.32 Colt Conv. to .380

[RCouch]

Was looking thru GUNSAMERICA and noticed the following in an add for a .32 Colt 1903 model. It was under Ft. Bend Armory and GA#: 976469202. In part it read, " I rewarded it by up grading it to a 380. Simply bought a 380 barrel and magazine, Wala." Is this Possible? If so, where do you get a barrel and magazine and wouldn't you need at least a new recoil spring also?
Someone with more knowledge about Colt's educate me.
Thanks

 

[los]

Didn't know this was possible. You'd think the Slide would have to be milled to accept a larger diameter barrel?..

 

[myusername]

I've been told by a few people on the web that it is possible but I think it was a few different parts.

I've got a 1903 that was my grandfathers carry gun. I really like the feel of the gun. I've thought about trying the .380 mod but am going tojust leave it alone

 

[Mac Attack]

For what its worth, I was researching the same thing on the Nurmrich Colt forum but I wanted to know if you could go from .380 ACP to .32 ACP. I found that the frame and slide on a 1903 .32 ACP is the same as that of a 1908 .380 ACP. The Nurmrich site (e-parts site) states they have a few .32 barrels and some .380 barrels for 1/8 and 3/32 inch extractor cuts.

My .380 barrel is pitted so I plan to pick one up as well as a .32 just for fun.

Mac

 

[Jim K]

Not to rain on parades, but the main problem is that the .380 magazine won't fit in the .32 frame, and the .380 cartridge won't fit in the .32 magazine. So the magazine well of the .32 has to be made larger to take the .380 magazine. Also, the recoil spring of the .380 is stronger and has more coils.

Jim

 

[Old Fuff]

There can also be a problem with the ejector, which includes cartridge guides. While the same part was used in both .32 and .380 pistols, they were individually modified by the final assemblers for each respective gun. Colt depended largely on their skilled work force. In March 1945, a government inspection team looking into problems with the .380 pistol ask Colt for a set of drawings for the 1908 pocket pistol, caliber .380 - and were informed that such drawings were not available.

These pistols were largely had fitted, and mix & matching parts can bring one to grief.

 

[RCouch]

I thought this all sounded too good to be true. Glad Old Fuff and Jim Keenan chimed in 'cause I was about to order some parts. Guess I'll just have to find a .380 somewhere (that's what I really wanted to do all along).

 

[Old Fuff]

In all fairness I am aware of some .32 to .380 conversions that have worked, but like Jim I'm aware of some that didn't.

During the time that the model M was made Colt, was able to do an extraordinary amount of handwork on each pistol. Since the "M" designation covered both caliber pistols I suspect that the raw frames and slides might have been the same, but that those intended to be made into .380 pistols were altered by someone, or the final assembler using a file(s). This could account for the reason that some .380 pistols (at least those sold to the armed forces during late World War Two) had some feeding and other problems that didn't show up in the 1903 .32 pistols.

I had a friend that was an officer in the British SAS who had, shall we say, "extensive experience in handgun combat." He was a solid fan of the .32, which he called, "The most reliable pistol of its kind," but never said anything in like terms about the .380 pocket model.

From a user's point of view, the big problem today in either caliber is to find decent, but reasonably priced, magazines. As is the case with all pistols, good magazines are critical for reliability.

 

[ravencon]

Excuse my ignorance about the 1903. But would the increased pressure of the .380 be an issue in a conversion of .32?

 

[Old Fuff]

No, the pistol is more then strong enough to handle either cartridge. The .380 did come with a stiffer recoil spring though.

If one had a 1903 (.32) pistol, and wanted to completely rebuild it into a 1908 (.380) they could do so, if they had the knowledge, skill, and parts to do it. But his would involve modifying the frame in most cases, and a .380 slide with internals would be recommended. Then a .380 magazine would be required, as well as a new recoil spring, and possibly an ejector - this at a minimum.

Browning designed the pistol to be a .32 caliber. Colt brought out the .380 version later, and over decades ignored possible problems until in November, 1944 the U.S. Navy filed a complaint. That they couldn't overlook or sweep under a rug.

So does this mean that all of the .380 pistols are suspect? No, because Colt's usually meticulous hand fitting made up for any design flaws.

 

[RyanM]

I would not ever trust someone who says they "rewarded" a pistol, and can't spell voila, to work on a gun, not even something as simple as replacing grip panels.

 

[Jim K]

Wow! I started this post to say that I didn't believe the pistol magazine well was simply filed out on the .32 frame to take the .380 magazine.

But I measured the mag wells, and then noticed that the frame on either side was the same thickness. How could that be, unless the frame itself was wider? So I measured the frames and slides of .32 and .380 pistols, and got a surprise.

Not only is the .380 magazine wider and the magazine well wider than those of the .32, the frame is wider, as is the slide. The slides will usually interchange due to the tolerances in manufacturing, but it is clear to me that they are different. Conventional wisdom has it that Colt simply took the .32, installed a new barrel, made some small changes, and produced the .380 version. Not true. Not only are the magazine and magazine well sized specifically for the .380, the whole gun is different, made for the larger cartridge.

So, here are the measurements, .32 first, followed by .380:
Width of magazine: .423" - .439"
Magazine well width: .435" - .446"
Magazine well length: .1.070" - 1.129"
Frame at rails: .615" - .629"
Slide width: .767" - .779"

Conventional wisdom, hell, they are different guns! Colt didn't just do a quick barrel change, they made a whole new gun, specifically tailored for the .380.

Jim

 

[Old Fuff]

Usually when Colt made a different frame they would assign a different letter to identify the model - this to insure things didn't get mixed up in inventory. It gets more interesting because in 1944 Colt couldn't (or wouldn't) provide an Army/Navy inspection team with a set of blueprints. The parts it seems were made to guages, not prints. The military services bought them as an off-the-shelf item.

I'll do some more research, and we need to measure some more guns. I know that .380 slides have been fitted to .32 frames.

Jim: Were the frames and slides you measured made during the same era (or within the same decade?)

 

[soutex50]

Gents, I've posted on this before, and here are my findings......
had a 380 1908 with bad frame
purchased a 32 1903 parts gun

the 380 slide fit and worked on the 32 frame by changing the recoil spring and the mag disconnect plunger thingie plus mag.

the 32 slide DID not fit or work on the 380 frame.

Major difference in frames was the magazine safety disconnect feature.

 

[Prof. A. Wickwire]

I own a Colt 1908 in .380 ACP (1934 vintage). A standard Colt .32 ACP barrel works just fine with no other changes. Also, the standard .380 ACP 7-round magazine will hold and feed 8 .32 ACP cartridges.

I had no failures to feed, fire, extract, or eject while testing this theory.

Just my experience, your mileage may vary.

Sincerely,

Prof. A. Wickwire

 

[Old Fuff]

soutex50:
Prof. A. Wickwire:
Jim Keenan:

Gentlemen...

If you would, please post the partial serial numbers of your .32 and .380 pistols. I am looking for evidence that there were dimensional changes made in the frame and slides between 1903 and 1945.

 

[Prof. A. Wickwire]

Old Fuff,

My Colt 1908 .380 ACP has a serial number of 1101XX. According to Colt Autos it was made in 1932 (not 1934 as I stated above).

Please share your results with us once you have amassed the evidence you are looking for.

Sincerely,

Prof. A. Wickwire

 

[Mac Attack]

So can I convert my 1908 .380 ACP to shoot .32 ACP by swapping the barrel and mag (or not) only? for what it's worth I have a Type III 1908 with a serial number of 59xxx.

 

[Old Fuff]

Well Jim sure did stir the pot....

I've found some evidence that he may be right, but at the same time we know that in some cases a .32 to .380 conversion is possible. I'm less sure about a .380 to .32 set-up though. One issue is the ejector. Colt apparently used the same ejector on both guns, but if the larger .380 case hit the ejector to soon it could cause a jam. Colt got around ths by having final assemblers modify the ejector in .380 pistols when necessary, rather then stocking two different sizes. If one puts a .380 slide on a .32 frame that still has an unmodified .32 ejector there might be a problem. On the other hand if the ejector is opened up for the .380 case it might, or might not still work with the smaller .32's. Extractor hook fit might be an issue too. They were also hand fitted. To tell the truth, the whole gun was hand fitted.

The Old Fuff is a blabber-mouth of the worst kind. Of course he will tell all as the picture becomes clearer...

 

[Jim K]

I didn't say the slides wouldn't interchange. They did on the two pistols I checked, but the .32 slide was very tight on the .380 frame. It would have needed some fitting to really work right. I didn't check the ejectors. The .32 barrel will fit in the .380 slide but not vice versa, as the front lug is too big.

Old Fuff, the serial numbers are 158521 for the .32 and 59589 for the .380.

Want some more? I just miked a brand new USP .32, 570125, and its mag well dimension is the same as the older .32, but the frame and slide measurements are the same (within normal tolerances) as the older .380. Further, the frame thickness at the magazine well (which first attracted my attention on the older guns), is noticeable thicker than on the older guns. All of this indicates that eventually Colt went to the same frame (maybe under wartime pressures) for both calibers, but making the .380 mag well larger. Note that a .380 magazine won't fit in the USP .32, so there was still a difference in that area.

I will check out a couple of more when I get a chance, but been pretty busy lately.

Jim

 

[Old Fuff]

Ya, what I'm finding seems to go along with what you are saying. Perhaps the most important being that Colt serial numbered the .380's in their own series, starting in 1908 @ #1. If the frames were EXACTLY the same it seems certain that they would have been numbered in the .32 series on the basis they were interchangeable between the two models - but because of the magazine they weren't. Slides would have been easy to identify because they were marked with the intended cartridge. Some dimensional changes were made over the years, but the what and when wasn't too well recorded in the records - at least those that remain.

R.L. Wilson calls the .380, "a distinct model."

 

[Onmilo]

OK I'm going to wade in to this discussion,
I own a first generation Model 1903 #3039X,(That's ten choices as to which one it is guys),
I obliguarantee nobody is going to drop a 1908 .380 acp barrel in this pistol and make it work.

Now, if the seller had a late third or forth Model 1903 it is possible to fit a .380 barrel and magazine.
By 1940 or so Colt had fairly standardized the guns to the point the .380 and the .32 were about identical dimensionally.
Even so you can't just drop in a barrel and slap a magazine in place and make the pistol fire reliably.

The extractor cut out on the barrel must be identical to the extractor dimension of the slide one wishes to use.
The barrel must be fitted to the slide in a similar manner as one would fit a 1911 replacement barrel as should the bushing be fitted to the slide and barrel unless you have a late issue bushingless pistol and the you need to fit the muzzle to the slide port.

A 1903 Colt/Browning is not a 1910/1922 Browning, the magazines can not be interchanged as to cartridges, one must use a .380 magazine with a .380 barrel and a .32 magazine with a .32 barrel.
Using a the wider .380 magazine with the .32 cartridges and barrel will eventually cause the slide lock to wear excessively and fail.
Using .380 cartridges in a .32 magazine will place excessive strain on the feed lips and center seam of the magazine and eventually the magazine will spread and crack down the rear center, ruining a magazine that is already begining to become harder and harder to obtain.
Oh yeah, the slide lock is a seperate and distinct part between the .32 and the .380, this must also be replaced when attempting a caliber conversion.

Simple answer, can the caliber conversion be done on one of these pistols?
Within the Parameters, yes, it is feasible.
Did the seller do the conversion correctly?
Probably not.
What a waste of a decent and collectable pistol.

 

[Old Fuff]

Apparently you have an extensive collection of 1903/08 pistols. If you will measure the same dimensions as Jim Keenen did (see post #12) with matching partial serial numbers it would be very useful for our investigation.

... and the you need to fit the muzzle to the slide port.

Do you perhaps mean the breech end to the slide port?

...the slide lock is a seperate and distinct part between the .32 and the .380, this must also be replaced when attempting a caliber conversion.

This pistol does not have a slide lock as such, as the slide is locked back using the manual safety (aka "slide lock safety"). Are you perhaps refering to the ejector?

Thank you for your interest.

 

[brownie0486]

Very interesting and enlightening thread here.

I have a Colts 1908 hammerless serial #12120*. I purchased the pistol in the mid 80's. I bought a 32 barrel and mags for it back then, and the gun functioned perfectly with the 32 set up in the 1908.

Hope that serial range helps in the thread. Lots of knowledge being passed in this thread, looking forward to the resolution/findings by others.

Brownie

 

[Old Fuff]

At least one .380 was converted to a .32 at Rock Island Arsenal, using the original frame and slide (the slide was re-stamped to show the correct cartridge). I presume, but can't confirm, that they changed the magazine to a .32 size.

Over the years a number of minor dimensional and cosmetic modifications were made to the 1903/08 pistols. In some of these cases the changes and dates were recorded, and the details are known. Apparently in other instances this was not the case, and may have been overlooked by later researchers. Depending on the date of manufacturer, a conversion from .380 to .32 may be more practical then the other way around. In any case one major roadblock would seem to be that an unmodified .32 ejector may cause stovepipe jams in a .380, and one modified to be used in a .380 may strike the .32 casehead too far out. Also in all of these pistols both the ejector and extractor were hand-fitted, as was the whole gun for the most part. Thus parts that are purchased from Numrich/Gunparts Corporation for example, that were removed from otherwise scrapped guns and originally fitted to those guns, may not work correctly in another - at least not without retrofitting. Clearing making a conversion is not a "drop-in" sort of thing unless Lady Luck smiles on you..