Of bullets and things

[semtav]

Since its too cold to shoot, i was sitting here mulling over life. Thinking maybe stirring the pot will warm me back up.
First question i keep coming up with is:

Why does everyone think a bullet expands into the transition area and then has to be swaged back down again as it goes into the rifling. ?

After picking up hundreds of grease groove bullets from around targets over the years, i see no indication of this happening.

[Distant Thunder]

To think a bullet would "expand" to fill the rifling and not "expand" to fill any other available space would be contradictory.

[DeadEye]

OK Brian I'll play, please help me with what you call the transition area? For my part I have always shot bore riding, GG bullets mostly Creedmoor and Postell from BACO. I always load to engrave half of the first full diameter band. Noses are .449. Yet recovered bullets show that the nose has expanded to be engraved by the rifling. Is that what you're getting at?

Paul

[semtav]

OK Brian I'll play, please help me with what you call the transition area?
Paul

I'm thinking of the area from the end of the case to the start of the rifling.

[Kurt]

Brian,

The gap between the end of the case and the standard 45º chamber end does have an effect o the bullet. The shorter the case the worse the damage is.
A GG can be set in the transition with the lube ring over that gap can protect the bullet and it will usually pass with out cutting a lead ring. I have spent a lot of time checking what the transition does to bullets because of the lead and paper rings I found. They are there and if you took the time carefully checking you will find them.
I could show you examples on bullets what that 45º transition can cause to the bullet shank if that gap opens up, but you need to give the case some room to move when the bullet gets sent down the barrel. I cut my unsized cases .005" of that transition and it seems to take care of most of the damage.
With a Bore diameter PP you can see the wrinkle mark if it's shot with the 45º chamber, some with very deep cuts.
With the 4º, 5º, 7º that damage is very minimal to almost none existent even if the case is short. I have looked at bullets shot with a .45-70 case in the .45-90 chamber with very slight signs of the transition something you will not get away with a 45º chamber end.

[semtav]

I just had a long reply typed out and just as I was finishing it my computer erased it, so maybe I'll retry tonight.

[Kurt]

I just had a long reply typed out and just as I was finishing it my computer erased it, so maybe I'll retry tonight.

It must be a MacBook Pro mine does that also from time to time. plus it has it's own idea what to print

[Woody]

My computer does the same and it's a HP loaded with Microsoft. Always when I am about to post a well thought out reply.

As for the lead rings. I have found actual lead rings in one 40-65 chamber. It's a lever gun and my cases were too short with the bullet properly crimped. Although very accurate, the lead ring was not very reassuring.

I always try to load so that at least half of a grease groove is exposed. This seems to work extremely well to prevent the lead rings from grease groove bullets. It also makes the exact length of the trimmed case less critical. As long as your case mouth falls within the grease groove, accuracy will not be affected to any measure-able degree.

Woody

[semtav]

Just an old laptop one of my pilots leaves in the office.

Now if I can remember where I was going!!!!

Brian,

The gap between the end of the case and the standard 45º chamber end does have an effect o the bullet. The shorter the case the worse the damage is.
A GG can be set in the transition with the lube ring over that gap can protect the bullet and it will usually pass with out cutting a lead ring. I have spent a lot of time checking what the transition does to bullets because of the lead and paper rings I found. They are there and if you took the time carefully checking you will find them.

That's kinda what got me to wondering.
I'm not a physics major or an engineer, but I can't picture the flowability of cold lead flowing in and out of that gap as the bullet moves past it.
I'm sure the softer the lead, the more chance some does wind up in there tho.
I was looking at bullets like the 457125 and that front band probably sat right in that gap . Was all that lead forced in and out of that gap as it accelerated

I know you did some tests with the DD bullet that showed the bullet didn't even bump up at all so.
So I'm wondering, at what hardeness do GG bullets that are already Groove dia just slide past that gap.

Lot more wonderings but I'll stop at that for a sec.
got to get to all those things Bruce says leads to leading yet too.
Only two more days of cold weather to get it all figured out !!

[bruce m]

i have had lead rings and paper rings with 45 degree transitions.
what made me aware of them was that the slivers come out on a patch when wiping.
that was before i learned to push patches through.
when i changed the 45 to 7 degrees that went away.
another giveaway is studying confetti.
if you don't get full length strips with base fold under attached watch out.
the bullet and patch have been forced inti the transition, then started to move, leaving a paper ring.
here is serious potential for leading.
using greasers i feel that putting the groove level with the case mouth, 1/2 out and 1/2 in works the best, but is no guarantee.
it is certainly one of those things to muck around with in your rifle with your ammo.
blowtubers might never notice lead rings.
bruce.

[bruce m]

further to the above, there is one way to avoid the issue.
do what the old dead guys did and also modern scheutzen guys do.
breech seat bullets.
using a breech seater you push the base of the bullet past the transition.
tuning the load with the airgap in front of a casefull of powder+wad can give accuracy unattainable with fixed ammo.
and all you need to do is droptube the powder..
of course this will take courage by some.
bruce.

[mdeland]

I have two 45-70s with the 45 degree transition angle and have never had rings of paper or lead appear when shooting my standard load of 74 grains of Swiss 1.5 or duplex loads. The softest alloy I have experimented with in GG bullets is 30-1.
I think Semtav may have a point as I doubt much expansion of bullet alloy occurs in the throat. At ignition the front of the powder column and wad cushion the bullet base as it throttles up into the throat and bore. Greatest pressure in the expansion ration in farther up bore when the whole bullet body is in the rifling.
If you measure the length of the transition plus say a .005 shorter case there is not much of a gap for lead or paper to extrude into to be sheared off. Also if you seat a GG bullet over the gap then a snow bullet should show some signs of lead expansion in the grease groove bottom if expansion in the throat is occurring. The grease supporting the groove would surly extrude into the gap and the lead would follow leaving signs of expansion in the grease groove bottom.
Also maximum pressure does not occur until several inches up bore when the whole powder column is ignited and the full bullet is in the rifling and full resistance is encountered.
I wonder if the rings aren't made or at least initiated from the sharp case mouth when seating bullets into them. They are usually snug enough at this point to hold a bullet firm to qualify as fixed ammo. Some are given a taper crimp.

[mdeland]

I just went out and measured the angle length plus .005 for case clearance length and my caliper shows it to be about .035 long, tapered gap. The depth would be around .010-.012 at the back of the taper that angles into the full throat diameter. Not much room for lead or paper to suddenly extrude into and be sheared off especially on a taper, if it is actually happening there.

[Kurt]

Brian,

Here is what is going on with the 45º chamber transition.
I don't have much with the GG bullets because I just don't like shooting them.
Most of my bullets I have looked at are mostly checking alloys and how they react with different loads and chambers.
Curiosity got me wondering what some of the effects on bullets with some of my cases that were a little short and the paper rings I was finding some stuck on the case mouth when extracting them from the chamber.
Some of the recovered PP bullets looked good but some had damage at the point just below the case mouth and most I find in this area just some slight wrinkles. The wrinkles are normal on just about every bullet, more than less.
I cut some cases a little short of the chamber and seated the bullets very deep in the case on purpose to see what the effect is with the short case and that 45º transition into the throat and I found the 10 test loads like the bullet below.
They all showed a ring some 1/8" long and deep where the lead got pushed back and this particular bullet picked up a lead or maybe a paper ring.
You can see the groove it left on the ogive.

IMG_0645.JPG

This bullet was shot with my .45-90 that has a chamber that was cut with my reamer that has a 5º/2º.30' compound transition (funnel type) and this bullet was loaded in a .45-70 case shot in the .45-90 chamber. The bullet was deep seated. If you expand this photo you can see a brighter patch but no wrinkle or strip groove.

IMG_0841 (2).jpg

This bullet was shot with my first .44-90 bn Shiloh that has a 45º chamber end but the case is .005" short of the chamber end. You can see a wrinkle but no damage to the shank and that's what a bullet will look like shot from a funnel type chamber.

IMG_3334.JPG

The .45º will turn out a smooth no damage bullet, but you have to get the case a proper length.
But even with a case that is only .005" short I have looked for paper rings and found some very thin rings and some thin rings stacked on top of several rings.

The only way you can get away from any signs of chamber ends is to breach seat a bullet like Bruce mentioned. But I just seat then at the end of the lead (but only in my 45º chamber ends because my funnel transition run at .243" deep) .003" over bore diameter. I like that diameter because of a good gas seal without needing a heavy wad stack for that job. A .023" card wad on the very end of the case mouth with a very slight roll crimp holding the wad so the light compressed powder don't spill.

[Kurt]

This is about all I can show you with the GG bullets.
These were sent to me with instructions how to load them and request shot from a standard chamber.

IMG_3278.JPG

IMG_1484.JPG