by B.B. Pelletier

Part 1

Today you’ll read part 2 of Vince’s guest blog. As usual, he’s done an extremely thorough job.

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by Vince

You’ve loaded the magazine, and now you’re ready to shoot. Almost.


Lock & load!

Suppose the rotary mag wasn’t indexed quite right when you put it back into the gun? That could be a problem. To make sure there isn’t a problem, get into the habit of pulling back on the cocking lever after reinstalling the mag, as if you’re trying to reset the sear. As mentioned in part 1, this last little bit of travel is what indexes the mag, and the action will rotate it to the next position and line it up properly. If the mag is halfway between pellets, the feeding pin is going to be blocked from going forward. This means that the lever is not going to want to move toward the firing position. But only a little. Because of the immense amount of leverage in the cocking lever, there won’t be much resistance, you might force it and break the pin without even realizing it.

Now you’re ready to start making holes…and making holes is something the 300R does rather well.


Pretty good 6-shot group with Crosman Premier hollowpoints.

The above target is a quick 6-shot group at 10 meters with open sights using Crosman Premier hollowpoints. It can do even better — and I’ve done better. More on that later. The rifle is about as hold sensitive as any other non-breakbarrel Diana springer, which is to say not too bad. Just remember that you have seven shots with no indication when those seven are done. To make sure the mag is empty, you’ve got two choices: dry-fire the gun (a no-no, although it will happen by accident on occasion) or remove the mag.

making holes is something the 300R does rather well

Fortunately, you don’t have to completely cock the gun to do so. Back when I described the picture of the pin retracting, I pointed out the position of the cocking lever. I was only starting to pull it back, but the pin was retracted almost all the way. Fact is, the pin is out of the way well before the lever is even halfway cocked. So, you CAN remove and replace the mag without cocking the gun if you hold the lever in the partially cocked position. Familiarize yourself with exactly where this is before making a habit out of it. Don’t let the lever go while you’re in the process of removing or reinstalling the mag.

So far, I’ve described how this gun is supposed to operate. What goes wrong and what do you do when it does go wrong?

The most obvious boo-boo is to try to remove the mag with the lever all the way forward. A real easy mistake to make. What does this do? Well, first of all the mag doesn’t want to come out because the pin is running through it. Second, the thin, brittle pin probably breaks. The next real easy mistake to make is to say to yourself “Oh! Right! I forgot to cock the gun!” So, you cock the gun, but the now-broken pin is still lodged in the rotary mag and won’t let it index to the next position. Again, you’ve got so much leverage in the cocking linkage that you don’t notice the increase in resistance. You force it without realizing it, and you break the magazine. Yet, it still doesn’t want to come out. Since you’re probably holding the gun muzzle up while you shake the gun, pump the lever and fiddle with the mag — that broken pin will eventually come loose…and fall into the guts of the gun.

Hoo-boy. Now you’ve got three major problems, and you’ve collected them all in the space of about 45 seconds.

Some time ago, I wrote up a sheet of cautions and procedures to follow with this rifle, and I tried to cover every contingency. I’ve listed those instructions at the end of this blog, so I won’t rehash everything here.

The last thing I want to talk about, though, is what happens when the gun is operated without that pin. In that case, the air will blast the pellet out of the mag. The cylinder pellet holes are sealed pretty well at the front and rear of the magazine.



Front and rear seals help stabilize the rotary mag.

That rear seal is on the end of a spring-loaded plunger. When the lever is forward, the rotary is firmly sandwiched between these seals. Combined with the relative power of the rifle (compared to an Umarex pistol or a Crosman 1077), it should make for a nice, strong burst of air that will reliably feed the pellet from the cylinder to the breech…pin or no pin.

The only possible fly in the ointment, as far as I can see, is that the rapid blasting of the pellet into the breech might be more inclined to damage the pellet if there’s a significant mismatch between the hole in the cylinder and the barrel bore than if it was gently fed by the loading pin. Theoretically, this could affect accuracy. I’ve tried it both ways and could not detect any difference. In my basement range, I managed to shoot a .18″ group (don’t remember if it was 5 or 7 shots) at 12 yards with a pin-less gun with a scope. Frankly, I just don’t do any better than that. So, no, I don’t think the accuracy issue is a significant one.

That wraps it up for the 300R. It’s a unique experience that definitely keeps you on your toes. Like many unique relationships, it’s frighteningly easy to mess things up, but there’s no need for despair. One way or another y’all can patch things up again and literally find yourself repeating the experience.

Below is my list of things to remember when shooting the Diana 300R.

Read all factory instructions. The RWS 300R has a unique mechanism that can be accidentally damaged by mishandling.

The pellet is loaded from the magazine into the breech by a very thin, brittle pin that cannot tolerate any significant side loading. This pin is retracted when the cocking lever is pulled back and pushes the pellet forward as the cocking lever is returned to its normal (or firing) position. With the cocking handle in its normal position, this pin runs through the magazine.

Never attempt to remove the magazine unless the gun is cocked and the cocking lever is to the rear — or you will probably break the pin.

If the mag holder is inserted when the cylinder is not properly lined up, the feed pin might hit the cylinder between two pellets — or it might hit a pellet off-center and jam or mangle the pellet on loading. Here’s how you prevent this: After reinserting the magazine, pull the cocking lever all the way to the rear as far as it will go (just as you would when cocking the gun). This ensures that the magazine is indexed properly.

A cocked gun may be uncocked without firing and with the magazine installed or removed. Pull the cocking to the rear until it just reaches the point of meeting resistance from the piston and spring. Holding it firmly (just as you would while cocking the rifle), push in the safety and pull the trigger. This should release the handle. Let it return, under pressure, to the uncocked position.

The rotary magazine is indexed (rotated to a new position) during the cocking cycle just before the trigger engages. If the rearward part of the cocking stroke meets with unusual resistance right before the trigger catches and doesn’t want to fully cock, stop pulling the lever or the magazine might break. Something has probably jammed the magazine and won’t let it rotate.

Try to remove the magazine with the lever pulled back MOST of the way. If it’s difficult to remove, stop, reseat the mag, allow the lever to return to its normal position and service the gun (or have it serviced). The 300R is not a particularly difficult gun to disassemble, and the powerplant does not have a lot of spring preload (about 50 lbs.). If you’ve disassembled other spring-piston air rifles, you’ll probably be able to service this one.

If the magazine does come out, let the lever return forward. Is the loading pin visible in the magazine port? If it is, try recocking and decocking the gun without the mag. If it feels normal, empty and reload the magazine and try again.

Never attempt to remove the magazine unless the gun is cocked and the cocking lever is to the rear — or you will probably break the pin.

If the pin is not visible, it’s broken. Sometimes, the 300R will feed and fire just fine without it, but the owner must first make sure that the broken pin is not inside the barrel or inside the gun (trapped in front of the sliding cylinder). The barrel bore can be visually inspected. In order to check the cylinder, bring the cocking lever all the way forward and lock it into position. Look in the magazine port, and you should see the air nozzle with a blue seal protruding into the rear of the port. The outside metal shell of the nozzle should be protruding into the mag port by about .050 inches. If it’s much less than this or not protruding at all, the pin is probably in the gun and it needs to be disassembled.

Otherwise, the pin probably just fell out or was discharged behind a pellet. You may try operating the rifle without this pin. If it functions properly, go ahead and use it. The only risk is that if the pellet doesn’t discharge it might be lodged halfway into the breech. Given the relatively high power of this gun, this isn’t very likely, If you think it happened, do not recock the gun. Pull the cocking lever back slightly and try to remove the mag. If it comes out, you can easily check the mag and barrel for a damaged or jammed pellet. If it doesn’t want to come out, go in from the muzzle with a cleaning rod and push the jammed pellet back into the mag.