New BKL mount adjusts for barrel droop: Part 1
by B.B. Pelletier
Announcement: Due to a mix-up, the most recent Big Shot of the Week winner wasn’t announced last Friday. Jeffrey Aaron Demers is this week’s winner of Pyramyd Air’s Big Shot of the Week on their facebook page. He’ll receive a $50 Pyramyd Air gift card.
Today, I’m going to show you the new BKL adjustable scope mount that will soon be available. I mentioned this mount in the Part 3 test of the new RWS Diana T06 trigger last week, which is where the first picture comes from. I’ll show all the nuances of the new mount and discuss how it works.
Looking up from the underside of the mount’s rear ring, we see the two legs that slide up and down for elevation compensation. Note that the ring has two cap screws.
The front ring is captured, so all it can do is rotate as the rear ring goes up or down. This prevents stress on the scope tube.
These first two detail shots show how the mount works. The rear ring moves up and down on forked legs that are open on the bottom. Two screws on the sides of the legs jam the ring tight in position when the right elevation is achieved.
The front ring is captive and is only able to rotate when the rear ring moves up and down. This prevents stress on the scope tube.
The black elevation pad is a Delrin screw that the scope tube rests on. It’s located just ahead of the rear ring.
Another key feature of this mount is the elevation pad, located back by the rear ring. The scope tube rests on this pad, which is used to make very small adjustments to the elevation of the scope. A small Allen wrench inserted into one of the holes in the periphery of the elevation pad lets you turn it up or down like a capstan, providing tight control over the elevation changes made. When the scope rests on the pad, it provides additional support against random movement once the scope ring screws are properly locked down.
Does it work?
I tested this mount on an RWS Diana 34P that I’ve retained for tests just like this. The rifle in question has 21 inches of droop at 20 yards (the only sight-in distance I use, since the pellet strikes the same place as the 30-yard point of intersection when it crosses the line of sight for the second time), making it a severe case of barrel droop. When I developed the UTG droop-compensated scope bases for RWS Diana spring rifles, this rifle was the worst test case, against which the base for the RWS Diana 34 base was designed. If the BKL mount can fix the droop on this rifle, it can fix anything you’re ever likely to encounter.
And fix it, it did! With the mount adjusted about as far up as it could go and still be locked in position, the scope was sighted-in dead-on at 25 yards, which is in the center of the 20-30 yard sight-in distance. And, the scope was in the center of its click-adjustment range. This was an acid test that the BKL mount passed with flying colors.
Another factor I was watching was the BKL mount’s ability to hold its position on a heavy-recoilling spring rifle. When the mount was given to me for testing, it had already withstood the jackhammer recoil of a Hatsan 125, which is even harder on scopes and mounts than the UK-produced Webley Patriot. Indeed, the scope that had been in that test was destroyed, but this mount held fast.
On the RWS Diana 34P, the mount also held fast under two different scopes, the intial one that finally gave up the ghost during my test and the replacement scope. Hundreds of test shots were fired without a hint of scope mount movement or scope movement in the rings. Despite there being just two screws per scope cap, both scopes remained in place throughout the test.
This mount also offers 11mm dovetails on both sides of its base. If you want to attach a laser, tactical flashlight or rangefinder, your base for them is built right into the scope mount. Because BKL recesses the Allen screw heads into the base, both sides of the scope base have this feature and can be used in this way.
Here you can see one of the two 11mm dovetails in the base of the BKL mount. There’s another one on the other side, and recessed screw heads make it accessible for this purpose, as well.
The final feature this scope mount offers is the facility to mount a bubble level to the base of the new mount. It attaches to one of the three spreader holes in the base, though I think you’ll choose the hole that’s farthest from your eye so you can focus on the bubble. I used this level in the test of the RWS Diana 34P, and it worked well.
If you need to spread the base of the mount to get it on a gun, the ring screws also have to be loosened. Then, the base can be spread evenly by the three spreader screws.
The best part
I’ve saved the best for last. When this mount was shown to me at the BKL factory, I was told that the motivation for making it the way they did wasn’t an air rifle, but a popular air pistol! The cuts on the mount are specific to clear the front sight on the Beeman P1/HW 45 spring air pistol.
The profile of the new BKL adjustable rings was made to accommodate (to clear) the front sight of the Beeman P1 pistol.
Because this is the first mount I’ve seen that was made for the P1, I think I’ll order a BSA pistol scope and give it a test. Whatever scope you select has to fit into the two rings that measure 4.0625 inches apart on the outside. Because this is a one-piece scope mount, those rings cannot be moved, so pick your scopes accordingly.