Of bullets and things

[semtav]

Kurt
That last picture is exactly what i would expect to see from a bullet that was being swaged thru a gap. What alloy was it?

[semtav]

Looks like that bullet second from the right is the perfect alloy if they're all different

[bruce m]

yes brian it does.
and was cast to good dimensions.
if 3rd from right is the same bullet, it illustrates my point about how the paul jones creedmoor looks like a better design that has set back the nose excessively.
bruce.

[beltfed]

It is notable on how those GG bullets collapsed the grease grooves as they set back
The third from the right also looks like the base "took a hit" and is now not "square" to the bullet .
must be very soft lead /tin alloy
beltfed/arnie

[Kurt]

Looks like that bullet second from the right is the perfect alloy if they're all different

Brian I would have to go from memory. Those photos they are old and have been cropped and the date stamp is gone. The full photo's are someplace in a bunch of hard drive storage if they were not lost with the blue screen the last computer.
But all of those bullets were cast with the same mould. The first on the left is unfired.
But the second from the right is what my mix of lead, tin and antimony would look like.

The last PP is a bullet shot from my tight chambered .40-65 with a 5º/2.5º compound transition and that chamber will not except a .404 diameter patched bullet seated in a starling case. It was cast with 18# lead and one roll of no lead 95/5 solder (95% tin 5% Antimony)

[semtav]

It is notable on how those GG bullets collapsed the grease grooves as they set back

beltfed/arnie

Would you say they collapsed or did flowing in and out of the transition gap cause it? Until we know how deep they were seated we dont know.
The two bullets above it look like they were seated shallow and only the lower portion was drug across the transition gap. If one wants to make that argument.

[semtav]

Mike you're starting to make sense I'm not sure if that's scary or what ?

[Kurt]

Going through some of my files I have to make a correction.

The bullet in IMG-0841 was not shot using a .45-70 case in the .45-90 chamber.
It was fired loaded in the .44-75 Ballard case and shot in the .44-100 Rem chamber.

Seeing collapsed GG is common. Also seeing GG with rolled back trailing edges.

Also I seen bases pushed farther in on one side and cutting the bullet in halve there was what looked like dross close to the base.

[mdeland]

A couple more possibly lucid thoughts I had on the transition angle : The angle being cut at 45 degrees in the chamber and the case mouth chamfer cut at 60 included ( 30 degrees acute per side) inside and out. means the gap can be snugged up considerably without the mouth being constricted from the transition angle. The 30 degree angle on the outside of the case mouth chamfer going up against the 45 degree transition angle means the gap angle difference of 15 degrees closes the length to a very small amount if fit well.
I'm wondering if it is the case mouth inside chamfer is where the lead ring is extruded into then swaged back as it inters the rifling or perhaps inward mouth peening from tumbling that is making the rings occasionally ?
It's hard for me to visualize the 45 degree transition angle causing any shear to paper or lead. It's on an angle not a square shoulder edge.

[Kurt]

Mike,

I only chamfer the inside of my cases and only if they need it.

This is a borescope photo of my .50-2.5 chamber and it has the 45º transition. This rifle has been shot 23K before I lost track with the first primer shortages several years back. I would guess it has better than 25 K rounds through it.
That shiny strip you see is front of where the case would be against the 45º. If you look close the wash of the rounds going off has eroded the front of the case making it deeper than the chamber wall. My cases are .005" short of the 45º that makes it a very thin gap the paper or lead to get sliced off the bullet shank, but it large enough that it does.
That photo is a 24X magnification scope.

bore 1.jpg

[Kurt]

It is notable on how those GG bullets collapsed the grease grooves as they set back

beltfed/arnie

Would you say they collapsed or did flowing in and out of the transition gap cause it? Until we know how deep they were seated we dont know.
The two bullets above it look like they were seated shallow and only the lower portion was drug across the transition gap. If one wants to make that argument.

Brian,

Look at the unfired bullet. You can see the ring where the ogive meets the shank. Below that line it's groove diameter and that line would be where the bullet makes contact with the lead.

[bruce m]

i still believe 45 degrees transitions causes lead and paper rings in cartridges loaded with black powder.
this statement is based mostly on swiss powder as that is mostly what is available here.
the fact that they just went away when altering 45 degrees to 7 degrees speaks for itself.
it seems that 45 degrees is steep enough to shear alloy or paper that has bumped into the gap between the 45 angle and the front of the case.
when you think about it, if a bullet can bump into the corners of the rifling well enough to form a perfect gas seal quickly enough to do that, it can also bump into the transition gap.
many people have success with the 45/70.
could this in part be that the 45/70 has a 12 degree transition.
possibly 12 degrees is the steepest angle that will not shear bullets.
it is also a greaser chamber the type of bullets most used.
i took a chamber cast of an original hepburn 40/70 and it was more like a 4 degree transition, certainly a lower angle than my 7 degree reamer.
these guns in that chambering were known to be virtually idiot proof in the day for mid range and hunting.
we can minimize bumpup with harder alloys, but the old dead guys used 10:1 to 14:1 in long range rifles using only a card wad.
the wad offered no seal as it was bore diameter.
this left the bullet to make the gas seal.
to get an effective gas seal the bullet must bump up instantly.
my own study of patches has shown no black marks on paper.
and bullets recovered hav looked dead smooth on the sides from the 7 degree transition.
bruce.

[semtav]

Kurt
the two GG bullets pictured together are what intrigue me. That is very similiar to the bullet I am currently working with.
It has 3 bore dia bands, and 3 groove dia bands.
Noticing how the bottom three bands are deformed much more than the top three,
One could make a couple assumptions based on that picture and either could be right or wrong.

1. the bottom three bands were seated in the case and their flowing into the transition gap is what cause the deformation of the lead into the grooves.

2. Because the bottom three bands are larger diameter, one would see more deformation just going down the barrel.

the only way to answer which is correct, is to shoot them in a rifle with no freebore, and shoot them in a rifle with enough freebore to allow the third band to rest in the freebore and beyond the transition gap. Studying their differences would likely give you some indication of which is causing the deformation of the bands.

[mdeland]

Bruce,I don't believe that is correct, that the bump up is instantaneous or complete in the throat. When a bullet or slug is driven up bore with a rod and mallet it will enter the throat and rifling most of the length before it get really hard to drive it farther. When it is fully engaged in the rifling it will often stick fast and need to be melted out if the bore is not pre- lubed. Each blow of the hammer bumps it up more thoroughly into the groove corners duplicating pretty closely what is happen when the light comes on.
Perhaps a good way to test this theory or at least get an idea about it is drill open the base of a case with the normal mouth chamfer (leaving the head and rim intact)insert a bullet and wad normally used through the head (as in breech seating) and drive it up into the bore with a rod, remove the case, bump it back out and see if it expands into the transition angle. If it mic's larger than the mouth diameter than it expanded into the transition.
I'm thinking it may be the interior chamfer angle on the case mouth causing the rings instead of the tapered transition.
The inside taper angle on the case mouth chamfer is directly opposite of the angle on the chamber transition and would set up a shoulder to be sheared.

[mdeland]

I meant to say if it mic's larger or show shear than the outside case diameter at the mouth than it expanded into the transition.