DISCLAIMER: I DID NOT WRITE THIS COMPARISON. IT WAS TAKEN FROM TRADERSAIRSOFT AND WRITTEN BY MEMBER: RSP. ALL CREDIT GOES TO THIS INDIVIDUAL.I found this browsing another forum and found this to be very interesting, Information such as this should not be kept in the dark and should be widely known as it has always been a debatable subject for years. I've always like Prometheus (More widely known in the pistol world as Nineball) better as far as accuracy goes based on some theories I had about a better gas cushion propelling the BB straighter out the barrel than the tight tolerances of a 6.01. Of course, this can't be 100% proven due to BB Diameter is a BIG factor when dealing with GBB Tightbores as they act differently than AEG barrels. On a related sidenote; I've also found that Tanio Koba Rifled barrels work wonders in the GBB design.
Anyways....
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"When conducting an accuracy test with a pistol, it's important to be sure of what you're testing. For example, clamping the frame or grip of the pistol in place and firing away at a target tests how accurate the pistol will be for someone who uses the frame or grip to aim (which is useful for certain pistols using red dot sights anchored to the frame). The outer barrel, slide, recoil rod, and inner barrel will be moving in relation to the frame with each shot; as such you are testing the variation between inner barrel and frame in addition to the variation in the barrel itself. Most people use a slide mounted sight - that is, iron sights or an Optima 2000 type red dot, so in this test I will be using the sights on the pistol to align it for each shot (testing with variation between inner barrel and slide in play).
For this purpose I spent a few minutes constructing a crude adaptor for an old camera tripod. The adaptor consists of a piece of polycarbonate sheet which mounts to the camera tripod with a nut, then to the bottom half of a scope ring via two Allen screws. This allows the tripod to be used for anything with a Weaver or Picatinny accessory rail in a suitable location, including the Glock pistol to be tested.
I loaded the pistol's magazine with 10 KSC Perfect .25g BBs, a common brand and weight. Then I filled the magazine with unlubricated propane until excess gas spurted from around the fill valve. For general use, propane should be lubricated to maintain the O-rings of the magazine valves and piston head, but to ensure consistency of the tests unlubricated propane is best. After allowing the magazine to sit for 10 minutes for its temperature to return to normal, I locked the slide of the pistol back, inserted the magazine, and hit the slide stop lever to chamber the first BB.
My target was taped to a cardboard box, so that every BB would make a hole in the target, but not ricochet back through and distort the grouping. The tripod was positioned so that the pistol's barrel measured 20 feet away from the target. I aimed carefully at the center of the target, ignoring the three dots of the sights and instead focusing on the dark outlines of front and rear sights for the most precise sight picture. When satisfied, I locked the tripod's mounting bracket in place and fired. For the subsequent shots, I allowed 10 seconds for the magazine to warm, carefully checked the alignment of the sights, adjusted if completely necessary, and fired again.
When the test was complete, I removed the upper assembly from the pistol, leaving its frame locked into the tripod, and replaced the barrel with the First Factory unit. I then taped a new target in place and repeated the process exactly.
The results? Surprising. The PDI 6.01mm barrel grouped thusly (1" grid):
Whereas the First Factory 6.03mm barrel actually performed a little better:
On measuring the size of the groups, from center to center of the holes farthest apart, it turns out that the FF barrel produced a grouping of 28mm, while the PDI barrel came in at 39mm. About a centimeter of difference in group size at 20'.
I felt that another test was required to cement the groups. This time, I used the same testing procedures, but fired at 35' and with 15 shots. My hope was that the greater distance and number of rounds fired would lessen the possibility of error. Additionally, I considered the possibility of variance in assembly, and uninstalled and reinstalled the 6.03 barrel before performing more tests. For obvious reasons the 6.01 barrel would also be reinstalled.
Once again, the First Factory barrel outperformed the PDI barrel in accuracy. This time, the group produced by the PDI 6.01 measured 59mm, while the First Factory grouped a tad tighter at 50mm. So, the difference is not as great in this test, especially considering the increased distance, however the PDI still didn't beat out the FF.
Comparing products using a sample size of one is unlikely to produce exact numbers that can be applied over an entire range of products. However, I would cautiously conclude that, at least in a Tokyo Marui Glock with a barrel length of 112mm, a First Factory 6.03mm barrel is slightly preferable from an accuracy standpoint. The 6.01mm barrel can be expected to produce a bit more power in a gas gun, though I do not have a chronograph and so will have to wait until a skirmish to confirm this.
Of course, I am left to wonder why a 6.03mm barrel would have better accuracy than a 6.01mm barrel. The immediate answer which comes to mind is the quality of the barrel in matters other than interior diameter, and [url="http://www.6millimeter.info/joomla/index.php?option=com_content&task=view&id=150&Itemid=42"]this test[/url] offers one possible explanation. The pictures and a very rudimentary knowledge of German make it clear that a precise measuring machine was taken to a number of barrels, measuring their roundness. Scrolling down, one can see that PDI and Prometheus both were very close to a perfect microscopic circle, but Prometheus (AKA First Factory) was a little better. Notably, the PDI barrel beat out both DB Customs 6.01 barrels.
In conclusion, inner barrel quality is more than mere diameter - accuracy tests may bear this out. Both PDI and Prometheus/FF make great choices for inner barrels, but based on what I have observed in my testing and experience, out of the two PDI is the choice for power, Prometheus/First Factory for top accuracy. If you have a different testing procedure to suggest I would be happy to read it and if it is not too time consuming or expensive, try it out.
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Related comments in the thread on the subject:"It also backs up some off hand "testing" others have put forth which is that KM 6.04mm and PDI 6.05mm tight bores are more accurate than the PDI 6.01mms." -
hkssr20det"I think one of the key differences in the barrel designs can also account for the accuracy of the larger bore barrel. That deeply recessed barrel crown probably improves barrel harmonics, controlling vibration and increasing accuracy. My 6.02 Mulberry Field barrel in my g18c shot outstanding groupings and gave great range too. It too had the deeply recessed muzzle crown of the FF and KM barrels." -
twin_cam"My own uneducated guess upon looking at the difference between the crowns was that the deeper one would mean a more gradual widening of the barrel, so any effect on the BB's flight from an imperfection at this point in the barrel would be softened. I didn't think of it as responsible for the difference in group size, but since you mention the KM barrels with their excellent reputation for accuracy and your G18C barrel also shared this feature, it's definitely worth considering." -
RSP"Again I must point out that the 6.01 mm inner barrels are made for power, but are less accurate than looser 6.04 and 6.05 mm inner barrels. I don't see a reason why PDI - the manufacturer of 6.01, 6.04, 6.05 and 6.08 mm inner barrels - would lie about the qualities of barrels when they make all sizes. I would like to see the Nine Ball 6.03 mm inner barrel against the PDI 6.05 mm barrel, and maybe even the PDI 6.08 barrel.
PDI and Prometheus got near-perfect figures in that German test. Prometheus got higher marks mainly because it stuck to the nominal 6.03 mm value better, while PDI 6.01 was actually 6.02 mm. I don't think the difference in groupings that you shot comes from the manufacturing quality - these are both incredible pieces of engineering.
We know for a fact that there has to be a clearance between the inner barrel and BB. A too tight inner barrel would interfere with the hop-up spin. How small can you make the gap? Looks like 6.01 leaves too little clearance with KSC BBs. It would be interesting to see how Excels would group with these barrels, since they are smaller than other BBs.
When I shoot groupings, I shoot five shots in one string, and several strings to various targets. I've shot 30 mm groupings with five shots from 10 meters (33') off-hand with an airsoft pistol, so I'm quite confident about my findings even without a shooting rest. This is the best accuracy I've seen from a self-loading airsoft pistol, and it was mainly the result of a "compensator" mounted on an extended frame, with an O-ring inside to hold the inner barrel tightly supported. Freedom Art makes those." -
Sale"Your comment regarding the offhand 10m group bears out the importance of consistent postion of inner barrel and hop-up unit in relation to the sighting device after each shot. I've been looking carefully at anything I can do to improve fit in the relevant parts. Currently with this G34 the slide to outer barrel fit is secure and the strong recoil spring pushes the outer barrel axis down slightly into the bottom of the slide, wedging it in place. From there it's a matter of inner barrel to outer barrel fit, and I think I might play around with O-rings and see what I get. On the other hand the slide to frame fit has a little rattle so I wouldn't be surprised if I had a noticeable loss in accuracy with a frame-mounted red dot." -
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