Problem of Case Swaging Boolit Down During Seating -- When is it an issue?

[Dannix]

Well I've reading a lot around here recently as I prepare to transition away from j-words to boolits for my 9x19mm. Got a question though:

I've read of the importance using an expander like a Lyman M so the boolit does not get swaged down by the case during seating. But I know one here simply flares via the Lee Unviversal Expander Die and has no problems with ACWW. So at what point does the 'boolit-swaging-by-case' problem manifest itself? 50/50? 20:1? Does it affect one case type more than another, straight/bottleneck? Other factors involved as well?

[Echo]

The M die won't alleviate boolit swaging. All it does is alleviate boolit shaving when seating. Boolit swaging is an interaction of boolit hardness and case rigidity. A soft boolit seated into a rigid (GI? Thick neck? Whatever...) case will probably be swaged down. If the neck is small enough to provide enough neck tension, then a soft boolit may not have enough integrity to expand the case - rather, the case swages down the boolit, and problems arise.

I learned long ago not to use GI .38 Special cases for my target loads. Commercial soft HBWC bullets would be swaged way down, and accuracy was marginal. Cast of even medium-hard alloy worked fine. Commercial HBWC bullets w/commercial (thin-necked) cases were no problem.

The key is the concept of 'interaction'.

*Commercial HBWC's are properly called 'bullets', since someone else made them, and they were swaged, not cast. Although great bullets, I can't give them the honor of being called 'boolits'.

[RobS]

It becomes a problem when the boolit is swaged down past the point of your intended application. The clear way to see if this is happening is to simply pull one after it as been seated and crimped. The boolit needs to come out of that case at a diameter that is going to work for the firearms bore diameters. That is the basic and simple explanation as there are just too many scenarios i.e. different brass, different reloading dies, different calibers, straight wall vs bottle neck, BHN hardness vs bullet toughness and the list goes on and on.

Ways to work around this issue can go in a few different directions. A person can find a mold that cast larger than the diameter needed and/or size the boolit larger than needed. What does the larger diameter needs to be????................ It depends on how much the sized case swages down the boolit as well as depends on the hardness of the boolit being used. This method can present a problem however for as the case swages down and makes the section of the boolit inside the case the right diameter it also leaves the other portion outside the case (front drive band) at a diameter that may be too large to chamber in the firearm.

Another way is to buy or make an expander plug and one that is usually .001" smaller than the intended boolit diameter. This plug also needs to be at least as long as the boolits seated length for best results. This works for many however there is the possibility of looser neck tension on the boolit. This may be a problem or not depending on what powders a person is trying to use etc, etc.

The next option is to use a harder boolit and one to the point that it meets the strength to resist the pressures the case has on the boolit. Many have problems with air cooled WW boolits because of timing and some individuals reload them too quickly after casting. WW alloy takes about 2 weeks to age harden and sometimes 3 weeks. The same bullet that was cast a few hours or even a week ago could swage down where as one that is 2 or 3 weeks old won't. Age hardening of WW boolits is often times over looked and is a large part of why some say air cooled WW works for them and others say the alloy doesn't work worth a darn.

The only way to figure it out is to work with the parameters you have, pull boolits to check diameters, and keep good records of what you are doing.

[462]

Another factor can be seating and crimping in one operation rather than two.

Though I have no intention of knocking the company, at least in my case, Lee seating dies were another factor.

[Larry Gibson]

Depends on the alloy and the neck tension. Too soft an alloy with too much neck tension means the bullet will get swaged down. The M die does help alieviate some of that as it expands the case neck below the flare. The trick is to use the right size expander in the M die. With ACWWs in a PB'd bullet you can generally have .003 - .005" neck tension and not have problems. With GC'd bullets swaging is not generally a problem but distorting the nose or even bending the bullet is. It is with the softer alloys that this happens.

I like to use an expander in my 9mm Mdie that is for the .38/.357 if I am using bullets sized .359+. For regulst .356/.357 sized bullets I'll use the expander that comes with the die. With cartridges meant for auto loaders such as the 9mm, .40s and the .45 ACP you must either have enough neck tension to prevent bullet set back in the case on feeding or you must have a canelure in the case below the bullet as in many factory and milsurp rounds. Another technique is to use the case sized down more and the case is "coke bottled" below the bullet when the bullet is seated. That works fine but you must over size the case and have an undersize expander. That can very easily lead to the bullet being swaged down if the alloy is too soft.

In the 9mm I like to minimally size the case so there is just a tudge of the coke bottle effect under the bullet after seating. This is easily done by backing the sizing die out until you get the right amount. I usually disassemble the handgun and use the barrels chamber as the "case gauge" both after sizing and after seating the bullet. I've been using that technique for years (shown to me by an "old guy") back in '70 when I got a S&W M39) with a multiple of old and new 9mm handguns and have not had a sigle problem. I even fired several hundred of my cast loads through Mac 10s, a Swedish K and an MP38 without a single stutter. I do recommend if loading a single load for multiple guns that complete FL sizing be done and that a bullet of sufficient hardness be used to prevent swaging or nose distortion on seating. WQ'd WWs will work fine for this but most often ACWWs will also work. If you load for just one gun then tayloring the load to that one gun will give the best performance.

Larry Gibson

[geargnasher]

I think Larry about covered it.

Boolit swaging during the seating and/or crimping operation is a problem if the boolit doesn't come out of the case the correct size for your bore.

Often with cast boolits it is necessary to use larger diameter than with jacketed, and since the die sets commonly available are set up for the smaller jacketed bullets, they compromise the much softer lead.

The solution sometimes is to both enlarge the sizer die and the expander. For 9mm and other straight-walled cases that usually employ carbide sizer rings, enlarging the die is not really an option, nor is it really necessary since brass is cheap and we aren't too concerned with overworking the brass. Getting an expander ball the correct depth and diameter is ususally necessary, though, unless you're using really hard alloy.

Boolit retention, boolit diameter, loaded case diameter, and expanded depth is a balancing act that sometimes has to be done for each particular gun to achieve optimal results.

And remember, with straight-walled automatic calibers, you probably won't need any actual crimp on the case mouth, just enough to remove the bellmouth and make it reliably chamber. Case tension on the boolit is critical to safety and needs to be correct.

Gear

[243winxb]

Lee Universal Expander Die- This only flares the mouth, it does not open the inside diameter of the case. When you seat your bullet, the bullet becomes the expander.

[Buckshot]

.............Before 9.3x62Al clued me in on using the Lee Makarov dies to reload my 38 S&W ammo I used Lee's 38 S&W dies. I've mentioned before that reloading die makers assume everyone is reloading jacketed, like .308" in 30 cal and the neck ID gets sized to like .304" or some such and you're wanting to stick in a .310" cast slug with just a bit of flare. So the Lee 38 S&W dies (like probably everyone else's dies) they assume you're gonna use .357" jacketed ..................

http://www.fototime.com/1E675673BEE6C9D/standard.jpg

.............. so the above is what happens. Of course these were cast of pure lead so the result is a bit more dramatic, but when you're wanting .362" for the whole length of the boolit, it's a bit discombobulating. In this situation the Makarov die is the bee's knees as it's set up for a .363" jacketed slug so a ho-made 'M' casemouth expander takes care of it easily.

................Buckshot

[MtGun44]

Never had an issue with AC WWts. I expect that softer alloys could have this problem, and I
thin Buckshot has some solid proof with pure lead. I only use pure in a couple of
muzzle loaders and one trapdoor with a really worn and oversized bore.

Bill

[S.R.Custom]

Never had an issue with AC WWts. I expect that softer alloys could have this problem, and I
thin Buckshot has some solid proof with pure lead.

Never had an issue with ACWW either. (I've checked.) It's kind of a non-issue as methinks that any boolit so soft that it swages down on seating will also be so soft that it will obturate, or "bump up" upon firing.

[Larry Gibson]

Never had an issue with ACWW either. (I've checked.) It's kind of a non-issue as methinks that any boolit so soft that it swages down on seating will also be so soft that it will obturate, or "bump up" upon firing.

S.R.

Many times the obturation or bumping up is exactly what is wanted. Also consider HBWCs for .38 Special target loads or almost dead soft lead HPs for expansion at 700 - 900 fps. They will swage down real easy if the neck tension is too great. Just food for thought about the use of alloys different than WWs.

Larry Gibson

[Dannix]

Guys, thanks a ton for all the great input. I'll probably be shooting ACWW or WDWW mostly, but I wanted to play with soft stuff for HPs which I why I posted.

geargnasher, thanks for the "reminder" on crimping, or not doing so that is. After reading HeavyMetal's post on this thread (http://castboolits.gunloads.com/showthread.php?t=89435) it makes sense.

First the crimp: It's very likely that you aren't generating enough pressure ( or the alloy is to soft) to straighten out the crimp when the round is fired. The result is the crimp shaves the boolit as it exits the case making it undersized and causing some flame cutting.


I'm currently seating and crimping in two different steps, but then that's my j-word setup right now with the Lee combination crimp/seater and the Lee factory crimp die. For boolits, is two separate steps still recommended, or is seating and crimping as one step a non-issue as really only the bell is being straighted out and no actual crimping is being done?


I had a very helpful PMer offer a lot of helpful input as well. One of his PM's included this photo of the "crimpless coke bottle" route. Posting it here for the benefit of other fellow 'casters in training' here.
http://img138.imageshack.us/img138/7987/img0664t.th.jpg (http://img138.imageshack.us/img138/7987/img0664t.jpg)

[Bret4207]

Sometime case annealing will help if that is the only thing causing the issue. Work hardened brass can do ugly things to a nice young boolit. In a steekin' auto peestol you may not want to try that though.

[Mattog22]

I just had this problem. My solution was a larger expander I got from RCBS. Bullet setback has not been an issue, I've been checking. I am using ACWWs.