Bullet swaging gear to Australia

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fgregorio

Guest
Hi all, who would be the right person to get in touch in order to ship me dies and presses?
I'm planning on having the dies coated with titanium nitride at my end (low friction coating).
My plan is a .308 hpbt 155gn with a base cavity.
Smaller static margin and lower base drag.
Appreciate your input.
Thank you
 
Call george ulrich and see if he can export. If not you can buy all your stuff from him then get it thru an exporter. Not sure what all you need but be prepared for a long wait.
 
Base cavity

There is a rotating low pressure vortex behind/ touching the tail of the projectile. Picture a rotating smoke ring with a lot of turbulence attached.
Base drag (caused by low pressure behind the tail that kind of sucks the projectile back like a suction cup) is a very important and relevant component of the total drag- as important as the frontal drag (at hyp vel directly related to the meplat area).
So this is the importance of a base cavity:
The boat tail reduces the size of that vortex due to the fact that the tail base area is smaller.
The base cavity sucks that vortex inside the body of the projectile through the tail thus further reducing base drag.
Added benefits:
the centre of gravity moves forward so increasing the stability factor, reducing the nose up attitude of the projectile in flight, reduced tip precession.
Final goal is to have a fully core filled ogive, secant design (von karmann ratio).
It takes balls to try a design like this and no bullet maker that I contacted has the will to do it because it breaks with the traditional designs where (for target shooting) the HPBT is the ultimate design.
So either some does it or I'll make my own in the very near future :)
Keep in mind that this is NOT NEW tech.
The US artillery has been doing this for aaagees to great results. A lot of shells use base cavity and/or base bleed.
... which means that the maths are well proven in this subject.
 
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It's been done buy custom bullet makers, not in 308 but 6mm for sure. There are pitfalls to the design but you can figure all that out on your own time and money. Did you ever notice that the military doesn't make any "bullets" with that design? Also, why would you want to take a perfectly good set of dies and get them coated?

I don't want to dampen your enthusiasm but a die maker is going to tell you right off the bat that if they make what you want, you're on your own if it doesn't preform to your expectations.


Bart
Barts Custom Bullets
 
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Thanks Bart,
The titanium nitride coating is a very low friction coating with a thickness of 0.1 thou and a vickers hardness coefficient 0f 2400 (stainless steel is 180 at most and iron is 80 at most). I use it extensively in titanium firing pins for example. So it combines low swaging friction with high durability.
I know the pitfals of the design. Also know it's potential.
I do research for your military and I'm aware of so. This type of projectile (HPBT) is prohibited by the Hague Convention and obviously NATO members do not use small arms projectiles that are hollow point.
Obviously as well, this base cavity design is not practical in a FMJ design with an open base. The FMJ design already has problems with lead sublimation (patent in the lead fouling present at the bore) from the tail at the time of ignition and expansion, so a base cavity would just make matters worse.

Bart, what would you consider to be the best swaging sequence? Is it practical to impart the boat tail and the base cavity simultaneously when sitting the core? Your input is most appreciated.


Thank you :)
 
Dusty Stevens said:
So are you just gonna use copper tubing for jackets? How do you form the base?
Click to expand...

Hey Dusty,
I haven't gotten that far yet :)
What do you suggest mate?
I reckon that the base cavity and the boat tail can be swaged in the same step.
 
fgregorio said:
Hi all, who would be the right person to get in touch in order to ship me dies and presses?
I'm planning on having the dies coated with titanium nitride at my end (low friction coating).
My plan is a .308 hpbt 155gn with a base cavity.
Smaller static margin and lower base drag.
Appreciate your input.
Thank you
Click to expand...

Many seasons ago - so long, I cannot recall when - I shot some 22 & 6mm caliber bullets which featured [what I call]
a base cavity; though of flat-base design, they shot quite well. The "cavity" was actually, more like a concave base - probably a domed point-up punch - not over 1/16Th" deep. The heels were sharp, and the "base-ring" (flat, around perimeter of base) about 1/16Th" wide. I also cannot recall the manufacturer - was it the Remington custom shop bullets?? Any help? :confused:

In my experience, while filling the jackets increases mass (the fastest path to BC), it reduces/erodes precision. Regarding "fill", for a given nose profile, there seems to be a tipping point where precision begins to diminish. Experimentation is GOOD! Do not let us discourage your efforts; just sharing info. Please keep us posted! :cool:

Every time a jacket comes up short, during point-up, and I place a piece of lead-wire between the base and punch, in order create false length, allowing for point closure, and ejection, I get a base cavity . . . and always think about obtaining punches to do it deliberately! ;) Good shootin'! RG

P.S. Please note, I incorrectly used convex :)() in my original post, thus, have corrected it!:eek:RG
 
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That is why I'm consulting the experts :)
BTW Bart, I'm very impressed with the track record of your work :)
That is very important info- so full filling the ogive deteriorates precision. What would be the ideal
filling?
 
I have made more than 100 BT point punches in 2015 with the convex portion built into the punch. I make them for many of my customers. Paul Sullivan and Jack Neary used this Bullet design at 2015 worlds group shoot and did fantastic. This design has some very good benefits. Furthermore, Wayne Campbell won it all with a convex BT punch that I made for him.


Jeff Peinhardt
Jeff@pr2racing.com
717-786-8321
 
StaMoly Jackets said:
I have made more than 100 BT point punches in 2015 with the convex portion built into the punch. I make them for many of my customers. Paul Sullivan and Jack Neary used this Bullet design at 2015 worlds group shoot and did fantastic. This design has some very good benefits. Furthermore, Wayne Campbell won it all with a convex BT punch that I made for him.


Jeff Peinhardt
Jeff@pr2racing.com
717-786-8321
Click to expand...

That punch can work. I think it's best attribute is it takes pressure off of sides of the bt punch. However you run the risk of breaking the core loose. You can make great bullets and some really bad ones if you don't know what you're doing. I shot beside Wayne the week prior at the Nationals and he shot some really nice groups and then he'd have a flyer from hell for no reason.

Bart
 
Shots from Hell...

Bart is correct with that statement in The Nationals.. There were certainly shots from Hell.

In this case though the culprit was just a barrel and set up that was not what I thought it would be in real world competition. Didn't get to test it enough at home before I left and it was intended to shoot the WBC. After arriving in St Louis and practicing with it a couple of days I realized I did not have what I thought I had. Was tight at times but not consistent.. Ended up shooting it in the Nationals and used another in the WBC w decent results. Same bullets were shot in both matches.

Hope this helps....
 
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