Diana Diana 250 accuracy issues

Need some input. Just bought a new .177 Diana 250 from Airgun Depot for my son. Pitched the scope, tightened all bolts, and put on my Sightmark Wraith that I had on another rifle. I think I have put 150 shots into the target at 25 yards and can't get any consistency. Thought the scope was acting up, so I put the Wraith on my HW 97. Never had it on that but took 3 shots to zero like it usually takes to zero. Went back to the 250 and tried again with the Wraith. Felt like I was chasing cats with it hitting everywhere but where I aimed. Will try cleaning the barrel and check with my Arken this weekend. Or, is it just the rifle? Any advice is appreciated, thanks.
 
I’m guessing since you said you bought it new it’s likely a Diana “Two Fifty” (letters not numbers). Different gun as far as I know.
Anyway I bought one a couple of years ago and mine was not a great gun, it’s a typical Chinese break barrel with the associated shortcomings. If I remember mine was putting out around 17-18fpe in .22 with a rough shot cycle.
 
I wouldn't think of trying a new springer, German or Chinese, for accuracy before at least a large tin of pellets was put through the gun. German springers start to really sing after a couple thousand pellets (when breaking in a factory spec gun). I haven't broken in Chinese guns such as the Two-Fifty, but don't think they are quicker in this regard.

You don't name the pellets you have tried. Again, springers, no matter where from, are pellet picky things. Unless you've tested a half-dozen+ different quality pellets, dozens of shots each, you can't really tell if a gun is inaccurate or just pellet picky.

Factory new guns generally have filthy barrels. There's no expecting accuracy before cleaning the barrel, and then leading it with a couple dozen shots.

FWIW, German Diana springers are as accurate as ever. The Chinese Dianas may not be.
 
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Action

1. Chrono your rifle. This will point to spring, seal, breech seal, compression chamber or over lubing issues. If you are not getting consistent chrono numbers, you need to rule these out.

2. check the condition of your breech seal (damaged? cut?)

3. I'm not familiar with the Diana 250. You may need to do some research/google but the bolt that the barrel assembly pivots around probably needs to be torqued to a certain level...too loose and the action may have side to side movements.

4. Check your barrel lock up. There should be no observable movement.

scope/scope mount

Put a piece of painter's tape on your receiver and mark on the tape the position of your scope mount. After every shooting session (20-40 shots or more), check to see if your scope mount moved.

Stock
During the cocking cycle, position your (non-cocking) thumb/finger at the end cap. you are feeling for movement of the action in relation to the stock to see if there is a fit issue or a bolt issue.

pellet
As suggested already, try different pellets. I highly suggest quality pellets like JSB, Air Arms,

rifle rest/shooting technique

1. Have someone watch or take a video of the tip of your barrel for 5-6 shots. See if there are a lot of movement and different movements and do these movements correspond to "fliers". This would indicate a rifle rest issue, a consistent hold/technique issue, a trigger technique issue (lighten the trigger) etc.

2. After testing all the above...and it's still not grouping, have someone who shoots springer on a regular basis test your rifle.

When you say not consistent,
A. are you seeing a tight group (close to touching) at 25 yards with 1-2 fliers? (2-3 pellet away)
or
B. a 10 shots shotgun pattern of 2-3 inch at 25 yards?

Have someone who shoot springers on a regular basis shoot your rifle and see if they get pattern A or B

If pattern B...think about warranty and returning the gun, get a different gun (but same make/model) or upgrade to a quality springer (HW, Air Arms). There are others who have shot and/or own accurate budget springers, Unfortunately, my experience with budget springers were a series of disappointments. I leave it up to others with positive budget springer experience to guide you.

tune in a tube
I don't have personal experience with the tune in the tube. The theory as I understand is to heavily smear/saturate the spring/spring guide full of dampening grease so that it dampens the spring vibration/recoil. You may get migration of that grease into the compression chamber and an increase risk of denotation. Continual denotations may damage your seals or spring or other components.



Pictures of
1. your groups what distance (windy?)
2. your rifle +scope
3. your rifle resting on your rests (bench)

would give us more information to help you.

Good luck.
 
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Thanks for all the feedback.

JP,806TX, 25 yards, no wind, no grouping, like a shotgun. Sightmark Wraith & Arken SH-4J on the two-fifty Diana. Bench. 7.6, 7.9 & 10.5 pellets.

Will clean & run 500 shots & clean bore a more few times. Just surprised that it is taking so long. I think the worst rifle I have is a Gamo (don't use anymore), and it didn't take that many shots to zero. Guess I am spoiled with the Weihrauchs. The inconsistency is surprising, guess I am impatient to shoot with my son.

Appreciate the comments & will update. But if what you guys say that this is crap, will return.
 
I have one of those, an earlier 250 in .22 with the coil spring. I understand the newer ones might have gas springs.
At any rate it was still shooting harsh and shotgun-like after a tin of pellets, so I took it apart, swapped the heavy piston top hat for a lighter one with less preload (I shoot lightweight pellets), and lopped a couple coils off the spring. Then it shot nicer and would group on a good day. Then I thought, "what the heck", took a couple inches off the end of the barrel, re-cut and polished a crown, and sawed an inch off the stock, to make a handy carbine. Now it is fun to shoot and groups OK as long as I hold it lightly and follow through.

Point is, it's not a classic. Feel free to play around with it with your son.
 
Need some input. Just bought a new .177 Diana 250 from Airgun Depot for my son. Pitched the scope, tightened all bolts, and put on my Sightmark Wraith that I had on another rifle. I think I have put 150 shots into the target at 25 yards and can't get any consistency. Thought the scope was acting up, so I put the Wraith on my HW 97. Never had it on that but took 3 shots to zero like it usually takes to zero. Went back to the 250 and tried again with the Wraith. Felt like I was chasing cats with it hitting everywhere but where I aimed. Will try cleaning the barrel and check with my Arken this weekend. Or, is it just the rifle? Any advice is appreciated, thanks.
Sorry to hear of your accuracy problem with your new Diana two fifty, were I you I'd send it back to AGD for a replacement, you either got a lemon or my adult son and I were very, very, lucky with ours, mine is in .177, my son has the .22 cal. version, both have been great rifles in every respect, accuracy equals my German rifles, power, smoothness, and fit and finish are way above their price point, we.ve had ours for about six months and have had zero issues with either.
Ours are shooting great with Crosman Premiers, 14.3 in .22 cal. and 7.5~8.5 gr. in .177 cal., triggers are also sweet and the scopes are decent quality, though we would prefer variables instead of fixed, which we may change out in the spring, but both rifles are stacking pellets at 20 yds., 1" at 30 yds,. and about 2" at 50 yds, you really can't expect much better from budget priced break barrel air rifles.
Just saying, try different pellets and if it doesn't get better let AGD know and send it back, take the money or a replacement, judging from my experience with the Two Fifty I'd opt for a replacement.