Well guy's I went and bought a Diana 240 classic!

[39M]

I like it.

The stock looks longer than my Daisy 131. And I like without the cheek rest.

I think I'll trim the cheek rest off the 131 when I refinish it, and add a recoil pad to make the LOP a little longer.
The 240 stock shape looks like a good one to emulate.

[WolfyW]

My first D34 had a good piston seal. The last one I bought was sliced up. Wouldn't be shocked if you find a bad seal.

[Grover]

PICS!

[Mark 611]

here it is! 

[Mark 611]

 larspawn, that's a nice collection u have there!

[RinCG]

Mark, in regard to the 50S not getting the power level you want. Try this one:
http://www.airrifleheadquarters.com/catalog/item/251488/10308577.htm

Take any HW piston weight out and lighten the piston(as mentioned before) to around 220 grams.

The D240 looks like it may be a ready-made answer though. I mulled that particular one over myself, Gratzi! I'm still holding out for a D280
.     

[DonH]

here it is! 

Looks great. I'm sure you'll tweak every bit of accuracy out of her.

[Grover]

So how's she coming along Mark?

Update?

[Mark 611]

well I shot it and put about 100 or so pellets thur it, then I tore it down, It still will not group consistently, I have tried JSB, 8.44's Croaman 7.9 hps and the pointed hunting pellets, RWS super domes, Gamo match wadcutters and some Daisy wadcutters and H&N Spitzkugel pellets, the H&N spitzkugel shot a dime size or smaller with 5 shots @ 23yds but then it opened up again and started shooting all over the place! the Gamo WC's shot the same, then it went back to shooting all over the place! it vertical strings and then shoot left right{ect} I went thru the same thing with the HW50! ok here's what I've done to it, I had to scrub the bore with a bronze brush! it was that nasty inside there from the milling process, I had to replace the breech seal right out of the box! the spring to rear guide fit was very sloppy lose! tightened it up, the piston seal has a slight blemish on the parachute lip edge from the mold it came out of, I lubed it properly and opened up the leede into the breech, I also changed the trigger sear spring, trigger is excellent! I put another 500 pellets thru it, the accuracy seem to be getting tighter but still all over the place! I'm going to tear it all back down and replace the piston seal as soon as I get the chance and get some more breech seals O-rings instead of the cheap synthetic one from the factory! I think its a seal issue and I have a few 25mm piston seals that should work? its just a common doughnut type piston seal and I have a few JM seals I think its a nice rifle it just needs a little TLC right now for sure! and if I get the power plant figured out and it still wont group I will probably put a LW barrel on it! I like the gun as said it is very quiet! also on the days I got to shoot it, it was very cold here and the wind was gusting 5 to 7mi per hr, and this thing doesn't shoot very fast to begin with! I love a good challenge and I think this is gonna be 1!

[39M]

Hope you get it right.

I'd probably do something stupid like try and rev it up a bit with a heavy spring and a heavy top hat so I could shoot heavy pellets.

[rufus80]

How's the breech lockup? Does it have the ball bearing detent?

[Mark 611]

The lock up is good! and yes it has the ball detent, I took it apart before I went to work last night and yes the piston seal is damaged enough to be causing some of the accuracy issues! I also stopped at some the local hardware stores and bought some different O-rings for the breach seals! I'm going to order some JM piston seals for now and hone out the tube { cocking slot} and the compression area of the tube to make sure its de burred and cross hatched before I install the new piston seal, just for GP I'm gonna lap the bore with Mother's metal polish while I have it apart so I don't have to go back later if it needs it? I will report back on this and keep u all up dated on what happens after I get what I need to put it back together, I'll let you know!

[Artie]

I for one appreciate your updates, finding them instructive. I'm going through precisely the same process with two different guns, same symptoms. The effort has surpassed challenge, it's now an indulgence. I call them my "prodigal guns."

[Mark 611]

air guns are pretty simple to figure out if u have enough knowledge and hands on with them, IMO here's why I think we have the issues with them we have today, for 1 the demand! air gunning has gotten very popular in the last 10yrs, if it wasn't a booming business they would not be coming up with all the stuff u see today in the industry, and that lead's  to mass production to keep up with the demand! That's why I'm having to replace the seals in a brand new rifle! if I did not have the ability or knowledge of how to do this and figure what is going on with the rifle I probably would have sent it back! but to me its a challenge and something to tinker with and it helps other people here to gain knowledge about air guns I know a lot of people would have sent this rifle right back no questions asked! even if I have to re barrel this rifle to me its no big deal! it a $200 dollar Diana and I like it! and besides if I have to put a LW barrel on it, it will have an LW barrel on it {Lothar Walther} and I know it will shoot the Crosman pellets usually right out of the tin with 1 hole accuracy! I have had lot of air guns re barreled in the past and they usually turn out to be awesome! but were not their yet with this rifle! from my experience with a rifle with these issues I'm having they usually turn out very well ya sometimes they take a little work to get them where u want them but that's why we do what we do on here

[TF89]

Hi Mark,

Just bumping this thread.  Curious if you made any progress on this?

Thanks,

Dave

[Mark 611]

well here's what was tried with the rifle! WhiteFang, {OC} my friend and air gun tuner, was sent the rifle, he chopped and choked the barrel several times, and lapped it and did everything we knew to work a barrel over to make it shoot! The rifle would not group well at all no matter what pellet we tried, so I decided to not put anymore time or money into this rifle, for what it would have cost me to re barrel it I decided to just purchase an HW35 from Krales before their prices went up, best thing I ever did! anyway I gave the rifle to my 72yr old neighbor who just loves the gun, he's not worried about shooting 1 hole groups with it he's just happy shooting tin cans so even tho it didn't do what I want it to do as far as my accuracy requirements I made someone else very happy with the rifle IMO money would have been better spent buying the HW to begin with!

[TF89]

Thats sad even though  it has a happy ending.  Thanks for rounding out the story.

[Mark 611]

well their are lessons to be learned from other peoples experiences like mine not all that glitters is GOLD! I'm not the only 1 who has recently purchased a Diana 240 in the past year that has had this same problem with the accuracy of these rifles! I wanted a rifle in the size and power range of the of the HW30 but didn't want to spend the money for the HW30 at that time so I thought $200 for a Diana was a good deal {NOT} so after I bought the HW35 I turned around and bought an HW30 anyway from Krales! HW quality and accuracy out of the box is hard to beat for the money and what u get for an air gun! in my experience with Diana's the only really good 1's I ever been happy with are their upper ended guns 48's/460 {etc} YMMV