1866/74 St Etienne Gras reloading assistance

[soflarick]

I obviously did not do adequate research on what I purchased. I started cleaning my 66/74 French Gras in anticipation of shooting it. Slugged the barrel, and as the lead slug got close to the chamber, resistance increased quite a bit. Measuring with digital calipers showed .439" diameter. I ran another slug down the barrel, but not to the restriction, and came up with .456". I saw what appeared to be a sleeve at the point where the chamber throat reaches the rifling, as if someone drove in an insert to fire a smaller caliber bullet. Turns out the conversion from the Chassepot to the Gras involved driving in a full length insert, and that's what I'm seeing. I don't understand how the jump from .439" to a larger groove does anything positive.

I have 2 older Lee molds: the 445/290 and 445/288 hollow base singles. Would those of you experienced in handloading for the 66/74 consider those molds adequate for handling the jump in diameter? I intend to cast with pure lead, perhaps 40:1. What black powder charge is adequate for accurate plinking out to 100 yards? I have Pyrodex RS and Black MZ FFG.

[salpal48]

I have several Gras rifles. all different Models. I only use a .446 Bullet. If I bring all to the range @ the same time Using the same load , They will all shoot in different Directions. I strickly use smokeless. They are Fun toshoot

[Earlwb]

I had found this on a forum sometime in the past. Unknown source. Apparently the insert serves to center the bullet and allow it to obturate correctly into the larger bore of thew barrel. Thus it seems accuracy isn't really affected enough to notice.

The Model 1866 Chassepot was changed to the Model 1866-1874 Gras
by the modification:
To replace the former chamber with a new one suitable to fire the Model 1874 metal cartridge, it was necessary to begin by sleeving the breech of the barrel. The sleeve had the shape of a truncated cone with the extreme diameters of 19.1 mm (.752") and 16.1 mm (.634") and was bored in the 11mm (.433") caliber. Two ribs were located toward the rear section of the cone. The sleeve was installed and lightly secured by shrink-fitting it into a barrel seat made to its size. A new chamber was then machined into the sleeve to the Model 1874 rifle specifications. Next the threaded end of the barrel assembly was screwed into the receiver until it bottomed out. In this way, the sleeve was secured on one end against the bottom of its seat in the barrel, and on the other by the bottom of the female threaded hole in the receiver. The two ribs kept it from rotating in its seat, and by these means, the sleeve was solidly fixed in every way to the barrel and the receiver. The new chamber being shorter than the old one, there was a free space of 27 mm (1.063") forming the junction of the chamber with the barrel. Comparative experiments showed that it was not necessary for accuracy to extend the rifling to the entrance of the chamber. The best results were obtained by giving this smooth part an intermediate diameter bore of 11.15 mm (.439") in diameter. This constriction kept the bullet centered while establishing the gas pressure needed for it to obturate into the rifling of the larger bore.
(Note: The Mle 1874 Gras does not have or need this constriction in its bore. Some Mle 1866-74 rifles were rebarreled with new Mle 74 barrels and are marked by a N on the right side of the barrel.)
lastditch

'

[GregLaROCHE]

Here is a link to a good video about the Gras and explains about the conversation from the Chassepot.

https://www.forgottenweapons.com/the...cartridge-era/

[GregLaROCHE]

Don’t forget that those rifles originally were paper patched. If you want to paper patch them, you might need a smaller diameter boolit.

[soflarick]

Thanks for the info. I'll try the hollow base Lee molds for now.

[BP Dave]

I have not encountered an undersized sleeved barrel throat like you describe in a Gras rifle. The usual restrictions I find are a chamber neck that will accept a cartridge with a .446 bullet, and a groove diameter of .455-.457.

Your .439 dimension seems awfully small, and I wonder if, instead of a cartridge conversion sleeve, perhaps the neck of a cartridge case has broken off in the chamber and is now adhered to the chamber wall.

It might be worth checking before taking other actions.

--DJ

[soflarick]

I tested the chamber with a Buffalo Arms reformed case, and it fit. I can do a chamber cast, and I have a usb bore scope I intend to run in there to make sure. I once had an SKS that had a piece of case neck stuck in the chamber, but it was obvious to see with a flashlight and physical insertion of a case. Got the piece out using cerrosafe and brass rod from the muzzle end.

[Greg G.]

A Mondern Cartridge For The Gras Rifle.pdf
Here is some info that I found on the net. Written by a french guy in French and google translated. Once you get past the not so perfect translation it is very good info and explains the differences between the Gras and the Chassepot converted rifles. Also gives info on bullets and how to load without special dies and powder types and load data.

[GregLaROCHE]

A Mondern Cartridge For The Gras Rifle.pdf
Here is some info that I found on the net. Written by a french guy in French and google translated. Once you get past the not so perfect translation it is very good info and explains the differences between the Gras and the Chassepot converted rifles. Also gives info on bullets and how to load without special dies and powder types and load data.

There is a lot of good information at this link. Thanks.

[soflarick]

Checked chamber with bore cam, and the portion up to the rifling is part of the chamber insert that was used in the conversion of the Chassepot to Gras metallic cartridge. That pdf link indicates one could open that up, but then it would no longer be "correct original". Appears a near pure lead hollow base boolit is necessary to provide best accuracy. Little more poking around revealed that what I've got is a more rare example, as many were later converted to M80 spec, and had the overpressure scallop machined. Mine has neither, nor is there an "N" on the barrel.

It appears to be an earlier conversion; perhaps it sat somewhere for years in an attic, and was eventually sold when the owner passed on; much like what happens when American vets pass, and their heirs sell off the history for cash or some social justice warrior nonsense.