6.03;6.08;6.13;6.23 barrel?

[ThunderCactus]

http://www.x-fire.org/etop/05.html

[chaz]

PDI over Prommy?

[warplane95]

I'm searching for PDI barrel.

My VR16 have a inner barrel of 363mm, should I pick the PDI 360 or 375mm?

[ThunderCactus]

12mm of extra barrel isn't going to make any difference when 200mm of barrel length also makes no difference.
Get the shorter one

[warplane95]

last question:
wich one?

[Drakker]

Same price, same barrel. PDI tend to list as many AEG models as possible, so they list the same barrels multiple times.

[Cobrajr122]

There is no difference.

Its only listed twice because it happens to be used in 2 different guns.

[warplane95]

weird they have two part number for these.
Thank you for all

[Comeau-SCS]

Originally Posted by ThunderCactus

They float. If they rolled along the top, there would be a clearly visible line along the top of a very dirty barrel.

Not to hijack the thread but i've seen the bb line on top of a dirty barrel. Just spread 4-8k rounds of biobb out of a stainless barrel and you should see it. I cant say they all run on top but certainly some of them are because I remember the bb line was visible before cleaning.

[DipTwit]

Never said that some people don't have issues that cause a bb to scrape or roll along inside the barrel, just that it would indicate a problem if they do...

A bb should be spinning slower than its forward speed, so if it touches it would be scraping (in fact it must be scraping to leave a skid mark) and that can only do bad things for your hopup results. Insert typical suggestions on barrel cleaning etc. here...

[airsoftmaniacman]

Originally Posted by ThunderCactus

They float. If they rolled along the top, there would be a clearly visible line along the top of a very dirty barrel. And there never is. Keep in mind chamber pressures in shorter barrels are often in the 60-120psi range as well, that's a lot of centering force. AND the magnus effect gains effect only as the BB slows down and gains more "grip" on the air. During the first 10-20ft there's almost no magnus effect at all. Otherwise the BB would start lifting immediately upon leaving the barrel, instead of 60ft into it's flight path. It's a very gradually increasing force over distance and deceleration (of forward velocity and backspin), not a constant effect.

The bore has never seemed to make any particular difference.
I've seen everything from a 6.01 to a 6.23 under ideal conditions and honestly never found one that works noticeably better than the other.
Physics is physics, but science works by applying theories to field proven fact. Not trying to DISprove field proven facts with theories.

Same is said for barrel length, haven't seen any really solid evidence for longer barrels being more accurate than short barrels. The hopup is a far greater contributing factor, making comparisons more difficult. But there hasn't been any real correlation between length & accuracy, or you'd see short barreled guns like pistols, P90s, TW5s, 9" cqbr ptws and the like consistently get worse groupings than M4A1s, M16s, 24" sniper rifles and the like.
The fact remains, once the BB has been stabilized in a straight flight path, no extra amount of barrel will ever make it any more stable. And higher pressures seem to stabilize the BB in shorter distances.

Bore quality; consistency and circularity, are still the most important factors.

Accuracy will degrade as the barrel fouls and the one thing i HAVE found is that wide bores and short barrels tend to foul less quickly.

6.03-6.08 is still the ideal range. The downside to going to a 6.13 or 6.23 is the incredible amount of air loss around the BB, requiring more air volume for not a lot of gains. The PDI 6.05 is my go-to for rifles, 6.13s for LMGs.
6.00 & 6.01 are specifically for exploiting higher fps, not for accuracy.

I agree with everything except for the statement that the BBs float.

If you head on over to ASM, you'll be able to read up on the details.

Somebody took high speed footage of a BB traveling through a transparent barrel. The resulting footage definitively proved that the BB initially bounces around immediately after being hopped, but then eventually travels along the top of the barrel until it exits.

Unfortunately, this video was removed from the public view soon after being posted.

BBBastard attempted to replicate this same test in their Real Time Airsoft Barrel Dynamics kickstarter campaign. However, it never received enough funding.

http://airsoftcanada.com/showthread.php?t=145636

Numerous other tests involving coated BBs and then milling off parts of the barrel revealed similar results.

Based on this, we can comfortably assume that the BB does ride along the top of the barrel.

We can explain the better long range performance of widebores by assuming that a larger bore means less surface contact of the BB with the barrel. This means less friction and thus less change in the angular momentum of the BB as it leaves the barrel. Additionally, the large bore and air volume provided by HPA systems will likely stabilize the BB from its bouncing stage in a shorter time and thus shorter distance as compared to a tightbore barrel.

[ThunderCactus]

Even assuming the BB really does travel along the top of the barrel, a wider bore may reduce contact area, but there hasn't been any serious test to prove widebores are any more accurate than tightbores.
We certainly haven't noticed any difference in the field. The aspect of a barrel that's made any noticeable difference in accuracy has been the quality/concentricity of the bore.

[airsoftmaniacman]

Originally Posted by ThunderCactus

Even assuming the BB really does travel along the top of the barrel, a wider bore may reduce contact area, but there hasn't been any serious test to prove widebores are any more accurate than tightbores.
We certainly haven't noticed any difference in the field. The aspect of a barrel that's made any noticeable difference in accuracy has been the quality/concentricity of the bore.

I agree wholeheartedly.

The quality of a barrel, or more specifically its concentricity, overall straightness, and rugosity (surface consistency) are far more important than its length or bore diameter.

I personally don't buy into the widebore hype, and typically use lapped PDI 6.08 for my HPA builds and lapped PDI 6.05 for everything else.

However, enough people have claimed better performance with a widebore as compared to a tightbore that this issue deserves looking into.

Far more important than the barrel is the ammo and hop-up. For a BB, if its mass, diameter, center of mass, and sphericity are perfect, then a more noticeable increase in precision can be seen.

For the hop-up, the amount of backspin placed on the BB, and thus its angular momentum, will have far more effect on range and precision than the bore diameter.

However, the only way to determine whether or not the widebore theory holds ground is to take a lapped 6.01/6.03/6.08 and compare it to a lapped 6.13/6.23 using BBBastard Pearls or similar ZrO2 bearings. The hop-up in this case will not matter since it would be turned off for a close range test. However, a long range test would create far more issues since it would be harder to standardize the hop-up unit.

[ThunderCactus]

Between 6.23s and 6.03s I haven't seen any difference in accuracy. The only factor of note is the 6.03s foul faster and lose accuracy due to fouling before the widebores do.

How did you find the PDI 6.08s? I worked on 3 of them and I thought their quality was completely sub-par for a PDI product.

[airsoftmaniacman]

Compared to my 6.05, the 6.08mm did not seem to have much of a quality difference.

However, I mill out the barrel windows on all of my PDI barrels into a square window, and I extensively lap (2000+ iterations) them. As a result, any difference in bore quality between the 6.05 and 6.08 is essentially nullified by the lapping.