Identify German 10.75x54 mm cartridge

[Karl]

I'd like help to identify this rifle cartridge. -- 10.75x54 mm rimmed -- for a J.P. Sauer hammer drilling built in 1891. I took a chamber cast with Cerrosafe. The dimensions of the cartridge are:
54 mm (2.11") length
12 mm (.472") base
12 mm (.472") neck
13.4 mm (.528") rim diameter

Thanks for any info or leads.

. Drilliing Rifle Cartridge cast.jpg

[mike ford]

Herman,
See my comments above, in your thread about identification of the drilling. 11.15x52R LK Express (of course I might be wrong).
Mike

[Karl]

Mike just saw your post. Here's what I've discovered:

Using pin gauges I determined that the bore is .424” (10.76 mm). With light taps I easily drove a .428 lead bullet though the bore filling the Henry rifling. Allowing for a short free-bore throat the closest match I’ve found so far is the 10.75x52R Grundig cartridge. However, the Grundig dimensions and chamber cast dimensions do not match exactly. Identifying the European cartridge may not be necessary as I have found that a dummy .410 shell fits perfectly, including the rim fitting the extractor, except it is too long and engages the rifling. I’ve ordered .410 2 ?” brass cartridges and will cut the cases to 52mm. I’ll assemble a couple of test cartridges.
I'll update you after I test a round.

[mike ford]

If I remember correctly, the Grundig cartridges have head diameters larger than the chamber cast. Chamber cast and cartridge dimensions will never match exactly. The chamber must always be larger than the cartridge, from 0.005 to 0.015", generally, depending on the age and manufacture's tolerances. In this case, the Grundig cartridge would be larger than the chamber, whereas the LK Express and .410 cases would be small enough to fit. Depending on the length of the particular LK Express cartridge, I would usually use 8X57R, 7X65R, or 9.3X74R cases as donor, but others often use metal .410 cases, if they don't have metric cases available. I prefer the rifle cases because they are made for rifle pressures but understand the thinking of those that use the .410 cases. I use 444 Marlin cases to make carpenter fly cartridges (using polishing media shot) for a 2 1/2" .410 pistol. They fit the extractor but would have to be trimmed to length for your rifle. The 444 is a simi rimmed rather than rimmed cartridge, so it takes care to keep from letting the simi rim from slipping behind the extractor. American rims usually need to be thinned to fit metric extractors (i.e. 38-55 cases for 6.5x58R, etc.), but haven't had this trouble with the 444 in.410.
Mike

[Karl]

Mike, I looked again at the 11.15x52R description in Dixon. I agree with your reasoning. Upon reflection, I think it may be the correct cartridge. The dimensions not only look right, given your reasoning, but also it's stated in Dixon "These have been described as for Sauer 'Drilling' rifles .... The groove diameter will, of course, be larger than the bore diameter. Bullets larger than bore diameter would be used -- e.g., .308 dia. bullets in .300 bore rifles. I'm going to develop loads with black powder. I have many black powder shotguns and rifles and shoot black powder extensively. I enjoy bird hunting with my 19th century British hammer guns. Indeed, tomorrow I'm hunting over my Gordon setter with my Charles Lancaster 12 gauge "hare's ear" hammer gun built in 1867. I'll let you know how things work out. I have many .428 diameter lead bullets for handloading my .44-40s (another cartridge that fits the drilling chamber well). Thanks very much for a most informative conversation. We can PM if you want to continue outside of the forum.
Herman

[Karl]

I drove a .436 slug through the barrel (again without using brute force). The barrel is Henry rifled with 7 grooves and lands. You may know that the grooves are wide and flat and that the lands narrow. I have an Alexander Henry rifle chambered in .500 BPE with which I've done extensive load development. Henry developed the rifling for accuracy. (and not to reduce black powder fouling as often thought). Thus, it somewhat surprises me that it was used in this Sauer drilling. Any how .... Using a 7 fluke mike, I obtained a groove diameter of 0.429 only .005 larger than bore diameter. By the way, I also ordered a few .444 Marlin cases that will arrive next week. I'm probably going to stick with the .410 brass as it will only require shortening. Bit-by-bit the gun is revealing itself.

[sharps4590]

To be selfish, please leave your posts in the forum. This is the kind of things I both love to do and learn about.

Speaking of Henry rifling....for many years I had an E.M. Reilly double in 500 BPE. I had some very accurate NFB loads but the ONLY way I got that dang blasted rifle to shoot lack powder was to paper patch the bullets, an exercise I loathe. I always understood Henry developed the rifling specifically for paper patched bullets.

At any rate, I determined to never own another with Henry rifling. Glad you had success with it.

[Karl]

I never got good results with paper patched bullets. I've paper patched many bullets for my original 1874 Sharps .40-70 BN. I actually enjoy it. Jacketed bullets worked well in my .500 BPE. I went through many load combinations to get regulate the barrels and good accuracy and have a notebook full of records.