Thanks for writing,   
   >   
   > bob prohaska   
   >   
   > -------------------------------------   
   > What you are missing may be proprietary trade secrets concerning the   
   > relative strengths and weaknesses of hammer forging, button rifling and   
   > drawing over a mandrel, all of which are similar. I suspect the fittest   
   > survived.   
   There is definitely a certain amount of derogatory push back against the   
   un-anointed in the firearms industry.  I have two books on gunsmithing.   
   titles Basic and Advanced.  Both authors spend the first chapter ranting   
   about cleanliness and organization.  In other chapters they get into   
   painstaking detail about it taking away from the main topic as well.   
   Then they talk about things like heat treating either in mysticism that   
   can't be shared with somebody who had to buy a book, or in very advanced   
   technical terms and advanced general material formulas intended to weed   
   out and actively shun those who just want a reliable recipe.  My college   
   math ended with Finite Mathematics (supposedly Calc for finite sets of   
   data primarily for programmers and data analysts).  This left me   
   struggling with most of it without asking my son who could easily teach   
   calc and has tutored many other students.   
      
   The thing is a lot of things can be figured out in reverse.  If you   
   don't mind marking up some guns you can use tools as simple as a set of   
   hardness files to get a ball park for the hardness of a part.  Reliable   
   recipes for hardening various alloys are as close as your cellphone.  If   
   you aren't wildcatting hot loads you can build a safe firearm by working   
   backwards and ignoring the fat ugly old wannabe gun bunnies who worship   
   at the alter of the anointed and deride any who dare to learn.   
      
   Okay, that was a bit harsh.  There are some great guys in the industry,   
   but most just don't respond when you ask modestly technical questions.   
   They may know the answer you seek, but they just don't say anything.   
   You can always get a bunch of people to tell you how stupid you are when   
   you just say what you plan to do, but unlike other topics giving the   
   wrong answer on the Internet doesn't usually illicit the right answer.   
      
   There are a couple guys on the gunsmith section on Home Shop Machinist   
   that are helpful if they can be, but answers to hard questions sometimes   
   end with, "Well you should build a gun for a low pressure cartridge   
   instead."   
      
      
      
   --   
   Bob La Londe   
   CNC Molds N Stuff   
      
   --   
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    * Origin: you cannot sedate... all the things you hate (1:229/2)