Hi Folks -

I was exploring my 350 a few days ago trying to learn the mechanics. I removed the stock, then did a partial cocking of it to see how it worked. I assembled the stock and when I next cocked it there was an awful spring against metal feel and sound, and the cocking was very difficult and would not complete. I built a spring compressor and removed the spring.

I found an exploded schematic of the 350 and a parts list, which can be found here:

http://www.pyramydair.com/schematics/rwsmodel350_content.asp

Note part number 84 which Diana calls a "tube." The spring is inserted into the tube, which then fits into the piston.

I've not disassembled any other air rifles, so my familiarity with the "tube" is limited. For all I know, all air rifles have this tube. However, as far as I can tell, the model 34 does not use a tube based upon the parts listing below, nor does any other rifle made by Diana for which I could find exploded schematics.

http://www.pyramydair.com/schematics/rwsmodel34_content.asp

The tube for my gun has a ribbed area and is out-of-round. I don't know whether this tube intentionally is ribbed or whether I did it trying to cock the gun, but I am sure the out-of-round issue was caused by me.

Here are pictures of the damaged tube:









My questions follow:

1. I cannot find schematics of other Diana guns that use this tube; is this tube necessary? If I reassembled the gun without the tube, will that likely create any problems after repeated shootings?

2. I am now attempting to round the tube; anyone know whether the ribbed area should also be smoothed? Anyone else taken apart a 350 recall whether the tube has ribs as my does?

I may just have to "spring" for a new tube.

I can tell you that it should be smooth. Whats it does, I dont know?

It's hard to tell which area is ribbed on yours, unless you're talking about that long scratch at the end of the tube.
The way the 4th pic looks is what mine looked like after I sort of did what you did with cocking it without the stock on.
I acidentally bent the barrel a tad down to begin cocking the gun and it scratched that tube also. The tube does have
some scrtaches on it though as that is where the cocking mechanism slides on. I pulled mine out and just rolled it
back to being smooth and it's fine now. Maybe somebody can be more technical on this but I think all is OK.

BTW: It does look like you need some lube on the spring for sure. It looks as dry as mine was new also.

I don't know about all of the Diana guns, however I have seen that tube in the 350 schematic, it is very hard for me to tell what the deal is with it from just the pictures in the parts diagram. I would replace the tube as I could already tell from the picture that the cocking linkage must have put that groove in it, not shure why it did that to it or where exactly the tube rides in there. all of the Diana guns I have owned so far do not use that tube, you could try to straighten it and see what happens or to get your gun back going untill you get the new part. Is strange that without the stock on the linkage would groove the tube like that there must be a reason why it will do that though, hope you have success at fixing the gun, but really if you take a look at the other schematics you will notice that most of the guns do not have that tube in them.

Thanks for the replies guys. Think I will bend it back into shape and give it a go (after lubing the spring).

and if possible burnish and polish the rough area on the outer surface . Try not to remove much material so as to avoid sloppy fit .

is there anything you do not know?

put a wood dowel inside, brilliant. that will work 100 times out of 99 times

I would of written to this guy "buy another one" but then, I am not a DIY Magician like you

warren

and remember "it's 30% the gun and 70% the shooter"

I tried the dowel earlier, but it was a no go for me. I could not get the ribs or bumps out of the tube, and in the end the tube became more misshaped and fit poorly in the piston.

I decided to reassembled the gun without the tube and have a try with that after lubing the spring. My gun is .177, and with CPL (7.9) my chrony showed the pellets traveling now about 960 fps, which is down from 1010 fps before disassembly. I am not sure why there is such a decrease in fps.

I don't mind the slower fps, but the gun still shoots poorly (inaccurately). I know some of the inaccuracy is due to me, but given the performance of the gun (e.g., shoots 3" too low, then 2" to far to the left, then 2" too low, etc. at 20 yards), I think something may be wrong with it. I was hoping some of this poor performance would change somewhat after the lube. I'll have to give this some more thought -- this gun is turning into a $350 learning experiment for me.

My. 22 was an inaccurate lump as well. Here's what 'fixed' it:

80% improvement:
Leupold 3-9x33 EFR in a BKL 260 D7 mount.
- The Leupy is the only scope I found that didn't have Erector Dysfunction, and would actually hold zero. Bushnell 3200, Barska, Leapers - all failures with skiping erector tubes and skipping POI.
- For this gun, the BKL is the only mount worth owning. Period.

Remaining 20% improvement
Macarri seal/spring.

These changes brought my 14yd groups down from about 3/4 inch to 0.2".

The tube is designed to keep your cocking shoe off the spring. You'll ding it cocking the gun out of the stock, which is really just plain unsafe to begin with.

Mine on my 350 in 177. was the same way i use my fingers to round mine out and thin coat it with moly.Mine seems to work fine and shoot ram jets or kodiaks ,cpl 7.9 are to light for mine.