T06 d34 in .177 what's wrong?

[SwampHunter]

Hello all, I bought this rifle on the numeric sale, I want to love it but it pisses me off! I know I'm not the best shot with a springer but this one is driving me crazy. After atleast 1500 rounds it's still dieseling? I know that in itself will cause accuracy issues but I don't know what to do about it? I thought about a 12fpe tune kit, but it turns out some great groups SOMETIMES as it is. I took it out yesterday as I had a couple new pellets to try, 10gr hades and 10grn jsb. I know, basically same pellet but I had heard they were usually good option and groups could be different between the two. First pic is cold with hades...doesn't like these apparently.

[SwampHunter]

So I switched to the jsb 10 grains and was really impressed at the first group minus the flyer,  all shots are at 18yrds by the rangefinder. Next groups are all with jsb 10 grain, as you can see after the first group things went down hill quick.

[SwampHunter]

Then I decided since I had it out, I would try the 10gr hades again, same range. As you can see, out of the next few groups, one stands out minus the flier. My chrono isn't working currently as my son assassinated it  but I'm pretty sure it's dieseling as I don't believe it has the power to send 10gr pellets supersonic? Very frustrated as I really want to like this rifle.

[Toxylon]

Springers never stop dieseling unless they are fixed from their factory status, no matter the make or model. The fix is to disassemble the gun, thoroughly clean all the grease / oil / lube inside the powerplant, likely replace the seals, and relube the internals appropriately and in appropriate amounts, which is not much at all.

I'm not sure what the numeric sale is (Numrich sale?) Was the gun new? Used guns can have almost anything done to them.

Dieseling enough so that wild shots occur from it, after 1500 rounds, indicate the gun has a leaky piston seal, which is common as mud. The condition will not fix itself, as you have found out.

Disassembly and reassembly advice is readily available here, many of us have done D34's. If you have zero inclination to do the job yourself, you need to find someone in your area to do it for you. It doesn't need to be a gunsmith, and most gunsmiths aren't really keyed to springers, anyway. Airgunsmiths aren't common, but there's a good chance someone on these forums could help you out more or less locally.

Pellet choice and shooting technique are biggies, too, as you know. JSB's aren't necessarily the best match for your Diana, and 10.34 grains is really quite a lot for the D34 powerplant. You need to test many more pellets, especially H&N's. My D34 shoots best with Baracuda FT 9.57's, but I'm not done pellet testing.

Tensing up inadvertently, even a little, can destroy accuracy. Especially trigger hand control is critical. I find unless I manage to grip the gun like the most delicate thing in the world I won't hit / group worth anything with most springers. Everything, from front hand position to shoulder / cheek pressure needs to be done exactly as the best shots were done.

[SwampHunter]

Thank you for your help, I would like to try and do the work myself, I believe I need a spring compressor? Looks like they are kinda simple to build, pretty sure I have a 2x6 and a  big c clamp. I think by the smaller groups I'm getting occasionally that it would shoot good with a full power kit? Seems like most run arh spring kit with a vortex seal? I tried to replicate the hold as much as I could, I know more practice is needed as  not the best shot with a springer, that's why I shot at 18yrds vs 25-30 lol. The chamber also seems loose to me, cphp will fall out on closing if not careful. Maybe there is an oversized h&n like the .22s have? Sorry, misspelled Numrich, yes it was a new rifle.

[Roadworthy]

You don't NEED a 12 fpe kit to shoot accurately.  It would make easier cocking and smooth the shot cycle as well as eliminating twang.  I built my spring compressor on a 2 X 4 as I didn't like the sideways C clamp - personal preference.  If you've not cleaned your barrel with Ballistol or Hoppe's that is a starting point.  After that step run a couple dry patches.  That is my first step with a new gun.  The pivot screw on newer Diana 34 rifles is frequently too tight.  It should be loose enough to allow the barrel to fall with some resistance when the gun is cocked.  This will allow the barrel to latch properly.  Be sure to lube the latch ball.  I prefer an 8.4 grain pellet in my 34.  All newer Diana breeches seem to be loose.  Use a pellet seater to be sure the pellet is fully seated.  That will also ensure consistent pellet insertion.  I think the oem Diana piston seal is the best you can get for your rifle.  I would place ARH seals next on the list.  Vortek has too many different seals for me to recommend them.  Many are too hard to achieve a good seal.  You didn't note the size of your groups or your goal.  You should easily achieve 3/4 inch c-c groups at twenty yards.  A little practice will drop those to 1/2 inch, perhaps less.  Hold is everything.  The gun does not actually hit where you're aiming.  It hits based on where the barrel was aimed when the pellet launched.  That's why a consistent hold is essential.  Be sure your trigger pull is straight back - always.  Good luck.

[mpbby]

I would buy another chrono; it will be always useful.

[SwampHunter]

Thank you for the information roadworthy,  I would definitely like 1/2 or better as occasionally I can get 1/4" now but no where near consistently, see 1st group of 2nd pic. I understand that is only at 18yrds, hopefully I can get 1/2 or better at 30, that's my goal anyway.
A new chrono will be on the short list after the new year, have birthdays, Christmas and an anniversary to get through first lol

[splitbeing]

Is it a t06 34 or the t06 EMS (originally branded as a 34 EMS)?

To solve the diesling, you're likely gonna go inside. Most of the t06 diana rifles come pretty dry, so that you are having such diesling is a bit odd to me.  Do you have a compressor or large enough clamp to get inside the gun?

[SwampHunter]

Is it a t06 34 or the t06 EMS (originally branded as a 34 EMS)?

To solve the diesling, you're likely gonna go inside. Most of the t06 diana rifles come pretty dry, so that you are having such diesling is a bit odd to me.  Do you have a compressor or large enough clamp to get inside the gun?

It is the classic, not the em's and no I do not have anything to get inside of it yet. I have a clamp somewhere I bought from harbor freight just to cut down to make one though

[splitbeing]

The classic is easier to work on than the newer EMS.  Roadworthy is the best at helping folks through that process, but I and others are also here to help once you are ready to go inside.

[SwampHunter]

Thank you, maybe I should build the compressor and tear it down before ordering things I may not need? I think think that should be the next step, so I will do some research on building this contraption lol. Will the same size work as the one you sent me pics of for the 48 work roadworthy?

[tjk]

Just a spitball guess, but after that many shots, your rifle should be broken it a bit and dieseling should be at the very most, very minimal. I would venture a guess that you have a damaged piston seal and it is allowing excess lubrication to bypass it into the compression area. You really can’t go wrong with a kit from Vortek or ARH. I’d lean to the full power kits over a softer kit unless you shoot indoors. Jmo

[SwampHunter]

I want to go with arh I think, only thing that worries me at this point is his seals have to be sized and I'm not sure how to do that

[Denby95]

I want to go with arh I think, only thing that worries me at this point is his seals have to be sized and I'm not sure how to do that

Personally, I chuck up the piston with seal mounted to it, spin it up on a hand drill or drill press and hold some fine grit sand paper like 400, take a little off, test the resistance in the cylinder again until you achieve the desired removal. It's easy.

[Methuselah]

It also couldn't hurt to check that the screws are tight, maybe also do a tissue test on the breech.

The chrono connect app may still be around as well, but I tend to agree there's a really high probability of needing a new piston seal.

[splitbeing]

I size the ARH seals by holding the piston in one hand and holding sand paper around the seal with the other.  Then twist, test, twist, until it's the right fit.  I am careful to avoid holding or pressing the piston stem, keeping my grip to the piston itself and leaving the stem alone untouched.

[SwampHunter]

Thanks guys, sounds like I have been over thinking it lol