by B.B. Pelletier

Part 1
Part 2

Now it’s time to assemble and test the RWS Diana 48 with the Air Venturi Pro-Guide spring retainer installed. Because I removed the piston to photograph, I put it back in the gun first, but you normally wouldn’t take it out. So, the Pro-Guide system goes into the spring tube white end first. That’s the end with the guide inside the spring.

I mentioned in the last report that the Pro-Guide isn’t as long as the factory spring, so the trigger assembly also sits lower in the spring tube. Now the rifle is put back into the mainspring compressor again, and tension is put against the end cap shelf. As the tension increases and the end cap moves into the spring tube, it may twist so the pin holes in the cap go out of alignment with those through the trigger block and the mainspring tube. The trigger block will limit the twisting, but the black plastic end cap can get out of alignment just enough to make pin insertion impossible.

When the compressor bottoms out the end cap, the two pin holes are close to up-and-down alignment with the holes in the spring tube, but you may have to back off on the compressor tension just a touch. Then, you may have to work the end cap to one side or the other so the pins can be tapped through. A tapered punch is a good tool for this job, and you may have to start out using a thinner pin punch until the holes are close enough to insert the tapered punch.


The trigger unit is installed in the mainspring tube after the Pro-Guide system. It slips down into the mainspring tube farther than the factory spring because it’s shorter.
Tap in the rear pin first. Don’t force it, but to get it started may require a few hard taps with a plastic hammer. Once it starts going into the hole, it’ll pull the trigger block into perfect alignment with the mainspring tube..and the rest is easy.

When the rear pin is all the way in, pull the trigger once to release it. If you don’t, you’ll discover later that the rifle won’t cock and the safety slide will be stuck. After the trigger’s pulled, tap the front pin into place. The rifle may then be removed from the mainspring compressor. The next step is to connect the sidelever. Insert the hinge pin first, making sure the two large washers are on either side of the hinge bushing and inside the flange that’s welded to the mainspring tube. The smaller washer goes under the head of the hinge pin.

After the hinge pin is installed, you can connect the cocking link with its pin. Be careful that the link hasn’t been unscrewed while you worked on the rifle; because, if it’s too long, the sidelever won’t stay tight against the side of the rifle after the gun’s cocked. If you have that problem (you will sooner or later), just tighten the link by screwing it in as far as it’ll go. That usually fixes it. It’ll have a little bit of flex as the sidelever is brought close to the spring tube, then it snaps the sidelever closed and tight against the tube when adjusted correctly.

Next, put the action back into the stock and tighten both screws. You’re ready to test the Pro-Guide system! This procedure takes someone familiar with RWS Diana rifles about 15 minutes, start to finish. If you’re doing it for the  first time, allow about an hour.

The velocity of this rifle shooting .22 caliber Crosman Premiers with the factory mainspring was 797 f.p.s. With the Pro-Guide, it measures 805 f.p.s. That’s not a large increase, but I think the rifle will continue to get a little faster as it breaks in with either the factory spring or the Pro-Guide installed. There’s still a little velocity fluctuation because of how new the rifle is, and that was observed with both the factory mainspring and the Pro-Guide. Remember, there was no lubrication or anything else done during this installation.

Shooting notes
With the factory spring, I could feel a small amount of buzz after every shot. It wasn’t objectionable and died off quickly. With the Pro-Guide, there’s no buzz whatsoever. Just the solid “thunk” of the piston coming to rest. I can feel a definite difference. There’s no measurable difference in cocking effort between the Pro-Guide and the factory spring, and the recoil also feels the same.

Is the Pro-Guide for you?
The advantages are zero vibration, possibly a small velocity increase, and a drop-in tune that you can do at home, as well as customize in several ways. You could add more lube to the mainspring if you like or you could put a washer ahead of the forward part of the Pro-Guide to bump up the velocity a bit. The Air Venturi Pro-Guide spring retainer system gives you one more alternative to expensive tuneups, and it’s one you can install yourself if you’re so inclined. Of course, you can also order the Pro-Guide to be installed when you buy the gun.

What’s next?
Well, I won’t insult your intelligence by claiming the Pro-Guide increases accuracy! Instead, I thought it’d be nice to see what the Pro-Guide can do for a .177 RWS Diana 34 Panther I’ve had for over a year. This is the same rifle I tested for you, and it’s also one of the rifles I used for the Leapers scope base development project. It now has many hundreds of shots through it. You’ll get to see what a Pro-Guide can do for a rifle that’s already broken in.

This just in!
A customer just submitted a nice review of the Pro-Guide, and I thought you’d like to see what he has to say. It’s also posted on the Pro-Guide product page:

“I did the install on my 34 Panther and it was quick and easy. She was clocking in at about 776fps prior to this addition and is now clocking in at around 839fps (10 rounds each, 14.3 grain chps). The gun cocks much smoother now and there’s a solid ‘thunk’ when fired. The recoil feels a little harder than stock, but it’s a nice and solid feel. I have another 34 that has a well-known aftermarket tune kit installed. That rifle shoots really well, though there was actually a small drop in velocity after installing the other tune kit, but her accuracy is incredible. I’d take accuracy over velocity any day, but won’t complain if I have both. There’s lots of speculation and rah-rah going on about this pro-guide kit so I thought I’d be one of the first to give it a try. So far so good; easy installation, good fitting parts and a velocity higher than that advertised for the stock gun. I’ll post a follow-up after a couple hundred more rounds with this to see how it holds up compared to my other 34 with the other custom tune/spring kit installed as far as durability, velocity and accuracy goes…”