I was wondering if there is a official load data that matches the GP11 cartridge. Anybody know where that is?
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January 31, 2012, 04:16 AM
I have looked for that myself and have come up empty.The closest thing is Hornady I think sst 150gr.I figure it must be the powder in the GP-11 cartridge.
January 31, 2012, 07:08 AM
Ask at the K31 forum at Gunboards.com or swissrifle.com.
January 31, 2012, 11:42 AM
I have easily improved the accuracy of this round with current reloading data in loading manuals using pulled fmj bullets.....chris3
January 31, 2012, 04:24 PM
There might be some helpfull information if you scroll down to the chart titled "Variants Overview"
But I honestly have no clue.
A lot more data here. (http://www.texastradingpost.com/militaria/swissrifle.html)
January 31, 2012, 07:54 PM
Heck if I know an "official load".
I conducted some load development for the 7.5 Swiss. I was given Swiss ball to shoot, pictures of the ammunition below.
Notice that the bullet is greased. According to Gen Hatcher's Notebook, grease raises pressures "dangerously". I think that claim is bogus as evidenced by Swiss service ammunition.
AA4350 gave excellent accuracy and just about duplicates Ball velocities with 51.0 grains and a 168 Nosler Match bullet. As you can see 52.0 grains produced velocities over Ball, so I do not recommend that load. It is here for reference.
Instead of AA4350 I am shooting surplus WC852 in the 7.5 Swiss. This is a ball powder, and I purchased my lot from Jeff Barlett at GIBrass.com . It turns out Accurate Arms purchased a 90,000 pound lot of WC852, faster burning than Jeff’s lot, and now it is labeled as 2700. My lot of WC852 shoots extremely well, was dirt cheap, and I am using that up. But if I did not have the surplus powder, I would give IMR4350 or AA4350 a go as it shot very well.
7.5 x 55 Swiss Model K-31 AP11 Swiss Ball headstamp DA 78
24 Mar 04 T = 70 ° F
Ave Vel = 2565
Std Dev = 11
ES = 23
Low = 2551
High = 2574
168 gr Nosler Match 51.0 gr AA4350 INDEP brass and primer OAL 2.850
22 Dec 01 T = 58 ° F
Ave Vel = 2536
Std Dev = 17
ES = 45
Low = 2510
High = 2555
168 gr Nosler Match 52.0 gr AA4350 INDEP brass and primer OAL 2.850
22 Dec 01 T = 58 ° F
Ave Vel = 2624
Std Dev = 31
ES = 72
Low = 2588
High = 2660