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Old May 22, 2018, 05:28 PM   #1
AKolomiets
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Reloading 7.5x55 Swiss

Does anyone out there reload 7.5x55 Swiss? The military surplus ammo is almost impossible to find, but looks like reloading dies, brass, etc are still available. That 7.5mm bullet, on the other hand, not so much.... any suggestions or past experience?
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Old May 22, 2018, 05:52 PM   #2
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Ahh, one of my favorites and frustrating subject!

Welcome, need some more details. What rifle?

I have a K-31, 1911 and a Savage 110 I re-barreled to 7.5 Swiss.

Regardless of what anyone says, 308 is the right bullet. It all has to do with specs variation but it is a so close to a true 308 that .308 is the right bullet.

There is almost bullet that comes close to matching the GP11 projectile profile. Some reports of Berger RDF. It acualy looks like it might, have to get some to see for sure.

I do have a few rounds of GP11 a very kind person sent me, I have taken one case apart. It truly is an unusual bullet compared to the rest I have.

Seating deep seems to be a key but still playing with that.

Sierra 175 Grn Match often works good in the K-31

Powders that work are R-17 (that is the original, up around 46 to 50 but start low. This one cams over pretty quick. )

4350 (any of them) is a good one, its in the region of R-17 burn rate wise though that is just an approximation of what works and does not.

PPU Brass is readily available, its good stuff and the cost is reasonable. Lapua no longer is or rare, it may come back but had not seen any in a while.

I went with RCBS dies as you can get the side slot loading with the sleeve, I believe its much better seating bullets, I don't know the sizing dies makes any real difference but I got the set.

COAL for bullet seating seems to need a jump to work (still playing with that)

There are some tuning things to be done to the rifle if its a K-31.
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Old May 22, 2018, 06:18 PM   #3
AKolomiets
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RC20, you're a wealth of knowledge! I have a K31. I've been shooting the Ruag military surplus ammo through it since it was somewhat easy to find about 2 years ago, but supplies have definitely dried up and I need something to keep feeding it in to the future. I have some H4350 so I will likely start playing with that. Any concerns with resized cases getting stuck in the rotary action?
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Old May 22, 2018, 06:46 PM   #4
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Mine has done fine.

I do minimum shoulder bump back and its happy with it.

I have issues with the Savage being too tight, had to increase the bump back to .003 average and that has some a bit more going into the .005 area.

I fell for the cartridge but as noted, challenge getting reloads to work in both guns (I have not shot the 1911 much as I can't see iron sights too well)

I do have the clamp on scope adapter on the K-31. It works really well and leave no marks.

Oddly the only rings that its designed for are the 22 rimfire type 3/8 base (Warne in my case). No issues with hold the scope tight. I find that pretty funny but no issues with the recoil.

Same ones I have on my 22 rimfire (CZ)
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Old May 22, 2018, 08:45 PM   #5
AKolomiets
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I've been looking in to getting one of the clamp on scope bases as well. A friend of mine has one on his K31 and he loves it.

I have some PPU and Hornady (GRAF) brass that I will be using. What loads would you recommend for H4350? I can't seem to find any guidelines online.

Is milspec GP11 berdan or boxer primed? Are the cases reloadable?
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Old May 23, 2018, 08:23 AM   #6
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gp11 is berdan primed. it's reloadable with some extra steps and berdan primers. gp11 can be converted to use boxers with a bit of work. Do work up any loads, but the Swiss since 1908, have been shooting the ballistic twin to the 7.62X51(about 1953) gp11. So I,m saying use 308/7.62 load info. Be safe work up! Check out SwissRifles.Com
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Old May 23, 2018, 08:55 AM   #7
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CAUTION: The following post includes loading data beyond or not covered by currently published maximums for this cartridge. USE AT YOUR OWN RISK. Neither the writer, The Firing Line, nor the staff of TFL assume any liability for any damage or injury resulting from use of this information.

I haven't seen this data published, hence the warning. Always work up your own. That said, I have matched GP11 using Re-17. Other powders do well also, but manuals and Quickload indicate high pressure before reaching the target velocity.

GP11 goes 2,579 avg/12.3 std out of my K-31. A 175 SMK (#2275) 0.308 over 48.5 gr Re-17 goes 2,570/7.7. QL "calibrated" to this velocity predicts 38,618 psi vs. CIP max of 55,114. I am comfortable with that margin, even though it is not a direct measure.

Note that SAAMI max for .308 Win is 62,000. I would not recommend using .308 data as a basis for safe 7.5x55 loading.
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Old May 23, 2018, 02:35 PM   #8
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That 7.5mm bullet is a regular .308" bullet. Regardless of which flavour of 7.5 Swiss you have. It's one of those daft military things. 7.5 French and 7.62NATO uses a .308" bullet too. Despite the fact that .308" does not mathematically convert to 7.62mm. That's the nominal bore diameter, not the bullet. 7.62 x 54R uses a .311" bullet. Don't even try to figure out why a cartridge is called what it is. It'll give you an aneurysm.
There's lots of 7.5 Swiss data on Hodgdon's site.
"...using .308 data..." Absolutely not. .308 start loads are very close to the 7.5 max loads.
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Old May 23, 2018, 05:21 PM   #9
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https://www.loaddata.com/Cartridge/7...idt-Rubin/1074

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Old May 23, 2018, 08:10 PM   #10
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Great timing. I just acquired a K31 project and was researching the reloading option. Looking forward to playing with it and do some deer hunting.
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Old May 23, 2018, 09:40 PM   #11
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I am bookmarking this thread, it has a lot of good info in it. I am thinking about collecting some older military bolt rifles and the K 31 will be one of the first
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Old May 24, 2018, 05:53 AM   #12
AKolomiets
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Thanks guys. Duster340 I’m right there with you - aside from match loads I’m planning on putting together a deer load. Considering the 165gf SST.

As far as primers go, would a standard WLR do the trick or would a “tougher” primer like CCI 34 be preferred to account for the higher bolt thrust on the K31?
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Old May 24, 2018, 11:43 AM   #13
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Sierra and Hornady have good data on the 7.5 Swiss.

This is in the for what its worth the GP11 I took apart was 48.3 and per all the reports, identical appearance to R-17. That looks to be in line with other reports.

Oddly Hornady even with X book does not list R-17.

Also oddly they do all their tests with the 1911 not the K-31. The two rifles differ a lot other than the same load fit them, what works COAL for the 1911 not likely to for the K-31.

Hornady powder for 168 and 178 gr were: IMR3031, 4064, 4320, 4350
H4895,
Accurate 4350 (staring load was 2.3 grains higher so they are not all that similar load wise)

Sierra: H4831 and IMR 4831 added to the list for 165 and 175 gr range.
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Old May 24, 2018, 08:23 PM   #14
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I got my first K11 in 1967 and purchased the Hornady Reloading Manual 1st Edition, first printing (1967) because it was the only manual with data for the 7.5 Swiss....no other manual had it.
.308 dia bullets work just fine. The K31 has a shorter throat , the K11 can use longer bullets and longer OAL . Dies should be no problem...an influx of K31's a few years ago brought in boxer loaded ammo so it could be reloaded. In the late 60's all we could get were berdan primed ammo....no reloadiong them. We made cases from 284 Winchester brass , a simple resize made it usable 7.5 Swiss.
PPU ammo or once fired brass is fairly easy to find , I poked around the net and found 200 rounds of once fired PPU brass two yeas ago with no trouble.
Follow the data from a reliable source ,,,Hornady still includes it in their newer manuals, and you should have no problems. The berdan primed 7.5 Swiss taught me what a boxer primer was and how to look inside the case for one big or two small holes...and which ones my redding dies would decap.
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Old May 25, 2018, 03:46 PM   #15
lonniemike
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NATO 26" tube 175 grain 2550 fps

Gp11 26" tube 174 grain 2550 fps
looks like a twin to me
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Old May 25, 2018, 03:48 PM   #16
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Which start load is close to max?
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Old May 25, 2018, 03:53 PM   #17
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What part of work up is wrong? I can safely put gp11 or any 308 equvilant down range in any of my 1911 series rifles. The 1931 series is even stronger. BesttoAll
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Old May 29, 2018, 08:44 PM   #18
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Even thought he ammo is the same, its my understanding that the K31 has a tighter chamber than the earlier 1911. I bought RCBS dies and they work, however, they produce sized cases that are a pretty snug fit in my rifle. I believe RCBS may have cut their sizing die to be a compromise for both rifle models.

I then went to Redding; the sizing die is cut with the K31 chamber in mind and my rounds chamber like factory GP11 now.

This was my experience with my rifle, my brass and my dies. Your experience could be different.
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Old May 30, 2018, 09:55 AM   #19
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My K-31 has no issue with the RCBS dies. I do have the competition set, I don't know if that makes any difference.

I use them for the K-31, the 1911 (not much) and the 7.5 x 55 I built up in a Savage.

I just measure the fired case should COAL (COAS?) and push the shoulder back .003 no matter what gun it was fired in (I have split the K-31 rounds out separately).

The .003 is deemed a bit excessive but if I don't, I get the occaiao0nl one that is too tight (I don't like a hard bolt turn to close)
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Old May 30, 2018, 10:34 AM   #20
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I did some reloading for the 7.5 before I finally sold the rifle I had.

Bullets were simple. I had great success using standard .308 bullets. Same as my .30-06 or my .300 Savage.
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Old May 30, 2018, 11:12 AM   #21
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I have read that the 1911 had the chamber cut with generous clearance and less taper than the K 31 to ensure reliable feeding under potentially adverse conditions. Seems logical to me that a case fired in a 1911 will expand in every direction from the base forward.

So if it is the case (I have not definitively proved that with Cerrosafe castings) that RCBS gave their sizing die more clearance in deference to the 1911s, it's not going to be just a issue of shoulder setback.

My advice is, if you only are shooting a K 31, buy the Redding dies.
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