Fit 30 cal cast in Swiss 7.5x55 cases

[Pablo232]

If this topic is in the wrong thread or has been covered before, please pardon my ignorance.

I have bought a Swiss an 1889 Schmidt-Rubin for which I want to reload. I have trimmed some new 7.5x55mm brass down to 7.35mm.

In various threads throughout the web I see that many people use 30 cal bullets, cast and jacketed to load for these rifles. The typical 30 cal bullet, .308 or 7.8mm is 0.3 mm larger than the Swiss 7.5mm calibre.

My question is, how are these folks getting the larger 30 cal bullets into the smaller Swiss case neck.?

Possible ways I have identified are:

- Bell the case neck, use some graphite powder and force the bullet into the neck.
- Anneal the case neck and then force fit as above
- I had thought of sizing the bullet, or the base of the bullet, like a heel, down in my sizer-luber but the only sizer die
close would 7.24mm - too small, unless I were to paper patch the bullet.
- Fire form the case using Bullseye powder, cream of wheat fill and a soap neck plug to expend the nexk.


Any help, or tips for loading for this beast would be greatly appreciated

[Adam Helmer]

If this topic is in the wrong thread or has been covered before, please pardon my ignorance.

I have bought a Swiss an 1889 Schmidt-Rubin for which I want to reload. I have trimmed some new 7.5x55mm brass down to 7.35mm.

In various threads throughout the web I see that many people use 30 cal bullets, cast and jacketed to load for these rifles. The typical 30 cal bullet, .308 or 7.8mm is 0.3 mm larger than the Swiss 7.5mm calibre.

My question is, how are these folks getting the larger 30 cal bullets into the smaller Swiss case neck.?

Possible ways I have identified are:

- Bell the case neck, use some graphite powder and force the bullet into the neck.
- Anneal the case neck and then force fit as above
- I had thought of sizing the bullet, or the base of the bullet, like a heel, down in my sizer-luber but the only sizer die
close would 7.24mm - too small, unless I were to paper patch the bullet.
- Fire form the case using Bullseye powder, cream of wheat fill and a soap neck plug to expend the nexk.


Any help, or tips for loading for this beast would be greatly appreciated

Pablo,

Welcome to this Forum. I bought my first M1889 Swiss in 1961. I do not reload for my 1889s, but do reload cast boolits for my M1911 carbines and rifles and M1931.

Be careful with the M1889 because that old long action was not too robust.

Be well.

Adam

[garandsrus]

The 7.5x55 bullet size is listed as .306. 30 Cal are commonly .308 as you mentioned. There isn’t a problem using .308 bullet in the 7.5x55 case. I have a 1911 and K-31 that I load for. I don’t know if the 1889 is different.

If you use a cast bullet, make sure your round chambers easily. A bullet with a short bearing surface in front of the case is commonly needed. The Lyman 311413 shoots well for me.

There should be quite a few posts here about the 7.5x55.

[M-Tecs]

Since the adoption of GP11 in 1905 .308 diameter bullets have been used. Your Swiss 1889 Schmidt-Rubin predates that. It appears the bore size is different between M1889 and the M1889-96. Neither of which are the same size of the later K11's and K31's

https://www.ballisticstudies.com/Knowledgebase/7.5x55+Swiss+GP11.html

7.5x55 Swiss (GP11)
History

Following European trends of the mid to late 1880’s and after exhaustive testing, the Swiss army adopted a 7.5mm small bore cartridge designed by Eduard Rubin and a straight pull repeating rifle designed by Rudolph Schmidt. The Schmidt-Rubin rifle was officially adopted in 1889, replacing the 10.4mm Vetterli rifle, the new 7.5x53.5mm cartridge was officially adopted the following year bearing the designation GP90.

The GP90 was initially loaded with a 211gr paper patch bullet loaded to 1970fps. Soon after this cartridge was modified to use a less corrosive primer, changing the designation to GP90-03. Further modifications lead to the GP90-23 this featured a 1mm longer 54.5mm case, a change in bullet diameter from .328” to .3075” along with the adoption of a 190gr Cupro nickel jacketed round nosed bullet loaded to 2050fps. After cartridge modifications Swiss military officials discovered weaknesses in the M1889 rifle action. By 1895 a redesign of the action shifted the bolt locking lugs from the rear to the front of the action, resulting in the stronger M1889-96 rifle adopted in 1896.

In 1905 Germany adopted a superior, lighter faster pointed bullet for their military service rifle forcing other European countries to make similar advances. By 1908 the Swiss army had developed a lighter and handier rifle and eventually a new cartridge, the GP11 or 7.5x55 (1911). The GP11 load consisted of a 174gr .3087” bullet giving 2640fps. Initially production of the new rifle occurred by re-barreling M1889-96 rifles to fire the GP11 cartridge. In 1913 production of a new, rather than re-worked rifle, began with the introduction of the M1911 rifle. The M1911 rifle remained in service until the adoption of the K31 rifle in 1931. The Karabiner (carbine) 31 is considered the finest of the Schimdt-Rubin style rifles delivering smooth reliable feeding and superb accuracy.

History of the different rifles

https://en.wikipedia.org/wiki/Schmidt%E2%80%93Rubin

https://en.wikipedia.org/wiki/K31

[1Hawkeye]

As the other posters have said it is actually a .30 caliber The Lyman 311299 mold should be a pretty close match for the GP90 bullet.

[Gewehr-Guy]

Pablo, I have been shooting my 1889 lately, with some success, and like using a long heavy bullet such as the .311299 or .311284. A chamber cast revealed some interesting characteristics of this rifle, namely the fact that they were trying to transition from large bore paper patched bullets, to a smokeless small bore paper patched bullet cartridge. So they really didn't quite know what chamber dimensions were ideal, so they chambered it LARGE. My chamber cast shows a neck diameter of .355 in., and the throat measures .338 for a length of .500 in, then tapers down for another .400 , where the rifling starts. So the throat is .900 inches long, and looks like a tapered funnel!

As for loading, I only neck size , and then use a .311 expander that also expands the mouth to about .313, to about the depth of the gas check. I only seat the bullet a little deeper than the gas check, to keep the bullet closer to the rifling, for better accuracy. To use the magazine, they would have to seat them deeper. After firing the necks are going to expand a lot, so the less you size them down, the longer brass will last. As for the bullets,I think they can be sized rather large, and shoot safely, but don't make them too hard, as they have to form to the odd three groove rifling. I am sizing mine too .311 now, but have shot a few paper patched to .321, and survived.

As for loads I like 23-24 grs. Alliant RL-10, also Shooters world Buffalo Rifle at around20 grs., and 16.5 grs Alliant 2400. These shot OK in my rifle, seemed safe, but use your own judgment. At 200 yards they would shoot through a 4 foot wide grass hay bale, and I found a couple bullets on top of the hard snow. Swiss Products makes a scope mount that requires no drilling, and it works pretty well.

[Pressman]

https://www.swissproductsusa.com/faq Everything you ever wished to know about your Swiss rifle, plus how to reload for it.

[Whole Bunches]

I have a M1889 made the first year of production. Friends gave me a variety of bullets sized to different diameters, .308, .309, 310, .311, .314”. I’ve never slugged the bore. Using Alliant 2400, every bullet shot accurate enough for me with no leading visible in the bore after about 1/10” from the start of the rifling. However, every bullet diameter except .314, shooting 5 shots, left visible lead buildup at the beginning of the rifling. It was easily removed with a few passes of a brass brush. I have no idea if it would have continued to buildup, I was just shooting 5 shot groups and the visible lead bothered me. Bottom line: I use Lyman 314299 sized .314” with fine accuracy and no leading. I’ve not cleaned the bore in hundreds of shots fired.

My Lee case sizing die is unscrewed from shellholder contact and only sizes about 1/10” of the neck. You can see the remaining unsized case neck is bulged due to the generous chamber. Using a Lee neck expander I expand the case mouth just enough that the gas check barely starts into the case mouth. I do not crimp or remove the slight amount of belling...reloaded cases chamber easily. I keep brass separated by rifle and use moderate charges of 2400. My point is to experiment; you might be pleasantly surprised.

Prior to this, I’d been working on jacketed loads for the M1889. Friends giving me cast boolits to try is what got me back into casting. From there I started casting for all my Swiss and Swedes and got into casting for obsolete caliber rolling blocks. See what they started!

[Pablo232]

First, thank you very much to everybody who responded, and for some very useful inks that I had not encountered before. While I have lurked Cast Boolits for several years, this has been my first thread request for help, and resonse was quick and worthwhile. Thanks again.

I have a set of Redding 7.5x55 dies, and have ordered up two neck size buttons in 30 cal and 303 brit cal. Delivery time is currently anticipated up here in 10-16 weeks by which time we will be well into summer up her in snowy Canada.

In the interim I have found a couple of jacketed boat tail jacketed bullets which I will seat into my empty cut down 7.5x53.5 cases for the 1889, and then pull the bullets with my kinetic puller. That should expand the neck enough to seat a 30 cal cast boollet.

I will likely slso see if I can seat a 303 jacketed bullet to expand a case further to accept a cast .311 boollet

My thanks for the cautions on the strength of the 1889 action. For my older rifles I enjoy shooting "bunny fart" loads typically starting with 10gr of Unique. Low pressure and easy on the shoulder. As the 1889has a reputation for blowback I will use a face shield in addition to my safety glasses till I see how things go.

The weather is supposed to go up to just below freezing for a couple of days so I will cast a bunch of medium hard boolets.

Of course having got this far I suppose I will have to try to find a Swiss M31 to play with as well.

Thanks again, stay safe

[Whole Bunches]

I had forgotten about the blowback with mild pressure loads. I too experienced that here and there until the cases had expanded to make a better seal of the chamber. After about the second firing, that went away.