Reloading for the K31 ?

[mac1911]

I have not reloaded much yet. Although I have seen a few things that make me go Hmmm.
Headspace? Theres really not much in the way of information on headspace. Poking around I find little info on headspace and only a few ways to meassure bolt play.

Anyway I decided to dissect a GP11 round and a Factory PPU. What i find is the factory rounds are much shorter than the fired cases. More detail later. I was a bit surprised at how much. Now my reloads sized with Lee dies and set per instructions feed and fit no problem BUT i find its pushing the case and most likely the body way to much to be good for long term brass life.

I know reading and Hornady make specific K31 dies but honestly there is not enough info out there to really understand why these special K31 dies are so different if you have both regular swiss 7.5 dies and the K31 dies I would like to see the real world differences.

So the fun part. I had some of my fired cases handy and i decided to see if they chambered easily and was going to neck size only. Well they would not close with out some hard push.

Now i get the mil chambers tend to be generous to make room for mud,blood,snow,ice and everything else that might find its way into the chamber or on the ammo. Fun stuff.

So it took some die adjusting the lee dies to get the shoulder to only push back .003-005" and chamber easily and hope this increases case life. I will post some measurements later. I would say the lee dies work just fine and when adjusted per directions get the brass close back to GP11 and PPU specs. I will be loading up some more test rounds for tomorrow and report back.

UPDATE:
as always be warned camera skills suck

View: https://www.youtube.com/watch?v=Bw5UTnE92nA



View: https://www.youtube.com/watch?v=a1bADC_wYP8


I cant find my once fired GP11 its buried in the shed I think.

So basically from what I gather K31 "headspace" is measured by axial end play of the bolt. With a minimum cartridge and a max chamber this end play is not supposed to exceed .017" . From what I understand there are no swiss armory head space gauges. Pacific tool list a swiss 7.5 head space gauge but yet to respond to a email where they get this info?
So basically Im getting aprox .019" case stretch with the PPU factory ammo
PPU Factory ammo av1.785" Fired PPU case av1.804" with a =/- .002"

Swiss GP11 5 factory rounds I have on hand min 1.788" max 1.7890" I need to find the once fired gp11 to compare but im sure it will show the same fired length.

So is this a loos chamber? Is a .019" case growth after firing something to worry about? Out there in swiss rifle world, not so much. I have a few more test batches to try before the next Vintage match and im trying out a lower powder charge. Theres really no reason to run them as hot as I was for 200 yards.

 

[s11033]

I would love to hear back, as I’m about to start loading for my K31 and G96/11. I plan to do some experimentation with WC872 to see if it can produce a viable mild load that doesn’t leave too much unburned powder.

Any experience using .284 brass? I was planning to use that instead of the Swiss because it’s so much cheaper.

S11

 

[DW357]

Any experience using .284 brass? I was planning to use that instead of the Swiss because it’s so much cheaper.

S11

I just stick with new PPU 7.5 brass. Can be had for ~50 cents per case shipped. I don’t have the patience to fool around with .284 brass.

 

[s11033]

I just stick with new PPU 7.5 brass. Can be had for ~50 cents per case shipped. I don’t have the patience to fool around with .284 brass.

Fair enough. I’ll look for it. Thanks!

 

[mac1911]

I would love to hear back, as I’m about to start loading for my K31 and G96/11. I plan to do some experimentation with WC872 to see if it can produce a viable mild load that doesn’t leave too much unburned powder.

Any experience using .284 brass? I was planning to use that instead of the Swiss because it’s so much cheaper.

S11

I was given a handfull of .284 to use to reform for the k31. I found it very tough going through the die and just bought PPU 7.5 swiss and use that brass and bought 50 new cases when it came up for sale a few years ago for .29 each.

I dont really experiment with powders out side published data I have no experience with WC872?

Sadly the one old timer I know deep into the swiss rifles has passed. He said he did not have time or patience to resize to individual rifles. He told me just use lee dies, adjust as direction say and they will work in any swiss rifle in 7.5 swiss.
I only have the one k31 so resizing to fit the chamber is ok

 

[s11033]

I was given a handfull of .284 to use to reform for the k31. I found it very tough going through the die and just bought PPU 7.5 swiss and use that brass and bought 50 new cases when it came up for sale a few years ago for .29 each.

I dont really experiment with powders out side published data I have no experience with WC872?

Sadly the one old timer I know deep into the swiss rifles has passed. He said he did not have time or patience to resize to individual rifles. He told me just use lee dies, adjust as direction say and they will work in any swiss rifle in 7.5 swiss.
I only have the one k31 so resizing to fit the chamber is ok

Cool, thank you. I’ll probably just pick up about 100 cases and some Lee dies. I think I’ll adjust the die for whichever of my two chambers is smaller so I can keep ammo commonality.

WC872 is an extremely slow surplus powder mostly used in .50 BMG, 20mm. It’s also used to load large magnum cartridges. It’s really cheap at about $5/lb in bulk. It generally produces very mild loads that are nice for plinking with milsurps, but it’s pressure curve is so low that in most calibers it leaves too much unburned powder to be useable. I’ve been able to use it to load 6.5 Swede because it’s quite overbore. I’ve read it can be used in the 7.5 Swiss too, but I’ll have to do some testing to know for sure.

S11

 

[mac1911]

updated post 1

 

[Mountain]

I think I'm going to break down and get a prepared case to figure out OAL better than my swagging in the past. Brian W swears by 2520 but cautions that SMK's must be loaded way shorter than one would expect. As you know, he's pretty good at this stuff & used 2520 in his K31 to win Perry. I'll try the 2520 and Varget as well this winter. I might even try some Ranch Dogs if they don't need to be pushed in so far that I don't have any powder capacity left.

At Vermont, my combined slow and rapid prone stages were actually higher than Brian's- I effed up in offhand as usual. As far as reloading for Vermont, I got lazy and just used GP11 because GP11 and my best reloads thus far are shooting the same.

edit- how short did you end up to get away from the lands? IMO they look funny when seated short enough to be correct, but you well know about the short throats...

 

[mac1911]

I think I'm going to break down and get a prepared case to figure out OAL better than my swagging in the past. Brian W swears by 2520 but cautions that SMK's must be loaded way shorter than one would expect. As you know, he's pretty good at this stuff & used 2520 in his K31 to win Perry. I'll try the 2520 and Varget as well this winter. I might even try some Ranch Dogs if they don't need to be pushed in so far that I don't have any powder capacity left.

At Vermont, my combined slow and rapid prone stages were actually higher than Brian's- I effed up in offhand as usual. As far as reloading for Vermont, I got lazy and just used GP11 because GP11 and my best reloads thus far are shooting the same.

edit- how short did you end up to get away from the lands? IMO they look funny when seated short enough to be correct, but you well know about the short throats...

I forget the COAL length at the moment. There pretty short looking vs a GP 11.
2520 from all i can tell is a tad slower than H4895 but not as slow as varget. I would use it if its on sale next time i need to powder up.
as for those ranch dogs. Should have no problem. i forget what i seated mine at. The nose does not drive the lands. IIRC the nose is .299 back to the driving band?

 

[NavelOfficer]

Buy Prvi ammo or Wolf Gold and there's your supply of boxer-primed brass. Assuming you can swing a case of ammo, it's about $375 for 500 rounds of ammo and about $285 for 500 pieces of brass (Prvi).
I don't recall dimensions off the top of my head, but I've neck-sized my brass only and have fared okay. Granted, I'm shooting light loads, usually powder-puff loads with my go-to 130g LRN bullet.
As a rule, I take any fired or sized brass and test chamber them to verify the brass is okay before reloading them. The few pieces of multiply-fired brass on my bench is 2.175". Some recently acquired (yet loaded/fired by me) GP11 brass is measuring 2.19" to 2.20", but my K31 is stuffed away for an upcoming move, so I've done nothing with this brass yet.
My dies are Lee, but my NS die is Redding.

 

[Mountain]

Buy Prvi ammo or Wolf Gold and there's your supply of boxer-primed brass. Assuming you can swing a case of ammo, it's about $375 for 500 rounds of ammo and about $285 for 500 pieces of brass (Prvi).
I don't recall dimensions off the top of my head, but I've neck-sized my brass only and have fared okay. Granted, I'm shooting light loads, usually powder-puff loads with my go-to 130g LRN bullet.
As a rule, I take any fired or sized brass and test chamber them to verify the brass is okay before reloading them. The few pieces of multiply-fired brass on my bench is 2.175". Some recently acquired (yet loaded/fired by me) GP11 brass is measuring 2.19" to 2.20", but my K31 is stuffed away for an upcoming move, so I've done nothing with this brass yet.
My dies are Lee, but my NS die is Redding.

Those loads on the right look like they would jam way into the throat. Maybe not a big deal for powder puff loads?

 

[NavelOfficer]

They are loaded for my specific rifle; seated to be set back enough not to interfere with the lands or throat. These are Norm's 170 grainers (looks like an RCBS bullet), I believe. They had to be seated all the way to the front of the nominal diameter shoulder.
Generally, any .30 caliber bullet gets seated deeper in the 55mm compared to any 7.62x51mm/63mm rifle.
FWIW, I've used the Berry's/X-Treme 150g FN and even the semi-jacketed 100 or 110 grain bullets in the 7.5x55mm. The FN don't always feed smoothly, but they fired okay.
Even .22 LR in sabots work...

 

[DW357]

They are loaded for my specific rifle; seated to be set back enough not to interfere with the lands or throat. These are Norm's 170 grainers (looks like an RCBS bullet), I believe. They had to be seated all the way to the front of the nominal diameter shoulder.

I knew those bullets looked familiar. Now that I have more of those 170’s and a bottle of Trailboss, I’m planning to load some powder puffs. I’ll need to figure out what OAL will work as well as the powder charge. I think I read that 7.5 and 30-06 have the same case capacity?

I had good results using 12.5 gr in 30-06.

I ordered a 7.5 lee crimp die because I’m sure I’ll need to expand the casemouths to properly seat the 170’s like I had to do with my 30-06 loads. Then crimp/close the flare.

 

[NavelOfficer]

I ordered a 7.5 lee crimp die because I’m sure I’ll need to expand the casemouths to properly seat the 170’s like I had to do with my 30-06 loads. Then crimp/close the flare.

I had some data on case capacities, but you'd find out quicker by just filling both cases and measuring yourself.
I have a 7.62x54R FC die that works fine. A .308 FC should work, too, just shim as needed at the shell holder.
Actually, the 7.5 case won't fit into a .308 FC die body...never mind. Use the 54R with a shim, if necessary.
It appears as though the 7.62x39mm FC die will also work, but you'll need plenty of shims (just checked it downstairs).

 

[DW357]

I had some data on case capacities, but you'd find out quicker by just filling both cases and measuring yourself.
I have a 7.62x54R FC die that works fine. A .308 FC should work, too, just shim as needed at the shell holder. Actually, the 7.5 case won't fit into a .308 FC die body...never mind. Use the 54R with a shim, if necessary.

Yeah I realized shortly after I posted that it wouldn’t take much effort to measure the case capacities. I don’t reload x54r and Amazon has the Lee 7.5 crimp die for $13 shipped. Cheap enough.

 

[NavelOfficer]

Good deal. Always easier having the exact caliber die (but you can improvise when possible, too). Good luck!

 

[DW357]

Good deal. Always easier having the exact caliber die (but you can improvise when possible, too). Good luck!

Thanks. I've had a scope on my K31 for the last couple years as it is laser beam accurate. I wonder if my scope would have enough elevation adjustment for these powder puff trailboss loads

I would assume that the bullet drop at 100 yards compared to my GP11 equivalent reloads, would be significant. Have to load them and find out!

 

[mac1911]

I knew those bullets looked familiar. Now that I have more of those 170’s and a bottle of Trailboss, I’m planning to load some powder puffs. I’ll need to figure out what OAL will work as well as the powder charge. I think I read that 7.5 and 30-06 have the same case capacity?

I had good results using 12.5 gr in 30-06.

I ordered a 7.5 lee crimp die because I’m sure I’ll need to expand the casemouths to properly seat the 170’s like I had to do with my 30-06 loads. Then crimp/close the flare.

Trail boss is easy, find your bullet seating depth then fill your case to where the bottom of the bullet sits inside the case. Thats you max load. You dont want to compress Trail boss. Im not sure if 7.5swiss and 30-06 have the same case capacity.
Some cast bullets have a small "nose" up until the driving bands some cast bullet designs have a nose that drives into the groves and lands. Over all the K31 should shoot cast well as it has a short tight throat and even if you have you cast loads kissing the lands it would help improve "accuracy". Ideally in cast loads you want the bullet fit to the throat anyway.

edit: 7.5 swiss shows 65.1 h2o vs 30-06 @ 68 h2o capacity so not the same.

 

[NavelOfficer]

Thanks. I've had a scope on my K31 for the last couple years as it is laser beam accurate. I wonder if my scope would have enough elevation adjustment for these powder puff trailboss loads

I would assume that the bullet drop at 100 yards compared to my GP11 equivalent reloads, would be significant. Have to load them and find out!

You can simply aim at the head for a 10-ring shot on a B27 target, or whatever amount is suitable.
I have a 2x EER scope on a Swedish Mauser, which fell over in the basement right onto the top scope adjustment knob cover, so when I remove the cap, it pulls the innards out with it (ie. can't adjust elevation anymore). It's zeroed for my light loads, so when I use full-power loads, I simply aim lower and generally manage okay.

 

[MJ1]

Good gawd, no need to reinvent the wheel.

4064 and RL22
168 to 174g SMK's

Lee dies

I used GP11 cases till I ran out of Berdan primers then PPU are fine.

 

[mac1911]

Good gawd, no need to reinvent the wheel.

4064 and RL22
168 to 174g SMK's

Lee dies

I used GP11 cases till I ran out of Berdan primers then PPU are fine.

What are you using for COAL or From olive?
Lee dies work fine especially if your just loading to fit any 7.5swiss rifle.
I only have the one rifle. As Lee instructs I will push my shoulder back .020” that’s crazy for brass life.

If I have trouble seeing the rear sight again (seems to improve when I blacken the sheet out of them) I will be getting the aperture target sights and setting up for cast.
There’s not a lot of data for K31 with all bullet types and profiles. Hornady 155 data will get a nosler hard into the lands.

 

[mac1911]

I think I'm going to break down and get a prepared case to figure out OAL better than my swagging in the past. Brian W swears by 2520 but cautions that SMK's must be loaded way shorter than one would expect. As you know, he's pretty good at this stuff & used 2520 in his K31 to win Perry. I'll try the 2520 and Varget as well this winter. I might even try some Ranch Dogs if they don't need to be pushed in so far that I don't have any powder capacity left.

At Vermont, my combined slow and rapid prone stages were actually higher than Brian's- I effed up in offhand as usual. As far as reloading for Vermont, I got lazy and just used GP11 because GP11 and my best reloads thus far are shooting the same.

edit- how short did you end up to get away from the lands? IMO they look funny when seated short enough to be correct, but you well know about the short throats...

I seen that sitting score on the results and just mumbled ..... well that sucks.
Nothing like tanking in one of the posistions . That’s usually off hand for me. Last match I kept 9/10 in the black and it’s been a long time since I did that.

 

[DW357]

Good gawd, no need to reinvent the wheel.

4064 and RL22
168 to 174g SMK's

Lee dies

I used GP11 cases till I ran out of Berdan primers then PPU are fine.

168 gr Noslers and 44 gr of 4064 @ ~2.86" using Redding dies, works for me.

 

[DW357]

They are loaded for my specific rifle; seated to be set back enough not to interfere with the lands or throat. These are Norm's 170 grainers (looks like an RCBS bullet), I believe. They had to be seated all the way to the front of the nominal diameter shoulder.

You happen to remember the OAL using norm's 170 gr bullets? I'll have to experiment with my K31 of course but was just curious. I read on one of the SASS forums, guys having to seat Norm's 170's to 2.795" max.

Post #2 if interested
Trail Boss in BAM Rifles

 

[MJ1]

What are you using for COAL or From olive?
Lee dies work fine especially if your just loading to fit any 7.5swiss rifle.
I only have the one rifle. As Lee instructs I will push my shoulder back .020” that’s crazy for brass life.

If I have trouble seeing the rear sight again (seems to improve when I blacken the sheet out of them) I will be getting the aperture target sights and setting up for cast.
There’s not a lot of data for K31 with all bullet types and profiles. Hornady 155 data will get a nosler hard into the lands.

My olives are not uniform but I can tell you the GP11 bullet is it's own critter so you have to settle for what lets the bolt close and still fits in the magazine. I used a fired case with a slight crimp to get the dead head in the rifling and pulled it back .010" on the 168g SMK. Seems to work fine in all three of my rifles. I have not loaded the 174g bullets yet but they are just a small bit longer and should not be a problem. I will check closely on the 96/11 when I get back to it. Now that thing shoots the 168g SMK and RL22 like a dream.

Cheers

 

[mac1911]

My olives are not uniform but I can tell you the GP11 bullet is it's own critter so you have to settle for what lets the bolt close and still fits in the magazine. I used a fired case with a slight crimp to get the dead head in the rifling and pulled it back .010" on the 168g SMK. Seems to work fine in all three of my rifles. I have not loaded the 174g bullets yet but they are just a small bit longer and should not be a problem. I will check closely on the 96/11 when I get back to it. Now that thing shoots the 168g SMK and RL22 like a dream.

Cheers

I only had direct contact with one shooter loading for swiss rifles. He used M1 ball 174 grain bullet which is close to GP 11. He used the 174 grain M1 ball bullets in everything! He basically had 5 gallon buckets filled with them. I tried buying some before he passed but he already had all his stuff accounted for when he dies. Which sadly he did not long after.
He did say lapua made a nice bullet for the swiss but they dont come state side to often.

 

[Mountain]

I seen that sitting score on the results and just mumbled ..... well that sucks.
Nothing like tanking in one of the posistions . That’s usually off hand for me. Last match I kept 9/10 in the black and it’s been a long time since I did that.

I intended to post something relevant about that sitting score on the Vermont thread... Thanks for the reminder, LOL.

 

[mac1911]

I intended to post something relevant about that sitting score on the Vermont thread... Thanks for the reminder, LOL.

Yeah, i was just up late trying to distract myself from some nice joint pain and started scanning the match results. Seen your sitting score and .......fudge! Sucks. Reminds of a sitting score at Reading shooting XTC "outstanding group" cries out the score keep. Followed by "shitty score though" . Pulled off a nice little 4" group at 300 yards. Low 5 ring with 2 misses!

 

[Mountain]

Yeah, i was just up late trying to distract myself from some nice joint pain and started scanning the match results. Seen your sitting score and .......fudge! Sucks. Reminds of a sitting score at Reading shooting XTC "outstanding group" cries out the score keep. Followed by "shitty score though" . Pulled off a nice little 4" group at 300 yards. Low 5 ring with 2 misses!

LOL!

 

[NavelOfficer]

You happen to remember the OAL using norm's 170 gr bullets? I'll have to experiment with my K31 of course but was just curious. I read on one of the SASS forums, guys having to seat Norm's 170's to 2.795" max.

Most of my ammo is packed away, so I don't have them handy. I do recall seating them to a point where the leading edge of the driving band (ie nominal bullet diameter) is even with the case mouth.