Handgun nose shape

[Brad]

Is some of that success because of exactly what Rick mentioned- long enough bearing surface to have the rear supported by the cylinder when the nose enters the rifling? The bullet is held in line with the bore just enough to let the cylinder move io alignment with the bore.
Having a moving chamber does change the dynamics some.

 

[Ian]

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.

Yep. With rifles we can use less neck tension, no crimp, slow powder, and often get the bullet to self-align with just the primer, but in a revolver the bullet accelerates so quickly out of the gate that if it's headed sideways, the alloy isn't strong enough to correct the direction of the bullet without getting crushed. How many bullets have we recovered with deep rifling marks on only one side of the nose???

 

[quicksylver]

Brad what also happened with your drawings is that the OAL of the bullet changed when you changed the angle..
I would suggest maintaining the OAL as shown in the drawing with the 20 degree nose..

Some visual clues..sorry they are a little crude

 

[Brad]

Those drawings help a bunch. Changing from 20 to 30 as we approach the nose gives an effect of making it a radius.

 

[Rick]

That's what I was trying to explain to you Brad. Keep the bearing surface length and the crimp groove in the same place, two angles on the ogive making the meplat smaller.

 

[fiver]

that is also what I was talking about.
the 30 at the bottom is the little roll that would align in the cylinder throats better.


I think Rick's explanation of the cylinder moving a titch to come closer in alignment is what happens.
you need some slop in a revolver to allow that to happen even with line bored cylinders drilled on center from the barrel end.

 

[Rick]

On a revolver with slop built into it the cylinder does need to center. This slop is quite intentional, when the machining isn't precise enough to have the center line of the chamber/throat line up perfectly if the cylinder is loose the bullet can do it. Plus I suspect powder gases exiting ahead of the bullet can paly a role there also. None of the FA's I've had or worked up loads for had any cylinder slop, not fore and aft or side to side. A properly timed revolver doesn't need it.

 

[Pistolero]

Yes, Rick, which is why the Colt hand-bolt lockup theory of revolver mechanisms is .....shall I say "less than wonderful"? If the cylinders are almost exactly lined
up at moment of firing, all is well - WHEN they are not, the bullet WILL align it, hammering the hand tip in the process, which is why
some Colts, IMO the ones with a bit of cyl hole machining error, will not hold time very long. Need that slop in the cylinder to launch
things "straightly".

Bill