9mm cast bullets and fouling

[GLOOB]

I just wanted to post the results of an experiment that is 3 years in the making. Well, it took me 3 years, anyway.

Long story short:
3 years ago I tried MBC .356 Small Ball 18BHN bullets. Had fouling and poor accuracy. Shot up all 1000 bullets, anyway, and got familiar with Chore Boys.

Tried home cast at .357 and about 10-12 BHN. Had extreme fouling. Measured base of pulled bullets and found OBVIOUS swaging of the base as small as .353. Tried an oversize expander with home cast bullets. Fouling gone.

So at this time, I thought that maybe the bores of my guns weren't really oversize. And maybe the MBC bullets would have worked, all along, had I tried the bigger expander. 3 years later, I finally ran out of alloy, and I decided to give the same MBC bullets another try in my same 9mm handguns (3 different Glocks with stock and one LW barrel). They shot perfectly clean, this time around.

So I pulled out the old expander plug and made a few cartridges to pull and measure, which I never did 3 years ago. The results are surprising.

I took 3 different cases, Win, FC, and S&B. I selected 3 Small Ball bullets which measured close to the same per my calipers. On each of these bullets, I found one spot that measured .355 1/2, the rest .356, as measured as close to the bevel as possible, and rotating the bullet to take a measurement every 10 or 20 degrees around the base. I flared with the regular Lee 9mm expander, seated the bullets to my usual OAL (which is long and barely covers the lube groove!). The bullets seated easily with no shaving. Then I pulled the bullets and measured, again.

Well, I must be tired, because I forgot to keep the bullets separate, so I don't know which bullet came out of which brass... but.

All 3 bullets pulled easily with one whack from the puller. One of the bullets measured the same. The other two measured .356 on almost all points, and had I done a cursory exam, I would have stopped. But expecting to find SOMETHING, I plugged away and found one tiny spot on two of the bullets where instead of measuring .355 1/2, they now measured .354 1/2. That's a measurable difference of only 1 mil, and in only one spot on the base of the bullet. And yet a big difference it apparently might make.

So if you have trouble shooting cast in 9mm, and you haven't tried an oversize expander because you think your bullets aren't being swagged by the case, well maybe you should try a bigger expander, anyway.

True, there could be some difference in the batches of bullets. True, I haven't actually SHOT this new batch of Small Ball using the original Lee expander to see if the one tiny swagged spot will reproduce the fouling I originally experienced through 1000 rounds. But I haven't cleaned a 9mm bore in over two years, and I would like to keep it that way.

 

[robertg5322]

Tried shooting 9mm lead a couple of years ago, with same fouling results you mention.

Slugged the bores (Beretta 92, Springfield XD), they were within spec.

Checked internet and followed all advice given (most advice).

I suspected that the case was swaging the bullet a bit, especially since I was using Lee sizing dies, which are nice in that they make rounds tight, but I was speculating that they were making my bullets undersize.

Long story short, I sold my supply of MBC bullets and switched to jacketed bullets. They're not that much more expensive, and a lot less headache. And you don't get gunked up dies.

Thanks for confirming my suspicions.

Bob

 

[LiveLife]

Glad you got things figured out after 3 years.

When I first load tested 124 gr MBC SmallBall using 4.3 gr W231/HP-38 powder charge I used with harder 22-24 BHN 125 gr bullets, I got full-length barrel leading in my Lone Wolf barrels.

I checked the groove diameter of the LW barrels and they were .355"-.356" with SmallBall at .356". When I referenced 1999 Winchester load data which listed 4.0 gr as max charge for 124 gr lead bullet (Hodgdon listed 4.4 gr max for 125 gr lead CN at 1.125"), I deemed I was pushing the 18 BHN bullets too fast with higher chamber pressures as shorter 1.080"-1.100" OAL caused the bullet base to seat deeper to create high chamber pressures. See comparison picture below of SmallBall with substantial bullet base and discussion of deeper seating depth/neck tension/chamber pressure increase in this thread - http://www.thehighroad.org/showthread.php?p=9881654#post9881654

When I lowered the powder charge to 3.8-4.0 gr, leading went away. The lower powder charges for shorter OAL worked well with even softer 14-16 BHN ZCast bullets.

To not swage the bullet diameter smaller, I use almost no taper crimp of .377"-.378" with .356" diameter bullet which all drop in freely in my KKM/Lone Wolf barrels.

Yes, be gentle with lead bullets.

When blarby casted me some 45ACP 200 gr SWC from virgin lead alloy, he told me they were water quenched and like jellybeans, outer shell maybe harder but the interior is softer so bullet base still squish to seal with the barrel. To this day, these bullets are more accurate than any commercial bullets I have shot and I take greater care to not swage them during reloading.

 

[greyling22]

my lead 9mm life got a lot better than I switched out my 9mm expander plug for a 38s&w plug. Leading is mostly gone, but the accuracy isn't what I can get with jacketed.

It also got better when I moved from a .356 bullet to a .358.

 

[TimSr]

There are 3 major factors in cast bullet leading.

1. Size

2. Hardness

3. Powder and charge and its effects in bullet base expansion and velocity


The right combination of all 3 is critical.

 

[Walkalong]

Very interesting, thanks for sharing.

 

[LiveLife]

my lead 9mm life got a lot better than I switched out my 9mm expander plug for a 38s&w plug. Leading is mostly gone, but the accuracy isn't what I can get with jacketed.

It also got better when I moved from a .356 bullet to a .358.

Using .358" sized bullets for oversized barrel works if the chamber allows it.

When some new reloaders I was working with experienced leading in their factory barrels sized over .356", .357"/.358" sized bullets were tried but found they would not fully chamber in the barrel.

So we were limited to using .356" sized bullets and I suggested using softer lead bullet. Using softer 14-16 BHN ZCast RN with faster than W231/HP-38 burn rate powder like Red Dot/Promo created enough of initial powder burn "pressure pulse" to deform the bullet base (obturation) and seal with the oversized barrels to decrease the leading and maintain accuracy.

Now, I am less quick to say "Bullet to barrel fit is King" and suggest checking if .357"/.358" sized bullet rounds will fully chamber in the barrel and recommend using softer bullet if not.

How much can softer BHN bullet deform?

Quite a bit. My Taurus PT145 barrel is oversized beyond .455" and .452" sized 18 BHN bullets will lead a lot regardless what powders/charges I used. Using 12 BHN MBC Bullseye #1 200 gr SWC, even lighter powder charges like 4.6-4.8 gr W231/HP-38 and 4.0 gr Red Dot/Promo will not cause leading in the barrel. This tells me that softer bullet base is deforming properly to seal with the grossly oversized barrel.

So I am a contrarian in saying size is not everything but softness is also key.

There are 3 major factors in cast bullet leading.

1. Size

2. Hardness

3. Powder and charge and its effects in bullet base expansion and velocity


The right combination of all 3 is critical.

I agree and Glen Fryxell talks more about this in detail in chapter 5 of his book where he also points out the role of bullet base plastic deformation during initial powder ignition and lube channel compression to create "O" ring seal with a film of liquefied lube that gets blown forward by expanding gas to coat the bullet to further reduce leading. I never imagined the initial powder ignition phase forcing ring of lube back towards the lube channel as bullet accelerates forward until I read this chapter - http://www.lasc.us/Fryxell_Book_Chapter_5_Lubrication.htm

 

[rsrocket1]

9mm cast can be tricky to load and shoot successfully.

1. Bore sizes vary considerably from 0.3545" to >0.358"
2. Chamber sizes vary considerably across the board
3. The 9x19 Parabellum spec case is tapered for reliable feeding, but some chambers are not so fired brass can be all over the place
4. The interior dimensions of the cases can vary. Look into the "stepped" Freedom Munition cases

You should really slug your barrels to see what bullets you need to load. A 0.356" bullet will not work in a 0.358" barrel. On top of that, if the throat is narrow, you won't be able to use a wide bullet because it will hang up and not pass the "plunk test". Most case expanders do not open up the cases enough to allow a 0.356" bullet to be seated without swaging.

A Lee 38 S&W expander plug in the 9mm PTX die acts like a Lyman "M" die and expands the case deep enough to allow most of the bullet to be seated without swaging. Here is a picture of the 38/357 expander (right depth and width, but the body is too short), the 38 S&W expander and the stock 9mm expander (too short)

 

[GLOOB]

When I lowered the powder charge to 3.8-4.0 gr, leading went away. The lower powder charges for shorter OAL worked well with even softer 14-16 BHN ZCast bullets.

I'm glad you have figured out your 9mm. But I still wonder if maybe you would be shooting clean with ANY of those charges and OALS if you had ponied up for a larger expander. My soft slugs were shooting fine with anywhere from 4.7 to 5.0 grains of Unique, with the large expander. And my MBC Small Ball of harder BHN, likewise. Maybe I got lucky, but I did not have to experiment with OAL or charge. Maybe one day, you will do your own "3 year experiment" and go back and see. Heck, there are some folks out there that could do a 30 yr experiment.

You should really slug your barrels to see what bullets you need to load. A 0.356" bullet will not work in a 0.358" barrel.

Well, I dunno. Seems to me I already know my bores are no bigger than .356, since I can shoot .356 bullets without any fouling. I also know my chambers can handle .358 bullets, cuz I have also loaded some Cowboy#2's, and they chamber fine. So what would slugging my bores do for me?

Most case expanders do not open up the cases enough to allow a 0.356" bullet to be seated without swaging.

I tend to agree. Some folks insist that their bullets are not being swaged, so they never try a larger expander. My observations and experiences appear to suggest that the swaging can occur even on a hard commercial .356 bullet, and futhermore, that the swagging can be so subtle as to seem statistically irrelevant even if it is picked up on! The Lee 38S&W expander solved my problems. I measured it at .356. But I've been using the NOE .356/360 plug for the last few months with equivalent results. I just like it a little better.

If I save one person the grief of cleaning a bore with my experience, for them to know that hey, maybe they should just try a larger expander that costs as little as $3.00 on up to a whopping $10.00, then my post has served its purpose.

If you have solved your problem with a mix of hardness and oal and powder charge, and you have never tried a larger expander, yet, then I hope that one day you try and post your experience. Bumping is great, if your chamber is tight or your bore has constrictions. But if your bore is "good", you shouldn't need it.

FTR, a custom expander also has my 40s/10mm's shooting clean as a whistle. In this case, I couldn't find an expander to buy, so I turned one myself. It expands to 0.401 - 0.401 1/2, with a 0.404 flare. I load MBC bullets measuring 0.401 - 0.401 1/2. This solved 99% of my fouling with this caliber, off the bat. The only exception was in my 40SW Glock barrel I still had a tiny bit of fouling right ahead of the chamber. I figured out the minimum taper crimp needed to get the rounds to chamber in that barrel was causing bullet swaging with the thicker Fiocchi and S&B cases. The crimp was pressing into the bullet, slightly, and in that chamber it had no room to open up. Sorting out the thick cases and using them for my other guns has me shooting 40SW completely cleanly in all my guns.

For w/e reasons, my 45ACP cast loads shoot fine with a regular, tiny expander that is 5 mils smaller than the bullet. But I think it's telling that my 40 SW ammo loaded with an expander the same diameter as the bullet have way more neck tension than my 45ACP ammo. I think the thinner brass , larger case mouth diameter, and my more generous 45ACP sizing die dimensions ensure that case swaging doesn't occur, at least to any degree that causes a problem in my guns. I can flare just the mouth on my 45ACP ammo, and that's enough. The case doesn't need any expanding, as it comes out of the sizing die. Essentially, my 45ACP die is neck-sizing my brass. Further evidence of this is that most of my RP brass gives reduced neck tension with jacketed bullets, and I have had to toss some W-W headstamped cases, entirely.

 

[LiveLife]

wonder if maybe you would be shooting clean with ANY of those charges and OALS if you had ponied up for a larger expander.

I would have if the need was there.

I usually flare the case just enough to set the bullet and use .377" to .378" taper crimp for all of my 9mm lead loads using Lee carbide dies.

Only reloading variable I changed was the powder charge and the leading went away for the same barrel.

 

[GLOOB]

I usually flare the case just enough to set the bullet

If that works for you, that's fine, of course. And if your sizing die happens to be on the generous side, as is my 45ACP die, then expanding the case any more might not even do anything, at all.

I'm pretty sure a lot of us have sizing dies that never, or at least only rarely ever, get a case beyond the elastic stretch limit of a nominal bullet dimater to begin with. My 45ACP and my 223 dies both fit this category. The expander only serves to give me some tactile feedback as to how much tension that case is going to give, as well as adding the case mouth flare. I have to especially pay attention to 223, because I have to cull about 1% of my cases every reloading cycle due to poor neck tension. OTOH, my 7mm-08 die is so darn tight that it would size a neck as thin as tinfoil several sizes too small.

If I were a betting man, I'd guess that Gamestalker's pistol dies are all on the generous side of the line, seeing as he has loaded for his handguns for years without using a flare/expander die, at all.

OTOH, I'm just as sure there are many of us with dies that size cases smaller than necessary. Well beyond the elastic stretch limit of a nominal bullet diameter. In this case, minimally flaring the case mouth leaves the bullet, itself, to finish expanding the case. This subjects the bullet to greater forces for exactly zero gain in resultant neck tension. That bullet will be harder to seat, but it will be just as easy to pull as if you used a larger expander, approaching the size of the bullet but not quite matching it. That size of expander can not reduce neck tension, no matter how loose or tight is your sizing die, and it may improve the quality of the ammo, particularly for cast bullets, if your sizing die is tight. An expander that very slightly exceeds the diameter of the bullet (by say half a mil) may not be particularly harmful, either. Many of my 223 and 45ACP reloads are probably having less neck tension that what that would cause. Many folks who intentionally do minimal neck-sizing are potentially reducing their neck tension on some cases by a greater amount. In some cases with bolt actions, this is even intentional.

 

[joem1945]

I shoot MO Bullet In .44 mag, .41 mag,357 mag, 9mm, .38 spl, .30 mauser and a couple of others. I only buy B18 except for .45 colt which is B12. I use a slower powder and have no leading or fowling problems

 

[jcwit]

Started to powder coat my 9mm, brought the end to all my problems with 9mm.

 

[GLOOB]

Started to powder coat my 9mm, brought the end to all my problems with 9mm.

I'm glad you figured out a method that works for you. Thanks for sharing.

Edit:
If you would be amenable to furthering my experiment and reporting back on the forum, I would gladly send you, at my cost:

1. An NOE expander plug and Lee 9mm expander body.
2. A sample of MBC Small Ball and Cowboy #2 bullets.
3. If you're brave enough to shoot them, some of my own cast reloads.
4. A Chore Boy, when I can find one, and my sincere apologies if this doesn't work for your guns.

Alternately, I would be interested in acquiring your 9mm sizing die for inspection, after you receive a 9mm sizing die of your choice at my expense.

PM if you're interested! Your access to and history of fouling in 19 different 9mm handguns puts you in a unique place for increasing our understanding of lead fouling.

 

[Walkalong]

I have a .45 ACP sizer that is too tight, and one that is too big. Tolerances happen, and sometimes out of tolerance happens.

I have more than one .38/.357 sizer that doesn't size enough to suit me. One in .32 as well.

 

[MajorMagnetic]

Hello...I have a S&W MP9 that had an extreme leading problem. First it had a rough barrel, which I could only see when I cleaned it with a paste bore cleaner such as Iosso. So I fire-lapped the barrel to get it smooth. Then I switch to 147gr lead bullets because the 147gr has a much longer bearing surface. Then I started using Titegroup powder, to get the velocity down. Now I can shoot 125 rounds with no leading. The fire-lapping really works. Even if I use other lead bullets weights now, it is much easier to get the lead out of the barrel. All I use is Hoppe's #9 and a stainless steel bush.

HTH....MM

 

[GLOOB]

The longer bearing surface is probably not what is helping. I feel like the heavier bullet is probably bumping up, more. Unless your bore has a constriction or tight chamber, you may be able to shoot all you bullets weights without leading by using a larger bullet.

You could either slug your bore or just find out the largest bullet that will chamber in your gun and start there. But if there's a significant hump where the bullet sits, you will most likely need a larger expander. Measuring pulled bullets is the gold standard. Be sure to check the entire circumference of the base of the bullet for any swaging.

I would avoid using a steel brush, if possible. A lot of folks use copper chore boys for removing fouling.

 

[rsrocket1]

If you have a tough time finding Chore Boy, check out Walgreens or similar drug stores. Strangely enough, they tend to carry it. If you can't find it there, go to a hardware store and look for bronze wool which is usually in the paint and sandpaper aisle. HD and ACE usually have it. Even though it's categorized with the steel wool, make sure you get the bronze stuff.

 

[Dudedog]

My 9s are fine with MBC lubed cones and the Lee 9mm expander. When I started loading 9 I started with lead MBC cones having not heard how hard it could be. (no problems, just luck I guess)
I have not had any leading that would not clean up with 4 or 5 strokes with a bronze brush and Hoppes #9. (And I use the 9mm FCD to! lightly)
However others have had leading issues and I have no reason to doubt them.
Even though I have had no issues with the lubed bullets lately I have just been paying the little bit extra to get the coated ones for 9mm/.357/.45, they are just cleaner over all and it's nice not to have exposed lead.

Interesting to hear how the expander change solved the problem.

 

[moxie]

Hope your luck gets better.

I've shot scads of MBC SmallBalls with great results. No leading in my S&W M&P 9c.

Regular RCBS carbide die set. Just enough flare to seat the bullet. Taper "crimp" just enough to remove flare. OD at case mouth is .377".

I use 4.3 grs. Bullseye, mixed range brass, various SP primers, and get 1121 fps avg. OAL is 1.116".