[seth]

Hello!

I headed out yesterday to do a little zeroing in with my ASR, and was not exited about the accuracy I got. First up, here is a list of parts/ modifications I have done:

Echo 1 Upgrade Kit
Mad-bull Version 2 509mm 6.03 barrel
PDI 96 hop up
Guarder bucking with dental floss insuring tight fit
Six barrel spacers
Polished and slightly widened cylinder head as per here: http://www.airsoftforum.com/board/Upgraded-Cylinder-Head-t87014.html
Teflon taped cylinder head, and piston head screw

I shot from 100 feet using .25's at a torso sized target, and while I could hit the target every time, there where no good groups to speak of. I then moved the target out to 240 feet, and had no consistency at all, any hits were pure luck.Also, while the time it took the BB to hit the target at 100 feet was roughly one second, the time at 240 was incredibly long. I had time to lift my head from the scope, and count to 3 before hearing the hit. Seems like the fps are slowing down a lot, but my gun is shooting hot (550fps).

I'm getting .3's and .4's soon, I'm assuming this will help?Any suggestions/comment would be appreciated!

Seth

 

[WorstInFinlanD]

Heavier bbs are going to help for sure.

 

[wesley810]

It's probably the ammo you were using. You set-up looks pretty good. I would try out the .3 and .4 weights. You should get better results from those weights.

As for the FPS, I'm not too sure about that. I would think a .25 would get to the target very quick if it could hit it. Have you checked airseal or actually chronoed it at 550 FPS? I would put my finger over the barrel and fire to see if there is a leak (make sure there's no ammo in the rifle).

 

[seth]

I have not chronoed using a real chronograph, only using a soda can, the "poor mans" chronograph. It punched through the bottom as well as the top of a soda can, putting it around 550 fps.

 

[wack2011a]

The lighter the ammunition used the quicker the round will slow down. A .3 or .4 is able to hold its momentum and can punch through the air with more ease than a lighter BB. A .25 for example will have a much higher starting velocity but will slow down much faster as well. A .4 will have a slower initial velocity but will retain that velocity much better than the lighter BB.

It would be something like this in numbers:

.40g Starts at 450FPS ------ .40g at 100' is 430FPS ------ .40g at 200' is 400FPS ------ .40g at 300' is 350FPS

.20g Starts at 550FPS ------ .25g at 100' is 400FPS ------ .25g at 200' is 325FPS ------ .25g at 300' is 220FPS

None of that data is real just showing you how the BB acts in the air. You'll notice that the .25 has the advantage of velocity up to around 150'.

 

[newbie]

heavier bb's are a plus, not saying it is the sole factor but I have never been a fan of madbull barrels. I personally have not had the best results with them. Ideally you should have at worst a 8 inch group at 100 ft. First get good bb's then try out different bucking nub combo's.

 

[wyvernfist]

Also did you polish the new barrel?

 

[seth]

So I did a compression test, holding my finger over the barrel and dry firing. I heard air hissing out after the shot was fired. It seemed to be coming from the hop up area, but I am 99% sure the hop up to barrel to bucking connection is good, but I suppose the nozzle to bucking connection could be bad.

Peyote, thanks for the information! This is what I had hoped would happen as far as a heaver BB.Though slower at the beginning, it retains its speed longer.

Newbie, yes unfortunately Mad-Bull is the best I can do at the moment. Eventually I want to get a PDI 6.08 and an R-hop...but that's another topic

wyvernfist, no I haven't "polished" it yet.I have swabbed it with normal gun cleaning patches, but I was under the impression the the Version 2 barrels were not supposed to be polished. It seems to have a almost glassy finish in the interior. I was a little afraid to polish it up.

 

[akfortyseven]

I heard from somewhere that madbull barrels are slightly smaller than most barrels. Could that be the problem with compression?

 

[seth]

Could be. Do you remember if it was a smaller inside diameter or outsider diameter? I'll take some calipers to it and see.

 

[akfortyseven]

The outer diameter