Bullet core stripping

Stephen,

You'll time out if you stay in the message box too long. If you write in the advanced box & regularly click on the Preview Post button, that won't happen.

I was caught that way until some kind person wised me up.

John
 
Gene,
Very interesting discussion you've kicked off.
Now I may be way off base here (it's happened before:rolleyes:) but I'm gonna go out on a limb and guess that your current interest in core stripping has to do with the gain twist barrel 'buzz'.
I've been following the gain twist barrel discussions with great interest myself. Easing the rotational acceleration/core stripping problem is the only rational argument I can understand in favor of the gain twist idea, but there are too many compelling pieces of evidence contrary to that simple assertion.
First of all, there are plenty of accounts of 'faster than PPC velocities' producing accuracy with standard 6mm BR bullets, which would imply that the cores are not stripping at higher than PPC velocities. So why would they strip at PPC velocities?
Second, the rate of gain twists cited are very gentle, on the order of 1" gain per 20" of barrel. Knowing that the max pressure chamber (and accompanying max rotational acceleration) happens just a few inches ahead of the chamber, the rate of gain seems quite irrelevant at alleviating the 'shock' of rotational acceleration and jacket-to-core stress. I could see how a 'zero twist' to 1:14" twist could alleviate the stress, but that's not what they're using.
Furthermore, the idea of a non-constant twist 'smearing' the engravings on the jacket just seems non-conducive to precision. Maybe it is. Maybe it actually helps to further align the bullet in the bore as it travels. Who knows.
Finally, I'm not convinced that the results of the gain twist barrels are 'unarguably' superior to constant twist barrels. First of all, the barrels are made by one of the best precision barrel makers in history on the most sophisticated machinery, and shot by some very experienced people. I dare to say that good results would be obtained even if the gain twist were a slight hinderance to precision!

Like I said, I may be way out of line. Your intent might not have been aimed at the gain twist discussion at all. If that's the case, just ignore me:eek:

Mike, I'm right there with ya man. Learning more everyday and constantly impressed with the knowledge that seems to come out of the woodwork here!

-Bryan
 
As long as we're kicking off wild theories about why slight gain-twist barrels *might* produce better accuracy, I'd offer this one: Perhaps, for some reason, there is a correction in in-bore yaw (the amount not attributable to CG offset in the bullet) when the twist changes. In bore yaw per se. isn't a big issue, but the effect of the wind on varying tip-off rates does cause shot dispersion.

Correct me if I'm wrong Bryan, but this could be tested if enough groups to be significant were shot in the tunnel and then in outside in varying wind, with both a gain twist barrel and a standard twist barrel as a control.

FWIW & that's not much
 
Gene,
Very interesting discussion you've kicked off.
Now I may be way off base here (it's happened before:rolleyes:) but I'm gonna go out on a limb and guess that your current interest in core stripping has to do with the gain twist barrel 'buzz'.
I've been following the gain twist barrel discussions with great interest myself. Easing the rotational acceleration/core stripping problem is the only rational argument I can understand in favor of the gain twist idea, but there are too many compelling pieces of evidence contrary to that simple assertion.
First of all, there are plenty of accounts of 'faster than PPC velocities' producing accuracy with standard 6mm BR bullets, which would imply that the cores are not stripping at higher than PPC velocities. So why would they strip at PPC velocities?
Second, the rate of gain twists cited are very gentle, on the order of 1" gain per 20" of barrel. Knowing that the max pressure chamber (and accompanying max rotational acceleration) happens just a few inches ahead of the chamber, the rate of gain seems quite irrelevant at alleviating the 'shock' of rotational acceleration and jacket-to-core stress. I could see how a 'zero twist' to 1:14" twist could alleviate the stress, but that's not what they're using.
Furthermore, the idea of a non-constant twist 'smearing' the engravings on the jacket just seems non-conducive to precision. Maybe it is. Maybe it actually helps to further align the bullet in the bore as it travels. Who knows.
Finally, I'm not convinced that the results of the gain twist barrels are 'unarguably' superior to constant twist barrels. First of all, the barrels are made by one of the best precision barrel makers in history on the most sophisticated machinery, and shot by some very experienced people. I dare to say that good results would be obtained even if the gain twist were a slight hinderance to precision!

Like I said, I may be way out of line. Your intent might not have been aimed at the gain twist discussion at all. If that's the case, just ignore me:eek:

Mike, I'm right there with ya man. Learning more everyday and constantly impressed with the knowledge that seems to come out of the woodwork here!

-Bryan


Bryan!! Thanks for joining the discussion! It's good to hear from you my friend. :D

Actually, the present excitement over gain-twist rifling is not what prompted this core-stripping discussion. When Frank Green mentioned that he could make a barrel that started out with 'zero' twist, progressing to whatever, it sounded like a good idea and a way to 'soften' the rotational acceleration of the bullet, which might reduce the likelihood of core stripping. But,, there is no concern for core stripping if the bullets are made properly; is there? The zero to 14 rifling thing might be just a solution to a problem that doesn't exist; huh?

I agree with you; I don't believe the gain-twist barrels are inherently more accurate. You summed it up nicely by saying,

(Bryan Litz, Quote) "I'm not convinced that the results of the gain twist barrels are 'unarguably' superior to constant twist barrels. First of all, the barrels are made by one of the best precision barrel makers in history on the most sophisticated machinery, and shot by some very experienced people. I dare to say that good results would be obtained even if the gain twist were a slight hinderance to precision!"

Well said Bryan.

For many years, I have studied everything I could find on making match grade bullets and spent many pleasant hours discussing the subject with such greats as Walt Berger, Harold Broughton, Jeff Fowler, Eric Stecker, Skip Otto, Ed Watson, Don Neilson, Lowel Frei, Gary Sinclair, Stu Harvey, Cecil Tucker, Charles Huckeba, Ronnie Cheek and many others who make match grade bullets. I soon found I had much to learn and developed great respect and appreciation for those who make these marvelous little projectiles.

I'm looking forward to more good discussion on the subject. :D

Later,

Gene Beggs
 
Getting the core/seated RIGHT

Gene,
Very interesting discussion you've kicked off.
Now I may be way off base here (it's happened before) but I'm gonna go out on a limb and guess that your current interest in core stripping has to do with the gain twist barrel 'buzz'.
I've been following the gain twist barrel discussions with great interest myself. Easing the rotational acceleration/core stripping problem is the only rational argument I can understand in favor of the gain twist idea, but there are too many compelling pieces of evidence contrary to that simple assertion.
First of all, there are plenty of accounts of 'faster than PPC velocities' producing accuracy with standard 6mm BR bullets, which would imply that the cores are not stripping at higher than PPC velocities. So why would they strip at PPC velocities?
Second, the rate of gain twists cited are very gentle, on the order of 1" gain per 20" of barrel. Knowing that the max pressure chamber (and accompanying max rotational acceleration) happens just a few inches ahead of the chamber, the rate of gain seems quite irrelevant at alleviating the 'shock' of rotational acceleration and jacket-to-core stress. I could see how a 'zero twist' to 1:14" twist could alleviate the stress, but that's not what they're using.
Furthermore, the idea of a non-constant twist 'smearing' the engravings on the jacket just seems non-conducive to precision. Maybe it is. Maybe it actually helps to further align the bullet in the bore as it travels. Who knows.
Finally, I'm not convinced that the results of the gain twist barrels are 'unarguably' superior to constant twist barrels. First of all, the barrels are made by one of the best precision barrel makers in history on the most sophisticated machinery, and shot by some very experienced people. I dare to say that good results would be obtained even if the gain twist were a slight hinderance to precision!

Like I said, I may be way out of line. Your intent might not have been aimed at the gain twist discussion at all. If that's the case, just ignore me

Mike, I'm right there with ya man. Learning more everyday and constantly impressed with the knowledge that seems to come out of the woodwork here!

-Bryan
bsl135



Yes, well said Bryan.

Furthermore, the idea of a non-constant twist 'smearing' the engravings on the jacket just seems non-conducive to precision. Maybe it is. Maybe it actually helps to further align the bullet in the bore as it travels. Who knows.
Finally, I'm not convinced that the results of the gain twist barrels are 'unarguably' superior to constant twist barrels. First of all, the barrels are made by one of the best precision barrel makers in history on the most sophisticated machinery, and shot by some very experienced people. I dare to say that good results would be obtained even if the gain twist were a slight hinderance to precision!


My thinking just the same...

Why is core seating pressure so critical? It's all about achieving the tightest grip (maximum friction) between the jacket and core. If the cores are not seated hard enough the jacket will not get a good grip on the core; if seated too hard, the jacket will be stretched beyond the yield point weakening its grip on the core.
Gene


As well as "poping a Jacket"... This one I did as I was sneak'n up on the "RIGHT" core seat tension on the press handle... Yes, this one went.. POP! Like a primer going off. Attached pic (6mm .790 jacket)

I backed the core seat die out a tad bit...Ha!

Yes, getting the core seat operation RIGHT IS really important..! As is having a lathe on site to continually be making core seat punches.... Darn it... too much lead bleed-by, gotta make another core seat punch....:rolleyes::D

Good thread!
cale
 

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I have a Post I wrote on cleaning and seatng cores on save. It took too long to write so it wouldn't post. Part of it I will give here, the full version I will re-post sometime later.

I also stay away from boiling cores using chemicals like rubbing alcohol and white vinegar to clean cores to get the dull grey core etching look that every bullet maker should look for. The rubbing alcohol is used first on the cores in my sieve, cores are rolled around. The alcohol doused as the cores are rolled removes tailings and minute traces of lead and grime from the squirting. After the alcohol soaking I go for the vinegar.. Next I fill a 2 qt pan half full of sink hot water and add a couple good sloshes of vinegar mixing good. Then I add the cores, mixing well and set the pan on a warm stove for 15-20 minutes stirring several times. Next I rinse the cores with hot water from my sink for 15 minutes to neutralize the vinegar and stop the etching process, let dry in the sun or indoors.
The rest on core seating and more detail on cleaning cores will follow once I figure out how to post my entire Post.

Stephen Perry
Angeles BR

Steve I hope you get it up man :)

Any good hands on bullet making experience is interesting.

thanks for taking the time.

al
 
"letting the core seated jackets rest a bit before point forming"

Bryan

Bryan,

I'm not a bullet maker but I know a few and I've toyed with the idea........

This matter of "letting the core seated jackets rest a bit" seems to be a common (and KEY) part of the equation, letting the jacket relax back onto the core. I've heard that controlling temperature during the whole process weighs into this too...... I remember a post where a guy would seat his cores and then leave them set overnight while his work area cooled down (he'd turn the heat off overnight) and he had failures.

Can you comment on HOW LONG you let them sit?? And on whether or not you think temperature control to be important?

I just find this whole thing to be fascinating. Partly because I've been blessed with two lots of "magic bullets" including a few thousand of Allie's bullets from "that die" ........ and good bullets are just wonderful things.

Teeeny round dots are sooo cool ;)


Right now I feel that the few hundred 118gr BIB's that I've got left are magical, and dumping bullets into a hole that doesn't change shape is totally cool but cranking over and wiping out another dot in the center of a HBR target has a certain mystical "accuracy" quality. It makes me feel like all is right with the world.


al
 
Very interesting thread. I'll share my 2 cents. I stopped using antimony lead 7 years ago because of the inconsistent mixing. I was getting large hardness deviations and went back to pure lead with excellent results. As for lead stripping or the melting of lead verses antimony lead, The difference in melting point is only a few degrees making this point mute. The jacket to lead bond is as I see it the most important ingredient in the bullet making mix. I don't boil my lead (This causes lead hardening with an inconsistent BHN and or Saeco reading in excess of 8 BHN) Pure lead on my Redding/Saeco hardness tester is 5 BHN or 0 Saeco. I use a chemical solution to etch my lead cores. As for lead build up on the core seat punch I tend to believe it is the Copper hardness that causes this. Have only seen 2 lots of jackets that this is a problem.

JDS Bullets


JDS, whatever you're doing; it's working well. I won a box of your bullets as a door prize somewhere and found them to be as accurate as any I have ever seen.

Gene Beggs
 
I consider core seating to be the most critical part of my bullet making process. You develop a 'feel' for core seating pressure with a certain lead/antimony mix in your cores. There is also a subtle, and short lived, visual indicator* ;) of core seating pressure that parallels the actual physical core seating pressure.

I'm very fortunate to have Randy 'R.G.' Robinett as my bullet making mentor. His help and guidance was invaluable when I got started and continues to this day. :)

Shiverin' in the frosty* Forbidden Zone. -Al

P.S. It's -8 with winds 35-45 from the NW and a virtual whiteout from ground blizzards here. Wind chills are in the -40 range. I'm headed in to work to do a couple of cases, now....people get sick in the da@&dest weather!
 
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As long as we're kicking off wild theories about why slight gain-twist barrels *might* produce better accuracy, I'd offer this one: Perhaps, for some reason, there is a correction in in-bore yaw (the amount not attributable to CG offset in the bullet) when the twist changes. In bore yaw per se. isn't a big issue, but the effect of the wind on varying tip-off rates does cause shot dispersion.

Correct me if I'm wrong Bryan, but this could be tested if enough groups to be significant were shot in the tunnel and then in outside in varying wind, with both a gain twist barrel and a standard twist barrel as a control.

FWIW & that's not much

Charles,
I agree that the slight gain might somehow 'wedge' the bullet straight as it goes down the barrel where a constant twist would keep the same level of yaw it entered the riflings with. I don't know how exactly, but if it does, I can tell you that reducing the in-bore yaw is a good thing for precision, wind or no wind.
When the bullet emerges from the muzzle in anything but it's natural flight orientation, it has to adjust. The adjustment depends on the orientation of the bullet as it exits, results in a tip-off rate, and causes dispersion.
The only way you don't get dispersion from in-bore yaw is if all the bullets have their yaw in the same orientation as they exit the muzzle. In other words, if all the bullets are emerging from the muzzle with the same amount of 'nose high' tilt, the dispersion will all be in the same direction, and magnitude. Maybe they'd all hit 1" to the right of the bore-line at 100 yards. Now if the bullets are exiting the muzzle at various levels and orientations of yaw, they will disperse 360 degrees to various amounts.
Bob McCoy (Chapter 12 MEB) shows an example for the .30 cal 168 grain International bullet, 2600 fps, 1:12" twist, with the bullet having only 0.1 degrees of nose high yaw at muzzle exit. The result at 100 yards is 0.75" of left deflection from aerodynamic jump, and 0.45" of right deflection due to lateral throwoff (Lateral throw-off and aerodynamic jump are the two mechanisms of dispersion for the in-bore yaw scenario) for a net dispersion of 0.3" left. If the next shot has the nose emerge at 6 O'clock with the same 0.1 degree yaw level, the shot hits 0.3" to the right of center, for a 0.6" c-t-c group, and that's just for 0.1 degrees of in bore yaw!
Some related reading on the subject can be found here
This article looks at the relation between increased drag and dispersion caused by initial yaw rate (not necessarily due to result of in-bore yaw).

Take care,
-Bryan
 
Cale, (Caroby) in your post number 31, you mentioned how you once 'popped' a jacket when 'sneaking up' on the right core seating pressure. Thanks for bringing that up and thanks also for posting the photo of the separated jacket so everyone will understand what we are talking about.

Of course, as you know, when one is adjusting the core seater die, the jacket length shortens as the core and jacket are expanded up. This shortening continues as the die is gradually screwed down in the press but there comes a point where the jacket suddenly begins to grow in length. I believe this marks the point where you have just gone a bit too far and should back the die up slightly. Skip Otto was the first to explain this to me, and of course at the time, it went in one ear and out the other. :rolleyes: It was Gary Sinclair, several years later, who finally cleared this up for me. :eek: Thank you Gary. :)

Guys, I gotta' tell you a funny story. ;)

After reading about core-stripping in Harold Vaughn's book, I began thinking of ways to increase friction between core and jacket. One of these hare-brained ideas turned out to be hilarious! :D

As model-building kids, most of us soon learned to solder wires and other small items together with a soldering iron. I got to thinking about how copper and lead/solder always seemed to have an affinity for each other and wondered if maybe I could 'solder' the cores in place. :cool: But how! Hmmmm,, Let's see,, I could touch a soldering iron to the base and hold it there till the lead core melted. Nah, that wouldn't work; the core would wind up lopsided. I know :cool: I could place the bullets base down in a pan and heat them up on my wife's electric stove! Yeah, that'll work! (Wrong)

I got to looking at the heating elements on the stove and noticed they were nice and flat. :cool: I thought, 'Why not just place the bullets in a row around the heating element and then turn on the power." Of course. :cool:

So,,, I placed about twenty bullets on the heating element and turned up the heat. :eek: It wasn't long before the bullets took on a silver hue and before I could switch the power off they turned black! Oh s--t ! :eek:

I knew the cores had melted because a few of the bullets had little drops of lead that bubbled up out of the meplats and ran down the side of the jacket into the drip pan of my wife's stove. :eek: So,, there they were, my beautiful, black, heat-treated bullets still hottern' hell. Now what?

I decided to use tweezers to remove the hot bullets from the stove and dropped them, one by one, into a pan of cold water. This caused some of the black oxide to flake off revealing a nice clean copper surface below. I had heard somewhere that vinegar would remove oxidation from copper and brass so I poured a little Hienz apple cider vinegar into the pan and let the bullets soak for a while. After swishing them around in the vinegar bath for a little while, the bullets came out shiny and clean with not a trace of oxidation but the jackets had sort of a dull, etched appearance. I thought, "I know what; I'll put them in my case tumbler overnight and polish 'em up!

Next morning, the bullets came out of the tumbler looking brand new. I put them in a zip-lock baggy and headed for the tunnel. What the hell, might as well see if they'll shoot. :cool:

To say, "Those bullets didn't shoot so pretty good" would be the kindest thing one could say. They wouldn't shoot in a basket! I'm talking 3 and 4 inch groups at 100 yards, in the tunnel. Needless to say, I haven't tried that again.

So beware. :eek: If someone tries to give you some bullets that look like they've been soldered,, start runnin' backwards!

Later,

Gene Beggs
 
alinwa

Al: Very seldom did I core seat and point form in the same day.....at least not with the same batch. I core seated as many as possible in one setting and stored them in clean J4 jacket buckets. Sometimes I'd core seat for several days, then start off a new day point forming. The dimension of the bullet immediatly after core seating is a wee bit different than when it has sat for a while. An hour or 2 would probably be just fine.
Temp control? Well, any of you who have seen my shop know it is very small.
Like 10x16 small:D It's also well insulated. It stays about the same temp all summer, and in colder times of the year the little NG heater I have keeps it toasty. The main form of temp control necessary is heating the dies themselves. I found that the air activated hand warmers sold in sporting goods stores work well. Just rubber band one on the die and let it heat for about a half hour before starting.
Keeping the dies warm helps keep the press running smoothly.
.8gr of Bill's proprietary lube is enough to take 600 jackets thru core seating AND point forming. A tenth either way, and the press won't run.
I etched the cores with a gallon of water and about 2 tablespoons of white vinegar. Soak them for about 5 minutes and then rinse in fresh running water for another 5 minutes to stop the etching process.
Hope this helps.
Bryan
 
The goal of achieving high loading between jacket and core to get high friction between jacket and core will be a function of clearance between jacket and core seating die. The highest loading will come when the jacket is stressed right up to the yield point of the jacket material. The idea that taking jacket past it's yield point will decrease loading is false. Any thing beyond jacket yield will only add distortion and variation in jacket wall thickness with little change in loading. Pressure applied when seating a core made of any of the normal lead alloys, probably never needs to go above 15,000 psi as recommended by Corbin. The clearance between jacket and die is usually not enough to allow the jacket to reach yield so increasing pressure on up to 50,000 will not change the jacket to core loading.

A jacket that is "popped" or failed by applying high pressure probably had excessive clearance or was excessively hard. With normal metal and clearance you won't fail a jacket until the die fails, regardless of how high you take the pressure. However, you probably may begin to extrude or lengthen the jacket at pressure over 40,000 if brass is soft.

Finally, it seems to me you might open up an uneven leak path with gain twist as the bullet exits the muzzle. With what we think occurs with a poor crown there may be reasons gain twist would have poorer accuracy as compared with uniform twist. Just a thought.
 
A dumb question

is the I.D.of jackets the same as the o.d. of the core, or is the I.D. larger or smaller than the O.D. of the core?

Thanks, Pete
 
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Al: Very seldom did I core seat and point form in the same day.....at least not with the same batch. I core seated as many as possible in one setting and stored them in clean J4 jacket buckets. Sometimes I'd core seat for several days, then start off a new day point forming. The dimension of the bullet immediatly after core seating is a wee bit different than when it has sat for a while. An hour or 2 would probably be just fine.
Temp control? Well, any of you who have seen my shop know it is very small.
Like 10x16 small:D It's also well insulated. It stays about the same temp all summer, and in colder times of the year the little NG heater I have keeps it toasty. The main form of temp control necessary is heating the dies themselves. I found that the air activated hand warmers sold in sporting goods stores work well. Just rubber band one on the die and let it heat for about a half hour before starting.
Keeping the dies warm helps keep the press running smoothly.
.8gr of Bill's proprietary lube is enough to take 600 jackets thru core seating AND point forming. A tenth either way, and the press won't run.
I etched the cores with a gallon of water and about 2 tablespoons of white vinegar. Soak them for about 5 minutes and then rinse in fresh running water for another 5 minutes to stop the etching process.
Hope this helps.
Bryan


Niice :)

THAT's what I'm talkin' about...... I print this stuff off, it's the actual info that might make or break a run of bullets sometime down the road.

thank you


al
 
If you have studied Chapter 8 of "Rifle Accuracy Facts" (RAF) by Harold Vaughn, you have a good understanding of core stripping but for those of you who do not have a copy available I will quote here the first paragraph.

Harold Vaughn, RAF Chapter 8 page 155

"The lead core in a jacketed bullet is subjected to a large shearing stress at the interface between the jacket and the core during spin-up. As the bullet enters the rifling a large angular acceleration occurs which spins-up the jacket. The lead core is heavy and has a large spin moment of inertia that resists this large angular acceleration. The core is driven by friction forces between the core and jacket and shear stresses developed by the internal indentations in the jacket caused by the rifling engraving. These internal indentations protrude into the core about two mils. If the lead core is too weak to stand this shearing stress, core stripping results and the core will have a slower spin rate than the jacket when the bullet exits the muzzle. The maximum differential spin rate that I measured (5.5%) results in the core roll angle lagging behind the jacket roll angle by as much as 20 degrees. After muzzle exit the core slows down the jacket spin rate and the jacket speeds up the core spin rate slightly until both are the same. The resulting spin rate of the bullet is slower than it would have been if core stripping had not occurred."


Now that we understand what is meant by core stripping, lets discuss how the bullet maker can insure it does not happen.

First and perhaps most important of all is the hardness and strength of the core itself. Pure lead is very soft and pliable. As Vaughn states above, "If the lead core is too weak to withstand the shearing stress, core stripping results."

Some bullet makers use only pure lead wire in making cores, others use a lead/antimony alloy which is harder and stronger. Pure lead cores are easier to squirt and seat from the standpoint of effort on the press handle but pure lead tends to stick to the core seating punch.

Dr. Jack Jackson, editor of "RAF" by Vaughn has conducted extensive tests with different alloys to determine the optimum hardness for bullet cores. Pure lead is generally considered too soft; Linotype, which is about as hard as you can get is too hard. Somewhere in between these two extremes lies the Holy Grail.

Let's take a break and think about this for a while. If you have any questions or comments, let's hear it. Next time we will discuss why it is so important to triple wash both cores and jackets before the core seating operation. We will also discuss the importance of proper core seating pressure.

Later

Gene Beggs

Not correct . I have been making accurate bullets for 25 years with pure lead cores and so have thousands of others.
 
Thanks Stephen

Allot of bullet makers use bullet boards to insert the cores into the jackets, I do. If you watched the cores as they drop, 200 hundred at a time, into the jackets most will drop in easily some will not. The ones that don't are trapping air but they do go easily in the jackets when the punch seats them. So to answer your question cores are a snug fit inside the jacket.

Stephen Perry
Angeles BR

the thought came through my head that if the cores were just a bit bigger than the jackets the issue of fit might be lessned. Don't know it that could be done mechanically but it should be able to be acomplished; pressed in, if you will.
 
Think tank, brainstorms etc.

Guys, let's try to come up with some new ideas; some new way to bond cores and jackets so the bullets are absolutely immune to core stripping. By 'bonding' I don't mean securing the core and jacket to prevent separation in game so as to retain maximum weight; no, I'm thinking only in terms of locking core and jacket to prevent core slip during initial spin-up.

I have already told you about my 'Heat treatment idea.' What a fiasco. :rolleyes:

Many bullet makers use some type of etching on the cores before seating, others boil them in some type of detergent or phosphate. At this time, I feel the best method is to simply insure the jackets and cores are squeaky clean by washing them in a triple bath of NuTri or Trichlorethane, but I'm always looking for ways to improve on this.

Have you ever considered the use of rosin? Could we make up a thin "Dip" using pure rosin dissolved in a suitable thinner such as MEK, acetone, toluene or such, dip the clean, dry cores in this solution, then pour them out on a clean surface to dry? Would there be anything better than rosin? What do you think? Worth a try?

Gene Beggs
 
Pete

You can't take a too large core and "press fit" it into a jacket with any success. The process is called "swaging up".......in other words, the core seating process EXPANDS the jacket, and the core seated jacket, ready to point form is smaller than the finished bullet. The final process of point forming expands the jacket a bit more to the final dimension.
Think of the jacket as that half empty toothpaste tube that has been squeezed in the middle, then you start rolling it up from the bottom........the rest of the tube expands:rolleyes: (this assumes you have the cap on tight);)
To give a little more insite, suppose you have a bullet that is 6mm and you want to make it a .22, like necking down a case. You could squeeze it down in the die, but the spring-back of the copper jacket would work in reverse and it would spring back towards it's original size and the core would quite possibly rattle in the jacket.
The only time a bullet component is reduced in size is when the core itself is squirted to a specific size. From there on out, everything expands.
Copice?
Bryan
 
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