Advice: Lead alloy and bhn

[popper]

My SuperHard (BHN) coated PB did fine but who needs 29 BHN at the target. Save the use of GC? It was 4% Sb and 2 % Cu H.T.'d

 

[Bret4207]

Different levels of ductility with strength, temperature and pressure softening that "hardcast", lube that maybe isn't really lube...LOVE IT! Thanks guys! I've read it but I'm going to have to re-read it all a few dozen time I think.

Nice picture of base riveting Ian and I'm happy to see "smushing" is the accurate scientific term I've always thought it was.

Now, will the Bhn believers read it and will the light click on?

 

[fiver]

maybe.
i'd prefer they ask questions, heck i'd prefer everyone ask questions.
that's kind of why we are here,,, ya know?,, and i'm starting to forget some of this stuff.

 

[Ian]

You condense a book and lifetime of experience into three sentences and nobody that doesn't already know can "un-zip" the file.

I unzip it as best I can and as soon as anyone who doesn't already get it from before sees it's more than three sentences and clicks off the thread.

Someone who doesn't know what they don't know but realizes there's more to know starts asking questions, but when you start dropping the hints that will start leading them in the right direction they start to see the amount of work they'll have to do to get their own answers with their own stuff, and it usually peters out.

These threads end up with the same handful of bullet geeks trying to remember what they used to kinda understand and posting a little about what they do now to get good results but can't remember half of why it works.

Since it's just us now, anyone hear from Allen lately?

 

[Bret4207]

maybe.
i'd prefer they ask questions, heck i'd prefer everyone ask questions.
that's kind of why we are here,,, ya know?,, and i'm starting to forget some of this stuff.

They DO ask questions and we answer them to the best of our ability and then they keep looking for the whole answer being a Bhn.

 

[Bret4207]

You condense a book and lifetime of experience into three sentences and nobody that doesn't already know can "un-zip" the file.

I unzip it as best I can and as soon as anyone who doesn't already get it from before sees it's more than three sentences and clicks off the thread.

Someone who doesn't know what they don't know but realizes there's more to know starts asking questions, but when you start dropping the hints that will start leading them in the right direction they start to see the amount of work they'll have to do to get their own answers with their own stuff, and it usually peters out.

These threads end up with the same handful of bullet geeks trying to remember what they used to kinda understand and posting a little about what they do now to get good results but can't remember half of why it works.

Since it's just us now, anyone hear from Allen lately?

I suppose it takes time. I'm still trying to get a clear mental image of lube being blown ahead of the bullet, but it's difficult for me. That idea was floated, what?, 2-3 years back?

 

[RBHarter]

You have to visualize that flavor injector with the leaky seal sucking air and passing fluid is all .

 

[Bret4207]

Easier for me to visualize the neck opening a smidge and gas pushing the lube up the space between bullet and throat. But it's happening so fast and in such a short space it still seems... iffy?, I guess? I dunno, greater minds than mine came up with the theory, I imagine they're right.

 

[Ian]

Bret, imagine an engine with completely worn-out piston rings.

 

[462]

Okay, but hasn't the bullet already obturated to fill whatever part of the barrel it's in?

 

[RBHarter]

Not in the gap between the mouth of the case , case mouth step in the chamber , and the top band closing the gas leak in the throat area . That's why we like long neck cases and long shanked bullets , there's more "time" and less distance without and open gas leak . The shorter nose and top band being almost in the throat helps a lot .

 

[fiver]

try visualizing vaseline in a pipe and you trying to shoot it against the wall with your air hose.

 

[462]

try visualizing vaseline in a pipe and you trying to shoot it against the wall with your air hose.

But, what if the bullet is engaging the lands?

 

[fiver]

ain't nuthin moving till the engraving pressure is overcome.

that's one of my slower powder tricks.
i use about .001 neck pressure and seat [about .0020-.0030] long, then use the bolt to seat the bullet into the case.
you can give yourself a 10-14K faster pressure rise without the little engraving spike.
the pressure rise is evened out by the bullet moving, so it levels the curve out longer.
if your using an appropriate powder.

if your running a faster powder use the/a jump and avoid the bad stuff that can happen.

 

[462]

For non-lever action rifle powders I use only published loads, have settled on .015" neck tension, and have whittled the powders down to Unique and 2400, because I don't need a lot of speed and I'm frugal. Are you saying using those two fast powders and having the bullet engage the rifling will cause an excessive (and detrimental) pressure spike?

 

[Ian]

Excessive? No. Your peak pressure happens early anyway, so it doesn't make much difference. Detrimental? What do your targets tell you? I bet they say the bullet didn't protest much about being in perfect form below 1,500 feet per second.

Where all of us run into problems is using low-node techniques trying to go past mach 3. Sorting those problems has caused many late nights and much missed scenery while driving.

 

[fiver]

definitely not with Unique, it just burns differently and a higher start still won't get you to a 100% burn of the powder unless your using like 24+grs. in a 30 cal rifle. [or using it to push jacketed bullets, and yeah i've used unique to push jacketed bullets]

2400,, well it doesn't care either.
if your using it to go 1900 fps. the push is actually a help to fight it's position sensitivity.
if your once again trying for like 2400 fps with it, then your working the line pretty finely.

 

[fiver]

and we typed on top of each other again... LOL

 

[Ian]

Lamar and Ian: voted "most likely to double" by ASBC seven years in a row.

Edit, did it again.

 

[Bret4207]

ain't nuthin moving till the engraving pressure is overcome.

that's one of my slower powder tricks.
i use about .001 neck pressure and seat [about .0020-.0030] long, then use the bolt to seat the bullet into the case.
you can give yourself a 10-14K faster pressure rise without the little engraving spike.
the pressure rise is evened out by the bullet moving, so it levels the curve out longer.
if your using an appropriate powder.

if your running a faster powder use the/a jump and avoid the bad stuff that can happen.

So I haven't been messing up by doing the same thing for 30 years! Well, at least I have one thing going right!

Serious question- Would I be anything close to right in my theory that doing this with faster powders, RD for instance, is a reason for backing the charge down a bit while still seeing the same basic fps? That one puzzled me a little, but seems to have borne out, at least with lighter for the caliber bullets.

ETA- I may have part of that answer in the posts following the one I replied to that I hadn't read yet.