Rolling Block carbine Tojhuus cobenhavn 1874

Started by Paul Tummers, 10. August 2013 kl. 9:55:28

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Paul Tummers

I just have got a Danish Engineers(?) carbine made by Tojhuus Cobenhavn in 1874 with a marvellous barrel.
The former owner stated, it was in cal .45-70 gvt, did not slug the barrel yet, no good size bullet or slug available, but will look for that.
As far as I know, the Original caliber will be some tenth's of a millimeter larger than .45, will this cause a problem when I use .458 size bullets?
Who can tell me somewhat more about recommended loads, BP and Triple 7, because obtaining BP is made very difficult over here because of storage rules for retailers for this little rifle that also is of the right size to accompany me when searching with the dog after a wounded hog in the brush?
Is there a way to change the back sight for one that allows for left-right adjustment without having to make any change to the gun like drilling extra holes- the Original sights allow only adjusting for elevation, the front sight is a fixed one and I am told, those carbines are quit rare to find so I do not want to make any changes that can be of negative influence on its value.
If it is good, do not rest and think, the

target has been achieved, but think about how improvements can be made.
The best improvement is usually the one which simplifies the process

considerably.

jke

Hello Paul,

You should slug the barrel as the bores are not all exactly the same in these old guns and you will want the most accuracy you can get if you are going to hunt with it. The chamber should be cast also for proper measurement. In most guns the 45/70 is just a little too long and sometimes the rim might be a little too thick.
I know of no windage adjustment rear sight for these but perhaps you can find one from a different gun that can be made to fit into the existing base without modifying the original sight.

Paul Tummers

Thank you for your reply!
Rim is OK, case lenght also is OK, found this out by inserting a case with a  slightly belled mouth,just enough to be touching the chamber walls, when too long it should have stopped at the end of the chamber.
I will have to slug the bore, but think it will be a narrow one because a .458 cast bullet looks like to be a perfect fit.
I want the adjustable sights for shooting it at the range, for hunting this is an emergency gun for short distances to protect myself and the dogs in case of a sudden attack from a wounded hog, have seen this happen once, result was a killed dog and a man who was not a man anymore even after intensive surgery!
If it is good, do not rest and think, the

target has been achieved, but think about how improvements can be made.
The best improvement is usually the one which simplifies the process

considerably.

Frank Ambruso

I modified an American WWII BAR sight by drilling a second hole in base and radiusing the bottom of sight to seat better on barrel, was able to use one screw and add a second.

Works well for me.

Frank Ambruso

What do the cases look like?, buldged on one side?

I run a .458 expander rod down inside the case to expand the base .015" or to fit your chamber, then trim to proper length for original cartridge and load .462" diameter bullets (no heavier then 460 grains due to slow twist) in custom made sizer.

 
I would have to disagree that the chamber has been altered to take 45-70 length cases,  I believe the only changes to convert/modify to use 45-70 is recutting the rim dimension a little bit.

I believe the Danes used a long throat/tapered neck originally for the paper patched bullets.

I have been shooting full length 45-70 cases with no problems and there are no discernible cuts in my chamber, I believe they used .460"-.462" diameter bullets and corresponding chamber expansion/dimensions.

Mine will shoot just under 1.75 moa with 400-460 grain .462" diameter bullets and 22.5 grains of IMR SR4759 or 23.5 grains of AA5744, spg lube, no crimp.

jbw

We / the danes used 3 diff. length, rimfire 41,5 mm, medium centerfire in 45,5 mm, and long, smokeles 51,6mm.
You will find drawing  of the cartridges produced at the danish army ammunition factory  
here http://s6.photobucket.com/user/jan_buchwald/media/AMA/patron1.jpg.html?sort=3&o=0

I use 45 grs blackpowder and a .462 / 420 grs bullet from an Australian (CBI) mould