Handgun nose shape

[fiver]

175 grains

this is a typical silhouette type bullet.
I have one super similar to it, only with a titch less lube groove capacity. [I couldn't get the one I have to upload a picture you could see or make sense out of]
I think it's also close to what Brad is talking about as far as nose shape.
it also has the 'hidden' drive band above the crimp groove and nose width and radius I was talking about earlier.
whether it would be the 'best' design or not I don't know, but it should hold things together out to 300 yds without too much trouble.

 

[Rick]

Your at 58% of bullet diameter in meplat, more than I would have liked to see on a target bullet but the paper hanging at 200 yards will tell all.

 

[fiver]

a little more streamlined nose would be a help [externally] but I think something like this could be made to fit the cylinder throats pretty well.
there has to be a decent balance between gun fitment and aerodynamics and a compromise is [I think] gonna be made between the two.

 

[Brad]

Compromise is the key. I can get more gun fitment, to use a Lamarism, with a wadcutters but it isn't gonna be pretty at 200. A long, streamlined nose is nice at 200 but that streamlined nose means I don't have throat alignment at ignition.
I tried to find a middle ground between the two. Proof will be getting the mould and seeing what the gun says.

 

[Tony]

I do not recall if I got this from his book or his website but Veral wrote that his ogival wadcutters were stable out to about 70 yards. The last time I checked his catalog online they were no where to be found.

 

[Rick]

a little more streamlined nose would be a help [externally] but I think something like this could be made to fit the cylinder throats pretty well. there has to be a decent balance between gun fitment and aerodynamics and a compromise is [I think] gonna be made between the two.

I agree, the question becomes as Brad has already asked - At what point in long range revolver shooting does it begin to act like a wadcutter? I don't think Brad is even close to that with this bullet but the paper will tell.
.

 

[Brad]

I don't think this bullet is even close either Rick. I considered a 30° angle but decided to stick with 20° as it is an angle that has been shown to work in other designs.
Keep the info coming guys. I'm learning more and more. The more I learn the less I know.

 

[Rick]

As you know I would have preferred a sharper nose and less meplat being a target bullet. It did come out with a pretty fair front driving band that will be inside the throat due to the placement of the crimp groove. Now it's wait and see, have I mentioned grip lately?

 

[Brad]

Oh, I have come to grip with you and grip.
I need to make a riser for the bench so I can get a bag under my wrists and to keep me from leaning forward so much. The club seems to like making benches for guys who are about 5'5" or shorter

 

[fiver]

you might be able to cheat the throat a bit and have the nose fit the throat of the barrel better.
we are still talking about cones within cones you just have one fitment here and another there a bit ahead.
if I had to choose one over the other I myself would prefer a smooth transition into the barrel.
the alignment there would pull the cylinder left/right/up/down slightly

 

[Rick]

The idea here is that the bearing surface of the bullet is long enough that when the front band is beginning to engrave in the barrel the rear of the bullet is still held straight in/by the throat. The longer the nose the more this is defeated.

 

[Brad]

Another issue is what I found from my pound cast. If the front bearing band isn't in the cylinder throats the bullet may be resting at a slight downward angle.
How do we beat ensure the bullet goes straight into the barrel? We make sure it is pointed there at ignition. Getting nose bearing in the throats is the best way to ensure a straight start.

 

[quicksylver]

Hi..reading this with interest...
I noticed the word "compromise"..I also noticed two different nose angle mentioned 20 & 30 degrees..
I also noted that the bullet in the above diagram has only one bevel to the nose..
Would it be unreasonable to suggest that the nose has two bevels...as a compromise ...say 30 deg. half way to
the metplat from the top of the top band and a 20 deg. from that point forward ?

 

[Brad]

I want to explain a bit where the talk of nose angles comes from. Rick wanted me to put as much full diameter nose as possible in the throat. Being a revolver there is a set limit to how long a nose can be forward of crimp groove.
I had a couple drawing made to show a 20° and 30° nose both with a .25 meplat.
Look at how much more squat the 30° nose looks. Think of how flat a 40° nose would be.
Advantage to steeper angle is that the tapered portion of the nose is shorter, with a common meplat diameter, so a longer bearing surface can be used. Disadvantage is that we have a much less aerodynamic shape.

My concern was going too steep on nose angle and getting wadcutter like behavior.

A rounded ogive, like LBT uses, is quite possible but can also lead to a reduction in the bearing surface Rick was looking to maximize. The compromise comes between aerodynamic shape and bearing surface. We are talking about a bullet with .485" from crimp to nose. How to maximize full diameter over that short distance yet have good long range potential. A shallower angle or smaller meplat means a longer tapered portion and a reduction in bearing surface in contact with the cylinder throat. That bearing was to be maximized.

Rounding surfaces would likely make things far better. Do we even need a flat meplat or could we make the nose elliptical?

 

[Rick]

quicksilver, I suggested those option's to Brad but he didn't seem to agree. I also suggested making the flat meplat radiused and that didn't happen either.

 

[Brad]

Rick, can you draw up what you would like to see? A rough drawing would help.
I will admit that some of my decisions were based on not having the software to draw up bullets and make compairisons in design. I did not want to keep asking Tom to change the drawing to factor in new features. I felt he had taken enough time from his schedule already.

I may but the software that Micheal uses to draw his RD bullets. It isn't horribly expensive and as they say a picture is worth a thousand words.....

 

[Ian]

Pens and ink are cheap. If you need something drawn up, Josh would probably be willing to it for you once, that way you could get the calculated CG and COP too.

I'd love to see some spark gap photos of some of these designs in flight. How much does the nose slug up in the throats when fired? Which alloy works best? Is it 18BHN htww launched with 296, and does that deform at all, or is it with AA1680 and 15 bhn annealed htww? Or 2400 and 20 bhn alloy? Does the addition of a little tin to WW help or hurt groups at long range in this application? How much (if any) does the nose shape change from being fired?

BTDT with rifles, I'm watching with interest from my armchair, not going down this slippery slope with handguns.

 

[fiver]

much of what we use in rifles also works in revolvers.

I have fought with chambering pistol rounds because of that little bit of space where the round transitions from the cylinder right into the throats too many times.
unfortunately it seems the harder I fight with them to chamber the better they shoot on paper.
my last go around with this was in my 357 mag Dan Wesson revolver.
I don't know why I bothered, it will shoot the 358477 in 38 special brass better than I can.

but I just had to go loading some 358091's that were powder coated in 357 cases then use my taper crimp die to keep rolling the front edge of the drive band until they would just barely thumb seat then I had to close and rotate the cylinder to press them the rest of the way home.
I do the same in my 41 Ruger hunter model except skip the powder coat.

I can drop a decent rnfp boolit in there with no problems because of it's nose shape and get close in short range accuracy, but it holds together better over distance.
the TC styles are a pretty good compromise between the 2 designs.
only if I were going to the trouble to design a boolit I would bulge out the base of the TC design to help fill that throat shape.
pre-slump it as it were. [like a rnfp design]
then slope it back into the straight line nose of the TC.
that should stop any damage to the bullet when fired, and still allow it to slide into the barrel easy enough.

if I were to buy software to design bullets again I'd get Tom Meyers stuff.

 

[Brad]

Tom's stuff is what I would buy.

Will be interesting to get the mould and see what fired bulets look like. How much slumping occurs.

Fiver, this is similar to a rifle. Think of a rifle with a very long straight freebore, no taper. This leads to a gap, then the leade. The bullet will have a good head of steam when it enters the rifling. Straight or crooked, it will likely stay the same on it's trip down the bore.

 

[fiver]

I tend to think of them that way.
but with a slightly adjustable piece about halfway down the throat.

my old black hawk in 41 caliber is about as loose and worn as a revolver can get and still be safe.
I had relegated it to jacketed loads and only with the XTP bullet on an 'as needed' basis.
I then tried a wad cutter design in it.
the square strong angles of the wadcutter apparently pulls everything into alignment and the thing shoots again.