MtGun44
07-10-2011, 02:40 PM
We have been having a steady flow of "9mm leading and hitting sideways" sort of threads, so I thought it might
be useful to report what I just did to check out my "new" Walther P1 (P38 w/aluminum frame) 9mm handgun before
shooting boolits in it.
First, I had fired about 20 rounds of factory 9mm ball ammo through the pistol, just to see if it would work properly
and how the accuracy was. No problems, and I was pleasantly surprised that the trigger was decent in both SA
and DA modes, and the sights are not at all bad.
First, let's clean the gun up a bit. Brass brush and a couple patches, nothing big. Now, I picked up a Lee 358-105-SWC
boolit that I happened to have handy and a 1/4" steel rod with a .25 ACP case permanently jammed on one end. I
dismounted the barrel and dropped the boolit into the chamber, and drove it through the lubricated barrel with a small
brass hammer. Before it miked at .359 x .360 and after, two rifling grooves were .3585 and one was .358, so the bore
is a good bit oversized, fairly common in European 9mms in my experience.
So now I take a case that was fired in the gun and chamfer the mouth and clean it inside with a brass brush and check
the inside with my pin gauges. A .356 (minus) pin gauge will just barely enter the fired case mouth. This is worrisome
because it is pretty clear that I will need .359 boolit or larger to make this one work, and now there is a question of
whether the chamber will accept (and release when fired!) a loaded round with a .359 boolit seated. I will start VERY
low and see if the chamber will safely release the fat boolits.
So now, I need to make up a dummy round and see how it will chamber with a .359 boolit seated. I size and expand a
case with my single stage 9mm die set (I have a Dillon 550 setup, too) and seat a .359 Lee 358-105-SWC boolit to the
crimp groove and then run it into the TC die. I drop the dummy round and it chambers up until about 1/8" is protruding
at the back. Since I don't know much about the P38 design, I slip the slide onto the barrel and close it all the way, noting
that the breech face is recessed about 1/8" into the slide, so the round is fitting the chamber just fine - good news!. Next, I
want to see if the brass is sizing down the .359 boolit when it is seated. I measure the expander in the die set and it
measures .3535, so there is some concern that the expanded case may size down the boolit as it is seated.
I also inspect the lead shoulder of the boolit which is protruding from the case, looking for rifling marks. I see nothing, also
good. If I was seeing rifling, or the round would not fully seat with 1 lb or less force, I would seat the boolit deeper
until it would. TC setting is also a controlling factor in the dummy round seating properly. Both are OK for my dummy round.
Pulling the seated boolit from the dummy round is next, and it still mike's out at .359, which is great news. So with my std
air cooled wheel weights with this Lee boolit, unsized at .359 and seated with my normal single stage press dies, I can
expect to deliver a boolit that is at least 1/2 of one thousandth of an inch larger than the groove diameter. I hope that is
enough, and it likely will be.
So - now I know that I probably need fatter boolits in this gun than my normal .357 or .358 diameter that I use in with my
Lee 356-120-TC mold which is my most commonly used 9mm boolit. I will try the .358 version of this one and see if it is
big enough to work in the .3585 groove diameter barrel without leading. I won't be suprised if it is not big enough.
So - if you are starting out with a 9mm this is the path you should take.
1. Slug the barrel, and measure groove diameter with a MICROMETER. A caliper is typically only +/- .001 or even .002"
accuracy and this isn't good enough for this job. You need a micrometer with .0001" accuracy for this job. Enco tools
online frequently has them on sale for under $35.
2. Plan on using a boolit about .001" larger than groove diameter, and you might even need .002 larger.
3. I recommend the two Lee designs 358-105-SWC and 356-120-TC used with NRA 50-50 lube. I do not
recommend the tumble lube designs from Lee, although some have had success with them, many have had serious
problems in 9mm. The Lee Alox tumble lube system is marginal, but very cheap to get started in, a signficant
advantage for the new caster. It seems to work most reliably in lower pressure and velocity loads.
4. Make a dummy round to set the LOA and degree of taper crimp (TC), and see whether a case with a boolit the correct diameter
will chamber properly. Boolit diameter MIGHT be too large to chamber, and LOA and TC are set to work with your
chamber.
5. Pull the boolit from the dummy round and make sure you have not sized it down during the seating process.
If you follow this routine, you will have a good chance to have good ammo which is accurate and does not lead, right
off the bat. Also, do not think that you need a super hard alloy or water dropping to harden them for 9mm. Air cooled
wheel weights will be just fine. In fact, too hard and too small are the root cause of most 9mm problems with boolits.
Bill
be useful to report what I just did to check out my "new" Walther P1 (P38 w/aluminum frame) 9mm handgun before
shooting boolits in it.
First, I had fired about 20 rounds of factory 9mm ball ammo through the pistol, just to see if it would work properly
and how the accuracy was. No problems, and I was pleasantly surprised that the trigger was decent in both SA
and DA modes, and the sights are not at all bad.
First, let's clean the gun up a bit. Brass brush and a couple patches, nothing big. Now, I picked up a Lee 358-105-SWC
boolit that I happened to have handy and a 1/4" steel rod with a .25 ACP case permanently jammed on one end. I
dismounted the barrel and dropped the boolit into the chamber, and drove it through the lubricated barrel with a small
brass hammer. Before it miked at .359 x .360 and after, two rifling grooves were .3585 and one was .358, so the bore
is a good bit oversized, fairly common in European 9mms in my experience.
So now I take a case that was fired in the gun and chamfer the mouth and clean it inside with a brass brush and check
the inside with my pin gauges. A .356 (minus) pin gauge will just barely enter the fired case mouth. This is worrisome
because it is pretty clear that I will need .359 boolit or larger to make this one work, and now there is a question of
whether the chamber will accept (and release when fired!) a loaded round with a .359 boolit seated. I will start VERY
low and see if the chamber will safely release the fat boolits.
So now, I need to make up a dummy round and see how it will chamber with a .359 boolit seated. I size and expand a
case with my single stage 9mm die set (I have a Dillon 550 setup, too) and seat a .359 Lee 358-105-SWC boolit to the
crimp groove and then run it into the TC die. I drop the dummy round and it chambers up until about 1/8" is protruding
at the back. Since I don't know much about the P38 design, I slip the slide onto the barrel and close it all the way, noting
that the breech face is recessed about 1/8" into the slide, so the round is fitting the chamber just fine - good news!. Next, I
want to see if the brass is sizing down the .359 boolit when it is seated. I measure the expander in the die set and it
measures .3535, so there is some concern that the expanded case may size down the boolit as it is seated.
I also inspect the lead shoulder of the boolit which is protruding from the case, looking for rifling marks. I see nothing, also
good. If I was seeing rifling, or the round would not fully seat with 1 lb or less force, I would seat the boolit deeper
until it would. TC setting is also a controlling factor in the dummy round seating properly. Both are OK for my dummy round.
Pulling the seated boolit from the dummy round is next, and it still mike's out at .359, which is great news. So with my std
air cooled wheel weights with this Lee boolit, unsized at .359 and seated with my normal single stage press dies, I can
expect to deliver a boolit that is at least 1/2 of one thousandth of an inch larger than the groove diameter. I hope that is
enough, and it likely will be.
So - now I know that I probably need fatter boolits in this gun than my normal .357 or .358 diameter that I use in with my
Lee 356-120-TC mold which is my most commonly used 9mm boolit. I will try the .358 version of this one and see if it is
big enough to work in the .3585 groove diameter barrel without leading. I won't be suprised if it is not big enough.
So - if you are starting out with a 9mm this is the path you should take.
1. Slug the barrel, and measure groove diameter with a MICROMETER. A caliper is typically only +/- .001 or even .002"
accuracy and this isn't good enough for this job. You need a micrometer with .0001" accuracy for this job. Enco tools
online frequently has them on sale for under $35.
2. Plan on using a boolit about .001" larger than groove diameter, and you might even need .002 larger.
3. I recommend the two Lee designs 358-105-SWC and 356-120-TC used with NRA 50-50 lube. I do not
recommend the tumble lube designs from Lee, although some have had success with them, many have had serious
problems in 9mm. The Lee Alox tumble lube system is marginal, but very cheap to get started in, a signficant
advantage for the new caster. It seems to work most reliably in lower pressure and velocity loads.
4. Make a dummy round to set the LOA and degree of taper crimp (TC), and see whether a case with a boolit the correct diameter
will chamber properly. Boolit diameter MIGHT be too large to chamber, and LOA and TC are set to work with your
chamber.
5. Pull the boolit from the dummy round and make sure you have not sized it down during the seating process.
If you follow this routine, you will have a good chance to have good ammo which is accurate and does not lead, right
off the bat. Also, do not think that you need a super hard alloy or water dropping to harden them for 9mm. Air cooled
wheel weights will be just fine. In fact, too hard and too small are the root cause of most 9mm problems with boolits.
Bill