Tuning poor accuracy dreamline

[Morbech]

Hi hope you can help me here.

I´m new to the pcp world and bought a dreamline 3 weeks ago.

I tried tune the rifle by setting the hammer to max and reg pressure to130 bar. then shooting over chrono and adjusting the hammerwheel down. I had to loosen the hammer some and found shooting jsb 15,89 grains around 905-910 f/s was pretty consistent. My shots are from 904 to 910 f/s.

My problem is:

I then tried group testing. There was little wind and about 7 degrees celcius.

when I just took the rifle out it was shooting mayby 1" high for some shots then it would start group pretty good and then all of sudden it could shoot low, high or right.. But sometimes I had 4 shots in a row that was hole in hole.. Filling the rifle again, and brought it out shooting, it shot a new place.. 



What is the problem here? is it just not in harmony? should I go lower in velocity? higher?



Frank 

Denmark

 

[JadedC]

The first thing I would try is to clean the barrel. Have you cleaned it since you got it? If that doesn’t work I would drop the speed of the hades down closer to 870 where the universally accepted optimal speed for pellets is. If that still doesn’t work I would try the regular 15 grains or 18 grains.

 

[Morbech]

thanks, I will try lower the velocity.. Did clean the barrel. but not with any oil..

The JSB are 15 grains..

 

[allenbowles]

pay very very close attention to even a slight wind.do not change point of aim,watch wind and point of impact before changing alot of stuff....you will have to learn your gun and environment....have fun

 

[qball]

Sounds it also could be your eye parallax alignment, make sure every time your shoot your eye/check position is exactly the same. It is obvious the gun is shooting accurately, you could also be pulling the trigger or multitude of other shooter errors.....ask me how I know! 

 

[Odoyle]

That's almost freezing does it shoot better when the outside temperature is higher?

 

[Morbech]

I havent shot a lot with it... But before I made any changes it seem to shoot more consistent. ( I bought it second hand) But the changes I made is pretty much the same as it was when I got it.. But again I havent shot a lot with it before i made the changes.. mayby it whas a bit warmer those days I shot it..

I dont think it is my parallax, but I will think about it. I am pretty experienced with guns. but again, it could be it, so I will think about it.. It just seems that the pellets just shoot high then low. it seems like there is a kind of point where reg pressure and everything is in harmony. But it has a regulator so it shouldent be it.



It might be the velocity is to high as mentioned above... 

 

[allenbowles]

forget what you know about powder burners,i have shot them for over 60yrs..todays pellets & guns are a different ball game.imo

 

[JadedC]

thanks, I will try lower the velocity.. Did clean the barrel. but not with any oil..

The JSB are 15 grains..

I’m sorry I was reading another post about hades right before. You should try cleaning with some ballistol or similar product. Lead can get caked into the lands of the barrels and running just a patch can’t clean it effectively. From the way you describe erratic groups with a consistent FPS it sounds like that is the problem.

 

[Bobbybeef]

I had the same problem dream tac compact i put barastol down the barrel patches until all the patches came out spotless still spitting groups everywhere 1 " rt left up down couple of groups here there everwhere i then put my 22 cal wire brush down the barrel about 6 passes then pellet on pellet wallowing out the hole at 35 yards i think there was a minut piece of lead.

 

[Long_Gun_Dallas]

The gun seem to like 18gr jsbs better. But 16 should still shoot pretty good. I'd say maybe try a little higher reg pressure if you havnt. (140?) But definitely make sure the barrel is clean. Might even consider polishing it.

 

[Morbech]

Just shooting this morning.. 

tried group testing 45 meters.. hammer tension from min,1,2,3,4,5 max..

Best group was within1,5x1,5 inch



Shot it in at 25 meters. again, could shoot it in so hole in hole..

Then going inside fill it up to 220 bar... reg pressure is 125 bar.

Going out shooting again in about 7-10 degrees



Then it could shoot 2 cm low, then after 3-4 shots it could come back to the same place. hole in hole or at least within 1,5x1,5 cm at 25 meters

10 shots later it could start shoot 1 cm right.. 

What I mayby noticed a little was, that it was when the rifle got some time to cool down, the accuracy got poor again..



Also at even 15 meters I could shoot it in, hole in hole. Filling it up, going out and then it could be 1 cm high or right.



Is it normal that when filling a rifle to like 220 bar the first shots, is not good?



The rifle has a regulator, I thougt that it would do that the rifle got the same amount of air every time, so I could shoot hole in hole every time... 

A bit frustrating when I need it to ratting, and would like to trust it every time...

I sold my brand new HW97 springer for this one... But with that I had better groups..

 

[Morbech]

Did a little cleaning of the barrel.. Need to do it better, but better than nothing..



Shot again at 45 meters...

top is hammerwheel on minimum

1

2

3

4

5

Max

nr 4 is witin 1 inch

I shot from left to right, so the picture is turned half a turn

 

[Morbech]

Here is the numbers.. it is the section in the bottom that is from today...


The numbers in the bottom is the spread, and the next is the average speed.

 

[tor47]

I had the same problem dream tac compact i put barastol down the barrel patches until all the patches came out spotless still spitting groups everywhere 1 " rt left up down couple of groups here there everwhere i then put my 22 cal wire brush down the barrel about 6 passes then pellet on pellet wallowing out the hole at 35 yards i think there was a minut piece of lead.

Same experience here. Patches alone is not always enough, espesially if you use the fishing line method. Patchworm might work with pathces only, as it make it very thight. Otherhvise use a brush first, then patches.