I greet you from Argentina, problems with keyhole

[Ballester molina]

Hello, I am reloading for a bersa bp9cc pistol and I do not stop doing keyhole. I am using a bullet of rcbs # 9mm-124-CN, w231 3.9grains with an oal of 1.080 ".
If someone can give me some advice, I would be very happy and grateful!

[onelight]

Welcome to the forum .
You might tell us what size your are sizing to and lube you use and the over all length you load to , the more information these guys have the better they can answer .

[Ballester molina]

It It is dimensioned at 356 and the lubricant I do not know its composition.

[skeettx]

Hello Ballester molina
Welcome to the site
Two things,

First, what is the diameter of the bullet
after you seat it? You will have to use an inertial
puller and measure the bullet

Second, have you tried .357 diameter bullets?

Mike

p.s. I assume the barrel has rifling and is clean :)

[dverna]

Sometimes the brass case will reduce the bullet diameter during the seating process. Either starting with a larger sized bullet and/or a harder alloy will be helpful. Adding antimony is the least expensive way to get hardness. Your ratio of antimony to tin should be about 3 to 1....My alloy is 92 parts lead, 6 parts antimony and 2 parts tin. It is what commercial cast bullet makers typically use.

Welcome to the forum. My load is also 3.9 gr of 231 with a 122 gr bullet.

[wv109323]

I suspect that the bullet is too small for the bore.
That can be caused by three problems;
1.) The actual bore is over .355" and the bullet is not getting the correct rotation. This should be associated with lead in the bore after firing several rounds. This is where bullet hardness may matter. The harder the bullet the less likely it will strip the rifling and be more likely to rotate.
2.) While the bullet is being seated in the brass, it is being reduced in diameter. This is common because die manufacturers dimension their necking stems for jacketed bullets. Necking stems may be as small .352. Make sure you are belling the cases where lead is not being shaved during seating.
3.) You may be crimping the rounds so much that you are reducing the bullet diameter.
You may oil the bore and drive a bullet through the bore. If you do not have micrometers you can observe the depth of the rifling into the bullet.

[Ballester molina]

the size of the bullet is .356 and once extracted with the inertia hammer it measures 355.5
the inside diameter of the barrel is .353.5 "measured with a bullet through the barrel

[onelight]

That should be okay
Are you getting any lead build up in you barrel ?
I have had certain bullets that tear a target (looks like a keyhole ) that are not key holing particularly when fried at a bit of an angle to the paper but they shot good groups . They were almost always Semi wadcutters at low velocity.
How do you loads group compared to factory loads ? In that gun.

[Eddie17]

I size my 9mm cast boolits to .357. They work with good results in my 9mm hand guns!

[Petrol & Powder]

There's a possibility that .353" is not the groove diameter. I think the OP may be providing us with the bore diameter.

[nueces5]

Hello Ballester, I m from Buenos Aires, I have the same mould and also the same problems, I have already solved them. I am going to send you a private message, you can click on the top right.

[Ballester molina]

I just measured with a micrometer and it gives me a diameter of .354 "
Is it normal that in the place where the bullet struck the side, there was lubricant on the target paper?

[Petrol & Powder]

I can't say that .354" is wrong but it seems a bit small for most 9mm barrels.

Technically they should measure .355" but in reality, most measure a bit closer to .356"-.357"

Your bullet weight is in the right range for a 9mm. The keyhole effect (bullet tumbling when striking the target) suggests the bullet isn't being stabilized.
I would suggest you clean the barrel and try sizing your bullets slightly larger, like say .356".

[Ballester molina]

I can't say that .354" is wrong but it seems a bit small for most 9mm barrels.

Technically they should measure .355" but in reality, most measure a bit closer to .356"-.357"

Your bullet weight is in the right range for a 9mm. The keyhole effect (bullet tumbling when striking the target) suggests the bullet isn't being stabilized.
I would suggest you clean the barrel and try sizing your bullets slightly larger, like say .356".

thanks for your advice, the cannon is like a mirror! Something happens with the bullet because when I use a jacketed bullet of the same diameter as the cast, the keyhole disappears. Could it be the lubricant?

[Petrol & Powder]

Some guns with large bores will shoot jacketed bullets well even when the jacketed bullets are undersized. But those same guns will not stabilize an undersized cast bullet.

[Ballester molina]

unfortunately I have no elements to get a bullet with a larger diameter than .356 "
that same cartridge configuration but with another lubricant I have used a glock 17 with sactifactory results.
I no longer have this gun for testing

[Ballester molina]

can I use liquid allox lee lubricant for a bullet with a traditional lubrication groove?

[Ballester molina]

LLA as they call it on their payments

[skeettx]

Yes, you can

Cast the bullet, and if you can, use harder alloy
Then do not size, shoot as cast, and use the LLA
to lubricate the bullets.

https://www.youtube.com/watch?v=STfJ3qCi5tY

Mike

[Dusty Bannister]

thanks for your advice, the cannon is like a mirror! Something happens with the bullet because when I use a jacketed bullet of the same diameter as the cast, the keyhole disappears. Could it be the lubricant?

rcbs # 9mm-124-CN, w231 3.9grains with an oal of 1.080 ".
----------------
It is usually a good idea to have the cast bullet larger than the groove diameter. Key hole bullet impact is usually due to the bullet not filling the grooves of the barrel. Often this results in leading after several shots are fired. So several questions come to mind.
If you are somewhat experienced with cast bullets, you will know that most times, the bullet diameter must be larger than the factory jacketed bullet. The jacketed bullet shoots well, the cast bullet of the same diameter does not.

The bullet alloy needs to be sufficiently hard, but perhaps not too hard. Can the bullet be marked with a thumb nail? Easy to do or hard to do?

The bullet lube might be too hard and while it helps seal the bore, might not be sufficient for the 9MM . Not knowing what the bullet lube is, does seem to leave unanswered questions.

The RCBS cast bullet manual does not give a cartridge OAL, but it does show the following load data. Cast 09-124-CN 231 powder Start 4.5 grains, Max 5.0 grains. Your load is 3.9 Grains and that seems a bit low given the data for the RCBS manual. This is complicated by the data shown in the Lyman Cast Bullet Handbook for the same bullet giving 3.9 to 4.3 grains as the starting and max loads. The data was developed in different types of test apparatus and with a different bullet alloy. The Lyman data shows the cartridge oal of 1.050" and your oal is 1.080" so is making less pressure in the small case.

If you have fired factory rounds, then you know the ejector pattern and most likely the cast loads are not ejecting the cases as briskly as the factory. With a clean bore, after 50 shots, you are probably not that much undersized, and may just need to increase the powder charge in very small increments and watch for case ejection, primer cratering or other pressure signs.

It is always good to be conservative and always, always, always work up your load to reliable functioning and no more.

[Ballester molina]

excellent when I have a chance to re-shoot I'm going to reload using your advice, and then comment the results

[Ballester molina]

I am very sorry I do not know the exact composition of the lubricant, I think it is grease from the beeswax but I am not sure. from what you all tell me and it is something in which the problem coincides is in the diameter of the bullet

[Petrol & Powder]

Ballester, your problem is far more likely to be a result of the bullet diameter than the type of lube used on that bullet.

[Ballester molina]

I just finished measuring the bullet that goes through the barrel and measures .354.33 ". take apart 7 cartridges and the bullet measures .354 "-355". I am resizing it by settling it!

[skeettx]

YES, that is why I mentioned that on my FIRST posting :)

[Ballester molina]

And now how can I solve the problem of resizing the bullet when it is settled?

[flounderman]

try a lighter bullet.

[Petrol & Powder]

And now how can I solve the problem of resizing the bullet when it is settled?

Use a slightly larger expander.

[Dusty Bannister]

Something to consider also is the maker of the cartridge cases. Not knowing your source, perhaps the brass cases are thicker, or you are using a variety of cases so some are thicker and that could also result in the bullet being made smaller as you seat the bullet in the case. Use only enough crimp to remove the flare as the case neck tension should be sufficient to prevent bullet set back when cycling from the magazine. It appears you are on the way to solving the issue, which most of us will believe is an undersized bullet. Is it possible that you can locate some bullets, similar in form and weight that have been sized and lube to .357"?

[skeettx]

Harder bullet, and bigger sizing die, and larger expander and larger seating die
What brand of dies are you currently using?

[Ballester molina]

I'm using dies lee and speer cases,

[skeettx]

do you have 38 Special dies?

[Conditor22]

do you have 38 Special dies?


The Lee 38 special "powder through die" will expand the case mouth more than the Lee 9MM powder through die; for less resizing the bullet when it is settled.

the bigger you expand the case before seating bullet - the less it resizes the bullet when you seat it.

NO crimp bullet too much, just to where it not move

[Ballester molina]

I have dies lyman for special 38 caliber

[Conditor22]

the Lyman dies won't have a Lee powder through expander for expanding the case mouth. :(

what you need is POWDER THRU DIE EXP 38 SPL / 357 MAG https://leeprecision.com/powder-thru-die-exp-38sp.html

or an https://leeprecision.com/pm-expan-plg-38sp.html for your 9mm powder through die.

You see the small end on the plug expands the case.

[skeettx]

Remember, he is in Argentina.

Try sizing them with lee 9mm dies
Expanding them with 38 Special expander die
Then if needed, powder them with the 9mm Lee die
Then seat some with the 9mm die and some with the 38 Special die
Shoot them and see what happens.
If you need to de-flair the case mouths, LIGHTLY bump them with the Lee 9mm sizing die
Mike

[Ballester molina]

I have a lyman monostation press, so I don't need the function of the powder passing through the die. i could use lyman's expander for 38 special and test what happens

[onelight]

When you use the larger expander just make sure you have enough tension on your bullet to prevent set back in the case when feeding or a malfunction .

[PositiveCaster]

It’s hard to believe that a difference of 0.001” to 0.002” would cause key holing. Leading, yes - but he is getting no leading (like a mirror) so barrel fit should not be the issue.

The OP is using a minimum load in a very short barrel (3.3”), the heavy bullet may simply be under stabilized. Increasing the velocity may solve his issue.



.

[Petrol & Powder]

It’s hard to believe that a difference of 0.001” to 0.002” would cause key holing. Leading, yes - but he is getting no leading (like a mirror) so barrel fit should not be the issue.

The OP is using a minimum load in a very short barrel (3.3”), the heavy bullet may simply be under stabilized. Increasing the velocity may solve his issue.



.

While that is possible; it is not likely. He is using a 124 grain bullet which should cause no problems in any barrel with a twist rate for a 9mm projectile.

Before we start throwing a LOT of different variables into the equation, let's rule OUT an undersized bullet.
In the words of President Lincoln, "One war at a time".

[skeettx]

Hello nueces5

What did you do to solve to problem?

THANK YOU
Mike

[Conditor22]

what lead are you using? lead too soft in 9MM will cause leading.

[JoeJames]

It’s hard to believe that a difference of 0.001” to 0.002” would cause key holing. Leading, yes - but he is getting no leading (like a mirror) so barrel fit should not be the issue.

The OP is using a minimum load in a very short barrel (3.3”), the heavy bullet may simply be under stabilized. Increasing the velocity may solve his issue.



.Actually I have been there with keyholing at 15 yards with a .001" - .002" difference. It was 44 Special loads in a Henry Big Boy. I was shooting Speer .430" swaged 240 grain swc's, and HSM Cowboy factory loads running about .429" and the HSM loads sure did keyhole. I then later switched to Oregon Trail .431" hard cast 240 grain swc's and all of a sudden they were even more accurate and did not keyhole. But between the Speer .430 and the HSM .429" there was an obvious difference.

261805

[nueces5]

Hello nueces5

What did you do to solve to problem?

THANK YOU
Mike

hi Mike,
When I had that problem with my glock and my boolits, start making a PC and increasing the diameter of my boolits solved the keyholing.
In my case I bought the expander for my dillon from Lathesmith and now I use a .358 lee sizing

[JoeJames]

hi Mike,
When I had that problem with my glock and my boolits, start making a PC and increasing the diameter of my boolits solved the keyholing.
In my case I bought the expander for my dillon from Lathesmith and now I use a .358 lee sizingThat's what I figured !

[Ballester molina]

the way to take

[Ballester molina]

hello good afternoon friends, I greet you another from Argentina.
I wanted to share with you that I have solved the keyhole problem I had with the bersa bp9cc.
using a mold reads 105-358- swc resized to .357, Thank you all very much for your advice

[Ballester molina]

hola buenas tardes amigos, os saludo a otro de argentina.
Quería compartir con ustedes que he resuelto el problema de ojo de cerradura que tenía con la bersa bp9cc.
usando un molde lee 105-358- swc redimensionado a .357, Muchas gracias a todos por su consejo

[Conditor22]

Glad you got it worked out

just a summary :)

The 2 biggest 9MM problems

The 2 biggest problems/causes of failure with loading cast in 9MM are OVER-CRIMPING & downsizing the boolit when seating.
The 9MM has a tapered case.

Crimping, I use the Lee FCD and only crimp to where the boolit won't move when the cartridge is pushed against a hard object.

For seating I like the NOE neck sizing dies so much I talked with a member ob CB who made a Lee powder through die with the NOE profile of several different diameters. I've had good luck expanding the brass using the same diameter expanding plug as the boolit diameter (brass springs back .001 after expanding and that.
.001 does the job holding the boolit in place!

A 38spcl/357mag expander plug should work also

I used to expand the neck with the NOE neck sizing die the use the Lee powder through setup to charge the case.

Ues a kinetic boolit puller and make sure you're not downsizing the boolit in either of these operations.

this will go a long way toward tightening up your groups and preventing leading/tumbling

I've found that barrels with shallower grooves prefer harder alloy. COWW, PC'd, quenched, sized .358 solves a lot of problems