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View Full Version : The story of a Brazilian Comblain, part 4



Buckshot
04-09-2005, 07:03 AM
http://www.fototime.com/EA42AD18D042DA2/standard.jpghttp://www.fototime.com/DC987B812F647C3/standard.jpg
As was mentioned and shown in the previous post I had to make an intermediate collet to accpet the cartridge case in the collet in the lathe spindle. The upper left picture shows the collet. No big thing to look at, but I was very pleased at the time (and still am, truth be known) with the accuracy and fine finish I could accomplish with my new lathe. Sorry, but I can't help it! Upper right is just another view of the shell holder.

While altering the brass cases for the 209 primer you have to put one in, drill it through, spot face it, and then take it out. I sure didn't want to have to stop and start the lathe that many times for each case. The supplimental collet was large enough around to get ahold of with the 5C collet opened, so I could pull it out and then put it back with a new case in it, while the lathe continued to run.

http://www.fototime.com/FB833F810B2C0FE/standard.jpghttp://www.fototime.com/8F2D7613C6820E4/standard.jpg
At left is loaded ammo ready to be fired. The sticky labels are there to allow even casehead expansion. The 32 guage case is close, but there is still a bit of windage between them and the chamber wall. A couple firings like that and the paper is removed and the case remains well centered. I opened the size die enough so it doesn't touch the casehead.

At right are the 4 targets shot with the new cartridge case on their very first outting! The bullet was the Lyman 457121 at 292grs. It dropped at .460+" so was just pan lubed. All the targets were 10 shot groups at 50 yards except for the Blue Dot, as they were used to get 'on' which required 3 rounds.

The sights on the carbine are typical, A little rounded nubby blade up front. The rear sight is 3 steps with a bitty short ladder with an elevator. You have a 'V' with the ladder down and a 'V' on the elevator. Rudimentary and NOT a 1000 yard setup. Also, the boolit at .460" is about .005" undersized for the groove. The brass while necked, goes into a chamber with NO neck, so the boolit has to do the centering and is engraved a bit. I'm totally blown away that they didn't go through sideways or just fly off on their own somewhere! At cleaning there was NO leading. Velocities IIRC ran about 1200 fps.

Options one of these days is to make a swage die to produce a slug with a .433" nose to fit the lands, and a .465" body. Maybe mashed up from a Lee 340gr 45 cal slug. Or a patched up .457" boolit to .465". Maybe cut a mould? Gotta accumilate some 'Round toit's' first.

Hope you enjoyed the process!

................Buckshot

Logan
04-09-2005, 07:14 AM
excellent work.
I thoroughly enjoyed the series, and would love to be talented enough to do the same.

(or to be done with it, and find a standard drill to rechamber it with) [smilie=l:

jh45gun
04-09-2005, 07:16 AM
Very interesting Article Buckshot and a neat looking old rifle. For most of us your project would be out of reach as I would guess most of us would not have your machining skills. Congrats on getting a old obsolete gun back shooting again. You should send your article to some of the gun rags it is sure a lot more interesting than some of the stuff they are printing today. Jim

joe
03-13-2006, 08:08 PM
Your story of a Brazilian Comblain was great. I have a Brazilian Comblain carbine that I would like to shoot. My barrel dimensions seem a little different. I pushed a slug through the barrel. The slug is 10.8 mm (.425) at its narrowest and 11.4 mm (.449) at its widest. What size bullet would you recommend? Also what dies would you recommend for seating and crimping (preferably something off the shelf)? Any help would be greatly appreciated Thanks.
joe

Buckshot
03-15-2006, 03:59 AM
................Hi Joe! Glad you found the post interesting. I had fun fooling with the little carbine and taking the photos and making the post.

BTW, welcome to the board.

Acording to a couple sources, there were a couple So. American Comblain contracts, plus some of these rifles got around a bit, it seems.

The Brazilians seemed pretty whacked out with their military rifle contracts, until fairly recent times. You can get up a fairly decent number of Mauser types if all you did was to collect Brazilian variations 8)

If you haven't already, you should visit Keith Doyon's site at: http://www.militaryrifles.com/ It's the most Comblain information in one place I've ever seen. There is (or was) a French (or maybe French speaking Belgium site) dedicated to Emil Nagant. Since he invented or buit the Comblain's there was some info there, if you could read Frog. Had some neat photo's too.

Have you taken a chamber cast of your rifle? That is something you REALLY, REALLY need to do. It will give you the info to base all kinds of decisions on. If you decide to have a set of custom dies made, the folks (C-H/4D) will need it to. It would be impossible to suggest a parent case to use without it. That's how I determined the 32 guage shotshell would be closest, and happily the least expensive route.

With that .449" groove, you're probably looking at some 45 cal pistol slug for starters. One dropping from the mould at .452-3" could easily be sized down if it needed to be to fit in a chambered cartridge case.

If you could post a photo of your chamber cast, or at least the dimensions of it, that would sure give us a basis for some intelligent guessing!

..................Buckshot

joe
03-16-2006, 06:34 PM
I'm new to all this and don't know how to post photos. Visited militaryrifles.com, does the shell labeled C04 have a paper jacket?
I made a casting of the chamber using cerro bend. Measuring the diameter along the length of the casting in mm beginning closest to the trigger:
Just above base 15mm (.5906)
mid mark 14.2mm (.5591)
beginning of neck 13.45mm (.5295)
top of neck 12.7mm (.500)
just below rifling 11.8mm (.465)
at rifling 11.45mm (.451)
The length from base of casting to beginning of rifling
48.4mm (1.906)
joe

Buckshot
03-19-2006, 05:57 AM
".............Visited militaryrifles.com, does the shell labeled C04 have a paper jacket?"

Yes, it shows one with a PP.

I'm not real clear on some of your measurement points. Your measurement, "Just above base 15mm (.5906)" could very well be the same 14.8mm shown on the site.

http://www.fototime.com/735C3CBD1CC9D64/standard.jpg

"...........just below rifling 11.8mm (.465)" I don't know where 'just below' is on the rifling, but the .465" I got for the grooves is right there where they begin at the end of the chamber. By simply measureing at the muzzle with calipers I got I think it was .452". This points to progressive depth grooves of some type or other. This is not a "Choked bore" as the lands remain at .433", breech to muzzle.

"...........at rifling 11.45mm (.451)" Nor do I understand where 'At rifling' is. As I wrote above, at the muzzle my groove measurement is very close to your 'At Rifling' measurement.

"..............The length from base of casting to beginning of rifling 48.4mm (1.906)"

I got a similar measurement if I recall, which means it actually could have been the 11x50mm cartridge, but I really don't believe so as when I checked mine that would have definately placed the mouth of the brass case into the rifling and not stopping short of it.

Add in these comments:

"................. The Brazilian M74 Rifle and all later Brazilian Models have their own modifications of the Comblain action peculiar to Brazil. These used the standard foil-cased 11x50R Belgian cartridge as did the later M78 and M85 Rifles. Brazil also adopted a Comblain Carbine in 1873 (M73 Carbine) which used the shorter foil-cased 11x42R Belgian Carbine cartridge,also used in the later M92 Army Carbine and M92 Police Carbines."

And mine is for sure a carbine, and the measurements I took most closely match those for the 11x42R

" ....................beginning of neck 13.45mm (.5295)"
"......................top of neck 12.7mm (.500)"

These measurements above I can't connect with anything I know to compare to. As you can see from my chamber cast, there IS NO neck. I suppose you could use the rifling - casemouth area as the "Top of the neck" measurement?

Are you measureing an unfired cartridge case or your chamber casting? Does your chamber cast have a neck, and doesn't look like mine?

To learn how to post a photo, go to the "Shooters.com" forum or the "Testing" forum, and there will be a sticky that explains the 2 ways to go about it. You may then experiment on the "Testing " forum.

.................Buckshot