Converting French MAS 1873 Revolver from 11mm to .45ACP

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Thiopento

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Hello,

I've got a nice condition French MAS model 1873 in 11mm and am hoping to convert it to .45ACP (easier to reload and no downsides that I can see- should be just as accurate). I live in the GTA and wondering if anyone knows any gunsmiths who would do that work ? I also hear that getting the chamber throats the right size is crucial or else you might blow the gun, can I assume a competent gunsmith would do that right?

Cheers-

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Only downsides are that it will no longer be a collectors piece and someone might unknowingly shoots regular hot .45 ACP ammo in it and blows the gun up.
 
Before we start a troll war, no it's not a good idea to shoot modern ammo through these (its 19th century steel) especially not full metal jackets as they cause excessive pressure. It's best to keep the pressures low hence reloading is ideal or even buying some select Wolf .45ACP ammo which is lower pressure and loaded with semi-wad cutter bullets. The reason I want to convert 11mm to .45ACP is I want to shoot my gun without too much hassle! Collector value isn't that high anyway, its been re-blued has a bit of wear and to be honest, if it can shoot .45ACPs it'll be worth more in Canada.

Back to the thread- anyone know a gunsmith who could do this near the GTA?
 
Actually it is made out of malleble iron, any decent gunsmith with a set of .45 reamers should be able to easily do the job for you, you can also buy the reamer yourself from Brownells. you need a chamber case reamer and a throat reamer. My local gunsmith quoted about $10 a chamber a while back.

With low pressure lead only ammo you should be fine.
 
It's not going to be worth more because it has been altered. I very much doubt any smithy will touch it anyway. Too many liability issues. The ID of the barrel is too small for a .45ACP anyway.
The 11mm x 17mmR French is actually a BP 10MM cartridge that used a .425" bullet. It was close to .25 and .32 ACP in power.
The ACP uses a .452" bullet. Plus the rimless to rimmed part. That isn't as big a deal though. If the dimensions and pressures worked, the .45 Autorim would be better. An Autorim is a rimmed ACP that was used in 1917 revolvers during W.W. I.
 
Sunray may be indeed right about some gunsmiths not wanting to do the modification, also he is right about the power of the original ammo.

Also it is better to convert these revolvers to .450 or .455 Webley, lower pressure ammo that more closely match the original ammo and less of a chance to end up with a damaged gun. As for .45 Autorim brass it has too thick a rim to work in these revolvers unless you first shave the back of the cylinder.

My M1873 has a .448 dia. bore and according to Barnes COTW this is the dimensions of the cartridge -

Case typerimmed, straight
Bullet diameter11.46 mm (0.451 in)
Base diameter11.45 mm (0.451 in)
Rim diameter12.5 mm (0.49 in)
Rim thickness1.4mm
Case length17 mm (0.67 in)
Overall length30 mm (1.2 in)
 
Almost all 1873 french guns ive seen bores there max Dia from a sluged lead bullet (thats the only way to measure a bore and not be guessing) theres almost all .452 or .451 its there chamber throats you need to check as well they can need reaming to .452 as well some are really tight.
they do convert to 45 acp pretty easy and thats why almost all of them you see converted are converted to 45 Acp.
Ive seen and sold alot converted to 455 MKII aqmmo as well.
455 is a good choice to.
tho if your gona reload the 455 ammos use a .452 Dia bullet soft not hard lead is best.
Theres lots of french 1873s converted to 455 and 45 Acp
Once its reamed in the correct way for 45 acp so the cases head space on the chamber throats that the reamer makes the gun will then also load and shoot 455 fiochhi. but not the longer 455 MKI ammos.
 
Thanks for the info guy, anyone know a gunsmith around the GTA that would do a conversion? .455 ammo is hard to get compared to ACP and load as well isn't it ?
 
Fiocchi and sometimes Hornady .455 ammo is easy to get at the moment, a number of the above site sponsors sell it, also reloading for it is easy and reloading dies are also available.
 
Thiopento said:
Thanks for the info guy, anyone know a gunsmith around the GTA that would do a conversion? .455 ammo is hard to get compared to ACP and load as well isn't it ?
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you do know that firing normal 45 acp in one of these guns , you risk permantly damaging the gun and your hands ?

if you rechamber it to 45 acp , it becomes handload only , with cast bullets and low pressure .
 
burnt_servo said:
is there any reason why 45 schofield wouldn't work ?
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.45 Schofield will only work if you trim the brass, which in that situation you would be better off just using .455 ammo, or you would have to seat the bullet deeply into the .45 Schofield case which means it holds just as much powder as a .455.

A friend has one converted to .455 and it is just about a perfect length cartridge conversion for this French revolver, standard .455 Fiocchi ammo fits like it was made for it.
 
i also agree with the 455 webley. still an antique cartridge, so less hassle with cops. If they dont know the antique laws very well they are less likely to think it should be registered by changing the caliber.
 
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