Leading in BBL throat, 9mm drama restarts

[milprileb]

I thought I had this under control with 9mm leading. I got to the point that I had zero leading using my alloy, BAC lube and powder charge and seating depth. I shoot RN 124gr and TC 120 gr bullets. I was getting not so hot accuracy but clearly there was no leading.

My .358 sizing die (I began with .356 and worked up) did produce bullets that did not lead the bore and were more accurate than .356 and .357 sized bullets but still, I was not getting the accuracy I know the pistol needs.

So, eliminating all other ways to improve cast bullets, I got the M die and yes, my bullets shoot more accurately than before (that validates they were being swaged upon seating as has often been discussed on this forum) but

I now have leading in the throat of the barrel. Maybe I seated these too long and got to seat deeper ?

I can think of no reason for leading in the throat. My load is 3.8 gr WW231 pushing 124 gr RN or 120 TC and these are not hot loads at all. Now I am wondering if .358 is wrong sizing when using a M die for my bore and I ought to
try .357 with M die.

Before I go to another battery of tests going down in bore size of bullets, will seating depth effect bore leading of throat ?

I don't think this is the alloy as this same alloy has worked with this load and not leaded when bullets sized to .358 and shot with same loads before I got the M Die.

I think this captures me at the momemt: :killingpc:killingpc:killingpc

I got this pound of Blue Dot here looking at me, before it did not give me better accuracy but its a slower
powder so I wonder if a retest of it might yield no leading in throat with no changes in seating depth of bullet .

Any ideas would be a life line thrown to a drowning man at this point.

[sabrecross03]

Leading in the throat is due to the bullet not sealing the bore upon being shot. The gases are escaping after detonation.

What is you OAL on your bullets? What is your bore diameter? Are you producing .358 bullets from your molds? Most likely, your 9mm case walls are swaging the base of the bullets and causing the problem I described above.

Hope this helps.

[milprileb]

There is one clue I did not state up front. My loads are now accurate but have leading in throat. Does this make any sense at all ?


When I did not use M die to expand the case, my .358 sized bullets did not lead bore with this same alloy and powder charge and bullet lube. Accuracy was so-so. Clearly to my mind the
bullets were being swaged when seated.

Now I use M die and bullets are leading throat.

I use 1.100 COAL which was same used before I had the M Die. The only variable that has changed is I am expanding cases with M die so my bullets won't swage upon seating.

Should I seat bullets deeper ?

bullet not sealing the bore upon being shot Noted fully and that has me stumped as I don't understand how this is happening since the only change is use of M die.

I really am stumped here. I am missing something obvious , hopefully one of you will pick up on it.

The bore of pistol is .357. My bullets dropping out of mold are .360. My alloy is 2# lead to 8#wheel wts, water quenched. My lube is BAC.

[Shiloh]

I have that mold. It's too small. Sub .357 at the mold lines. I had no leading with it, but it shot 5" at
25 yds.

Shiloh

[williamwaco]

Water quenched!

Drop that step and try Lee liquid alox.
Alox is the only lube I have ever been successful with in the 9mm.

You can test my theory by dipping the nose of the already loaded rounds into an alox lube up to but nit including the mouth of the cartridge case.

See this article.

http://www.reloadingtips.com/pages/lla_bullet_lube_2.htm

for more on the process of relubing already loaded cartridges.

And: M dies are great. I use them regularly. But you still need to pull a bullet. Just because you are using an M die doesn't mean you are NOT swaging your bullets on seating. Don't just measure the body of the bullet. Measure the very base too. The case is tapered on the inside and it may be springing back after the M die expands it.




9mm. The cartridge I love to shoot but hate to load.
.










.

[milprileb]

Which mold Shiloh... the RN or the TC Lee bullet molds?

I run into a lot of folks who had issues with the 120 gr TC mold bullets shooting well and had
better luck with 124 gr RN bullets.

I may be in a mind bend here as I like the TC design since the #68 clone 45acp 200 gr Lee bullets shoot so well in 45acp and I seem to always think this SWC design should do same in 9mm.

Maybe ditch 120 TC ???

[milprileb]

williamwaco

my loads have always had same alloy, same water quenching and use of BAC and never leaded.

I don't think lube and water quenching is in this mystery situation I am experiencing.

Does anyone think I have wrong seating of bullets ? That 1.100 is too long ?

This leading bullet load is most accurate ever out of this 1911 in 9mm. So I got the accuracy
I wanted but now have leading.

Before M Die: same everything but no leading and 5 inch accuracy.

I am thinking Shiloh has something on the mold and bullet style.

[odfairfaxsub]

9mm. The cartridge I love to shoot but hate to load.

i get a smear of leading towards the front of my barrel. loading with everything from red dot to universal clat tech to unique to tripple aloxing to water quentching so on so forth. i just deal w the smear and keep shooting my cookie cutter groups.

lead removal cloth helped the worst it like made the bore smooth

[HeavyMetal]

First; seating depth in a 9mm plays a very big roll in pressure curve so some slight changes, deeper, can really run the pressure level up.

So I'll make a few basic suggestion that you may, or may not, have tried already.

First lets select one boolit and stick with it until the issue is fixed. I have the Lee RNL, not tumble lube, and have been very happy with it strong hint to use this one!

1 have you pulled the barrel and done the dummy round thing? This means dropping a dummy round into the chamber, purposely left to long, to see how high it sits over the barrel hood? Then you slowly continue seating the boolit into said dummy case until the case head is flush with the barrel hood.

This removes any chance of the boolit being "cocked" as it pass's into the bore from the chamber area. In most case's I wind up seating a few thousandths less than the perfect fit to allow a little flex in chambering.

This also "solves" any "loose" headspace issue.

2 double check the diamensions on the M die the first step may be a little small, or not, and this could be swaging just a small portion of the boolit base on seating.

3 have you changed brands of brass? I've found case's that have cannalure's in them can damage boolits on seating as well "if" they are high enough up on the case to "interfer" with the boolit. Case's set up for light HP bullets are a case in point.

4 have you changed any component in the load? different primer?

5 once you've done, or confirmed you've done, all of the above take another shot at that pound of Bluedot the slower powder may be just what your looking for.

[RobS]

From the sounds of things it's possible that when you didn't have the M-die you had more case tension which could have created more pressures at the start of the barrel. If your boolit comes out of the case undersized at the very edge of the base of the boolit due to seating then it's hard to start life off without leading. I am assuming you've slugged your bore and pulled a loaded round to measure the very edge of the boolit's base to ensure "fit" for your gun. As to accuracy, well there are many variables but even though you are using a starting or minimum load of 231 this powder is a quicker powder for 9mm; it has more energy. Using a slower powder would help on many fronts (leading/accuracy). WSF is a great powder for 9mm and cast.

[milprileb]

Many thanks for the info Gents. I will pursue those immediately.

Will do tests with WW 231 and Blue Dot as I got both on hand. WSF has to wait.

I will focus on RN bullet as suggested.

[RobS]

Blue Dot will be easier on the start of the boolit into the barrel that's for sure. The only thing about BD is it doesn't meter as well so there's caution in those regards.

[milprileb]

RobS: many thanks on that point. I can't trust Dillon or Lee Pro type progressives measures
to toss it consistently. I got to use a powder measure approach.

It does meter better than 800X.... that stuff is a PITA in any measure. Got to tap my measure with wood block on base several times to get it to settle and toss almost consistent charges into load blocks. Painfully... it has always given best accuracy and shot groups in 9mm but its so much of a root canal to use.

[fecmech]

I've used BD lot when loading the 9MM on a progressive with a bushing type powder measure and always got good accuracy results. Really, in the grand scheme of things does it matter with BD if it varies a few tenths of a grain up or down? You cannot overload a 9MM case with BD, there isn't enough room in the case. Max loads of 8+ grs only give 30KPSI and that fills the case to the top. IMO BD is a nice safe slow powder that works well in the 9MM with cast bullets.

[milprileb]

FECMECh: I will run a test with my Dillon measure and see if I can live with variance. I know my Lee Pro scatters the charges all over the map and I don't fault it ... those flakes of BD are problematic to drop consistly.

Maybe I can get by with Dillon but it won't be the 650 progressive measure, it will be the old 450 push manually knob measure. It seems to be a bit more consistent in dropping powders.

All the best and thanks for input and experience with BD and 9mm.

[runfiverun]

my take on it is that the m die lessened neck tension lowering your pressures.
try upping the powder charge.

[Iron Mike Golf]

...my loads have always had same alloy...

Please tell us how you know your alloy is the same.

Same recipe or same batch of ingots? If the same batch of ingots, please tell us how you make sure the ingots are consistient throughout the batch.

Jeff

[Bullwolf]

It would also help if you load a round as you normally would, and then after crimping it, went and puled the loaded projectile.

Try using either a kinetic (hammer style) puller, or if you don't have access to one, you can even grip the bollit with pliers or a similar tool while it's above the press, and use the press ram's down stroke to pull the boolit.

Measure the pulled boolit with a micrometer. Get back with us here as to what the exact size is after pulling a loaded round. Until you do this, even though you are using a M-die you are just hoping and guessing really that your boolit is still the right size.

You really want to be completely positive that your finished boolit is still the correct size.

If one has bothered to take the time to slug a barrel, this is a relatively easy step to do in comparison.

There are a lot of factors like brass thickness, dies used, expander plug type and size, boolit hardness, bullet size, and even spring back that could affect your finished product, thereby letting your loaded boolit end up being too small.

It's just another variable to remove from the equation.

- Bullwolf

[FirstBrit]

I thought I had this under control with 9mm leading. I got to the point that I had zero leading using my alloy, BAC lube and powder charge and seating depth. I shoot RN 124gr and TC 120 gr bullets. I was getting not so hot accuracy but clearly there was no leading.

My .358 sizing die (I began with .356 and worked up) did produce bullets that did not lead the bore and were more accurate than .356 and .357 sized bullets but still, I was not getting the accuracy I know the pistol needs.

So, eliminating all other ways to improve cast bullets, I got the M die and yes, my bullets shoot more accurately than before (that validates they were being swaged upon seating as has often been discussed on this forum) but

I now have leading in the throat of the barrel. Maybe I seated these too long and got to seat deeper ?



Hi, you have already received some good hints from other shooters, but maybe I can add a couple of issues which I feel are also important.
a) small changes in seating depth does have a big impact on chamber pressure especially on small case volume calibers like the 9 mm Para. I just run a couple of parameters with your basic load through my QuickLoad software.
OAL of 1.100" should give about 20,000 psi with 3,8 gr. Win. 231
OAL of 1.060" about 24,000 psi
OAL 1.020" about 29,500 psi.
b) water quenching can be a bit of a hit & miss affair. Final hardness much depends on the temperature of the bullets just before they hit the water. To the best of my knowledge there will only be a significant effect if there are some traces of Arsenic or some other metals in your melt. Just wheel weights and roofing lead won't get you very fair. If you size the bullets after quenching from 0.360" to 0.357" then any surface hardning effects will be lost through the sizing. If you want to be serious about heat treating your bullets try getting hold of some hard bird shot since this invariably contains arsenic in small amounts.
c) I am coming to the opinion that with my 9 mm pistol and the 147 gr. lead bullets( 0.357") it gives better accuracy if I use my RCBS .357 mag. expander button ( 0.354" on the cylindrical section) rather than the original RCBS 9 mm expander button ( 0.352" on the cylindrical section).
d) Bullet alloy needs to be fairly hard for the 9 mm. I prefer BHN 16 or there abouts ( 92/6/2 alloy). basically because bullet travel a P-max for the 9 mm. is fairly low about 0,20" and the alloy needs to be fairly tough to withstand the strains of acceleration both linear and spin.
e) finally, the 9 mm. can be very finicky when it comes to brass. Most pistols don't take to mixed brass ( manufacturers) - probably due to the differences in case volume which again can affect chamber pressures dramatically. I also supplement my brass supply by collecting fired cases from the range. I sort by manufacturer and weed out the light and heavy ones and thus keeping the mid-range of +/- 1 gr. I even go to the extent of chamfering the primer holes inside and out. Whether that is really necessary I don't know, but at least my loads seem to like it at it helps build my confidence in the loads I shoot.

Best regards,
Adrian - Germany.

P.S. Here in Germany the serious target shooter using CB loads tend to go for the medium burning pistol powders like Hodgdon Longshot, VV 3N37 or something very similar.

[milprileb]

Will try to answer some of the questions you all propose so perhaps some clues will surface on what is happening here.
a. Alloy is 15 BNH. Its the same lot of bullets dropped and fired with same load, in same pistol before , with same lube but with no leading. THen using M die, I am getting leading so that is a ???
b. Pistol bore is .3575. Bullets sized to .358 and bases are .358.
c. I use lead (melted from X Ray machine) and WW. 2 # PB to 8#WW. I weigh it and this alloy has never leaded bore before.

My COAL was 1.100 for RN 124 gr and for 120 gr TC Lee bullets.

Could the issue be the M die sized case to big and I am losing tension on the bullet plus
the 1.100 is too long in the case?

I made a box of ammo up last night and used 1.095 and a lighter crimp: will see how these do.

[gefiltephish]

If you're still using the m die plug that came from lyman, it's too small for the bullet size you're using. You're likely still getting swaging. To be certain, seat a bullet, pull it and measure. As already pointed out by others, use the barrel drop test to determine oal.

<edit>Just noticed this:

b. Pistol bore is .3575. Bullets sized to .358 and bases are .358.
Is that right - .3575?? If so, you may need to size to .359 and good luck getting it to chamber (without getting stuck when you need to clear the loaded weapon).</edit>

[milprileb]

gefiltephish

So many variables and I will re measure this plug. However, once I use M die , my bullets at .358 slide into case easily with mild finger pressure. Could it be I am making the case too big and that my neck tension is too loose.

But... I will remeasure plug and double check. Thanks for the heads up... its something worth checking on for certain !~

[Cherokee]

I have followed your posted experiences with the 9mm. I have both the RN and TC Lee conventional 6 cv moulds. I have found the TC to be more accurate for my guns (1911, Witness, XDm) than the RN, but the RN still does well. My cast bullets are of a 3/3/94 alloy. I initially used a 2/3/95 alloy but the accuracy was not as good. I use .357 size and get no, or very slight leading. I use 3.8/231 with the RN but it is more accurate with HS6. The best TC load is with Power Pistol but HS6 is real good also. What ever leading I may get cleans up so easily I don't worry about it.

[HeavyMetal]

You can seat the boolits with mild finger pressure!!

Yep the M die is making the case to big for the boolits size! Measure the small part of the M die it should be 356 for a 358 boolit! You should not be able to seat a boolit in the manner you describe.

[Beau Cassidy]

Your alloy sounds a little soft to me.

[FirstBrit]

Will try to answer some of the questions you all propose so perhaps some clues will surface on what is happening here.
a. Alloy is 15 BNH. Its the same lot of bullets dropped and fired with same load, in same pistol before , with same lube but with no leading. THen using M die, I am getting leading so that is a ???
b. Pistol bore is .3575. Bullets sized to .358 and bases are .358.
c. I use lead (melted from X Ray machine) and WW. 2 # PB to 8#WW. I weigh it and this alloy has never leaded bore before.

My COAL was 1.100 for RN 124 gr and for 120 gr TC Lee bullets.

Could the issue be the M die sized case to big and I am losing tension on the bullet plus
the 1.100 is too long in the case?

I made a box of ammo up last night and used 1.095 and a lighter crimp: will see how these do.

Based on the informations you have provided it could be on your previous loads you were getting obturation ( spelling?) on your bullet bases and this gave you a better gas seal and hence no leading. Now it might be that if your M die is slightly larger than your previous neck expander this could give you less neck tension than before and hence lower chamber pressures. But this might not be the only rationale. Alloys with antimony or where antimony is higher than the tin content will tend to harden with age ( usually in 3-6 weeks). Is it conceivable that you bullets are now harder than before? This could also be a resaon why obturation is no longer happening. Try bumping up the chamber pressure somewhat by either using 4.0 gr. of W-231 or reduce the OAL from 1.10" to say 1.06"
Can you think of anything - else not obvious to me or others on the outside so to speak that could cause a possible change in chamber pressure between your old loads and current ones? Have you scrupulously cleaned the barrel recently?

Best regards,

Adrian - Germany.

[plainsman456]

Just one question from me.Why do you water quench boolits for the 9 MM?
I have been loading for the 40 S&W and just use air cooled.
I hope you get this figured out.

[milprileb]

Guys, I am spinning here. I thought I had all the mystic variables under conrtol for 9mm but now I am in free fall again. To the range for tests and will go from there.

I got to say this for 9mm... its not like 45acp or any other reloading experience I have ever had !

[RobS]

I got to say this for 9mm... its not like 45acp or any other reloading experience I have ever had !

Correct, think of it more along the lines of reloading for a magnum. The 9mm operates in the general pressures as a mag and then there is the added complication of the brass being short and tougher than let's say a 357 mag.

[MtGun44]

No need to water quench. Straight wwts works fine at .357 or .358 in my 9mms.

Bill

[gefiltephish]

I have to agree with others that your m die plug may be too big rather than too small. I don''t know what your mold is dropping, but what happens if you seat an unsized bullet in a case expanded with the m die? Will it chamber? If so, can you clear it? Try it with a dummy round. If all works out ok, take a few rounds to the range. I seat that bullet to 1.060 in my XD.

[357shooter]

Guys, I am spinning here. I thought I had all the mystic variables under conrtol for 9mm but now I am in free fall again. To the range for tests and will go from there.

I got to say this for 9mm... its not like 45acp or any other reloading experience I have ever had !I've been keeping up with this thread, my head is spinning too. Keeping things simple helps me find the most accurate loads so maybe it's time for that.

1) You had no leading without the M die. You tried it to improve accuracy. It seamed to help with that, but the improvement is cancelled out by the leading. So put the M die on the shelf. Now there's no leading problem to solve.

2) Work up the most accurate charge with your powder. I don't know if BD is a commonly used and accepted good powder in 9mm, if not. Use one, maybe W231 or Unique, if they are known to be accurate in 9mm. Work up the best load and find a good OAL.

3) From there, experiment with not quenching, using softer alloys and larger bullet diameter to see if accuracy improves more. Using the max diameter bullet that will chamber and cycle is a good idea to try, if you haven't already at this point. It may be time to try the M die again. If it starts to lead, put it back on the shelf.

4) Then try other powders, using the best OAL, diameter and alloy from the prior tests.

That's the bascially the approach I take, and it works well for me.

[popper]

Other than 1911, you didn't state what pistol you are using. Some have tapered chambers, some are pretty straight. As the M die increased your accuracy, I would suspect your chamber is straight. As your bullets push in by hand, you don't have enough neck tension, the pressure is low and the chamber isn't sealed. Bullet base gets eroded and you get leading at chamber end. You state it is a medium load, have you tried increasing the load to get better accuracy without the M die? Did you work out your original load for accuracy without the M die? If you chamber is straight, you can set OAL longer and increase powder to get better accuracy.

[milprileb]

The reason I went to M Die was my belief my .358 bullets were swaging down on seating. The M Die set conditions that precluded that from happening. I hit range today with bullets seated deeper and if leading reappears, I will change out powders from WW231 to BD.

The pistol is a Taurus 1911 in 9mm.

[Larry Gibson]

"My alloy is 2# lead to 8#wheel wts, water quenched"

There in lays the problem. Your WWs probably have very little tin in them (>.05%) and probably higher that 3% antimony. The antimony is crystalizing seperate from the lead, especially when WQ'd. Suggest you add 2% tin to the alloy. The tin will combine with the antimony and mix into the lead solution so the antimony won't crystalize seperately. This will give you a very good ternary alloy which is what is needed. You do not have a good ternary alloy with just your WW + lead at 80/20. Try the + tin bullets both WQ'd and AC'd, let the AC'd cast bullets age for 2 weeks before loading and shooting.

The bullets you use, sized a .359, lubed with BAC and loaded over that load using the technique you use should not lead. Quit "spinning" and use a correct alloy.

Larry Gibson

[357shooter]

The reason I went to M Die was my belief my .358 bullets were swaging down on seating. The M Die set conditions that precluded that from happening. I hit range today with bullets seated deeper and if leading reappears, I will change out powders from WW231 to BD.

The pistol is a Taurus 1911 in 9mm.The fact remains, before the M die there was no leading. Afer the M die there is leading. Put it on the shelf and pursue accuracy without and without the leading. Per my prior post, I believe popper made the same suggestion too. Your belief that the bullets were swaging down, and that was causing a problem, was disproven. Instead, it created a problem. IMHO

Changing powders is an option, after working up the most accurate load with W231, without the M die, but not beforehand. Otherwise you are spinning your wheels.