Tuning Tuning an FX dreamline .22 for slugs

[DaveT1]

I have had my Dreamline Tac .22 for about a year now. I've got it tuned for JSB 18.1's so that it will shoot ragged one hole at 50 yards. The 18.1's shoot at about 875 fps. Now I'm trying to tune for slugs. The gun is pretty much stock with 500 mm barrel, except for a power plenum. I've been testing FX Hybrid, NSA, JSB KO and H&N slugs. The weights have ranged every where from 17.5 NSA's to 30 gr. H&N's. I've gotten my best accuracy results from slugs ranging from 21 gr. to 25 gr. Muzzle velocity ranges from the low 900's for the 21's to mid 850's for the 25's. I've had the reg. set at 135 bar and Hammer Spring set to Max with the preload spring set to 15 mm.

My goal is shooting for accuracy at ranges greater than 75 yards. My longest has been 200 yards with an 8" fry pan.

Finally. My question. What kind of muzzle velocity should I expect from slugs out of this gun? Am close to as good as it gets or should I keep tweaking?

 

[2L8]

Dave

You have done quite well with your 500mm.I would keep this tune. Those speeds you mention are a great place to start with slugs in a DL. Upper 900's is a stress for long term reliability with this platform. Tune your best slug at 25-30yds and then tweak for 100.

As a side note, your non Superior or Slug liner barrel could be the limiting factor here for slugs at 100+yds. Just keep in mind, pellets RULE @ 100yds.

Keep good notes.

 

[DaveT1]

2L8,

Thanks for the input. I was guessing that 850 - 900 fps was a good muzzle velocity without putting excess stress on the system. I did fail to mention that I have added a Superior liner to the gun too.

As far as notes go, every time I chrono the gun, I go into the "notes" section of the FX chrono and record the ammo type and weight; the hammer spring setting, the HS preload setting as well as regulator and valve settings. All of that plus the shot string is printed out and added to binder. I'm not sure which has been more expensive. The ammo or the printer ink and paper... 

 

[gendoc]

i have the tac compact, converted from the lite version.

it has the superior liner and it dont do slugs very well, tried everybody's and 

had no luck.

tuned every which way but loose.......nada !

 

[qball]

Had great luck with 500mm superior and nsa 217 23 grain slugs. Great accuracy from 800-920+ FPS. Try 140-150 bars and a little less hammer or lower power setting. With 500mm you need a hotter shorter burst of air. Speed does not guaranty accuracy, if you shoot it too hot for the length of the barrel the accuracy actually decreases. 

 

[DaveT1]

qball,



Thanks for your input! Just did some chrono testing and I am getting 830 fps with the NSA 23 gr. and 890 fps with the 20.2 gr. The gun setup is: hammer spring - max, hammer spring preload at 15 mm, reg - 130 bar and valve - .30 cal. Accuracy for the 20.2 has been very good. Hitting 1 1/2" spinner 3 out of 4 at 100 yds. and an 8" fry pan at 200 yds on the first shot. Just ordered 3,4,6" gongs that I want to set at 150 - 250 yards.

I only had a sample pack of the 23 gr. As soon as I get a box of 230 gr., I'll try your suggestions.