Load Workup for the 7.5x55 Swiss (Schmidt Rubin)

[Grumulkin]

I've had this barrel chambered in 7.5x55 Swiss I bought several years ago just stored in the safe. I finally got around to shooting for the first time a few days ago. My idea was to buy some ammo, shoot it and then reload the brass. Since 7.5x55 Swiss ammo isn't the usual stuff for sale I bought some military stuff I thought was Boxer primed. Well, it wasn't, there was more smoke than with the powders I had been use to and the fouling in the barrel was the worst I've ever had with any ammo I've shot before. After laborous effort I was successful in getting the barrel clean and decided to buy new brass and reload my own.

I found two brands of brass available; Privi Partizan (reasonably priced) and Norma (unreasonably priced) so despite some bad reviews about the Privi Partizan brass (eccentric flash holes, etc.) I bought it.

Just so you know, I ignored two well established dictums in the reloading fraternity:

1. Even though the MidwayUSA site recommended full length sizing, trimming and chamfering the new brass I (GASP!!!) didn't do that .

2. I didn't use a chronograph even though there is a perfectly good one in my basement.



This was the first target shot. It was a 5 shot group since I thought with a newly cleaned barrel the first two or three shots might group a bit high. Actually, the first two went into the top left part of the group and the fourth or fifth went into the same area.



This is the second group I shot. I had made a scope adjustment.



The third group shot. I'm OK with minute of mouse but not so much with minute of deer.



The fourth and last group fired. The load is well below the published maximum with no signs of pressure but I doubt any load will be better than that obtained with 42 grains of IMR 4064 so this is as far as I'm taking it. I know if I hit a deer with that bullet in the right place it will be DRT even though I don't know for sure how fast the bullet is going.

I'll probably shoot some more groups the the 42 grains of IMR 4064 to see if my initial impression was correct. I might even get the chronograph out.

By the way, I thought the Privi Partizan brass was just fine. It was already chamfered and, so far, I've found no bent case mouths or eccentric flass holes. The rifle didn't ejected the military stuff consistently and I didn't have that problem with the Privi Partizan brass.

 

[mstreddy]

OP, which military ammo did you try in the Swiss? From what I understand there was a fair amount of Swiss GP11 out there, and it was supposed to be noncorrosive match quality. But, it's Berdan primed, of course. I have some in my stash, but I haven't fired any of it yet, nor the rifle - yet. I also picked up a couple hundred rounds of Privi ammo, and have since stocked up on components as well. One of these days I have to take that K31 out to the range.

That's a pretty decent work-up there.
I've stocked a fair amount of new Privi brass for some of my rifle calibers. In the ones I've loaded, I haven't seen any issues.

 

[Galil5.56]

Good shootin.

Don't have velocity figures for 4064, but I did test some 150 gr Hornady Spire Points, backed with 45 gr of IMR 4895 from my K31. They avg around 2550 fps, so considering the slightly 'slower' curve of 4064, I'd best guess just north of 2400fps. I have some 180 grain Noslers ready to fly with pretty stout charge of IMR 4831, and hope to get around to slinging them soon. FWIW, Privi factory 174 gr FMJ-BT's, crossed the screens with a 2485 fps avg.

As for Privi brass, it's all A-OK by me. Never any flashhole, or any other concerns. I will say I did spring for Redding dies, and find the results very good. Good luck, and glad to see a fellow 7.5x55 reloader; what a great caliber.

 

[Grumulkin]

It was Swiss GP11 and I was highly unimpressed. Accuracy was only so, so and I have never in my life had a barrel foul so badly after just a few shots. I thought something so bad might be corrosive so I commenced cleaning as soon as I was off the range. I usually don't use brushes for barrel cleaning but I sure did this time. It finally came perfectly clean after several days, several different potions and a lot of brushing.

 

[Duster340]

My K31 likes 165 gr Prvi SPBT over IMR3031 or IMR4895. Both loaded 1 gr under the respective published max loadings using PPU brass. I got it as a project gun from my brother earlier this year and have been really impressed with the accuracy. Gonna try to fill one of my deer tags with it this season.

Be well

 

[ZGunner]

It was Swiss GP11 and I was highly unimpressed. Accuracy was only so, so and I have never in my life had a barrel foul so badly after just a few shots. I thought something so bad might be corrosive so I commenced cleaning as soon as I was off the range. I usually don't use brushes for barrel cleaning but I sure did this time. It finally came perfectly clean after several days, several different potions and a lot of brushing.

That strikes me as odd compared to my experience. I've shot about 200 rounds of GP11 through my K31 and haven't had any of those issues. For me, it has been clean burning and very accurate.

As far as my reloading goes, I've tried a little bit with PPU brass and haven't had any luck. I've only worked up about a dozen loads at a time, but nothing that impressed me enough to fire all my loaded Privi Partisan ammo for the brass. When I go to the range a take a carton of the GP11 because it hasn't let me down yet.

Those look like some good loads for you. I'm sure with some more tinkering they will come in even more.

 

[Whiterook808]

I am using IMR4350 behind an Remington 165 grain pill in my K31. I tried 4064, but the Swiss Miss likes 4350 better. I have Norma cases, but I just bought 50 more PPU to try. I also just picked up a batch of the Everglades 168 grain match boatails to load those with.

 

[Grumulkin]

I did a bit more load testing today. I'm not entirely sure of the reason for the single high one. It could be because it's a cold bore shot. Another possibility is that it could be because I made a scope adjustment. Since it's a vertical string I think the latter is most likely. Even though the scope is a Leupold Mark 4, it could have needed a little jar for the new adjustment to settle in. I guess it will take a little more shooting to find out. In any case, I much prefer a vertical string over a horizontal string.



I decided to try Federal 210M primers instead of the Sellier & Bellot primers. At least with that powder charge, the gun didn't like the change at all. An increased powder charge might tighten the group but I think I'll stick with the Sellier & Bellot primers.