Brainstorming a light .30 cal. plinker

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  • Last Post 01 February 2014
Ed Harris posted this 28 January 2014

Interesting discussion here:

http://castboolits.gunloads.com/showthread.php?226399-HM2-light-30-cal-plinker-6-cav>http://castboolits.gunloads.com/showthread.php?226399-HM2-light-30-cal-plinker-6-cav

I'd really like to see this “fly.” Look over the thread and comment, either here or over there.

If interested in one of these molds please click on the link above and note your interest, because JT needs 20 orders to go ahead on the tool.  Six-cavity blocks to fit RCBS handles will be $125.

SEE REVISED DRAWINGS FARTHER DOWN THE THREAD!!

73 de KE4SKY In Home Mix We Trust From the Home of Ed's Red in "Almost Heaven" West Virginia

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mckg posted this 28 January 2014

I was wondering where they got the idea of a bevel base ;).

Would a “groove ride” ogive be detrimental in any application? Do acp's have a short throat?

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onondaga posted this 28 January 2014

Ed,

 I like the design drawing you present. The bevel base is practical for the intended use as a low velocity small game bullet. The bevel also aids ease in starting to seat  bullets when loading. The light weight and flat nose size are right there for small game too.

I do have a favorite I use in 7.62x39 for small game and I shoot it at 1160 fps with H TiteGroup. The little Lee TL314-90-SWC is bevel based also and has a small flat nose along with tumble lube grooves. It is a 32 cal. pistol bullet but is easily sized in the Lee push through bullet sizing dies for 30 cal. light small game hunting. I cast it in Lyman #2 alloy and have also tried it is soft pistol range scrap that tests BHN 7 to 8.

The softer bullets are not as accurate in my application as the #2 alloy. I didn't think it would make a difference at 1160 fps but the #2 alloy bullets group much better from my Remington Spartan 7.62X39 single shot rifle with a 24” chrome lined barrel. I get consistent .600” or less groups at 50 yards with the little  Lee 90 gr SWC bullet and 2.9 gr H TiteGroup. I have taken chipmunks, squirrels, woodchuck, and snapping turtles with the load easily out to 50 yards. For my particular rifle I size the bullets at .3125".

The new design looks as it would load and  perform equally and it has a better,  larger flat nose that will punch game harder.

The bearing area of the Lee bullet is much longer than the design you present and the Lee bullet is lighter, but it shoots fine for me. I'm not sure if the length of the bearing area is all that significant to accuracy, but I get ample accuracy and power at 50 yards  for small game hunting with the Lee 90 gr SWC in my rifle. My squirrel load:

http://s30.photobucket.com/user/rhymeswithwhat/media/6grTiteGroup.jpg.html>

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Ed Harris posted this 28 January 2014

mckg wrote: I was wondering where they got the idea of a bevel base ;).  Would a “groove ride” ogive be detrimental in any application? Do acp's have a short throat? Bevel base helps to mitigate the mid-body bulge you get in .32 ACP when loading bullets having a longer shank length than the factory 71 FMJ, where the base would start to impinge against the case wall where it starts to thicken.

Most .30 and .32 autopistols, .32 ACP, .30 Luger, .30 Mauser and 7.62x25 all have short throats or no throats, but simply a short angled transition into the rifling origin, so you can't chamber a groove diameter ogive.

73 de KE4SKY In Home Mix We Trust From the Home of Ed's Red in "Almost Heaven" West Virginia

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Ed Harris posted this 28 January 2014

onondaga wrote: ......I get consistent .600” or less groups at 50 yards with the little  Lee 90 gr SWC bullet and 2.9 gr H TiteGroup. I have taken chipmunks, squirrels, woodchuck, and snapping turtles with the load easily out to 50 yards. For my particular rifle I size the bullets at .3125". The new design looks as it would load and  perform equally and it has a better,  larger flat nose that will punch game harder.

The bearing area of the Lee bullet is much longer than the design you present and the Lee bullet is lighter, but it shoots fine for me. I'm not sure if the length of the bearing area is all that significant to accuracy, but I get ample accuracy and power at 50 yards  for small game hunting with the Lee 90 gr SWC in my rifle... In an ideal world, the bearing length for a pistol bullet should not be less than the bullet's diameter, but if the diameter of the bore-riding forepart is larger than bore diameter, to take the rifling even slightly, this helps to keep the bullet aligned in the bore.  In this case the bearing length, including the lube groove, is less only about 0.25", than a caliber, and would be considered marginal, except knowing the intent is for very light loads it “should” work, if cast of suitably strong alloy for its intended application and not over-driven.

I expect it should work very well in subsonic rifle loads and in the .32 ACP.  In the 7.62x25 it will be necessary to use hard alloys, such as quenched wheelweights, given the higher velocity and pressure of that round, but my hope is that it will at least perform to “ball ammo plinking” standards with charges which would cycle my CZ52.   

In rifle bullets, or handgun bullets driven at higher velocities, you really want the portion of the bullet which actually engraved by the rifling to be 1.5 calibers or greater.  When the bullet is very light for its caliber, such as this one, and when  it also must be used in cartridges having a short neck, such as the 7.62x25 or of small powder capacity, such as the .32 ACP, where it is necessary to limit intrusion of the bullet into the powder space to the minimum necessary, you must keep the shank short, but compensate by enlarging the bore-riding portion to the extent you can and still fit typical short auto pistol throats, and get what additional guidance you can off the nose.  This design is an attempt to compromise all those factors.      

73 de KE4SKY In Home Mix We Trust From the Home of Ed's Red in "Almost Heaven" West Virginia

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onondaga posted this 28 January 2014

ED,  I did test the Lee bullet in my rifle with zero bullet lubrication and both my alloys as you suggested to try at my velocity of 1160 fps.  The 50 yard groups opened to 1.125” and I had no noticeable leading using a BoreSnake dry and pulled through the bore once every 5 rounds as is my usual bench shooting routine with all cast bullets .

The 45:45:10 tumble lube makes an accuracy improvement difference in my application, 1.125” down to .600” at 50 yards with tumble lube versus none.

Gary

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mckg posted this 28 January 2014

Thanks Ed!

Gary, did you detect vertical stringing without lube, and/or greater speed spread?

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onondaga posted this 28 January 2014

http://castbulletassoc.org/view_user.php?id=7169>mckg

I had general dispersion increase only noted and no identifiable vertical dispersion was noted in 5 groups of 5 shots for each alloy with zero lube.

Gary

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mckg posted this 29 January 2014

Thanks Gary!

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Ed Harris posted this 30 January 2014

THIS is the MINIMUM weight, conventional plain-based version which will run 91-grains in wheelweights.  It is 0.500” long and useable in .30 Luger, .32 ACP, 7.62x25, .32-20, etc. and is shown in the drawing below.  This is as short and light as the tool will go.

JT can run the same tool deeper into the cavity to get bullets which are incrementally longer and heavier.  The full-width of the plain base band, is 0.100” which provides a 0.530” bullet length, for a conventional “Cowboy” style bullet for the .32 H&R Magnum or .32-20 weighing about 110 grains in wheelweights.  JT could add an 8 degree bevel base of any length and weight in increments of 0.030” up to the full 0.68” bullet length with 0.150” boattail and 125 grains shown in the other drawing posted farther below. 

He can also run larger diameter. 315-.316” for .32 S&W Long, 7.62x39, .303 Brit. , etc.

73 de KE4SKY In Home Mix We Trust From the Home of Ed's Red in "Almost Heaven" West Virginia

Ed Harris posted this 01 February 2014

The drawing below is the MAXIMUM length and weight that JT's the tool will cut. The "FULL LENGTH” bullet pictured is 0.68” long, weighing 125 grains in wheelweights. Its 8 degree boatttail is 0.150” long and at full length accepts a .30 cal. GC seated and crimped in the normal manner for high velocity use.  When used without a GC, the boattail design provides smoother aerodynamics than a conventional GC heel when used without the GC.   

73 de KE4SKY In Home Mix We Trust From the Home of Ed's Red in "Almost Heaven" West Virginia

Vassal posted this 01 February 2014

Boy the light version with dual FP and HP pins would be nice,,,     I guess this buy is limited to 6 cavity molds,,?

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Ed Harris posted this 01 February 2014

The current group buy is for 6-cavity molds. JT is not doing HPs, but you should be able to send a set of blocks to Erik and get some of the cavities converted. I'm thinking of doing just that.

73 de KE4SKY In Home Mix We Trust From the Home of Ed's Red in "Almost Heaven" West Virginia

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