7.5 Swiss Reloaders--How hot do you go?

[Dave R]

I'm a relatively new owner of a Swiss K-31. I have seen several posts saying that you can basically use .308 load data with the rifle. The case appears to have greater capacity than .308....I have some concerns, though.

Reloading manuals show 7.5 Swiss data that is noticably milder than .308. Is that because of the older rifles that use the 7.5 Swiss cartridge? The 1911 and earlier models?

Case in point. I'd like to use a load with H-335. I like the powder in my .308. But the load I use in .308 is 46 gr. It only fills the case about 2/3.

Now, take the larger 7.5 swiss case, and use the lighter load the manuals list--39 to 42 grains--and I'm worried the powder will fill less than half the case.

So, I guess two questions:

1) If you rleoad 7.5 Swiss, do you go to .308 levels?

2) Anyone use H335 for their Swiss?

 

[Sam Adams]

If you want the best information available on reloading the 7.5 Swiss, go to http://www.swissrifles.com/ and look under "Ammunition." Then look under "Reloading" to see about case prep (This will help a lot with your determination of the proper COL). Look under the 2 different sections with Pierre's data to get some good loads. Back in the main section, look under "Swissrifle.com forums" in the reloading section. There you will find a large archive of questions and very informative answers, and you can register and ask your own questions (although you should be able to find your answer by searching the existing threads there).

BTW, a lot of the reloading data in the manuals is for the 1911 rifle, not the K31. The chamber is a bit different, and the COL that you need to use is different (leading to different appropriate loads).

Good luck, and load carefully.

 

[lonniemike]

Sam is giving some good advise. FWIW, with similar bullet weights ballistically the GP-11 and 7.62 NATO rounds are vary similar. Dave, you don't mention bullet weight you used in 308 for the 335 powder. I'd imagine 147-150gr. A few Swiss rifle people report liking lighter bullets. Most seem to like heavier bullets in the 165-180gr range. I've used H-335 up to 44gr with 165 bullets in my K-11. The 1911 or any 1896 or later action that has been Swiss arsenal modified to the /11 action should not be considered a weak action. The 31 action is very robust. Be safe. Work up your loads. H335 may not be your best combo but you won't know if you don't try. Hodgdon#26 7.62 Nato 168-172gr Win(pg350 brass 42gr H335 GI(pg352)brass 40gr H335 and on page 329 7.5X55 w/165-168 bullets and unknown brass used 41gr of H335. With respective vels of 2548fps(24" barrel), 2558fps(24"barrel), and 2399fps(31"barrel). In my K-11 w a 23" barrel using165's and 41gr of H335 for 5 shots I had three vels of about 2300fps, a fourth of about 2350, and a fifth shot over 2400fps. 44gr of H335 vels were around 2500. While you can not substitute date directly between 7.5 Swiss and 308/7.62NATO, it is very close. Where you can find loads for both calibers;note vels, bullet weights, and charge weights. They are usually very close. Remember be Safe, Work Up Best-o-Luck

 

[Dave R]

Thanks for the input, folks. Yes, I have posted a similar question on SwissRifles.com. And I have reviewed their load data. The most popular powder there seems to be IMR4064. I have worked up a load with that, using 150gr. Speer bullets running about 2600fps.

My .308 load with H335 is the same 150gr. Speer bullet running 2800fps.

The GP-11 load which the K-31 was designed for is--IIRC--175gr. bullet running at 2500fps. Which is pretty much a .308 load.

So I guess I'm nervous about using H335 in a half-empty case going to 2600fps, when I'm getting 2800 in a .308 with a 2/3 full case.

 

[lonniemike]

2600 fps isn't real slow. The GP-11 uses 50.gr or so of a slower powder. You should feel a lot less edgy using med to slow powders. Best-o-Luck