doublegunshop.com - home Forums General Discussion Double Rifles, Paradox Guns & Gauge Rifles @ doublegunshop.com 10,75x52R Springer Dbl Rifle Arrived

Gun in hand and I was able to spend some time measuring.

Bottomline is I am unsure.

The 10.75x52R Springer case should measure out 51.94mm long, to the neck down 44.7mm, case dimeter 12.49mm, and the rim thickness should measure 1.35mm

I have not gotten the knack of doing pictures within the post. I have included a shortcut to a sketch layout of the round, pictures of the casting, a bullet blueprint for the ideal 10.75 bullet, and a picture of the gun. http://www.picturetrail.com/gid24335437

The reloaded rounds and brass measured out as follows:
53.03mm long, to the neck down 44.8mm, case dimeter 12.68mm, and the rim thickness should measure 1.66mm (when chambered the case is flush and gun closes without issue)

This is my first chamber cast adventure and I may not be getting it right. The chamber cast revealed the following dimensions 56.85mm long chamber to the bore, to the neck down in the cartridge 44.8mm, (I noted there is a slight barely visable line in the cast that makes me wonder if I should be measuring the length at 54.01 and not 56.85, this maybe a forcing cone, but I don' know) cast dimeter at base is 12.87

I could not drive my .43 cal slug down the bore. I may have been a little wimpy in not wanting to beat hard on it. So I cast with cerrosafe in front of the chamber and one from a few inches from the muzzle.

Further clouding things is instead of a bore of .423 or .425, which I believed I should find. I found the bore was .429 or so in front of the chamber and .429 at the muzzle. I did a long chamber cast and a second slug cast a few inches inside the muzzle. The groves are not deep but look clean and sharp.

At this point I am trying to figure out what I have. A longer than standard dimension chamber, or about a standard and accept the brass cases I got with the gun are about right, reproduce them and move on? Or go ahead and find longer 45/90 cases and mold them and trim them to a longer chamber?

On the bullet instead of finding the springer correct .423 round accept the .429 and find as close in terms of jacket and weight (258grns) to the original type bullet and move on?

Mechanicaly everything checked out. No issues so far. I still have to measure trigger pull and barrel twist.

As an aside I rarely see guns being lighter than advertised; the gun ended up lighter(6lb 14oz versus 7lbs). I am not sure The manuafacture and quality matched up to my other Jules Bury Christophes. I noted in terms of frame size it is a big step down smaller from the 16 bore I have. Almost if not a 28 gauge frame. I only wish I could commision a set of 28 gauge barrels to add to the rifled barrels for a two barrel set.

old colonel,
In my considered opinion,you have made out like a fat rat.By your measurements,you will be able to use 45-70 cases,with little if any modifications,and 44 cal bullets.If you want to do so,you could trim the cases to 51.94mm, but it seems the other owner only trimmed enough to square the neck.The only good reason to trim further would be if it is necessary to seat some particular bullet.Commercial jacketed bullets intended for 444 Marlin should work very well with full length 45-70 cases. Cast bullets should be sized .430-.431",as long as they will go into a fired/unsized case(check .429" jacketed bullet also).For powder, we have been having good luck with 5744 in similar cartridges.Good luck. If you have any problems let us know.
Mike

The german loading of a 10,75x52 Springer used a 258grn bullet with 45grns of N135 powder. I was thinking of going ahead and trying to get as similar a bullet as possible and doing and 80% load, what do think?

Another bullet I was looking at was a 275grn .429 copper jacketed Spitzer from Hawks Bullets. I am not sure if I should just stay with round nose bullets and stay as close to traditional as possible.

old colonel:
Are the tubes by Jean Falla?

Kind Regards,

Raimey
rse

old colonel,
Bullets of 240,260,280gr bullets should be avaliable from the mainline makers.Of course premimum makers like Hawk supply very good bullets. I quess the "german loading" is a modern load for a specific rifle.If it's not for the rifle "in hand",don't be too upset if it doesn't perform in your rifle.Don't be afraid to shoot at 80-100 yds(or meters),doubles are often more accurate than some writers give them credit for.The problems often come from poor bench techniques.If you have any problems, let us know. Have fun.
Mike

I am going to use 80% of the german load as a starting point to see what I get at 25 meters before moving out to a more distant target. I probably won't get a chance for about three weeks before I can get to the range with loaded rounds.

I intend to do a couple of different weight and type bullets to see wha happens.

Is a 6 bullet lot per type too much?

6 will be fine.

Excuse me while I smile....and this is just a silly observation. I wonder if 6, three per barrel, is a number all double rifle shooters magically choose? When I started with them 20 or more years ago that's what I shot when working up loads.

Good luck with it colonel and I look forward to your results!

6 seems like it'll give you a good idea if it likes that load.
It works pretty good for me and I hate trying to pull apart loaded rounds with the ones that won't fit into my kinetic bullet puller!!

I choose six as it was beaten into me young that three shots is the minimum to zero. Also I believe it is a good number to get an average pressure and velocity.