K31 - 7.5x55 - what are you using?

[Twotone]

Morning all,

Picking up a K31 in the next few weeks and am thinking about loads etc.
I understand the K31 is a bit of a pain to load for as far as OAL goes due to the shape of commercial projectiles being slightly different to GP11 (Swiss Military ammo), which means that the quoted OAL in manuals for 7.5 Swiss that is suggested is often too long and jams the round into the lands.

After I've played with the OAL length (I have a Hornady bullet comparator etc), I plan to make up some test rounds.

I've got some PPU 168grn .308 HPBT FMJ match projectiles, I believe 7.5 uses the same projectiles as .308.

I've got N140 which I use for .303.

Any thoughts? What does everyone else use?

Thanks!

 

[Muir]

Try the 3.06" that Hodgdon lists for it's Sierra 168 MK loads. ~Muir

 

[Twotone]

Try the 3.06" that Hodgdon lists for it's Sierra 168 MK loads. ~Muir

Thanks Muir,

Is there a general consensus over what the 'best' grn bullet is for 7.5 swiss? Would be good to replicate the factory round but if there is a definitively more accurate option im all ears!

Are the 168 weights any good?

Thanks

 

[Brno2e]

Congratulations on your taste. Hope you can find a good load for it.
RS 62 works for me but the COL makes me scratch.
Lee dies got replaced by Redding which helped.

 

[Twotone]

Congratulations on your taste. Hope you can find a good load for it.
RS 62 works for me but the COL makes me scratch.
Lee dies got replaced by Redding which helped.

Thanks!
What projectile are you using?

 

[25 Sharps]

I just use PPU, 1.5-2” at 100 and I’m not good with irons.

 

[25 Sharps]

Thanks Muir,

Is there a general consensus over what the 'best' grn bullet is for 7.5 swiss? Would be good to replicate the factory round but if there is a definitively more accurate option im all ears!

Are the 168 weights any good?

Thanks

174 as that’s what GP11 is…..

PPU 174s work well and that is what they load in the commercial ammo.

 

[Brno2e]

Thanks!
What projectile are you using?

Another PPU user.

 

[martin_b]

and 174 PPU's here as well with RS62

 

[DeLaRue1953]

Evening....Some years ago some Swiss K31 enthusiasts dismantled a GP11 round & found that the predecessor to the RS60 powder (not 100% sure but I think it was Reloader Swiss 17?) & the Sierra MK 175g was the nearest equivalent powder & head to GP11. I have always used Redding dies, PPU cases, Sierra MK 175g .308 heads, Murom Competition primers (until my stock runs out, then CCI 200's) I load 50.1g of RS60 & found that seating the bullet at 0.007" off the lands was optimum. I also F/L resize every time bumping the shoulder back 0,004". In January I scored 47/50 on Stickledown at 1000yds. with this set up, it was a very calm day with very little wind about, from memory about 1.5moa windage to be fair! I bought a Swiss Products PS Diopter sight some years ago which is calibrated from 75yds. to 1000yds & I had just under 2 moa of elevation left with that load at 1000yds. Not boasting here, I'm really not, but debunking some theories that the K31 cannot get "out there"...believe me it can & if you tune your loads right it is as accurate at 1000yds as it is at 300yds.
This load is safe in my rifle & I got there after some time consuming incremental load development so I'm not recommending you use it, you would need to gently build up to what is safe in your rifle. FWIW I have never had a minutes problem reloading for the K31 with Redding dies......
Hope that helps....

 

[25 Sharps]

Not quite 1000 but was at 900 at stickledown Sunday, PPU factory, standard sights. I’m not a great shot with irons but was happy with that and with that performance I don’t worry about reloading

 

[DeLaRue1953]

That's a very creditable score with factory ammo, well done!

 

[Stalker62]

Not quite 1000 but was at 900 at stickledown Sunday, PPU factory, standard sights.

Good effort.

What were your 'settings' on the iron sight (if any) and more importantly, what was your POA?

The issue (for me) with iron sights - either the sights are in focus or the target.

 

[25 Sharps]

Good effort.

What were your 'settings' on the iron sight (if any) and more importantly, what was your POA?

The issue (for me) with iron sights - either the sights are in focus or the target.

@kennyc is my K31 guru and the advice is to use the foresight centre of target out to 300 then ‘lollipop’ for any ranges after that. I was doing the latter and sitting the black circle off the top left corner of the foresight post due to the R to L wind, rear sight set at 900.

Again kenny told me that you’ll never get the rear and for sight plus the target in focus, so I get the sights in line then focus on the foresight with the target in focus in the background to place the POA. At least I think that’s what I do!

 

[25 Sharps]

That's a very creditable score with factory ammo, well done!

There was a little bit of wind to contend with too. I may reload one day for target but I load 8 or 9 calibres already so as the PPU shots we’ll I’ll probably stick to that

 

[DeLaRue1953]

 

[kennyc]

Morning all,

Picking up a K31 in the next few weeks and am thinking about loads etc.
I understand the K31 is a bit of a pain to load for as far as OAL goes due to the shape of commercial projectiles being slightly different to GP11 (Swiss Military ammo), which means that the quoted OAL in manuals for 7.5 Swiss that is suggested is often too long and jams the round into the lands.

After I've played with the OAL length (I have a Hornady bullet comparator etc), I plan to make up some test rounds.

I've got some PPU 168grn .308 HPBT FMJ match projectiles, I believe 7.5 uses the same projectiles as .308.

I've got N140 which I use for .303.

Any thoughts? What does everyone else use?

Thanks!

RS60 works best in mine, N140 will also work, but I prefer the RS60 (RL17) I use the PPU 174grn bullet loaded to the same length as the PPU commercial ammo,(which is where I get the cases from) 48-50 grn of RS60 (work up) and the primers of your choice, always full length resize, neck sizing can cause problems, if you use any other bullet then make up a dummy round to determine insertion depth, the ogive on the GP11 is well back due to its streamlined shape and the chamber was cut to be a tight fit for GP11, SMKs and the like tend to be dumpier and will jam into the lands if loaded to stock length.

 

[Twotone]

RS60 works best in mine, N140 will also work, but I prefer the RS60 (RL17) I use the PPU 174grn bullet loaded to the same length as the PPU commercial ammo,(which is where I get the cases from) 48-50 grn of RS60 (work up) and the primers of your choice, always full length resize, neck sizing can cause problems, if you use any other bullet then make up a dummy round to determine insertion depth, the ogive on the GP11 is well back due to its streamlined shape and the chamber was cut to be a tight fit for GP11, SMKs and the like tend to be dumpier and will jam into the lands if loaded to stock length.

Thanks for this, I don't suppose you have the COAL for the stock PPU round do you? Thanks

 

[Stalker62]

I don't suppose you have the COAL for the stock PPU round do you?

 

[Twotone]

View attachment 257908

Perfect! Thanks mate