Reloading for the Swiss Rifles

[Pierre]

Ok. Lets talk about that one. The serious rub mark on the lower fore end is as the Swiss armoury intended it. The shim under the lug is intended to pre-load the stock by about 6 pounds. This is one of my archives:

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Part 1:

I am not at all concerned with the built in accurizing technique of pre-loading the stock. It is now my belief that this accurizing technique from the manufacturer leaves too many variables in the mix. Any flexing of the stock (being in direct, tight contact with the barrel) will change POI at range. If ALL users of the k31 & 1911 were to shoot their rifles with the identical technique, EVERY time, I may not have an argument concerning the armory shim/pre-loading methodology. But............none of us do shoot identically other than those in the shooting clubs, and, I suspect, even those good folks introduce physical variables of their own at times. So...............

I've invested quite a bit of time in arriving at a rather simple conclusion I had always known, from experience, to be true. "Do not interfere with the barrel". That simple. Of course, none of us want to remove that classic stock and fore grip from the Schmidt Rubins, so I did the next best thing. I relieved all reasonable stress contact from the barrel.

I did this by designing a "spacer" meant to go between the flanges of both barrel bands. This simple spacer relieved the barrel of any meaningful contact with the stock. If the spacers are used correctly, the fore stock will feel "loose" at the barrel band. Of course, one could rout out the raceway to relieve the barrel, but I am loathe to remove any wood from the stock. Allowing the barrel to vibrate uninhibited definitely tightened up my groups. I had, of course, used a load capable of moa for these tests. This also meant that I could not use the sling in any kind of a bracing action. That would negate my efforts. Now for the second discovery. I found that "balancing" the tang screw against the receiver screw also had an effect on accuracy.
To determine spacer width requirements, loosen the screw on the front band until the band retainer will compress and release freely. The space you see between the flanges approximates the thickness required for the spacer. With the spacer(s) installed, the front to the stock should have a bit of "play", so that you can see/feel it move when you wiggle it. The rear band should also NOT grip the stock tightly. It, too should have a bit of play. This will leave the barrel relatively uninhibited by the stock. Also remember not to use the sling to "brace" the rifle. That tension will put pressure against the barrel too. Use the sling just to "steady" the rifle without undue pressure.

After installing the spacers, I begin by loosening both screws. I coat the rear screw with LocTite. I then tighten the receiver screw dead tight. I turn the tang screw down tight and back it our 3/4 of a turn or a little better. You'll need to have around 30 dependable loads ready for this test. Definitely do it from a bench rest, and if you have open sights, use a clearly defined target at no more than 75 yards.

Fire a group of 3 or 4 rounds. Tighten the tang screw in 1/8 turn increments, repeating the process and, using a new target for each run, note how the groups will spread or tighten to minor degrees. These differences will make themselves manifest at range. Once you find the "sweet spot" with the tang screw, allow it to sit while the LocTite cures.

This procedure will be all the more apparent with scoped rifles, but the Diopter and Williams will also show clearly what a difference can be made. Emails from subscribers to this method have proven to me that this method definitely works. Why "fix something that ain't broke"?......... because mine have the capability to outperform the ones that "ain't broke". The rest is up to the shooter.

Something I forgot to add. The zfk55 barrel band does NOT compress the stock tightly against the barrel. At least mine doesn't. This, and the fact that the bipod is attached to the receiver, tells me that someone in the armory felt that the barrel should be uninhibited too.

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Part 2:

Just so we have some reality into this.......... I've always said that there are many k31's that work very well with the preloaded stock, but the stock has to be an "as original issued" stable stock. Sometimes improper storage and simple age will cause a stock to apply pressure in the wrong direction, and those rifles are the main reason for our using spacers and screw balance to accurize our rifles. We never, ever remove wood.

Another possible way is to change the lug shim, but once again, if the stock puts pressure left or right on the barrel, then that may not help much. When I said that every rifle in the armoury is set up with his accurizing technique, that doesn't mean that yours must be. It's just like reloading. There are many ways to get to a great end result, not just this way. It works for us based on the stock/barrel relationship of our individual rifles.

Check your forestock. Is the blackened area only straight down on the bottom. or does is show an uneven area of dark wood to the left, right, off dead center or the upper foregrip? And don't forget that the flanges on the front ring must be tight and solid. The stock should not be flopping around when fired.
I strongly disagree with the notion that my method accurizing these Swiss rifles is a mistake. It depends entirely on the current stock/rifle relationship, and in the past 20 years I've proven that many times over right here in the SP armoury.

Do what works best for you, and it might be that your k31's preloaded stock is perfectly fine, but because of the age and storage of these rifles, I've found that to be a minor exception........ Not the rule.

P

[RC20]

Pierre: I had read that on the other site and I did make sure the clamps were loose. Still got erratic groups.

Like you, the mantra is not to do anything to the gun that affects its originality. Ergo, I won't remove any wood.

I finally shimmed up the front and rear with metal plates in the stock. Thats has helped a lot. Not sure its the right answer.

I had missed the comment about the discoloration, I will look at that again and see if the is bias there that would affect things. The gun is in really great shape, I have the Lyman boroscope and no carbon in it (it really looks to have not be field used, a few dings but barrel is like it came off the factory line)

Again I want to thank the guy (will not mention his name out of respect) that sold me both the K31 and the 1911. Exploring that cartridge has been extremely interesting.

I do know you have to persevere when you believe you have something good (and the K31 is that). The 1911 was shot in matches and did well so I expect if I can get sight picture that will be as fun as the 1917s.

I have a Savage with a XCB bull barrel, its alwyas been ok (3//4 MOA) but not what I feel it should do (and I can do) - this last session with the H168ELD I got one group of 1/4 inch and one of 5/16 (MOA, out past 100 yards). 5 Shot groups.

[Pierre]

Excellent!

P

[RC20]

If the loads are good (yep, case prep) and I am on, I can shoot under 1/2 MOA. I figure that is not too bad for someone who started target shooting at 60 or so.

If I can retire I might try my hand at low level competition. I don't expect any glory but amp up the game a bit and challenge myself.

I started out thinking 3/4 MOA would be a treat. That bug hole gets to you though.

I am looking forward to the 1911 try out with the Lyman Stick on diopters and getting the scope mount.

[Pierre]

Oh YEAH?? Well............. howzabout this one??

It was mid-may when I set up to shoot a 200 yard target at the range out back of the place. By the time I was ready at noon the temperature was a mild 75 degrees. I rode the Rhino downrange and stapled a solitary target to the frameworks. Dead center was a black one inch paster.

　 My shooting bench was the old redwood pic-nic table I had used for years, but it was solid and made a good bench. I set up the number 6 shot bags and took the Swiss k31 rifle out of the case, attached the bipod to the rail under it, uncapped the scope and began adjusting the height of the shot-bags. I set up the spotting scope on the tripod, broke out the custom loads and inserted 5 of them into the magazine.

　 I proceeded to send five rounds downrange at three second intervals. I checked the target though the spotting scope and said "Yep" to myself. "Yep, what?" came from behind me. Worden Hardy had walked up behind me just after the last shot. Hello, Worden. Yep, I put all five of them through the same hole again, sez I. "All five through the same hole?" sez he. Yep........ all five. "Let me see that scope".... and I moved over for him to look.

"There's only one hole in that target. Dead center. What makes you think all five went in the same hole?" sez he. They always do, sez I. Every time. Worden is standing with his hands in his pockets rocking back and forth on his heels looking at me through slitted eyes. "Uh huh. All five through one smooth hole. Right".

And I never could'a proved it if it hadn't been for those five dead coyotes that had been trotting in single file, three seconds apart piled up behind that target.
Yep. One smooth hole.

[RC20]

Got the 1911 down to the range. Cases were too big so I had to resize some.

I wanted to see what kind of sight picture I got not target.

It was amazingly good. Been so long since I shot irons I was sight wobbling but the Eyepals worked as advertised. I have some more 7.5 PPI headed this way for shooting in just the 1911,.


I ran tests with the 1917 as well, good and definitely better as well. I was out qt 110 yards and could see (barely) a 3 inch orange ball on black. Group was not bad for just random excess from the junk 06 box.

They may not work for all eyes of course but worth a try.

[Ovidio]

I just shot my K31 shabbily, only to find out after the last shot that the screws between action and stock were completely loose...
I’m really fed up today.
But Saturday!!!

[RC20]

I have had that happen a time or two. You check them and ok and you think they stay ok.

Then you think, its never been this bad and you find the screws loose on the gun, scope, mount and say nasty words for a bit.

[amadeus76]

Random question... I finally ordered a die set for my Swiss rifles (Hornady K-31 set) and I noticed that for the K-31 set for all the different manufacturers they'll listed as .308 diameter. However, for the 7.5 Swiss sets they're listed as .312. Is there a reason for the difference?

[Ovidio]

That sounds strange to me. Swiss 7,5 is definitely .308.