Super heavy .172" bore rider.
 

Has anyone tinkered with the idea of a super heavy .172"?

I copied one from a military ball ammunition example, in 4.6mm (.1815" ) using the Hornady 40gr fmj by turning it down to 4.3mm, or .172 with the front half of the bearing surface at .170".

It looks weird and I don't know if it will stabilize in a 1 in 9 at an estimated 2450fps from the original parent case converted to a .172"x30mm.

I just did it for grins. My 1 in 12 16".25" TC barrel in 223 is supposed to be incapable of stabilization of 69gr hpbt Sierras but it does it anyhow and ignored the calculation putting it at about .83 stab fact.

How long is it?

Aaron

Long
 

Compared to the 30 grain Kindler gold its still a fair bit bigger in length. 17.9mm

Holy smoke, I just ran the jbm calculator for stability and it came out 1.087.... wheels are spinning... H-4198.... I ran 30grain Kindlers up to 2980fps on a very compressed load out of my longer barrel... and without any severe pressure indications.

EDIT: This bullet weighes in at 36.4gr, still giving a 1.036 stability factor according to the JBM stability calculator.

I'm by far an expert but is'nt the bore .168"?

The Berger 37gr (BC .331) was ,855" long and needs a 1:6.5 barrel to stabilise

There must be some way to design an aero stabilized bullet. I am sure there must be some shape that will fly straight without spin. Larry

Depends on what you call straight.

What I was referring to is a design that will keep the bullet flying one end forward without spin, an aerodynamically stable bullet. Then impart some spin to keep it straight, any spin rate would do. Larry

I make a 37gr .172 bullet for my 1:71/4 twist 17-222.shoots very well.

Whats the BC on your 37gr? Could you post a picture of it?

Aaron

Chickenthief,

Yes, the lands are typically 0.168" I don't know what mine is, I do know that my chamber throat was rather odd shaped with an incline from a .1730" to 0.1724" for the first 0.03" then a 1.5° leade angle from there onward. The effect is that I can seat the GSC banded 17 and 19 grain solids that mic at 0.1730 on the tops of the bands with groves cut at 0.1695" is right into the case and right into this tapered throat and therefore it's practically ensured of a straight start. At 0.170" the front half of my heavily modified 4.6 now floats way up into the area about half way between the 0.1724" end of the throat and where the tops of the lands are encountered, it pretty much kisses this whole transition area for about 0.05" .

It sort of just eases in on the lands since there is only 0.001" difference in each side, maybe even less since the calipers are not precise enough for a 0.00001" measurement.

Larry, yes there is a way to get it to fly straight, put some feletching on it.

In my past life I had a little to do with MREV testing, they fly straight with no spin and no tumble.

Larry, what I was getting at was that yes there are designs that are relatively accurate; however what we (varmint shooters) consider accurate is beyond pie plate. Many muzzle loaders shoot fine with smooth bores, however they are not accurate enough. As you decrease the bullet size and/or increase the velocity this becomes amplified. Hence my comment of "it depends on what you consider accurate".

Satisfaction
 

I don't think that my goal of an 37+ grain bullet is going to happen, I guess I'll just be happy with the 30gr Golds from Todd Kindler which shoot beautifully.

Some years back , I heard of a 1000 Yard Benchrest shooter who was making very heavy bullets in 17 Caliber for competing at 1000 Yards in Pennsylvania . I hesitate to say the bullet weight because it sounded incredible . The Bullets were not Lead , and I don't remember the exact details . Maybe someone can calculate what Tungsten Bullets would weigh . Anyway , you might want to search 1000 Yard Gun Clubs in the Williamsport Pa. area , contact them , and try to track down more information .

It isn't normal bullet design, but if you can shift more weight to the front of the bullet it will not try to swap ends as much with less twist. I have seen where some have had long for caliber bullet stabilize using lighter weight core material in the rear of the jacket and lead in the front.

Yes, I know one of the custom makers would put a plastic bead in the jacket under the lead core to get the weight forward. Larry

Did you ever shoot any? How did they work? I can make the bullets.

I have made a few in 224. They shot ok, but not as well as a all lead cored bullet. However I must say that I didn't make or shoot many or try any different core materials. The balls must be perfectly centered in the jacket and preferably compress into a cylinder, some of the balls have some spring back. Powdered cores would also be worth a try.

I've made bullets with powdered cores before. W mainly for increased weight in the .17's and .14's without increase in length. More trouble than it is worth for my application. I've thought about the powdered copper/tin but again more trouble than value. The plastic ball idea is interesting to ponder, but again I never saw much value to it, however if there is a clear proof it may be worth a re-consideration.

I agree with your comments on the powdered metal. I've used the copper/tin before and it can make accurate light for length bullets, but making them in a hand press is time consuming.

Obtain a copy of RIFLE ACCURACY FACTS, by Harold Vaughn. Good shootin'!
RG

I'll borrow it if anyone has it available.

Heavy cast .172 bullets.
 

Someone listened!

http://noebulletmolds.com/photos/alb..._gr_Sketch.Jpg

http://noebulletmolds.com/NV/index.p...3tiq9labcqk9o7

Stability
Input Data
Caliber: 0.172 in Bullet Weight: 32.0 gr
Bullet Length: 0.559 in Plastic Tip Length: 0.000 in
Muzzle Velocity: 1200.0 ft/s Barrel Twist: 9.0 in
Temperature: 59.0 °F Pressure: 29.92 in Hg
Output Data
Stability: 1.390
11-Feb-16 16:27, JBM/jbmstab-5.1.cgi

Hi has any one used this mold . I would be very interested in a light load in my 17 sq. for small game hunting .

Bore rider
 

I have not used this mold but I'd suggest a lot harder lead than wheel weights. At a minimum of Lyman Number 2 hardness.

Bore rider
 

Interesting. Would you share your MV and load I cast and will have a 17-222 soon.

32grain NOE subsonic
 

Update: The N.O.E. 32grain, it is just fine for even subsonic velocity. It behaves similarly to the 60 grain Aguila SSS. In pure or almost pure lead format, it does this when fired into dry sand at approximately 1000 fps from a 1 turn in 9 inch twist. I also have a 1 turn in 10 inch twist to test with for stability.

http://www.saubier.com/forum/picture...&pictureid=446

Loads 1.2gr 700x to 1.8gr 700x, in 0.2gr steps, they shot just fine, @25yds., velocities of 1006 fps to just below 1300fps. They do deposit a bit of lead in the first few inches of the bore, so these loads require additional attention to bore cleaning. There was absolutely no tumbling with a 1 turn in 9 inch twist for this projectile.

http://www.saubier.com/forum/picture...&pictureid=441

http://www.saubier.com/forum/picture...&pictureid=450


http://www.saubier.com/forum/picture...&pictureid=459

Update:
I used the new digital scale to load up nine of these 32.9grain with 1.06 grains of Hi-Skor700X. Fired out of the 18.75" barrel they make a nice straight hole through 8 inches of gelatine after punching through a tin can and still has enough energy for breaking through three inches of packed topsoil. This load sounds quieter than my old 5mm air pistol.

What is strange is that the 1.06 grain powder charge manages to make the rifle kick a tiny bit, but wow is it quiet.

32 grain NOE medicine
 

Well, here is the end of one lawn cratering root ripping armadillo.
http://www.saubier.com/forum/picture...&pictureid=463
http://www.saubier.com/forum/picture...&pictureid=464
Range was about 20 feet using a subsonic 1020fps load of 1.10 grain High-Skor 700X under the 32g (32.92 grain actual weight as cast from nearly pure lead). Entry on opposite side, just a tiny hole but blood every where.

Why not change to the harder Lyman #2 alloy? I suspect if you have leading in the leade your pressure and accuracy will suffer, vs a harder alloy.

Are you loading them as-cast, or do you have a sizing die?

Looks like a fun project, I need to get back into casting this fall.

Thanks for the update

Allen

Leading is a non issue as it only is fired with these projectiles when there is an armadillo that is causing problems. Three or four rounds a night is max, and I still have plenty of those nearly pure lead projectiles. A harder alloy would be nice and it would allow higher velocities, yet when I want a quiet tool for dispatching armadillos pure lead is hard to beat.

100 yards .172"
 

Right at 48.5 to 49 grains for a bullet with the same volumetric capacity as the 30gr Kindler Gold.

That might give about a .430 to .435 BC as compared to the .270 BC of the 30gr Kindler BTHP.

After considering the difficulties in production of the projectiles, barrel life loss and other unknowns, I don't know if the effort would be worth it, but it sure would/could produce an "out of bounds" performance enhancement for a .172 caliber weapon in terms of ballistic efficiency and penetration. If you could extrapolate the velocity loss due to the super heavy bullet and use the exact right powder in a long enough barrel, the mass difference between a 30gr and a 48.5gr bullet might cause a velocity drop by as much as 1000feet per second. If that were true, and that is a lot of "IF", then you might get the following:

JBM Stability calculator

Stability input data:

Caliber: 0.172 in Bullet Weight: 48.5 gr
Bullet Length: 0.663 in Plastic Tip Length: 0.000 in
Muzzle Velocity: 2700.0 ft/s Barrel Twist: 9.0 in
Temperature: 59.0 °F Pressure: 29.92 in Hg

Output Data: Stability: 1.688

Barrel life on the other hand..... ehhhh,... probably not so enhanced. I think it would be very expensive in terms of accelerated barrel erosion.

You would obviously be much better off in terms of barrel life, component availability (bullets especially) by just using a .223" Rem IMP or .22PPC with an 80gr Berger.

Now, put that same projectile in a 6mm or 6.5mm sabot and fire it out of a rifle length barrel, and you would get a sort of super enhanced 6.5 x25mm CBJ.

I guess you could use something like this on those up armored prairie dogs when they charge your shooting position.

http://www.gotavapen.se/gota/sale/q/cbj_lmg603.jpg

http://airbornecombatengineer.typepa...5cbjcomp_2.jpg
http://airbornecombatengineer.typepa...5cbjcomp_2.jpg

http://www.gotavapen.se/gota/cbj/soap_proj1280.jpg

http://www.gotavapen.se/gota/cbj/soap_proj1280.jpg

http://www.thefirearmblog.com/blog/w...000851-tfb.jpg

http://www.cbjtech.com/dokument/6.5x...%20gelatin.pdf

http://www.cbjtech.com/sida.asp?sida=3_7.62%20CBJ