Need help with K31 Sporter made in Basel

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10-07-2019, 04:43 PM
mr humble

Need help with K31 Sporter made in Basel

This K31 was professionally sporterized in Basel. The barrel is crisply marked “G. BURGEN / BASEL”, the left side of the receiver is marked “7.5 PAT 11” and the top of the receiver bears the Swiss Cross. It functions just fine and shoot 1 MOA. The problem is with the scope setup.
The rifle has claw mounts with an overbore rail scope that looks everybit as used as the rifle. As we know the K31 ejects up, so guess what happens ? Yup the empties drop back in the action. I cannot imagine how it ever worked. I took off the scope and it works fine. (The front bead covered out 36" gong at 300 but I hit it with the sight set @300). It ejected just like my milspec K31 --- straight up. With the scope on and the magazine out it works fine as a single shot as the empty drops out the bottom (chuckle). I'm gobsmacked ---- whadda think ?

https://www.milsurps.com/images/impo.../pVvSKEh-1.jpg
10-07-2019, 05:27 PM
AGB-1

Remove your mount and scope and use this one.

K31 ALUMINUM CLAMP ON MOUNT | swissproductsusa

Accumounts - Swiss K31
10-08-2019, 10:10 AM
Pierre

And don't forget the correct sighing in process for the offset scope mount.
The attached rendering is the sight picture setup virtually all of us here at SP use for Swiss Rifles as well as for the M1D Garand Sniper.

The offset of the mount is 11/16", so leave it at exactly that POI at 100 yards and it will remain so out to 1,000 yards. No need to zero it on the bullseye. If you do, the POI will change the further out your target is.

If you can tell the difference beyond 200 yards, you're a much better shot than I am, Gunga Dihn.
scope you choose, remember that the lower and closer to the axis of the bore, the better.

https://www.milsurps.com/images/impo...ps94wal0-1.jpg
10-08-2019, 01:44 PM
mr humble

I already have that mount on my mil-spec K31. I am looking for an explanation of how this respected maker in Basel could have ever built this and made it work.

I'm thinking of building a shell deflector.

My K31 w/Leupold 12X

https://www.milsurps.com/images/impo.../3gWMSIZ-1.jpg
10-08-2019, 09:39 PM
Aragorn243

My thoughts were that it had a shell deflector that is now missing.
10-08-2019, 11:44 PM
mr humble

I tried making a shell deflector from flexible shim stock. The case continued to hit the rear mount and not clear the action. This came from Mark Benson's collection. I knew Mark when I lived in NY and he never would have had a rifle that did not function properly.

Since claw mounts are all hand fitted, I can't believe this is some other rig from some other rifle.
10-10-2019, 12:06 PM
mr humble

guess I'm on my own. I wuda thought somebody here had been down this road. Guess I have the only K31 sporter made by this guy in Basel !
10-10-2019, 04:39 PM
AGB-1

Defector

My K31 and Homemade Deflector Shield - Swiss Rifles dot com
10-11-2019, 07:56 AM
Pierre

This is a deflector we had considered manufacturing, but the base cost of the bending machine could not be justified by the projected number of sales, so this one sits on a shelf with all of the other prototypes. None of us here at Swiss products have this problem.

https://www.milsurps.com/images/impo...eflector-1.jpg

If your windage is on the right of the scope and the rings are spaced correctly you won't have this problem.

https://www.milsurps.com/images/impo...0/monta3-1.jpg

https://www.milsurps.com/images/impo.../monta4a-1.jpg

https://www.milsurps.com/images/impo.../monta2a-1.jpg

https://www.milsurps.com/images/impo...0/monta7-1.jpg

https://www.milsurps.com/images/impo...0/clamp6-1.jpg

---------- Post added at 07:56 AM ---------- Previous post was at 07:48 AM ----------

I'd forgotten about a solution we developed for gentleman with a 30 mm scope. 3M VHB (very high bond) is a tape that comes in various widths and can be found at most hardware stores. Three-quarter inches wide is the most that you will need. If you buy it in black it will come very close to matching your scope. VHB is double-sided and has a thickness like thin foam. If you apply it to the left underside of your scope, it will easily deflect brass if you have that problem.

Because it has adhesive on both sides, you will need to take a light oil and apply it to the exposed surface of the tape to kill the adhesive.
Make sure you prep your scope's surface area with alcohol and then follow up with a soft cloth to remove the film left by the alcohol. It's difficult to see but it will inhibit the adhesive effect.

As I said, with your windage turret on the right and the ring spaced far enough apart you should not have this problem.
10-11-2019, 12:19 PM
mr humble

Thanks for the posts. All the solutions use the Swiss products clamp on mount which I have on my Mil-spec K-31 the ejects fine w/o a deflector. My sporter K-31 has a OVER BORE scope NOT off set (see photo). So my problem remains.
10-11-2019, 01:40 PM
Pierre

MrHumble, if I had that set up here I could most certainly solve it for you, but failing that, if you could remove the scope, leave the mount in place and sends me some close-up photographs of both sides and as much of the underside as you can manage, I might be able to find a solution for you. My machine shop has both fabrication and manufacturing capability, but we do not do one off jobs or projects. the best I could do is probably a simple illustration to send of something you can make yourself to solve the problem.
10-11-2019, 01:42 PM
rcathey

Quote:

Originally Posted by Pierre

the best I could do is probably a simple illustration to send of something you can make yourself to solve the problem.

That’s mighty generous! Design work doesn’t come cheap in the manufacturing world. Good on you!
10-12-2019, 11:58 AM
mr humble

Here are the photos of the scope and mount. I'm thinking the rear mount is the problem.

https://www.milsurps.com/images/impo.../ZDxnwDg-1.jpg
https://www.milsurps.com/images/impo.../KTI95Vr-1.jpg
https://www.milsurps.com/images/impo.../fgexSYI-1.jpg
https://www.milsurps.com/images/impo.../OQJIcOS-1.jpg
https://www.milsurps.com/images/impo.../rG6XSfQ-1.jpg
https://www.milsurps.com/images/impo.../iHdHV2Y-1.jpg
10-12-2019, 12:51 PM
mr humble

Since scope ie really whupped, gonna take off claw bases and put on Swiss products base w/12X Leupold that works fine on my K31 w/no deflector. I've found the secret is to have a scope with a looong tube that allows rings to be far enough apart to avoid empties from hitting rings. Also no "focus" knob on the left side of the scope can be tolerated. Older Leupolds, Weavers, Lymans etc. fill the bill.
10-14-2019, 11:14 AM
mr humble

Well, the claw mounts appeared to be dovetailed and soldered (front) and screwed and soldered (rear) so removing them is not on my short list. On a happier note, my mil-spec K-31 loves the purpose built NOE plain base K-31 bullet. Cast of wheel weight with some added tin, unsized and powder coated, it dropped 5 in 1/2" @ 50 yds with 8.3 of TrailBoss.
10-22-2019, 12:55 PM
mr humble

Found another K31 sporter

This one has a different mount with a Leupold scope. We'll see if it works !

https://www.milsurps.com/images/impo.../ZAhPaS8-1.jpg
10-24-2019, 12:15 PM
mr humble

AH ha ! This new one has an overbore base BUT the bottom of the base has a 45 degree taper to deflect the empty. Never seen a mount like this before but it's very well made, rock solid and QD as well.
10-25-2019, 06:53 PM
mr humble

no joy

Ah ha, but it doesn't work either. Guess the drill ,when not shooting off bench, is to rotate the rifle 90 degrees so the port is down, then gravity will take over. At least it's overbore !
11-01-2019, 06:22 AM
Bruce_in_Oz

One useful way to stop cases bashing into the windage drum is to rotate the whole scope 90 degrees to the left. Some "buffer" material attached to the tube and reticule housing will keep things "tidy'.

This, of course, works better with "conventional" reticules like the classic "Duplex". Fancy reticules with ranging systems etc? Not so much. Maybe a nice scope maker or optical technician could rotate the fancy reticules.. $$$....

Obvious, but now somewhat more expensive solution is to seek out a proper ZfK 55. If you have ever fired one, they are an object lesson in "getting results- Swiss style". I was offered one about six or seven years ago but could not justify the expense at the time, even less so now. My trusty old K-11 will keep me amused for a few more years.
11-02-2019, 12:36 PM
mr humble

Rotating don't help

The K31 ejects up and slightly to the left so there is no turret in the way. that's why the Swiss prod mt is offset to the right. I sold the rifle w/the claw mounts.

As for my mil-spec K31 ----- don't buy a bore scope ! Erosion and pitting 12" up from chamber.

My rebore guy is willing to see if he can rethroat and rebore to 35 caliber, i.e. a .357x55.

Easy to make ammo w/38 special carbide sizer and expander.

https://www.milsurps.com/images/impo.../UqsRdzL-1.jpg
11-04-2019, 08:20 PM
Bruce_in_Oz

Good point about the K-31 ejection pattern. I'm just an old K-11 driver, myself. She seems to eject pretty much straight up, with cases sometimes bouncing off my back when the bolt is operated "vigourously" Most of the time, the empties get a short, sharp extraction stroke delivered by the heel of my hand, and then the rifle is tilted to the right as the bolt is fully retracted; the case just pops out right in front of me., and I have no plans at this stage to mount optics on the old girl. It gets a bit more exciting in "rapid" events, with there being a lot of walking around looking for expensive spent brass. (Another good reason to keep your cases shiny).