Madbull in - fps drop??

[rschris]

Just a quick question. Installed my Madbull tight bore 6.03 barrel...accuracy is awesome. just the fps dropped 30??

what could this be?

 

[Liam Porter]

This may be a silly question, but are you using the same BBs? What BBs are you using?

If so, are you using the same hop rubber/nub, and is it still set the same?

Have you cleaned it?

 

[rschris]

hi mate, using systema bucking.

blaster bb's

cleaned - yes

hop adjusted to get bb's straight but thats it :S

 

[Liam Porter]

Hmm, is the barrel the same length? Have you changed anything else, or had the gearbox apart while changing barrels?

 

[rschris]

Nope, just the barrel out changed and straight back in. No messing with anything else.

As i say the gun fires perfect and the BB's are straight as a dye so nothing is set up wrong. Just the FPS decrease. The barrel etc.. is all the same.

Purely just the 6.03tightbore and the Systema bucking went it.

 

[Airsoft-Ed]

That's very odd.

My theory is that because the barrel bore is tighter, the hop will need to be on more to protrude into the barrel the same amount as before, so because it's blocking the barrel slightly more = fps drop.

Just a thought.

 

[rschris]

That's very odd.
My theory is that because the barrel bore is tighter, the hop will need to be on more to protrude into the barrel the same amount as before, so because it's blocking the barrel slightly more = fps drop.

Just a thought.

Good thought, Played about with the hop today and it is amazingly accurate, the only problem is the lack of power, but......if it stays low it will get a M110 spring in

 

[Rock-climby-Dave]

what power was it sticking out before the change?

and is it still consistent for shot-to-shot FPS?

 

[rschris]

Prior it was consistent @ 337fps

Madbull @ 307fps

 

[Saltyyy]

307 isn't bad, I don't see why you'll really want to change it, I mean, what's 30fps?

 

[rschris]

itll add that bit of extra distance that I want when shooting long.ive got 43fps allowed so would like to take it up to the brink.

 

[Rock-climby-Dave]

and risk it going over?

seriously, 307 is fine, as long as it's consistent you can fire .25's all day long and not gain any extra range for 30 extra fps.

There is a point where at any site limit, extra fps just becomes a dick-waving contest, having the largest number really doesn't matter, it's how you use it that counts. and with a 350 limit, that point is around 310-320.

the argument of 'but the extra power will make someone more likely to take the hit' doesn't work either. 30fps equates to around 0.01Joules. All you are going to achieve is piss off those who DO take hits anyway.

Your time and money will be much better spent on a new hop up rubber and decent BB's than upping the FPS.

I apologise for the rant.

 

[TPI]

Dev LIKE BUTTON IS OFFICIALLY BEING REQEUSTED lol.

I can back up the pissing off the guy's who do take their hit's bit i have to keep a pretty face i have 40+ years to go yet atleast...

 

[rschris]

Rant away mate. Never used the 'itll make them take there hits' I find if they dont take the 1st shot, then the 2nd will assist followed by 3rd, 4th, 5th etc..etc..

Its not about how much pain im going to inflict on someone and certainly not a di$k waving competition as really not in to that. I noticed a different playing today, whilst my shots were perfectly on target, my shots were just dropping a little bit short of where they were doing before. Thus why I want to get the maximum from my gun.

 

[Airsoft-Ed]

The fact of the matter is, I still can't understand how a tighter barrel could possibly give less fps, even if the hop is a contributing factor. It's truly bizarre.

In my experience, fps does equate to better range though, so I can understand your frustration. Not football fields of range, but an extra 30fps, some heavier ammo and the right hop adjustment can give you about 20 extra metres.

The thing to remember though, is that you do have to do more than just up the fps.

For example, my L85 in my perfect set up shoots at around 310fps with .25s and I can accurately hit a torso sized target at around 45 metres. I can hit people out as far as 60 - 70m but it's not a one shot affair, more like a whole 30 round mag on full auto and not to mention having to aim about 3-4 feet above the target. I don't get chance to make shots like that very often because of tree cover, wind, etc etc but I have properly tested it before on an open road. 'Open' meaning no obstacles and of course it was part of the site I was at, not a public road.

310fps with .25s equates to 345fps with .20s but if I run the gun with .20s then it's terrible, range and accuracy are lost. If I want to gain the accuracy back then I have to use a weaker spring to give me an output of about 320fps with .20s and although the accuracy comes back, the range doesn't, I lose about 30m and it becomes thoroughly impossible to hit a man beyond 50m.

The difference .05g can make is truly amazing, the tiniest little thing can make a difference, so make as many tiny differences you can make, it will add up to a huge difference. Higher fps is just one of the tiny things you can change, learning the combination of changes needed for a good set up is the difference between shooting 40m at 300fps and shooting 70m at 300fps.

I'd say that as a rough rule of thumb for every 30fps you go over 310fps, up the BB weight by .05g

310fps - .20s

340fps - .25s - brings it back to around 300

370fps - .30s - brings it back to around 290

Despite the heavier ammo lowering the fps, you will get better range. It seems like backwards logic but it really does happen if you try it.

BUT, I still can't understand how a tight bore could cause a drop in fps lol.

 

[rschris]

At least you understand what Im saying Ed. As you know I play CQB at the stan and you have some very long areas to shoot at!! Think ill try putting some 0.25's in and see how it works. Just been using 0.20's at the moment.

At the stan if you stand on the entrance corner I can just hit the door the is blocked off near the yellow stairs. But it is dropping at this point so I would say 40-45metres. Before I was hitting it no problem but no accuracy.

Will have a play and see I think.

 

[RR01]

At least you understand what Im saying Ed. As you know I play CQB at the stan and you have some very long areas to shoot at!! Think ill try putting some 0.25's in and see how it works. Just been using 0.20's at the moment.
At the stan if you stand on the entrance corner I can just hit the door the is blocked off near the yellow stairs. But it is dropping at this point so I would say 40-45metres. Before I was hitting it no problem but no accuracy.

Will have a play and see I think.

Try swapping out your current hop rubber for a Madbull Shark Velocity Enhanced one. It should be a good match for your barrel and when I put one in my M16, which was running 340 fps in normal mode, I started getting average shots of 365 and a few up at 380, so had to downgrade the spring to compensate. It could just be your barrel and hop rubber aren't compatable.

 

[Airsoft-Ed]

At least you understand what Im saying Ed. As you know I play CQB at the stan and you have some very long areas to shoot at!! Think ill try putting some 0.25's in and see how it works. Just been using 0.20's at the moment.
At the stan if you stand on the entrance corner I can just hit the door the is blocked off near the yellow stairs. But it is dropping at this point so I would say 40-45metres. Before I was hitting it no problem but no accuracy.

Will have a play and see I think.

Next time I head to The Stan I'll let you know I'm coming and see if we can't organise a trip on the same weekend.

I'll have a go with your gun if you don't mind me having a look?

I might be able to advise something better if I actually see what it shoots like.

 

[Ian_Gere]

Well, going purely on the physics involved, rather than experience, fitting a tight bore barrel must increase the air compression behind the BB. So... if that extra air pressure now causes a seal to fail partially, that's a reason why power would be lost. Has your nozzle got an O ring to seal it to the cylinder head? There's also the seal between the nozzle and hop to consider...

One thing to try would be to try your new parts one at once, that way you might discover that it's down to only one of them - easier to pin down then, eh?

 

[rschris]

Well, going purely on the physics involved, rather than experience, fitting a tight bore barrel must increase the air compression behind the BB. So... if that extra air pressure now causes a seal to fail partially, that's a reason why power would be lost. Has your nozzle got an O ring to seal it to the cylinder head? There's also the seal between the nozzle and hop to consider...
One thing to try would be to try your new parts one at once, that way you might discover that it's down to only one of them - easier to pin down then, eh?

hmmm must be a leak then I guess.....good point....cant see the wood for the trees sometimes. think ill take a look at the seal between hop and barrel.