8mm Nambu Cartridge Conversion
 

One of my interests is cartridge conversions. This can be for pistols/rifles that are 'obsolete' and no one makes ammunition for them, or 'wildcats' that are not made at all except by enthusiasts. Conversions are not everyone's choice, but I find them fun & interesting.

Disclaimer: I am not responsible for any damage or injury incurred by these procedures. Wear safety glasses at all times; do not operate machinery while impaired. Approach any listed reloading data with caution. I am not soliciting work or services, and am not advertising anything for sale. There are many ways to do these cartridge conversion operations, this is just one of them. I encourage any interested parties to experiment and add your own experiences/conclusions.

8mm Nambu ammunition is hard to find. Making your own is the easiest way to get it. I decided that I needed a donor cartridge case at least 7/8" long, straight sided, and with a base diameter of ~.407".

My local gun shop has a box of 'range dug-ups' of all kinds. I took my vernier down and picked out some likely candidates. I'll start with the rimless first, since they're the 'easiest'.

Here is my assortment. All fired at least once; all old & dirty.

[first pic]

First order of business is de-priming them. I use the primer pocket to locate my cutting measurements from, so I use a 44 Magnum sizing die with a 22-250 de-capper. I don't want to stretch or squeeze the cases yet; this is the easiest way (with the assorted die sets I have) to de-prime the cases. The 44 sizing die does not come in contact with the case but holds the decapping pin in place.

[second pic]

Now I fit the case with a mandrel (just a drill bit that fits snugly in the case neck) and chuck it in the lathe. The tailstock has a live center and is set up so that pushing the case up against the tailstock/live center [set at 0] and then tightening the chuck will hold the case cutter right at 7/8".

[pics 3 & 4]

I break all sharp edges and de-burr in & out.

[pics 5 & 6]

Now we need to swage these cut down cases to size. These cases were all right at the ~.415" base measurement; I want .407" - .410". A member on another forum mentioned that by forcing rimless brass into a 30-30 Winchester sizing die, Nambu cases could be formed. The 30-30 die has the correct taper...IF you jam it in approximately 3/8" past the die rim. So to start, we run the cutdowns into the 30-30 sizing die as per normal fashion. Lubed generously.

[pic 7]

The next step is to remove the 30-30 die and invert it in my arbor press with a case inserted. I run the ram down until it is flush with the die.

[pics 8 & 9]

Now I position a plug to ram the case further into the 30-30 die, and press it in until it is flush. The case can just barely be seen after this operation.

[pic 10]

To get the swaged case out, I flip the die over and press it out with a 1/4" rod.

Here's a closeup of the die-to-press adapter, the plug, and the rod along with the 30-30 die and a compressed case. It is now ~.409" at the base.

[pic 11]

At this point I load all these cases into my tumbler and let it run overnight using crushed walnut shell media.

There are several sites with mention of using 38 Special cases to make 8mm Nambu cartridges. RCBS even makes a conversion die set. I decided to make some of my own 8mm cases from 38 Special.

Using once fired cases, I de-primed them using my 44 Special sizing die with the 22-250 decapping pin. The rim needs to be turned down to ~.415", so I mount a case on a 9mm drill bit and clamp it in my lathe chuck. Using a parting tool I turn the 38 Special case rim down to ~.415"

[pic 12]

Next step is to cut the extractor groove, again using a parting tool, but smaller. I cut it to .357" dia.

[pic 13]

After grooving, I cut a chamfer on the forward edge of the extractor groove, using the wider parting tool again.

[pic 14]

After the chamfer is cut and before releasing the case from the chuck, I run a file against the outer edge of the rim to facilitate the extractor engaging the case when feeding.

Cases are now ready for forming.

I also made up some 38 Special cases without cutting the extractor groove. But I needed to expand the cases, as the OD was [IMHO] excessive for the 8mm chamber - Something like .030" smaller. I've been told that unexpanded 38 Special case used for 8mm Nambu could/would split when fired. To counter this I made up my own 'expanding die' out of 1" steel rod.

[pic 1]

Turned down to ~ 7/8" diameter. The die body was also drilled & internally threaded to 1/2" x 20tpi for my 'ram'. The die body was also drilled for 3/4 of its length to 27/64" to contain cases expansion.

[pic 2]

Threading the die body OD to 7/8" x 14tpi.

[pic 3 and 4]

Turning the 'ram' out of a 1/2" x 4" SHCS.

[pic 5]

Expanding die in RCBS press, cranking out expanded 38 Special cases.

[pic 6]

Close-up of expanding die.

[pic 7]

Some expanded cases.

[pic 8]

One of our members mentioned having reloaded 8mm Nambu ammunition that was made from 40 S&W brass. I was able to filch some once-fired 40 S&W cases out of the brass barrel at my local club for conversion.

Using the fired cases, I de-primed them using my 44 Special sizing die with the 22-250 decapping pin. I left the case rim and extractor grrove alone.

I've read of extraction problems with the 40 S&W case conversions. The 40 S&W case is oversize for the 8mm Nambu specs, so I swage these cases. These cases were all right at the ~.415" base measurement; I want .407" - .410". I use the 30-30 Winchester sizing die again to resize the cases, same procedure as described previously for oversize cases.

My 40 S&W cases are now ready for neck forming.

Here are the cases that have been swaged or expanded. They are -

38 Special
375 Winchester & 30-30 Winchester
25 Remington & 32 Remington
40 S&W

These are now all straight-walled cases. The next step is to form the case necks in the RCBS 8mm Nambu sizing die.

Forming the neck.

RCBS 8mm Nambu 3-die reloading set. This is an older set, and the seller included an RCBS #25 shell holder. Nothing special here; lube the case liberally and run it through the RCBS 8mm Nambu sizing die with de-priming pin removed.

[Pic 1].

40 S&W in press.

[pic 2]

38 Special in press.

[Pic 3].

Trimming OAL to ~.862".

[Pic 4]

The various cases neck-formed but not yet trimmed.

[pic 5]

An experiment using a suggestion by a member in another thread (which I can't find now; sorry!), to power trim the cases.

[pic 6].

Finished 40 S&W case converted to 8mm Nambu and ready to reload.

[pic 7]


Notes

- The 375 and 30-30 Winchester cases were the most difficult to form & neck
- The 375 and 30-30 cases need the primer pocket reamed; the rest don't
- Winchester brass is softer than Remington, R-P, and military
- The rifle brass has thicker case walls, thicker base, and large primer
- 38 ACP/38 Super cases could also be expanded to form 8mm Nambu in the same way as the 38 Special. No groove need be cut and the rim need not be trimmed. I did not have any so there are no pics/comments.
- I test fit about 1 in 10 in my Type 14 Nambu; they all fit; bolt closes; extractor engages.

Conclusions

While many cartridges can be used to convert to 8mm Nambu, I found the 40 S&W to be the easiest.

The RCBS 36404 3-die set seems to be the best for forming & reloading.

In a surprise move, the president of our gun club presented me with a bag of 40 S&W once-fired brass last night. What a guy!

now that Starline now makes 41 colt brass, it can be used to make 8mm nambu brass. Neck to bottleneck and turn rim off and you are in business. I read this in an old Handloaders Digest, I forget the number, however. I do not own a nambu, but might buy one in the future.

Just reading on another forum about some Type 14 Nambus being able to use 357 Sig and 40 S&W cases without turning down the rim (or swaging them using the 30-30 Winchester sizing die)...My Type 14 will not take any rim over .417" and at that size it is tight...

Here is a comparison of the three...

Hi,

Great post!!!

I also enjoy shooting the Japanese Nambu Type 14, and own several of them. Though not a "Luger", they are really of quite good design and are quite accurate when handloaded properly.

You should know that the .40 S&W has a rim that is too thick for the extractor of the Type 14. In fact, given the inferior metal these extractors are made of, they will often "spring" when fired with the .40 brass, leaving you no choice but to repair or replace them. As parts are generally not available, this can be troublesome.

I have some Federal brass originally made for the 8mm Nambu I obtained sometime in the early 80s. They were going to market with it, but the project was canceled, naturally. Fred Huntington ended up buying all of this brass and selling some of it to me, just by chance.

Just a few thoughts on a the very fine article above.


Sieger

Thanks for reminding me! :thumbup:

I had noticed that it was thicker. On the cases that I had to cut an extractor groove, I also cut a bit off the rim. On the 40 S&W cases, I have manually stuck them in the bore and then racked the slide and they did flip out, so I left the rim alone.

I am not too far gone yet that I can't thin the rims on the 40 S&W cases. I see .042" rim thickness on the print. I'll check my 'test' cases and see how much needs to come off.

I recall seeing an ad or post somewhere about modified extractors for the Type 14 that would accept thick rims. Might have been Don Schlickman...I'll have to check his price list. I sent him a MO for a repro firing pin several weeks ago, maybe I can add an extractor to the buy...

Edit: Checking my 27 'test' 40 S&W cases, I'm seeing .052" rim thickness. The print I have shows .055". I'll rig up my parting tool bit and see what I can do to get it down to .042"...

Pic of the bag my gun club president dropped on me. I should be able to get several hundred out of these. :)

I forgot to mention that the conversion process does have a failure rate...About 1 in 15 or so is crushed or split during the neck forming operation... :(

the dog & pony show continues...
 

I turned ~.010" off the rims on the 40 S&W conversion cases...I tried for .042"; I'm close to it... :rolleyes:

Bob, I did a Search of this sub-forum to see if you had posted any of your Nambu handload data, and didn't find anything (only came up with six threads with Nambu in them, in this sub-forum)...

I still can't get any of the powder I'd like [4895, W231] but I have some Red Dot and Blue Dot left from before the freeze...

Do you have any loads for the 102gr FMJ Nambu bullet using Red or Blue Dot???

I was going to try a load for the 93gr 30 Cal Luger using Red Dot from a 1970 Lyman manual in my Nambu conversion cases...They list a low end of 3.9gr and max of 4.3...I may try 4.8gr to start, just a few to see if it cycles or if the primer flattens...Couldn't find any Red Dot data for the Nambu on the net... :mad:

Rim Revision 1
 

Bob/Sieger's comment about the rim got me thinking, and I ran my 40 S&W cases on the lathe and turned the rim down to approx .042"...(from approx .052")...But when I ran my mixed bag of other brands/calibers, there was some variation, as much as +/-.004"... :eek:

I was using a live center and locating off the edge of the primer pocket...But they weren't all the same...Some had a tapered edge, some not so much...So my 'zero' wasn't quite right...

So to make a better 'zero' I turned a piece of Nylon down to fit in my tailstock Jacobs chuck with a small primer 'nub' [.175"] on one end and a large primer 'nub' [.210"] on the other end...

Now I clamp this mandrel in the Jacobs chuck, set it at zero, push a case up onto the mandrel and then clamp the neck in the lathe chuck...Case is centered and rim base is up against the mandrel...And now I can cut my rim...

Works much better! Variation is cut down to approx +/-.001"... :thumbup:

I would rather use Teflon for my mandrel...But I'm all out... :(

I haven't done as extensive work with the 8mm Nambu as I have the 9mm Luger, but a good powder for me was Unique with the Nambu. When I find the time, ha!, I'd like to try my favorite Power Pistol and SR 4756 powders with the Nambu, as I think they would do quite will in this case.

Also, start low with your above load, say 3.5 grains of Red Dot or so, and work up until the action will just stay open. By doing so, you will have established the bottom load of your relevant range. Carefully work up one tenth of a grain from there and note accuracy. Also, a hot load is not usually an accurate one, in most cases.

Go ahead and try the same 3.5 gr starting load with your Blue Dot powder, working up until the hold open catches to find the bottom of your range as note above. Blue Dot for me has always been a flame thrower, but with bottle neck cases it may perform a bit better.

Sieger

I ran across this powder chart for the 8mm Nambu in another forum...It was supposedly copied from the Midway site some years back...

I haven't seen anything like that on Midway now...

I am not too sure how well the Blue Dot powder will work for you, but it is sure worth a try since you have some in hand. Blue Dot really shines when you load it up near or at max loadings. It is a magnum powder and likes to be loaded hot. I use Blue Dot in 357 Sig brass, and it produces superb velocity and accuracy. The only down side(to some at least) is the flash/bang that it produces. It is quite impressive!!!

I'm going to use the Red Dot first. Right now I'm trying to figure out this 3-die set, as it has no instructions and there is one die that I'm puzzled by... :confused:

Was it originally a 3 die set, or has someone added a die, and forgot to tell you?? With your experience in things like making modified/reformed brass and reloading, I can't imagine what kind of a die has you stumped!! You have definitely peaked my attention.

Right. :rolleyes: OK, here goes:

RCBS die set as shown in post #5 above. First pic below shows all three dies in the set I received, disassembled. They are marked as follows, in order as shown -

[first die] RCBS 8mm Nambu Size # 170 on die body

[second die] RCBS 8mm N on ram; no die marking

[third die] RCBS 8mm Nambu Seat #370 on die body

Second pic below shows just the middle die, with dimensions as shown.

Here's the problem...The ram in the middle [expander?] die expands the cases so that a .321" bullet falls right in. Very good fit; I can feel the air rushing out the primer hole. The ram also has a taper leading to another expanding size which is a sliding fit in a 38 Special/357 Magnum case but does nothing to an 8mm Nambu case unless you push it down to the beginning of the taper, when it will give the case mouth a very slight bell...But if you expand the entire neck, there is nothing to hold a .321" bullet in place to crimp it...It falls inside...

Pretty much every book I have [including COTW] shows the Nambu bullet as .320", which is even worse...

I first thought the middle die was the accessory die for expanding the 38 Special case, but the entire ram slides right through & bottoms out...Without touching the 38 Spl case...So it's not the expander for making 8mm out of 38 Special...

I can just push the middle die ram down a slight bit in my formed cases, but then I get no bell...

So...WTF is this die for???

That is what most of their 3-die sets do. This one is different...

Brass thickness would not affect the expander; it's going to expand it to .321" ID no matter what the case wall is... :(

RCBS may have made these dies for a larger bullet; say .322"-.323"...But besides Lebel & Nagant there haven't been any .322"-.323" 8mm pistol cartridges...According to COTW...

I expect I will end up making another expander ram for my home made die body and try to get it right around .320"...Make the first 3/16"-1/4" @ .320" and then a quick taper for a slight bell on the case mouth...

I'll try emailing RCBS and ask if they still have instructions for this die set and maybe find out what they intended... :confused:

Edit: HMOCC recommends using "Lyman bullet #32362 sized .321"...Maybe RCBS made their die set for this one bullet??? Maybe it was the only one available back when the 36404 die set was offered???

Edit2: This site shows the Lyman 32362 as a .325" cast bullet...

http://www.darkcanyon.net/lymancastbulletinfo.html

I tried the Lyman site; that number doesn't show anything...

Edit: Emails sent to both RCBS and Lyman. Waiting for replies.

I'm getting too old for this stuff anyway. I should be looking into shuffleboarding...Bingo...TV...Pottery making...Stuff that people my age do... :surr:

How about Belly Dancing? :rockon:

Bingo 7:30pm Thursday at the fire hall
 

I turned down another 1/2" x 20tpi SHCS to an expanding ram...It ended up .319"...With a slight taper for belling the case mouth...Seems to work pretty well... :rolleyes:

...But I'm still thinking about Bingo... :o

I believe that you are going in the correct direction with making a new expander/belling ram. I ran into a similar situation when I started handloading for the 30 Luger some years ago. My original die set (Lee 3 die set) would not function for me at all. The sizer die would not size the neck down sufficiently to give me any neck tension on .308in. bullets.

At first I thought it was that the expander/powder funnel was too large below the belling area, but that was not it. Anyway, I purchased an RCBS 30 Luger sizing die, then reduced the Dillon expander/ powder through die by .002in. and got sufficient neck tension on these .308in. bullets. I had to machine .040in. off of the base of the Dillon expander/powder die so that it would sit lower and give me enough belling for the case mouth. It works great also on the .309 and .311in. lead bullets. It surely had me scratching my head for a while.........bingo was looking good!!


Out of the 3 dies in the Lee set, I am using only the seating die. We live and hopefully learn.

I'm confused (and bewitched, bothered, and bewildered but that's another story) about what a 'powder funnel' die is...Is this for some kind of progressive loading press, with multiple stations that revolve with each pump of the handle (or maybe motorized)???

I only tried progressive loading once, and discarded the idea forever. (I had a 6-station press but the turret was too wobbly; I had to shim the rear with a feeler gauge to keep it from cocking at an angle when you cranked the ram up/down...I think it may have been an RCBS turret press but I can no longer remember...) I don't like the idea of cranking out a round with every pump. I'd rather do 50 de-primes at a time; then size those 50; then prime the 50; then charge the 50; and finally seat the 50 bullets...I'll even run 5 or 10 through all the steps and shoot them off to make sure I've got everything right...I especially like a 50 rd loading tray to charge the primed cases 50 at a time...And look in and see if I have a double charge, or a half charge, before I seat the bullets... :thumbup:

On Lee dies, when I first started reloading, I once had a set that had the plating flaking off... :mad:

I primed several cases and charged them with 3.5gr of Red Dot. Bullet seated to an OAL of 1.244". Ready to try them out... :eek:

I may not try any more until I get another set of springs from Wolff...(see other thread)... :(

Hi,

Where did you get your O.A.L. figure, as it should mirror an original Japanese round, somewhat.

Nambus are not as touchy as Lugers when it comes to O.A.L., thank the slightly straighter grip angle for that.

Good luck, and do replace your springs with a fresh set of Wollf springs, as the metal in the Japanese springs is inferior.

Sieger

From an original Japanese 8mm Nambu cartridge provided by Ed Tinker, and from data listed in Handloaders Manual Of Cartridge Conversions. 1.244" was the same in each case. Cartridges Of The World has it listed as 1.25"...Close enough. :thumbup:

Actually, my test showed no practical difference in the Nambu springs and the Wolff replacement springs. :(

I have no confidence in the Wolff replacement 'standard' springs which I received, as I commented on in my other Nambu thread. I placed an order tonight for their 'extra power' Nambu springs, which I'll test as I did their 'standard' replacement springs. :)

************************************************************************ ***********
In other news...

I had also emailed both RCBS and Lyman about different questions I had about their products. Lyman has not answered me about that #32362 bullet, but a CS tech at RCBS emailed me that they will send me out a replacement "expander/decap unit" for my #36404 die set...I had asked for the instruction sheet and explained that my expander was oversize for the Huntingtom .321" FMJ bullets...

Hi,

Then given a similar bullet nose contour, you should have a good starting place for continued A.O.L. experimentation.

Please also note that the Japanese were known to prefer short ogive bullets, leaving more of the bullet to actually ride on the lands. This was particularly so with their Arisaka rifles, the T-38 being, in my opinion, a simplification, yet refinement, of the Mauser action design.

Some golden daybreak, I'd like to design a truncated cone bullet for the 8mm Nambu, probably starting off with the DWM truncated cone for the 7.65 Parabellum as my guide.

Really, the 8mm Nambu and the 7.65 Parabellum both suffer from not having a decent selection of well designed bullets available to the handloader.

Regarding your powder, as soon as you get your feet wet with your new cases, I'd switch to the same True Blue powder you found so helpful in solving your 9mm problems, as the bottleneck cases should react particularly well to a slower powder.

Some fine day, when we can actually buy powder again, I'd like to experiment with the newer medium-slow/slow-slow powders to see if any of them are worth a hoot accuracy wise in the 9mm Parabellum pistol. Perhaps I'll be surprised, perhaps not, but the fun is in the experimentation and refinement of the various powders and other component parts of a load, always seeking that last little bit of perfection.

If you have the time to measure it, would you please give me the actual length of Ed's original Japanese bullet.

Thanks!


Sieger

I haven't had any 9mm problems...I don't use True Blue (never even heard of it)... :)

Only problem I have had in the last year is getting powder...And primers... :mad:

As stated above, it is 1.244"...A rare instance of a book value being right on the actual value... :thumbup:

Here's a comparison of the two Nambu cartridges I have plus my conversion (pic attached)...

The lead-bulleted cartridge is headstamped 'W C C 6 6' and was bought from a cartridge collector at a gun show in the late 70's/early 80's for $1.00...Ed's cartridge has no markings...Mine is the 40 S&W conversion...

Lead - .407" rim .376" base .844" case 1.240" OAL .320" bullet
Ed's - .412" rim .411" base .861" case 1.244" OAL .320" bullet
Mine - .413" rim .410" base .866" case 1.246" OAL .321" bullet

The lead-bulleted cartridge has a pronounced semi-rimmed configuration...I have no idea what it actually is (original case)...I am measuring the bullet at the case mouth, it may be larger inside the neck...

Sorry that I wasn't very clear on my description of things. Yes, I am loading my 30 Luger brass on a Dillon 650 progressive press. At station 2(after sizing and priming) the powder funnel enlarges the case neck and bells the case mouth, along with adding the powder charge. At station 3, the powder check die checks for the correct amount of powder in the case. Then on to seating and crimping. A total of 5 stations in all. It is a self indexing press.

Hi,

It might just be an optical, but it looks like the thickness of your rim base is substantially thicker than Ed's original. This causes the extractor damage mentioned previously. What is the original rim base thickness? What is your rim base thickness?

Sieger

Hi,

I was looking for the bullet length, not the cartridge O.A.L.

My comments regarding powder selection above are still on exact point; though brainfarted in from another thread. Frankly, I'd be surprised if you get accurate groups out of Red Dot in this case and caliber, though I'm sure the pistol will function properly with the correct charge.

Please note that both the Nambu pistol and Arisaka rifle use the old British style Medford rifling: shallow, wide and with grooves usually oversized. This means that you can use oversized diameter bullets and still get away with it. .323 lead bullets are often used in the Nambu pistol, and quite successfully. Also note that when compared to a Luger, for instance, the Nambu has quite a bit of free bore built into its chambering.

Sieger

Yes, it's an optical illusion. The case is tilted slightly away (you can see the primer if you look close). That plus my filing of the edge is only slight on this one. Ed's rim is an indicated .045"; mine is .046". I aim for .042" but it's difficult to measure. Difficult to machine too, as I can't get any measurement without removing the case from the setup. I have to rely on a dial indicator. I'm working on a better way to index the case between the live center and the parting tool. :rolleyes:

By the time I get it fully sorted, I'll have lost interest and gone on to something else... :D

Ah...I have no idea... :confused:

There's a couple of loads for the 8mm Nambu in another thread at -

http://forum.lugerforum.com/showthread.php?t=31825

Several articles there, couple of different powders & bullets...I added one from a 1981 article, might be the best to start with...

I believe that there are also some loads for 8mm Nambu in a past edition of Handloader Magazine. Mike Venturino writes articles for that magazine, and he owns and shoots a Nambu. If I recall correctly(always a real question), he is casting his own bullets. I will see if I still have that edition. Usually, if the magazine has no information of interest to me, then I discard it after reading it.....otherwise I end up with waaaaay too many magazines.

Hi,

Mike and I have spoken more than once, over the years.

For me, his articles are quite good regarding the history of a particular firearm and his wife is a fantastic photographer, but his articles lack the depth of precision I particularly enjoyed from, say, Ken Waters.

On the laughable side, in one of the articles he wrote on military pistol handloading, he, admittedly, couldn't get his 9mm Luger to shoot without constant jamming. Again, obviously, he has no depth of experience with nor understanding of this particular firearm's design, yet, he writes as an "expert" anyway.

He now, by the way, has proclaimed himself an expert on the military firearms of the two World Wars. Well, good luck to him, but from those of us who have been precision handloading for military firearms for decades, quite a bit of depth is lacking in his work, here, as well.

It seems like the old timers have past into history, pretty much the same as everything else has now a days.


Sieger

Hi All,

Well, while we are at it, what are your opinions on the strength of the T-14 Nambu design, as it is always called "weak" by all of those armchair experts out there; you know, the same crowd that claims that lead bullets won't shoot straight out of a 9mm.

Sieger

Revision 3
 

I drag mine over to the local gun club. Someone will read them. I've seen Venturino's byline occasionally over the years, but don't recall whether I thought he was full of hot air.

I made two new 'mandrels' for the 40 S&W cases yesterday, one for the swaging and one for the tailstock chuck. I wasn't happy with how the rim thinning was going. I went back over my cases and there was a tendency for the thickness to slowly increase as I went through more & more cases. The swaging process in the 30-30 die was leaving a small ridge on the edge of the rim, throwing my 'zero' off. A new primer-centered ram fixed that. I also replaced the Nylon mandrel with a brass one. A quick test run showed marked improvement. I'm going over the other 20-odd test cases to correct the ones that got too thick. :rolleyes:

Do you recall what part they considered 'weak'???

I thought the opening at the rear under the cocking knob was odd; and the inability to get a feeler gauge in the receiver to measure headspace is annoying...It's also somewhat distracting to pull the trigger and see the trigger bar emerging from the bottom of the receiver... :eek:

I was particularly interested in the barrel itself, and the almost exact similarity to the 120mm 30 cal Luger 'pencil' barrel...I am tempted to try to find an old shot-out Nambu barrel/extension and drill & tap it for a 30 Luger 'pencil' barrel... ;)

I do not know the gentleman(Ventrino) personally, and have never spoken with him on the phone. I do know that the first Luger that he purchased was a 30 Luger caliber, and he could never get it to run correctly. He sold it, and purchased a 9mm Luger. Apparently, he can get this Luger to preform reliably.

I was just trying to help out with some additional loading data for the Nambu. ANY handloader that is willing to take a loading "recipe" off of the INTERNET(non-factory powder company load) and use it without double checking it, is a fool as far as I am concerned. Perhaps I am overly cautious, but I still have all of my fingers, and both eyes!!