autogun

Military Guns and Ammunition

Hosted by autogun

This is intended for people interested in the subject of military guns and their ammunition, with emphasis on automatic weapons.

  • 3213
    MEMBERS
  • 182531
    MESSAGES
  • 2
    POSTS TODAY

Discussions

Exploring The Design Space   Ammunition <20mm

Started 25/7/15 by NathanielF; 114634 views.
JPeelen

From: JPeelen

4-Jan

The details of balle D manufacture are shown in detail in the 1916 book Cartridge Manufacture by Douglas Hamiltion. Scans can be found on the Internet. 

Red7272

From: Red7272

4-Jan

Mr. T (MrT4) said:

By the way , what are the current projectile manufacturing options being utilized other than lathe-turned as demand for lead-free ammo increases? 

There are a variety of machines for making bolts and screws that could be adapted to the role. They aren't particularly fast but they are simple so a lot of them is practical. Investment casting, swaging and rolling are all options for finalising billets.

Mr. T (MrT4)

From: Mr. T (MrT4)

5-Jan

I downloaded the Hamiltons book and indeed process seems similar to that used to make certain types of bolts and screws. I was surprised when R.G.C. told me that they used to pull these bullets for long range high power comps, i never taught the bullet quality was even remotely high enough for match work.

My current project of subsonic .30 cal AP for .300BLK , that is complementary to the rifle i am making ,will initially be made with a lathe-turned bullets, will see if we can progress from there i am not to keen to go into ammo manufacturing i rather stick to guns.

nincomp

From: nincomp

5-Jan

Mr. T (MrT4) said...

By the way , what are the current projectile manufacturing options being utilized other than lathe-turned as demand for lead-free ammo increases? 

 

It is possible that they could be pressure formed to final shape. I don't know if the tolerances would be good enough.   Those machines are relatively big and expensive, but they tend to have massive output, sometimes several parts per second. 

Screw-making machines would work too.  Twenty years ago I worked in a factory that made pneumatic tire valves (schrader valves and others).  The brass bodies of those valves are shaped, through-drilled and threaded internally and externally.  Each of our linear machining stations could produce one of those bodies in under five seconds.  At that time, the most popular machine in the world for doing that was made by Rudi Hutt.  The front page of his website shows some of the things that his machining stations machine and assemble.  https://www.rudi-hutt.de/overview/?lang=en

  • Edited 05 January 2021 15:57  by  nincomp
Mr. T (MrT4)

From: Mr. T (MrT4)

5-Jan

Valve body is likely way more complex than bulllets , but 5seconds would be  long for a bullet ,modern CNC lathe turned .30 bullet is made in cca 7 seconds , Beside speed issues swiss type lathe needs fairly calibrated barstock that is being feed so material alone is way more expensive than the weight of the material used would sugest  

nincomp

From: nincomp

5-Jan

Mr. T (MrT4) said...

Valve body is likely way more complex than bulllets , but 5seconds would be  long for a bullet ,modern CNC lathe turned .30 bullet is made in cca 7 seconds , Beside speed issues swiss type lathe needs fairly calibrated barstock that is being feed so material alone is way more expensive than the weight of the material used would sugest  

Those particular machines performed something like 10 operations, and the cycle time was probably less than 5 seconds.  Maybe as little as 1 1/2.  It was a long time ago.  We had so much equipment I have forgotten the various cycle times.  Our plant made about 300,000 tire valves per day with a group of those machines.   Making bullets would be much faster.   Since the machining stations were linear, they could be made almost any length with any number of operations.  Although we had Swiss lathes and old multi-spindle screw machines, the linear machining stations were more cost effective.

Cold forming would be preferable.  If the tolerances could not be held tightly enough, cold forming to near net shape could be used prior to final machining.  The individual pieces would be held in collets that move from station to station.   This is how many of our parts were made.

Even though we used etched wire (for better rubber adhesion), the raw materials were not unusually expensive.  Our cost for a completed schrader valve assembly with molded rubber base,  spring-loaded valve core and screw-on cap was well under $0.20.  Most of the cost was materials.  Increasing brass prices is what finally caused that plant to shut down.  US OEM's thought we were kidding when we asked for a price increase to cover increased material costs.  In the end, Chinese made tire valves were selling for roughly the cost of our raw materials.

Red7272

From: Red7272

5-Jan

Mr. T (MrT4) said:

Valve body is likely way more complex than bulllets , but 5seconds would be  long for a bullet ,modern CNC lathe turned .30 bullet is made in cca 7 seconds , Beside speed issues swiss type lathe needs fairly calibrated barstock that is being feed so material alone is way more expensive than the weight of the material used would sugest  

Lathes are not the idea. Chop rod to the right weight billet, Press it into the correct shape and then run it between rollers for the final dimensions. The rollers are adjustable so accuracy should be a lot better than conventional bullet dies. Depending on how accurate the press dies are will dictate the finish of the ends, which will be the biggest issue for making projectiles that way.

TOP