If you look at the inside of the gun, you will notice that when the front bolt is in its most forward position, it goes into the barrel adapter before the gas is expelled. If the valve pin were fully compressed to the point the hammer hits the face of the valve (this usually doesn't happen), the front bolt will actually go into the barrel very slightly. The Freak kit has straight tubular inserts that resemble cannoli forms and can be quite small in bore size. Most front bolts aren't that small, so there is no risk of the front bolt damaging the insert. However, their outer o-rings are usually larger than the inserts, so the front bolt may get stuck depending on the insert and front bolt used. Most barrels don't have to worry about this because the breach end of the barrel tapers down to the control bore after a short distance. To avoid this problem, Smart Parts added extra length to the breach end of the barrel back.
If we compare the ION barrel back to the A5 barrel back from the end the barrel front connects to, you can see the difference in length. Both backs have the insert butt up against the front, so the distance is the same. On the ION barrel back, the insert sits flush against the breach end of the back and is exposed, as you can see below.
Now keeping that in mind, take a look at the A5 barrel back. All of the extra barrel length is what was added. If you look at the inside of the A5 barrel adapter, there is a small amount of bore that the front bolt passes over that prevents the barrel from screwing completely through it. Where the two meet creates a lip and the bore is too large for the ball before it even gets to the control bore.
If you look at Scoreshot's picture, you can see the point at which the ball enters the control bore of different barrels. The barrels from left to right are the Freak, Hammerhead, and Palmer's.
As you can see, the ball doesn't create a good fit until later on in the barrel and at different points depending on the barrel. Scoreshot's idea of bringing the control bore as close as possible helped me find Lapco's ION to A5 barrel adapter. It lets you connect ION threaded barrels to the A5. I would post a link but it appears that they have just recently removed the link.
As you can see, Lapco also made their adapter longer to avoid the front bolts entering the inserts. This is what it looks like on the gun installed.
Although the barrel adapter is longer, the overall barrel length is reduced when installed.
I took the stock setup to the chrono and then swapped them out and here's the data I got:
As you can see, the difference in performance is staggering! It improved in all areas. The velocity increased, it's range and standard deviation were cut in half, the barrel was made shorter, and the sound was more crisp.
What this barrel adapter does is remove the extra step that the barrel back creates before the ball reaches the control bore. It also brings the control bore closer to the ball and helps eliminate blow-by gases.
I don't know how it will perform with breaks or accuracy as of right now, but as soon as I try it out, I will let you guys know.
EDIT: There is an update to this post later in the thread here: http://www.techpb.co...w...st&p=453213
Edited by Lord Odin, 03 July 2009 - 09:15 PM.