BadAce Low-Profile Picatinny Rail NDT (No Drill-Tap) Scope Mount for Swiss K31

I ordered this picatinny scope mount and delivery was very quick. Mr. Feng at Blackace also answered my email the same day I sent it. I watched their installation and video and in that video they show an adjustable deflector. The 2.5 version of this product does not have this deflector. The 2.5 version has a built in deflector which is much better according to Mr. Feng. OK, now for the couple of hints which I promised. First, the list of materials that I used. Kroyl Penetrating Oil, a double faced (one face plastic, one face hard rubber) midweight hammer, a lightweight 2 oz. brass head hammer, a 5/16" quarter inch drive deep well socket, a quarter inch drive three inch extension, 1.5 mm pin punch, Wheeler FatWrench torque wrench, several dual ended Q-Tips (the ones I buy have a pointed end and regular rounded end), CLIP cleaner/lubricant and a small LED flashlight. Step one is to put one drop of the Kroyl on the steel pin holding the rear site in place then turn the rifle over and put one drop on the other side. Give the Kroyl a couple of minutes to penetrate around the steel pin. The Kroyl will make removing the steel pin much easier. After the Kroyl has done its job use the 1.5 mm pin punch and the small brass hammer to remove the steel pin holding the rear site in place. I found it easier to do this with my K31 on its side so I could use the pin punch vertically. If you do the same make sure that you make some arrangement to catch the rear site assembly. The spring under the rear site will then easily lift out. Step next. I elected to clean the area underneath where the rear site & spring used to be. My rifle had a lot of black almost gummy oil so I cleaned that entire area with the CLP and Q-Tips. I put one drop of CLP on a clean Q-Tip and spread a very thin lubricant coating on these hidden metal surfaces. Step next. Here is where the deep well socket and extension come into play. I had to tap the steel base nut to first get it all the way in that area formerly occupied by the spring. The 5/16" socket fits perfectly over the steel nut. I then tapped on the base of the socket rather than trying to strike the steel base nut itself. Once I had the steel base nut in all the way vertically I used the deep well socket with its extension in place. The end of the extension protrudes high enough and far enough that you can strike it without any fear of dinging the wood or the rear band. It took a fair amount of persuading to finally get the steel base nut all the way forward. Step Final. Use the LED flashlight to see when the picatinny base rail unit is properly positioned so that you can insert the steel pin back into place. I used the lightweight brass hammer to gently tap it back into place. Follow the threadlocker instructions about cleaning everything then apply thee threadlocker to the threads of the provided screw. I used a Fat Wrench and torque things down to 20 inch pounds plus another quarter turn of the screw. At this point your finished.Put the K31 back in the safe and go have a margarita to celebrate. The whole process took me around 45 minutes and there were no hitches that I encountered but it wasn't as easy as their time lapse edited video showed.

If you have a hammer/ mallet (small preferred) you can do this simple few minutes' installation. Comes with two sizes of star wrenches and Blue locktite. If you don't have a torque wrench, then get back on Amazon or Midway and get one. Order at the same time as the mount so you are not tempted to just hand tighten it. I used blue painters' tape under the mount at the contact point of the receiver instead of black electrical tape as the instructions suggest being that it acts as a tiny extra shim to ensure there is no movement or mess with the receiver finish. It's not required but I recommend it. Just cut it to slightly shorter than the length of the top of the receiver that's in contact with the bottom of the mount. 1" blue painters tape thumb pressed under the mount will curve into the mount and works perfect. Keeps the adhesive on the mount and not on the rifle finish and doesn't protrude out where its visible. **Okay, the part you actually care about: It works great! I had zero issues with fit, it's perfectly aligned with the bore, doesn't shoot loose or cause a sudden drift in point of impact after 75 rounds. If you spend the extra ten seconds to apply the BLUE locktie that comes with it or BLUE (not RED) of your choice, and you use a torque wrench I think you will find you too will have excellent results. -Another review mentioned you have to pick your rings and length of tube wisely. Very true, there is only two recess cuts in the aft of the rail before the ejection port cut starts. -Get low profile rings and even then, you might need a cheek pad. This rail sits high! -The tiny adjustable brass deflector is helpful... once you get it tuned. I HIGHLY suggest you use an empty case and cycle the bolt several times at the speed you would normally to find where the brass deflector should be set. Pencil mark it then locktite it, BEFORE you mount the scope into the rings. This will make access with the locktite and your wench much easier. For recoil reference I shot 15 rds of 110gr, then 40 rds of 168gr then another 20 rds of 175gr ammo, no wobble, no shooting loose.

The rear ring location has only one slot. Sore rings have features to engage 2 adjacent slots in Picatinny rail.

I was a little concerned because the rear of the base is hanging in the air. But after I installed it I could see how rigid it really was and it holds zero just fine. No flex or anything when pressure is out on the base. I tried it without putting the thread locker on and saw that was a mistake. So put the thread locker on when you install it. With open sites I kept about a 8” group at 100 yards in a lead sled (yeah I’m not that good) with the peep sights I brought it in to about 5”, but with a crummy bushnell scope I kept it at about 1.5” MOA with Serbian ammo. I’m very very happy with this mount. It’s very rock solid. And the height is perfect and I think aesthetically it looks beautiful on the gun. I had been eating for years for someone to create this. So happy this company made this scope base. Such a beautiful and accurate rifle (eve though I’m not) and now I can use it to it’s full potential. You will not regret getting this base.

This product was easy to install once you realized that you really had to snug the female threaded piece into the sight assembly of the rifle. I mean really snug. A bit of gun grease helped a lot to do so. Once that was in, the original sight pin went in like a charm and the installation was finished except for mounting the scope. The unit allows the use of low rise scope rings even with a large ended scope. Mounts very close to the bore line. I will be shooting it this week end, hopefully and will see how it holds up to the shock of a 7.5x55 round and if the unit allows a decent ejection of the spent round. A very simple and well made product.

Great. The adjustable deflector plate is rather annoying to tighten if you've got a scope over it, so tighten and possibly threadlock it beforehand.

Like another reviewer noted, this fits the rifle very snug. You may have to do a bit of fiddling to get it it, but once it's there it won't move. I put this on along with a Vortex scope to go on my first deer hunt last fall (success!). The scope stayed solid during the zeroing process and on the drive to deer camp. No re-zeroing was necessary. Brass ejects just fine but you will no longer be able to reload with the cardboard stripper clips - which is not a big deal for me. If your old eyes need a scope, this is the mount to get.

The install took about 5 minutes. It would have been less if I hadn't took the time to use some CLP and clean the rear sight mount. Part looks to be of good quality, and it cleverly utilizes the original mounting hardware to solidly and securely mount the rail system. I haven't shot it yet as the locktite is curing, but I don't have any doubts it will function as advertised.