Prometheus 6.20mm Delta Strike Barrel
 

Looks like prometheus has produced some wide-bore barrel. They clain to get more range out of lower powered airsoft. If it is true it will be great to have great range out of sub 400 FPS guns.
I wonder if anybody have tryed those because I am a little bit sceptical about them.
http://www.redwolfairsoft.com/redwol...K47S_455mm.htm

$43? Ok. Im interested. I dont like brass tho, which im assuming it is. I like the concept and innovation tho

Side note: I was already excited to see Mad Bull's stainless steel 6.03mm tightbore for $45
http://www.airsoftparts.ca/store2/in...oducts_id=2698

orga's been making a 6.23 for a while, P* users seem to like them
Anyway we get great range from sub 400fps guns right now

Now this is something I have always been curious about as I have seen this discussion before.
Why do some argue that you can get better range-accuracy out of tight bore, while some say the same for wide bore?

There's obviously a point where you lose accuracy from a wider bore
The tightbores depend on very thing air chusions around the BB and are more susceptible to accuracy loss due to barrel fouling
Widebores are dependent on large air cushions, being less susceptible to fouling, but more to turbulent air flow and airflow or air pressure problems.

There's a good balance somewhere between 6.05 and 6.10
And there's no particularly accurate way to compare barrels in an AEG. It's hard enough to do with a PTW lol

We don't even know for sure how a BB travels in a barrel, much less how to effectively enhance a BB trajectory beyond bore and hop-up consistency.

An accepted theory is the BB floating center with an air cushion. Another popular theory is that the BB rides the ceiling of the barrel.

The R-Hop, as well as this barrel work on the second theory. Widebores are better because the BB often bounces a bit from the ceiling because of particles, irregularities in both the bore and BB, and if the floor is too close to the ceiling, the BB will hit the floor instead of simply going back to the ceiling.

The groove at the beginning creates an air pressure pushing the BB up. A few people at ASM are/were experimenting with barrel grooves cut on the entire length of the barrel to assist the BB in riding the barrel smoothly.

Just a small precision to ThunderCactus: Tightbores do foul faster, but when you're to the point where the fouling causes problem, your accuracy was already beyond screwed, and you shouldn't have reach this point.

(The previous post is a condensed summary of my personal understanding. I may well be wrong, but I'm not until proven otherwise.)

With my prometheus 6.03 in my VSR-10 I noticed accuracy loss due to fouling after just 120 rounds. However slight, fouling can occur very quickly, especially in AEG's where you're constantly spraying grease particles into the barrel and potentially oil from oiling your mag (that's why I say not to do it)

With my PTW I noticed the same thing, the widebores definitely negate a bit of the problem. Doesn't take many rounds to start to drop off in accuracy, but I wonder how many people actually notice?
And take into account LMG's that go through 2000-10,000 BB's in a game. If accuracy loss occurs at 120, 500, or 1000 rounds, they're still suffering from it. So the best option for sure is a wider bore 6.08-6.13 (still not convinced 6.10+ is a real benefit)

If the BB was riding the top of the barrel I'd expect there would be a contact line there, especially in heavily used barrels like my 249's. Regardless of whether the backspin is matching the fps at the beginning of travel, it won't be the same by the time the BB leaves the barrel as it's continuously accelerating and there isn't sufficient grip in the bore to further accelerate the backspin, creating friction and thus a contact line, right?

I do agree we have no idea what the maximum potential of a 6mm spheroid is though
We also contend with the fact we need to retain certain velocity. With the R-hop and ER-hop you can use heavier ammo than would normally be possible with some range and accuracy advantage, but unfortunately the reduces relative fps makes them much easier to dodge. So at 1.6j with an ER-hop let's say for example a .43g would net the best range and accuracy overall, it may not be ideal since it's going so damn slow.

I agree with most things Frank says, he really knows his stuff. However, there have been leaps and bounds in hop-up design the last few years, but airsoft guns got away from wider bore (6.08mm) awhile ago, because of their unreliability. That being said, we've also seen BBs go unstable with too tight of a barrel. Natural progression has gone towards heavier rounds the last 2-3 years across the board, as 6.04 barrels have been the standard, and are continuing to get wider again. It is possible that stable flight path in the barrel, perhaps due in part to higher quality, heavier weight BBs, is a catalyst for stable air cushion. And if your air cushion remains stable, then it is safe to surmise that you can use a wider bore barrel. Where a wider bore barrel may have been indicative to any number of issues, such as dirt and dust in the barrel, a crappy hop-up, crappy Or mediocre BBs, etc. Let's face it, 6.08 mm barrels just a few years ago were a curse, and not a benefit, but the technology surrounding them was not nearly as good. Better materials, better make, better rounds, better hop-up, more consistent guns, etc.

Just to know if I switch from a 6.04 m4 lenght barrel to a 6.2, do I have to change the cylinder with it ? Or the "m4 hole" cylinder will do fine ?

Should be fine, but you'll have an FPS drop. You may want to up your spring and/or put an aggressive bucking in your hop-up.

Well the big problem with the 6.08 barrels is that none of them were of any sort of quality lol

The prommy 6.03 and PDI 6.05 are high standard, super polished, stupid accurate, honed out stainless barrels, and they've been the basis of comparison for every other barrel.
The PTW barrel even at 6.04 is more concentric than any other brass barrel on the market

The 6.08's are primarily AEG OEM barrels made on the cheap, so it's quite rare to run into a fairly concentric and accurate barrel outside of marui

But with higher quality wide bores, like the orga 6.10 and 6.13, we've found them to have the same accuracy as the tighter bore barrels, and maintain their accuracy longer.
Problem is we still don't have anything in the 6.06-6.12 range for AEG's that comes close to the PDI 6.05/prometheus 6.03 quality

As well in the PTW world, right now the two best reviewed barrels are the OEM evo 6.04 and ORGA 6.10, reviews saying they're on par with each other


Switching to the 6.20 barrel, I'd recommend actually changing the cylinder as it's a pretty significant change in volume. As well expect to lose 45+fps
Going from a 6.04 to 6.10 PTW users generally lose 25-30fps

Increasing the springs strength wont give him more air to fill in the new gap and take advantage of the barrel. He had the right idea of moving to a cylinder with the hole further back, or a full cylinder.

Isn't the m4 hole cylinder over volumed anyway

It sill make a 5-6% difference I wonder if it will matter considering different cylinder are used for about 10% volume change.