Diana 300R repeating underlever: Part 1
by B.B. Pelletier
Vince is back with 2-part blog about another gun he’s repaired. I get a lot out of Vince’s guest blogs because he gets to play with and repair guns that I don’t have! I learn a lot and I’m glad to see that there’s someone who can do such fine work and be incredibly resourceful at the same time. He sets the standard high. For those of us who don’t work on airguns, it’s just nice to know that there’s someone this good who does.
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Guys know the type. Pretty to look at, but not overly flashy. Demure, faithfully consistent, does just about everything she promises to do, never lets you down, very forgiving and seems to be just about the perfect partner for a lifelong commitment.
Then it happens. One small misstep — one slight slip of the mind, an apparently insignificant momentary lapse in judgment or prudence, and BAM! It’s all over. The relationship lies in pieces, the damage is done, and the joy of newfound attraction is gone forever. IF ONLY YOU HAD KNOWN!
Well, after this article YOU WILL KNOW! And, fortunately, it doesn’t have to end this way. One can, indeed, live quite happily with the Diana 300R repeating underlever.
Repeater… the “holy grail,” in a sense, of better air rifles. A repeater that takes all pellets. A repeater that sacrifices nothing in accuracy. A repeater that’s easy to load and doesn’t misfeed and doesn’t mangle pellets. A repeater that…well, you get the idea.
The RWS/Diana 300R hit the market a few years ago as an upper-tier gun in the Diana line. I’m not sure what it cost, but it I believe it was in the range of $400. Whatever it got, it didn’t get for long, as the rifle disappeared from the catalogs after a relatively short run. All due to that hypersensitivity to even the slightest mishandling — if it was the wrong kind of mishandling.
The 300R is a fairly heavy underlever springer with a T05 trigger and a 7-shot .177 rotary mag. It’s equipped with Diana’s standard iron sights — open blade front and a rear adjustable for windage and elevation. As expected for a Diana underlever, it’s on the hefty side, with a weight of around 8 lbs. All that’s pretty standard in the way of specs.
The real trick to this rifle is in the magazine that loads from the top.
See where my finger is in the above photo? It’s pushing back on the top cover of the magazine, which is how the mag is released so that it can be removed from the gun. But wait! If you wanna mess things up real bad, this is the time you’re going to do it.
Notice where the cocking lever is. Yes, it’s in the cocked position (fully rearward). The position of that lever is very important when removing or replacing the mag. Don’t do either when the lever’s in the forward position. Sounds rather strange, doesn’t it? Let’s see why that is. First, take a look at the mag.
Correctly loading the mag is crucial to proper operation.
Shown above, the pellet carrier is actually a revolving cylinder similar to the Crosman 1077 and several Umarex pistols.
The magazine well with the mag removed and with the lever in the stowed position.
That thin (and hardened and, thus, brittle) metal rod running through the well is the feeder pin. Obviously, this pin runs through the mag when the lever is forward, which is why you can’t remove the mag when the lever is up. What does the pin do?
As you pull back the cocking lever, the pin retracts.
As you can see, as the cocking lever is pulled back the pin starts to retract into the rear of the action. Note the position of the lever. Also notice how the tip of the pin is this nice, rounded, bulbous shape. There are a couple of reasons for that, which I’ll get into later.
With the lever all the way back the pin is completely retracted, and the mag can be removed without incident.
Don’t remove the mag before the cocking lever is all the way back.
Likewise, the pin moves forward again as the lever is returned to the stowed position. This pushes the pellet out of the mag and into the breech of the rifle, from where it’s fired. That’s why the tip of the pin is rounded, so it doesn’t damage the pellet as it pushes it forward. Since the pin stays in place while the gun is fired, air has to flow around that pin to get to the pellet. That’s reason No. 2 for the nice, rounded tip — less drag on the airstream.
Go back to the picture of the magazine. See the indexing tab? As that tab is pushed upward, the cylinder rotates (indexes) to the next pellet. That happens at the very end of the cocking stroke, after the trigger sear latches. Which is important to know, as I’ll explain in a minute.
The mag itself is loaded with pellets in the usual way:
The cylinder is placed back into the carrier:
Make sure it’s seated all the way. You might have to rotate or wiggle the cylinder a bit to get it to seat properly. The entire magazine is then reinserted into the gun — AGAIN, with the lever pulled back!
Stay tuned for the rest of this story in tomorrow’s blog!