Finally addressed the problems with my D34

[desmobob]

This winter, I bought a new RWS Diana 34 at a great sale price.  It had some HORRIBLE barrel droop that wasn't really barrel droop... the breechblock was visibly angled downward when the breech was closed.  The barrel actually had some upward bend, but not nearly enough to correct the problem. I should have returned it, but didn't.   

The rifle shot well with the stock open sights but I don't care for those plastic fiber optic OEM versions and prefer nice traditional iron sights.  I replaced the rifle's rear sight with a Williams peep but had to install it on a .68" riser block due to the downward angle of the barrel!  I tried mounting a scope but, even with a drooper mount AND a set of Hawke scope shims, the POI was still too low to correct with scope adjustments.

Today, I finally got around to attempting to fix things.  I clamped the breechblock in a vise between two pieces of angle iron that i would use as a filing guide to carefully remove some metal and make a small change in the angle of the breechblock. I proceeded slowly, reassembling the rifle frequently to check on progress.  I also bent the barrel back down to remove the upward bend apparently done at the factory to attempt to correct the barrel misalignment.

I mounted up a Hawke 4-16x scope and sighted her in with no issues.  What a relief!  (I knew my repair was risky but figured I could buy a new barrel if I failed.) 

The biggest surprise was the rifle's change in POI with different pellets.  In stock condition, it loved RWS Superdomes and Crosman PHPs equally, but shot them to vastly different POIs.  Now, it shoots Superdomes, PHPs and JSB Exacts to a close enough POI that no scope adjustment is necessary when changing ammo! 

I did enjoy the D34 as a lightweight, open-sighted backyard plinker but I enjoy squeezing out all her accuracy with the help of the scope. My first 30-yard group had all five shots touching.  I have a new HW30 scheduled to arrive tomorrow that may become the D34's lightweight, open-sight replacement.

I wish I had taken photos of the project but, at the time, I thought I might have been doing something really foolish and didn't want to document it! 

Tight groups,
Bob

[Roadworthy]

Congratulations on a successful operation, Bob.

I priced a new barrel for a Diana 34 from Umarex a couple of years ago.  Their price at that time was $160.  Of course that was not including shipping.  That's also assuming they'd sell the barrel to an end user without demanding that they install it at whatever their shop rate was. 

My original barrel shoots fine, it's just ugly.  I kept my barrel.

[desmobob]

Congratulations on a successful operation, Bob.

I priced a new barrel for a Diana 34 from Umarex a couple of years ago.  Their price at that time was $160.  Of course that was not including shipping.  That's also assuming they'd sell the barrel to an end user without demanding that they install it at whatever their shop rate was. 

My original barrel shoots fine, it's just ugly.  I kept my barrel.

Thanks Thomas.  I tend to think of it not so much as a "successful operation," but "trying something stupid and getting lucky."   

I didn't look into the price or availability of barrels before starting but I had an idea they might be expensive, provided I could find one.  I think I got the rifle on sale for $199 so it would have been a tough deal if I had screwed up and had to pay nearly that for a barrel.

The rifle has a Vortek PG2 tune kit in it and cocks and shoots smoothly.  I'm not a big fan of the T06 trigger so far.  It adjusted to a very nice, light pull weight but lacks anything resembling "crispness."   I do notice some obvious torquing on firing; it's the only rifle I have where I really notice it.  I guess I need to take her back apart and polish the spring ends.  I ordered a PG2 kit for my new HW30 too.

All-in-all, I like the rifle, especially considering the price. 

Tight groups,
Bob

[TwiceHorn]

Ambitious undertaking.  Glad it worked out.  Makes you wonder a) how did a breech block get so misshapen and b) why would Diana let that one out of the shop, assuming, as you do, that they bent the barrel to try to compensate.

What, if anything, have you done to refinish the breech block?

[desmobob]

Ambitious undertaking.  Glad it worked out.  Makes you wonder a) how did a breech block get so misshapen and b) why would Diana let that one out of the shop, assuming, as you do, that they bent the barrel to try to compensate.

I'm thinking it might not have been the breech block that was the problem, but maybe the barrel pivot hole location in either the breechblock or receiver was a bit off.  It was hard to tell because with the pivot ears on the receiver covering the breechblock-to-breech fit, it's hard to get a good look at the way things match up.

In any event, the rifle should have never got out!  But I got it for a great price.  And, all's well that ends well.   

Tight groups,
Bob

[AG72]

Impressive work there! Glad it worked ot realy good for you, but that rifle must have been made a late friday afternoon when every want´s to go home and don´t care about anything else

[desmobob]

Impressive work there! Glad it worked ot realy good for you, but that rifle must have been made a late friday afternoon when every want´s to go home and don´t care about anything else

Thanks Jörgen,

I agree with your theory on my rifle.  Or maybe it was made by someone who had just returned from enjoying a "three-Martini lunch"!

Tight groups,
Bob

[AG72]

Impressive work there! Glad it worked ot realy good for you, but that rifle must have been made a late friday afternoon when every want´s to go home and don´t care about anything else

Thanks Jörgen,

I agree with your theory on my rifle.  Or maybe it was made by someone who had just returned from enjoying a "three-Martini lunch"!

Tight groups,
Bob

If martinis was involved, you probably would have one with  atleast two barrels pointing in different direction!

[Yogi]

Bob,

Do I have this right.  You took the slanted breech block and removed some of it?  Did you alter the angle, why they have a slanted breech block is beyond my comprehension, or just remove some material keeping the same angle cut?  So in essence, you changed the geometry when it is cocked and closed?
Wish you had taken photos.
Glad it worked for you...

-Y

[desmobob]

Bob,

Do I have this right.  You took the slanted breech block and removed some of it?  Did you alter the angle, why they have a slanted breech block is beyond my comprehension, or just remove some material keeping the same angle cut?  So in essence, you changed the geometry when it is cocked and closed?
Wish you had taken photos.
Glad it worked for you...

-Y

Hi Yogi,

You have it right... I changed (reduced) the angle of the breechblock by removing material to change the relationship of the breechblock, breech face and barrel pivot.

One other thing I forgot to mention in my original post: the rifle, when new, also had a barrel lock-up problem.   The locking mechanism barely engaged enough to keep the barrel firmly locked up and it sometimes bounced back open after closing or could be inadvertently opened if the rifle was moved around quickly enough; you could shake it open.

It locks up properly now.

Tight groups,
Bob

[Yogi]

How much material do you think you took off?  Did you use a file and then paper?
Did you do anything to the ball bearing detent and tensioning spring?
Just curious...

-Y

[desmobob]

How much material do you think you took off?  Did you use a file and then paper?
Did you do anything to the ball bearing detent and tensioning spring?
Just curious...

-Y

Yogi,

It's hard to guess how much material I removed.  I wish I had measured length of the top of the breechblock with the dial caliper before I started removing metal; then I'd have an answer to that question.  I think it's moot... When attempting to do something like this, it is critical to go very slowly and test fit the parts frequently. 

I didn't do anything to the ball bearing or spring but, as I removed material, I continued to check that the ball bearing was properly engaging the protrusion on the receiver to lock up the breech.

I used a fine mill file to finish the cut.  I still need to blue the exposed steel.  Brownells OxphoBlue will do the trick.

Tight groups,
Bob

[Yogi]

Thanks!

-Y

[desmobob]

Thanks!

-Y

You're welcome sir.

Tight groups,
Bob

[Rwils002]

Sounds interesting, but I can't help but wonder if you've got any sealing issues, since you've invariably removed material that would normally support the O-ring in sealing. Have you done a chrono after the mod?

[desmobob]

Sounds interesting, but I can't help but wonder if you've got any sealing issues, since you've invariably removed material that would normally support the O-ring in sealing. Have you done a chrono after the mod?

That was a concern of mine before I started the project.  I did end up removing a very thin spacer washer that was behind the O-ring.  It seals up fine as verified by a tissue test (and the accuracy results).

Tight groups,
Bob

[B67]

The RWS 34 is maybe the best air rifle available for the money....That being said they are sold to a market that can't usually afford scopes. They bend the barrel for the open sights and us "wealthy" Americans need drooper mounts...