Converting a .38 Special Revolver to 9 mm

Status
Not open for further replies.
O

Oyeboten

Member
Joined
Mar 23, 2008
Messages
3,696
I understand some people have converted, or, appealed to able Gunsmiths to convert, an erstwhile ( but one hopes, strong enough ) .38 Special Revolver, to hold and fire 9 mm Cartridges, using full Moon Clips.

Possibly, one could also do this for .38 Auto, or .38 Super.


I'd like to know more about this, maybe names of Smiths who are versed and experienced in the conversion, or any sundry details from those who did their own conversions.

Does one typically replace the Cylinder? Modify and install a previously smaller calibre replacement Cylinder, which when re-bored larger, allows proper Cylinder bore diameter and minimal jump?

Seems to me a .38 Special Cylinder, if left just as it is bore-wise, would have too long a jump for a shorter Cartridge Case of the usual 9 mm.

Cylinders posseing requisite strength of course, for the higher pressure of hese Automatic Cartridges, would be important.

Barrels...would generally be fine as they are?



I think this is a very interesting modification/conversion..!




Phil
Las Vegas
 
Seems to me a .38 Special Cylinder, if left just as it is bore-wise, would have too long a jump for a shorter Cartridge Case of the usual 9 mm.
Click to expand...
Seems to me you are right.

I know people do it, but a .355" 9mm bullet starts out undersize to begin with, then has to make the jump from case to .380" dia chamber to the .357" throat some distance away.

It simply can't be good for power (gas blow-by in the oversize chamber) or accuracy. (Bullet bouncing through the oversize chamber, hitting the oversize throat, and then the oversize barrel.

Seems to me rechambering a .38 Spl to 9mm would just be a good way to spend money and make noise.

rc
 
...or, if such a conversion were done well...


Lol...


Really, were one to bother, probably, .38 Super would be a nice choice to convert to, offering far better performance and a closer Bullet diameter than usual 9mm kinds.


Just interesting to think about these things, and find out about what people are doing...
 
Mark at Pinnacle did the conversion on my S&W 360. I've posted here and on other forums numerous times about my gun and how pleased I am with his work.

Typically, people that have no experience with 9mm revolvers decry the idea. Realistically the 9mm is perfect for a short barreled revolver becaause it is a short, efficient round. It fits the gun well and has more power and velocity than the .38spl, approaching .357mag velocities without the violent muzzle blast and painful recoil.

I had to qualify with my gun a few days ago, here's the link to my "range report". It says a lot about the accuracy of these conversions -
http://smith-wessonforum.com/eve/forums/a/tpc/f/3001000143/m/66510389

This is a link to a post on stoppingpower.net from a few years ago that compares 9mm velocities out of a S&W 940 (a factory 9mm snubby with a .357mag length cylinder) and .357mag velcities from a snubby.
http://www.stoppingpower.net/forum/topic.asp?TOPIC_ID=2123&SearchTerms=9mm,snubby

And, if anyone is interested, this is a link to one of my original posts about my gun when it was finished.
http://www.snipershide.com/forum/ub...73831&Words=9mm+snubby&Search=true#Post954001


BTW, my gun is chambered for 9x23. It'll shoot 9mm, 9x21, 9x23, .38 Super, and can still handle .38spl if needed.
Also, if you want to speak to Mark, call him, he's not so good with email.
I'll happily answer any questions you have about this conversion, just ask.
 
Hi WC145,




Very nice info, and a real story...does not get any better than that!


I've long thought that S & W should have offered various 'Rimless' Cartridge Revolvers, on the K Frame platform, using Moon Clips, in 9 mm, .38 Auto, .30 Mauser even...once seeing how well received their N Frame M1917 .45 ACP Revolver was.

9x23 is a very interesting choice...wow...very cool...
 
There's a couple of guys on the S&W forum that have done 4" K-frames and some L-frames that came out really nice. I'd like to have one but I need to find the right donor. Right now I have a 637 that I got a very good deal on, it will be my next conversion project.
 
I know people do it, but a .355" 9mm bullet starts out undersize to begin with, then has to make the jump from case to .380" dia chamber to the .357" throat some distance away.

It simply can't be good for power (gas blow-by in the oversize chamber) or accuracy. (Bullet bouncing through the oversize chamber, hitting the oversize throat, and then the oversize barrel.

Seems to me rechambering a .38 Spl to 9mm would just be a good way to spend money and make noise.
Click to expand...

The 9mm is a more powerful cartridge than the .38 is. The length of the .38 case comes from the time when it used to be filled with black powder, not nitrocellulose. Modern .38 cartridges have very little powder in them comparatively. A 9mm was designed from its outset to be used for war, hence the "parabellum" moniker.

As for distance, that seems to be par for the course for 9mm revolvers. My Smith 940 9mm and Ruger Speed Six 9mm were both chambered for 9mm from the factory, and each had at least 1/4" space in the cylinder to travel before they hit the forcing cone/barrel. My Smith 547, a revolver specifically designed around firing 9mm, is the same way. There is at least 1/2" space in the cylinder from the bullets to forcing cone. Lengthwise, a .357 mag cartridge would fit in my 547's chamber. Can't tell you why, but it works just fine regardless.

I have often wished for a S&W model 10 in 9mm
Click to expand...
The model you are looking for is the 547. Smith made 4 inch barrel and a 3 inch heavy barrel versions. The 4-inch looks a lot like a model 10.
http://www.vintagepistols.com/range_report_S&W_547.html

Here's a 3 inch model in action.:
http://www.youtube.com/watch?v=eQpiBsEdbmw
 
Last edited:
Very familiar with the 547. They're very nice, very cool, relatively rare, and very expensive. And they don't use moonclips, which I prefer. That isn't to say that if a great deal came along I'd turn my back on a 547, I'd love to have one. But, for me one of the great things about these conversions is that they do use moonclips. They are very convenient and very fast. When I qualified last week I loaded up 10 moonclips for each course of fire, loaded the gun, and dropped the other 9 in my cargo pocket. I was able to reload as fast as most of the guys shooting autos and waaayy faster than a couple of other revolver guys using speed loaders and loose rounds.
 
No, I know what a 547 is and I do not want a 547, I want a model 10 running moonclips. Oh and while I am wishing I want it with a 3" mid weight barrel, round butt grip frame and a semi bobbed hammer like the 547.
 
No, I know what a 547 is and I do not want a 547, I want a model 10 running moonclips. Oh and while I am wishing I want it with a 3" mid weight barrel, round butt grip frame and a semi bobbed hammer like the 547.
Click to expand...

Sign me up for one!
 
Very familiar with the 547. They're very nice, very cool, relatively rare, and very expensive. And they don't use moonclips, which I prefer. That isn't to say that if a great deal came along I'd turn my back on a 547, I'd love to have one. But, for me one of the great things about these conversions is that they do use moonclips. They are very convenient and very fast. When I qualified last week I loaded up 10 moonclips for each course of fire, loaded the gun, and dropped the other 9 in my cargo pocket. I was able to reload as fast as most of the guys shooting autos and waaayy faster than a couple of other revolver guys using speed loaders and loose rounds.
Click to expand...


Hi WC145,



Yes...to me also, full Moon Clips are an essential part of the appeal I am after.


Had the 547 emulated it's great grand Pappy, the Model of 1917, .45 ACP in that regard, it probably would have been a far better success, and, I'd want one.


9x23 does seem the most elegant Chambering...in so far as it reduces the jump to about nothing, or rather, once counterbored, there'd be no jump at all with it...though I'd feel nervous about whether an old or older Model 10 would handle the vastly higher pressures.

Now that I am thinking about this, once counterbored for Moon Clips, a .38 Auto/.38 Super would then suffer about no jump at all, too...


Hmmmmmmmmm...


Good discussion!


Phil
Las Vegas
 
No, I know what a 547 is and I do not want a 547, I want a model 10 running moonclips. Oh and while I am wishing I want it with a 3" mid weight barrel, round butt grip frame and a semi bobbed hammer like the 547.
Click to expand...


Yes...definitely..!


Really, on such a Revolver, I see no reason not to Bob the Hammer entirely.


One is best to have good Double-Action techniques, and, there is no need for Single Action anyway for something like this...


So, as for me, I'd Bob the Hammer completely, and politely Checker the 'top' of it...so if one does ever wish to shoot Single Action, one merely depresses the Trigger enough for the Hammer to begin coming back, then, one cocks it by the Hammer...


Easy and clean...and no 'Spurr' to catch on anything when drawing.


And if it is to be the 3-Inch, Round-Butt as a Pocket Gun...or if one is to carry it in Winter, or when riding Motorcycle, where one is likely wearing Gloves, one may as well remove the front of the Trigger Bow, also...



Phil
l v
 
Hi lanternlad1,

You'd menioned -


As for distance, that seems to be par for the course for 9mm revolvers. My Smith 940 9mm and Ruger Speed Six 9mm were both chambered for 9mm from the factory, and each had at least 1/4" space in the cylinder to travel before they hit the forcing cone/barrel. My Smith 547, a revolver specifically designed around firing 9mm, is the same way. There is at least 1/2" space in the cylinder from the bullets to forcing cone. Lengthwise, a .357 mag cartridge would fit in my 547's chamber. Can't tell you why, but it works just fine regardless.
Click to expand...



Yipes!


Whatever were they thinking??


My own undersanding, is that it has long been held, that as close to no 'jump' as possible, is best...and for several reasons; including how pressures may spike when the Bullet reaches the Forcing Cone after crossing a gap where the Gasses were going around it...as well as the possible distortions to the Bullet, for it's wandering a little in the larger diameter gap region, and reaching the Forcing Cone then at less than ideal align/orientation...


I'm surprised that erstwhile respectable Manufacturers would be so indifferent to fundimental cares which have been well undersood for well over a Hundred years.


Maybe...one could Order .32 Mag Cylinders...and re-bore them ideally, for the 9mm or similar diameter Cartridge one wishes to use, and arrive at an ideal fit for the Cartridge, with no 'jump' through a larger diameter Cylinder region...




Phil
l v
 
Last edited:
As I learn a little more about this, I am finding mentions of 'Moon Clip' conversions being done to .38 Special Revolvers, where, the conversion merely allows a use of 'thin' Moon Clips, on the same .38 Special Cartridges it always fired, which would be handy of course, but...


If a Revolver is strong enough, or, if a strong enough Cylinder may be obtained, converting to 9x23 as others have done and told of in his thread, or, as in the case of my own aspire, converting to .38 Super...seems a far more appealing and interesting gesture.

If a 'Snubby', and if the 'jump' issue were resolved, then convering to 9mm seems very appealing, since this is a Cartridge well suited for loadings which defer to a short Barrel.


Now, far as full power loads, my thought is that those would be the resort only for Carry or occasional practice, and for practice or plinking oherwise, to be reduced power loads, so as not to overstress the Revolver.


Even as was the case with the S & W Model 10-6 in .357 Magnum, or, the subsequent S & W Model 13 in .357 Magnum - the Magnum loadings were never intended to be the steady diet...but rather, only an occasional recourse or for 'carry' contingency.




Phil
Las Vegas
 
Whatever were they thinking??
Click to expand...

I think they were trying to make the gun as inexpensively as possible.

My 547 is a Smith K frame. Its usually used for a .357 magnum, and I think they just reamed out a .357 mag cylinder and added the special extractor for it. The K-frame can handle the .357 mag, so I guess it can handle anything the 9mm can dish out. The same thing with the Speed Six 9mm.

The 940 was made on the j-frame centennial platform, and isn't good with +p ammo.
 
For the record, chambering my gun for 9x23 was not my idea. That is how the gunsmith does these conversions, there's no choice of chambering, you choose what you shoot through it. It works for me, I like the versatility it affords me.

If a 'Snubby', and if the 'jump' issue were resolved, then convering to 9mm seems very appealing, since this is a Cartridge well suited for loadings which defer to a short Barrel.
Click to expand...

There is no 'jump' issue. S&W used a .38/.357 length cyinder in the 940 and it worked just fine. There is no loss of velocity, accuracy, or anything else due to the length of the cyinder. My Taurus 905 uses a short cylinder/frame. The only advantage is that it is a more compact gun (that weighs 9oz more than my 360).
 
!!

Converting to 38 super is less of a problem than 9x23, super 38 has less pressure and is a bit of a shorter case.
Click to expand...


Yes...and in the early-to-mid production ( pre 'powder-metal' ) Model 10s I have in mind to convert...the .38 Super might be the upper limit pressure-wise, of what it could stand...if..."if"...it could even stand it...and I have not found out yet on that. Maybe .38 Super would be too much for it.

The 9x23 seems such a wonderful Cartridge, and interesting to boot, but, I'd fear it'd be too much for a 10-6, say.

Possibly later Model 10s would have stronger Cylinders? Or, a .357 Cylinder, adapted...

I dunno...'Brainstorming'...


But, an earstwhile Model 10, four-inch Heavy Barrel, converted to chamber the .38 Super, would be a very nice package.


Phil
l v
 
it worked just fine. There is no loss of velocity, accuracy, or anything else due to the length of the cyinder. My Taurus 905 uses a short cylinder/frame. The only advantage is that it is a more compact gun (that weighs 9oz more than my 360).
Click to expand...

Hi WC145,


It's not the lenght of the Cylinder that conerns me, but, the location of the Step in the Cylinder Bore...

If the same lengh Cylinder is deferentially Bored for say 9mm, then, the step will be where the Case ends...

But, if the step is still present from .38 Special, or .357, then, it'll be a long way away from where a 9mm Case mouth ends...


Possibly, in practice, his would not make enough difference to be of any concern...but, my acceptance has been, that it should/could.


So, if I were to have my way, 'ideally', I'd want a Cylinder Bored for the Cartridge I intend to use, so the step occurs at the Cartridge Case mouth end, and, thus, leaving no 'jump' for the Bullet.



Phil
l v
 
Last edited:
The "step" is appropriate for a 9x23 round to headspace on. The cylinder can't be cut with a "step" for the 9mm to headspace on because it's already larger in diameter than the 9mm, hence the need for moonclips. To do what you're talking about you'd have to start with a smaller caliber cylinder than 9mm. Or you could just find yourself a S&W 940 and be done with it. They headspace on the case shoulder and don't require a moonclip except for ease of extraction, same as the Taurus 905.
 
I find ALL this very interesting, but keep going to the question that begs to be asked; why push a 9mm or sub a .38 super when you already have a .357 mag.?
and, does not the .38 special have a "jump" when in a .357 cyl. and still work well?
hmmmmmmmm
 
Status
Not open for further replies.

Similar threads

O
  • Locked
Who does good Revolver conversions from .38 Special to 9mm P-'08?
2 3 4
Replies
86
Views
4K
Old Fuff
O
O
  • Locked
Converting a Revolver to 9mm...sort of...
Replies
8
Views
557
Jim Watson
J
G
  • Locked
9 mm revolver question
Replies
5
Views
493
WC145
WC145
B
  • Locked
.38 Smith and wesson
Replies
2
Views
441
Sunray
S
M
  • Locked
.38 Super in Revolvers
Replies
19
Views
7K
MagnumDweeb
M
Back
Top