snub nosed barrel

[Rudz]

i kno i like smaller barrels..and i have seen alot of guys lookin for micro tiips and flash points..so i thought id get your ideas on this..



barrels


anyone use this barrel??

another small barrel..

[Vex]

The prices that they want for both of those barrels is ridiculous. You can buy a 12" for the same price.

People love their novelties though.

[buzzboy]

It would be more worth it to just get the flashpoint or like minitip. I don't see why anybody would want that. I think that you need at least to the second half of a two piece barrel(I don't know how long that usually is but it looks right). Plus the effieciency would drop substancially.

[Lohman446]

Three to four inches long should be enough. Look at the control bore on the stiffi switch kit, or Hammerhead system that were so hyped.

Pricewise the majority of the price of a barrel, I would guess, is the labor/machining that goes into making it.

[ZEROte]

It would be more worth it to just get the flashpoint or like minitip. I don't see why anybody would want that. I think that you need at least to the second half of a two piece barrel(I don't know how long that usually is but it looks right). Plus the effieciency would drop substancially.

actually it will be more efficient.no need to accelerate the ball over extra tube of barrel.

[Rudz]

lemgth

Does barrel length affect efficiency at all? I don't see how....

[luke]

Yes, (According to TK) 8-10 inches in the most efficient.

[luke]

06-17-2001, 10:59 PM
AGD
Former President of AGD Join Date: Oct 2000
Location: Chicago
Posts: 5,291

Barrel Efficiency, Tech Tip #1

--------------------------------------------------------------------------------


Guys,

I have decided to do a tech tips series of posts so you will understand certain technical processes that go on in the paintball gun. We have tested everything I will talk about and any speculations will be pointed out.

In the tech forum there is a long post on what is the most efficient barrel so here are the facts.

Barrel Efficiency, Tech Tip #1

Barrels are only there to accelerate the ball from a standstill to 300 fps. In theory they also help with accuracy but that's another post. The ball goes through incredible acceleration on its way down the barrel. The balls acceleration rate is approx. 50,000 feet per second to get to 300 feet per second in 10 inches. The entire barrel travel time is about 6 thousandths of a second and this means the ball is seeing about 1500 G's when its getting pushed out the gun. Although this may sound incredible if someone out there would like to do the math you will see that I'm close.

Air pressure behind the ball is what causes this acceleration to happen. This pressure varies between the different guns but is generally between 50 to 125 pounds per square inch at its peak. The air pressure peaks right when the ball starts moving down the barrel, after that, the ball moving down the barrel creates a bigger chamber so the pressure drops. This is why low pressure guns are a myth, in reality all guns shoot at considerably lower pressure than 200 psi.

Peak pressures above 150 psi tends to break balls down the barrel due to really high acceleration and G forces. If you don't have any way to control the peak pressure behind the ball, the only way you can change it is to go with lower pressure in the air chamber, hence low pressure guns. AGD uses the precise contour of the power tube tip to release air in a controlled manner behind the ball to limit peak pressures to around 60-80 psi..

It is simple to understand that the harder you push something the faster it will accelerate and get up to speed in a shorter distance. So what distance do we have to get the ball up to speed? The effective length of the barrel is from the balls position before it's fired, to the place in the barrel where the pressure gets released, This is usually at the first porting holes or the step in the barrel. Porting is there to release gas pressure!! You are effectively stopping the acceleration at the ports so your 14" barrel that is half full of holes only has an effective length of 7".

Now we understand that we need to limit the peak pressure behind the ball to keep it from blowing up, and that the pressure drops as the ball moves down the barrel. The next question we need to ask is, how far down the barrel does the ball have to go before the pressure gets to low to do anything useful? That answer is 8-10 inches. We know this from looking at the graphs that our gun dyno puts out. If your peak pressure is higher, say over 100 psi you can get away with a shorter barrel, if it's lower then you need a longer barrel. Since AGD is the only gun manufacturer to actually test their pressures behind the ball you might have a hard time getting this info for other guns.

So as far as our guns are concerned, the best efficiency would be had with an 8-10" effective length barrel. Since two piece ported barrels with an effective length of about 5-6" are the rage right now you hear a lot of complaints about gas efficiency. Under some circumstances there is a good reason to use a short effective length barrel. Short barrels cut off the acceleration abruptly by venting and this has the effect of tightening up the shot to shot velocity variation. If you need this at the expense of efficiency then go ahead. Tighter velocity control usually translates into some improvement in accuracy due to better consistency.

So if you want the best of all worlds, limit your peak pressure, let your ball accelerate all it wants, don't follow the crowd and keep asking questions.

AGD


Link is original thread.

[SummaryJudgement]

Snap!

[Lohman446]

But, in discussing efficiency this tidbit gets lost

Under some circumstances there is a good reason to use a short effective length barrel. Short barrels cut off the acceleration abruptly by venting and this has the effect of tightening up the shot to shot velocity variation.

Like most things in life there is a trade off.

[Arstron]

Also since every gun uses a diffrent preasure and volume of air to shoot the ball, wont the effective length for each marker be diffrent slightly?

[ThePixelGuru]

...A 4" Autococker barrel? It'd be at least an inch behind my pneumatics. Hell, I might even shoot the hose off if I tried to use that.

[topazpaintball]

This + Doc Nickel's drop in breech = Completely shrouded minimag

[buzzboy]

This + Doc Nickel's drop in breech = Completely shrouded minimag

Problem would be getting it back out again.

[Rudz]

uh huh

Yeah..but it eould look so friggin cool...lol worth the looks??? Hmmmmm