K31, 7.5x55 Swiss Reloading

http://www.hodgdonreloading.com/data/rifle

Always one of my first go-to’s.

Here's a few resources I used in MY rifle. As always start low and work up. I have had great results with IMR 3031 AND IMR 4895

http://stevespages.com/308_14_165.html

https://thefiringline.com/forums/showthread.php?t=135265

Hodgdon has data online, and if you go to Swissrifles.com, they have some posted too. Realguns.com had some SUPER HOT data, but it is no longer there. Sierra has posted data I attached (sorry, best copy I have), and if you email Ramshot they will send you data. Here is some more:

https://www.tapatalk.com/groups/theswissriflesdotcommessageboard/7-5x55-load-tables-t9041.html

I might suggest if you have not ordered dies yet, you splurge a bit, and go with Redding. I have a set for my K31, and they make the process a joy... They cut the sizer for K31 dimensions, and work so well. I wish we could get real GP11 bullets with the proper ogive... Maybe we have, and I just never saw any. Good luck.

+1 on the Swiss rifles forum. They tried to compile reloading data from responsible members and have more powder/bullet combinations than you will find anywhere else. Mostly good information IMO. It doesn't seem as active now as in years past.

+1 on the Redding FL sizing die. I had some issues with my RCBS that the Redding cured. As you noted, its not a SAAMI cartridge and K31 chambers are different from the 1911 rifles.

Pick up the Hornady reloading manual, and ignore their COLs. The loads are good, but the COL is appropriate for the Gew 11, not the K-31. You'll want to set an appropriate COL for your rifle and bullet near the lands with minimal jump. The K-31 has a very short leade, so long, fat ogives are not your friend.

I've found the 155 Nosler over 43.1 IMR 4064 to be about the ideal load in my K-31s. Mild recoil, extremely accurate and the bullet profile works well with the K-31s throat and magazine and does not require extreme seating depth to work. This load is quite close to GP11 point of impact for me at 200 and 300 yards with my rifles/ military sights (they both shoot quite high at 100 yards with GP11).

Hornady lists this powder from min ,35.5 to max 46.1 with 150-155 gr bullets.

It's hard to load the 7.5 Swiss wrong. The rifles are so accurate, it's just silly. Several years ago I competed at our local High power matches (reduced course) using one of my slightly modified K-31's. For the most part I loaded/shot a 150 gr. cast bullet designed for a 30-30 and ultimately reached an expert classification.

For jacketed bullets I'd recommend either Varget or Re-15. Here are some loads/targets from my K-31's. Hopefully you can read the data written on the targets-



Mine shot some of the best groups with the homely Hornady 150 gr. FMJ. Somewhere I have a picture of a group fired at 600 yds, and for an iron sighted military rifle firing FMJ bullets, it was quite impressive. Anyhow, here's a really good 100 yd. load/group-



A nice reduced load with the Hornady bullet-



Finally, if you can find some GP-11 ammunition, grab it. It's as accurate as handloaded match bullets.





35W

Be safe, start low work up and I'll bet your best 308 reloads will be about your best 7.5X55 reloads. They are pretty much ballistic twins. Best

I would caution against using .308 load data directly. It is PROBABLY safe, there are definitely some parallels to be drawn, but full house .308 charges are definitely on the warm side in the K-31 according to data I have for both rounds with the same powder. The K-31s short leade does very well with charges below max. There is no need to stress your brass or rifle. In addition to the above load I posted, which is on the mild side and the most precise I've found, I have had excellent luck with Varget in the same charge range +/- 1 grain (needed WLR primers to get good groups, others gave me vertical stringing indicating inconsistent ignition) and Viht N140 referencing Hornady Data.

I settled on the 43.1 gr charge with 4064 as it zeros my to my sights at 200 yards for CMP Vintage matches. Loads up and down the ladder showed similar precision, consistently under 2" with military iron sights from a rest. I have cleaned the SR2 multiple times with this load prone in match conditions.

I have had great luck in the 7.5 Swiss with H4350. Low SD's and good velocity. The 7.5 Swiss is not a real picky caliber, but it is short and fat and thus the appropriate powder must be used. There is plenty of data out there so I wouldn't bother with 308 Win data. Do keep in mind, and it's already been stated, that K31's have a VERY short throat due to the GP11 bullet. I seat .020 off the lands in my 1937 Hammerli and the bullet is WAY down there in the case. Shoots real darn good though.

+1 on the H4350, I also have had good luck with that and 168 grain projectiles.

I did say be safe and work up, as I have while reloading the k11 since the early seventies. My older Weaker Swiss k11models seemed to handle 308 loads class weights just fine. None of my k11's or 31's have come apart and I still got all my fingers and stuff. Okay, it is probably safe to work up using 308 data. Now it is all better. Let's see, our 7.62 NATO 175 grain bullet comes out of our 26" service rifle at 2550fps and the 7.5 Swiss 174 grain bullet comes out of their 26" barrels at 2550fps. go figure, geez extra room in a larger case same charge less pressure. Yea, be safe, work up and you can use 308 data. A chronograph is a pretty cheap tool these days. Check out SwissRifles.com and the Swiss Rifles Message Boards link of note.Best

To add more to my original posting... I found the smorgasbord of Ramshot data I received via email from Ramshot in 2012. The 'hot' Realgun data I must have not screen captured, but its performance as I recall had 30/06 numbers per bullet weight.

Data shown was copied verbatim from the Ramshot email I received. Note that some loads are compressed, and no mention of case brand/case capacity, or finished cartridge OAL was provided.

This statement was also included:

"Unfortunately we do not have any specific lab tested data on this caliber.
However, we can provide you with some guideline, based on calculations and information from other sources."

The email did not contain or state any pressure data. What maximum avg pressure std they used to determine maximum charge weights for the listed data, CIP or otherwise was not included. Consider and use at your own discretion.

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Caliber: 7.5x55 Swiss (Schmidt Rubin) GP 31
Suitable for the following guns: Model 1896/11 and Model 31
Barrel length: 24”

Note: We do suggest A-2520/A-4064 as the better options.

Caution: Due to variations in internal dimensions with guns manufactured for this caliber, it is extremely important to heed the cautions below by starting at the minimum START Loads and carefully develop loads in 2% increments.

Powder: Accurate – 5744®.

Bullet weight: 150 grains.
Low load: 24.0 grains (ca 1825 Fps)
Midrange load: 29.0 grains (ca 2125 Fps)
Maximum load: 34.0 grains (ca Fps).

Bullet weight: 180 grains.
Low load: 22.5 grains (ca 1725 Fps)
Midrange load: 28.0 grains (ca 2000 Fps)
Maximum load: 32.0 grains (ca 2200 Fps).

Bullet weight: 200 grain L.
Low load: 15.5 grains (ca 1300 Fps)
Midrange load: 20.0 grains (ca 1600 Fps)
Maximum load: 31.0 grains (ca 2100 Fps).

Powder: Accurate - 2460

Bullet weight: 150-155 grains
Start load: 41.4 grains (ca 2425 Fps)
Maximum load: 46.0 grains (ca 2775 Fps) LD ca 83%

Bullet weight: 168 grains
Start load: 39.6 grains (ca 2375 Fps)
Maximum load: 44.0 grains (ca 2625 Fps) LD ca 82%

Bullet weight: 175 grains
Start load: 38.7 grains (ca 2300 Fps)
Maximum load: 43.0 grains (ca 2550 Fps) LD ca 81%

Powder: Accurate -- 2495®

Bullet weight: 150gr:
Start load: 41.4 grains (ca 2550 Fps).
Maximum load: 46.0 grains (ca 2800 Fps) LD ca 92%

Bullet weight: 168gr:
Start load: 40.3 grains – (ca 2450 Fps).
Maximum load: 44.8 grains – (ca 2700 Fps) LD ca 90%

Bullet weight: 180gr:
Start load: 39.2 grains – (ca 2350 Fps).
Maximum load: 43.5 grains – (ca 2550 Fps) LD ca 89%.

Powder: Accurate -- 2520®

Bullet weight: 150gr:
Start load: 43.2 grains (ca 2550 Fps).
Maximum load: 48.0 grains (ca 2825 Fps) LD ca 90%

Bullet weight: 168gr:
Start load: 41.4 grains (ca 2450 Fps).
Maximum load: 46.3 grains (ca 2700 Fps) LD ca 89%.

Bullet weight: 180gr:
Start load: 41.4 grains (ca 2375 Fps).
Maximum load: 46.0 grains (ca 2600 Fps) LD ca 88%.

Powder: Accurate -- 4064®.

Bullet weight: 150gr:
Start load: 45.0 grains (ca 2625 Fps).
Maximum load: 50.0 grains (ca 2875 Fps) LD ca 102%

Bullet weight: 168gr
Start load: 42.8 grains (ca 2425 Fps).
Maximum load: 47.5 grains (ca 2700 Fps) LD ca 101%.

Bullet weight: 180gr
Start load: 41.8 grains (ca 2400 Fps).
Maximum load: 46.5 grains – (ca 2625 Fps) LD ca 100%.

Powder: Accurate -- 2700®.

Bullet weight: 150gr:
Start load: 44.0 grains (ca 2400 Fps)
Maximum load: 51.5grains (ca 2800 Fps)

Bullet weight: 168gr
Start load: 42.5 grains (ca 2350 Fps).
Maximum load: 49.0 grains (ca 2750 Fps).

Bullet weight: 180gr
Start load: 41.5 grains (ca 2250 Fps).
Maximum load: 47.0 grains (ca 2600 Fps).

Powder: Accurate -- 4350®

Bullet weight: 150gr:
Start load: 45.0 grains (2300 - 2400 Fps)
Maximum load: 53.0 grains (2750 -2850 Fps)

Bullet weight: 165gr
Start load: 43.5grains (2100 - 2200 Fps)
Maximum load: 51.5grains (2650 -2750 Fps)

Bullet weight: 180gr
Start load: 41.5grains (2050 - 2150 Fps)
Maximum load: 49.0grains (2500 - 2600 Fps)

NOTES:
It’ important to note that SAFETY is our prime concern therefore we strongly recommend.
1. ALWAYS BEGIN LOADING AT THE RECOMMENDED MINIMUM “START” LOAD.
2. If possible, measure the velocity and correlate with our data.

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And some more data they sent separately, listing their three favorite propellants. Methodology for the ranking, was not given or noted:

Caliber: 7.5mm x 55 SWISS. (GP-31)
Barrel length: 24”

Powder: Ramshot – BIG GAME®. (1 st Choice)

Bullet weight: 110 grains.
Start load: 53.1 grains (2950 – 3050 Ft/p/sec)
Maximum load: 59.0 grains (3250 – 3350 Ft/p/sec). LD ca 99%

Bullet weight: 150 grains.
Start load: 48.0grains (2600 – 2700 Ft/p/sec)
Maximum load: 53.0 grains (2800 – 2900 Ft/p/sec). LD ca 96%

Bullet weight: 165 grains.
Start load: 46.0 grains (2350 - 2450 Ft/p/sec)
Maximum load: 51.0 grains (2600 – 2700 Ft/p/sec). LD ca 95%

Bullet weight: 180 grains.
Start load: 45.0grains (2400 - 2500 Ft/p/sec)
Maximum load: 50.0 grains (2650 – 2750 Ft/p/sec). LD ca 94%

Powder: Ramshot – TAC®. (2 nd Choice)

Bullet weight: 110 grains.
Start load: 48.6 grains (2950 – 3050 Ft/p/sec)
Maximum load: 54.0grains (3250 – 3350 Ft/p/sec).

Bullet weight: 125-130 grains.
Start load: 46.8 grains (2725 – 2825 Ft/p/sec)
Maximum load: 52.0grains (3000 – 3100 Ft/p/sec).

Bullet weight: 150 grains.
Start load: 44.0 grains (2600 – 2700 Ft/p/sec)
Maximum load: 48.0 grains (2750 – 2850 Ft/p/sec).

Bullet weight: 180 grains.
Start load: 41.0 grains (2300 - 2400 Ft/p/sec)
Maximum load: 45.0 grains (2550 – 2650 Ft/p/sec).

Powder: Ramshot – X-TERMINATOR®. (Lighter bullets only)

Bullet weight: 110 grains.
Start load: 44.1 grains (2800 – 2900 Ft/p/sec)
Maximum load: 49.0grains (3200 – 3300 Ft/p/sec). LD ca 86%

Bullet weight: 125-130 grains.
Start load: 42.3 grains (2725 – 2825 Ft/p/sec)
Maximum load: 47.0grains (3000 – 3100 Ft/p/sec). LD ca 84%

NOTES:
It’ important to note that SAFETY is our prime concern therefore we strongly recommend.
1. ALWAYS BEGIN LOADING AT THE RECOMMENDED MINIMUM “START” LOAD and
develop loads in 2% increments towards the MAXIMUM load.
2. If possible, measure the velocity and correlate with our data.

I'd suggest getting a Hornady COL gauge and converting a once fired case for use with it. My typical load is 42gr of 4320 under a Hornady 150gr FMJ. Shoots really good for me.

SSGMANN said:

Alot of good info , thank you all. I have quite a bit of IMR4064 on hand ( I use it for my 6.5 Swed) and quite a few of hornaday 150gr FMJBT. A guy I work with does alot of reloading as well, the big thing is getting all the measurements good, length of case, then length of case with bullet. Have seen alot of info on other gun-boards, seems alot of old posts and very conflicting though! . Using PPU brass, once fired by me. Still waiting on all the dies to come in!

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Have heard a lot of good things concerning those Hormady FMJ's in 7.5x55. I have only used Hornady 150 SP's and the results were very good. Have some 180 grain Nosler SPBT's loaded up with IMR 4831, ready to put to the test. I like that they load looking 'normal', and still wish PPU would import the same 174 grain FMJ bullets they use in their factory rounds (same for importing 139 grain FMJ's used in their 7.5x54 MAS).

Good luck, and have fun loading this fine round.

You can set your zero freebore without a special guage. There are essentially 2 methods.
1. Start with a round that is long. Incrementally seat the bullet deeper until you are very close, by pushing the round into a chamber with your finger. Now black the bullet with a marker, and continue incrementally seating deeper and gently pushing in with the bolt, stopping when you feel resistance. When you extract, you should see the beginnings of engraving by your rifling leade. Continue this process until you stop engraving, and you are now at zero freebore.

2. Insert a length of drinking straw into the case so it extends into the neck from the web. Pre-stress the straw with a small crease near the center. Do not resize case, you'll need a clean neck. Insert bullet into case neck, you want some tension, may need to put a couple of micro strips of tape on the bullet. Slowly chamber the dummy round, crushing the straw inside the case. Very slowly remove the case, it may take a couple of tries, sometimes the bullet will stick at the rifling. This will get you to extremely close to zero freebore, but you'll still have to verify freebore with a blacked bullet as you set your final COL. This is the method I've used when determining the correct COL for a new K-31.

The accuracy of the K31's never ceases to amaze me.

Using a St. Marie bolt on / no drill mount and a older El Paso 4X Weaver scope my best 5 round 100 yd. group off bags is .678.

Here's my load if interested;

Frontier / Hornady brass....CCI BR-2 primers....Sierra Gameking #2140 165 gr. HPBT....43.5 grs. of Varget.

Tuesday I noticed that I was getting low on the Sierra 2140's and everybody seemed to be out of them then I remembered TJ Coneveras in Rockford, Ill. (tel. 815-968-5590 or order online) and I placed a order for three boxes which should arrive today.

SSGMANN said:

So maybe a bit off topic, but still referring to K31's. Has the GP11 ammo dried up. did a basic google search, all the sites were "out of stock" even gunbroker was pretty sparce! Anyone have any leads?

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Yes. It's basically a gunshow find only now. Remaining stocks in Switzerland, which are very low, are reserved for registered Swiss rifle clubs, and that supply is finite. RUAG has sold the tooling, and will not produce any more, ever.

Guess I'll be holding on to the several hundred rounds of GP11 I have left. It really is fantastic ammo...looks pretty too!