This was posted in http://www.tippmann.com/forum/wwf77a/forum_topics.asp?FID=1 - New Player Forum  by Beawolf under the subject

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Look through the following it will help

Flatline "How to" and Review
 debunking the myths, here's the real deal:

Having seen many questions on the OSOK forum, about the Flatline, I had posted info on
the board before, but the same questions keep popping up over and over. Here's the way to
assemble and operate this barrel system.
I have played with the Tippmann Flatline, (will be called "TF" Sniper rifle from here out), for a
little over two years now, and I also use a Flatline Autococker, (will be called the "FLAC" Sniper
rifle from here out), for about three and a half years. Let me clear up some things about shooting
characteristics.
Starting with the TF:
1. MYTH: "The TF shoots far, but is not accurate"
FALSE: The TF has a learning curve associated with its use, you have to get used to how
to shoot the marker. 1st when you shoot make sure the marker is not leaning left or right,
otherwise the ball will drift in the direction of lean. The barrel imparts backspin to the ball
this gives it the "magus effect", (lift), the axis of spin acts as a gyro, if the balls spin is
tilted left or right, it then "lifts" in that direction, (once you get used to how the gun
shoots you will learn to lean the marker to curve around bunkers and hit players behind
them, the curve is not great, but sometimes what the straight-on shot will miss, the curve
will get). The TF IS very accurate once you learn to shoot it and assuming you are using a
quality paint, The best I have found are the small diameter paints, i.e. Marbilizer, (best in
summer weather or temps over 40 degrees), and Anarchy's, slightly less accurate but a close
second and also a good cold weather ball, temps below 40 degrees, (Marbs break to much
at these temps). (There is a new ball coming out from RPS called "Flash" that is supposed
to be perfectly round, I will let you know what I find, when these become available).
The Maximum consistent effective range is about 180 feet, after that you have to hit a hard
object on your target for the ball to bust. This is about true for any paint marker, since the
balls velocity has dropped significantly due to air resistance.
Elevation of the marker is "0" up to 150 ft, meaning you don't compensate for ball drop,
this is the hardest to understand for most people who have shot regular markers before.
After 150 ft, compensate 1" per 10 yds.
I can constantly get 10"-12" group at 180 ft, this is good for center of mass on most
players, 8"- 10" at 150 ft, 4"-6" at 100 ft, guaranteed head shot at 70 ft, (mild or no wind).
One thing to remember, it's still paintball and is not perfectly round, so I save the fancy
"Head shot" shooting to ranges under 70 ft. These groupings are with a prone firing
position, bi-pod, scope (zeroed at 150 ft), HPA with reg, A CLEAN BARREL, and
proper barrel installation, (see below).

2. MYTH: "The Marker shoots like crap at 300 ft/sec".
TRUE: The best ft/sec for a TF is about 280 ft/sec, this speed gives the "flat line" effect.
Speeds above that makes the ball float up, then down, speeds below decrease the "flat
line" range by about 10 yds. per 10 ft/sec drop in velocity, at 250 ft/sec or lower all
advantages of the TF are lost, some scenarios make 250 ft/sec the max for night play, this
limits the max effective range of the TF to about 100 ft, (considering it is dark also, and
unless you have night vision, is about the practical limit at night), I usually change to my
Regular Autococker with a 18" Dye barrel or ZERO Gravity barrel 12", the Zero is more
accurate, but the DYE shoots quieter, (but that's another story).
Notice I say "about 280 ft/sec" above, this is because of the environmental/physics of
projectiles. The best way I have found for finding the "Sweet Spot" is adjust the velocity
screw upwards gradually, until the ball starts to "float up" then back it down, (small 1/4
turns), until it quits floating and flattens out. You will find that when you chrono you will
be on or close to 280 ft/sec., Barometric pressure, humidity, HPA vs. CO2, ball type and
size, pressure regulation all have an effect on what speed will "flatten out" your balls
trajectory, at a certain velocity, but all in all, the velocity will be around 280 ft/sec
+/- (5-8ft/sec).

3. MYTH: "The TF breaks balls all the time, and you can't shoot it fast"
FALSE and TRUE: Starting with ball breaks, you MUST SEAT THE BARREL
CORRECTLY. 1st To seat the Barrel correctly, you must separate the halves of the 98
into its halves. 2cd The barrel seating clamp threads should be wrapped with Teflon tape,
then Lay it into the barrel seat of the receiver and seat it all the way to the rear of the
receiver, no gaps, make sure its all the way back, DO NOT SCREW IT IN!!!. 3rd replace
the halves and screw them back together. 4th with the barrel screw in the barrel clamp not
tightened push the barrel into the barrel clamp and make SURE you push the barrel all the
way back into the clamp, make absolutely sure it is seated all the way in. As far as
shooting fast is concerned, I wouldn't try to shoot more than 3 balls/sec, more than that
and I think that the balls get hung up in the curve, hit each other and pop.

These are some other observations and recommendations, You can't reliably zero the scope on
the plastic shroud, (you can initially, but the first time you bump the scope, it's out of zero).
I highly recommend the metal shroud, sold buy the Tippmann pro shop, it's a much more stable
than the plastic, further a even better stabilizing trick is to mount small aluminum block under the shroud that attach to the top of the marker, and then drill/tap through the top of the shroud into the aluminum block that will give you a positive mount of your sight rail, that you can then attach your scope rings to. IF you shoot CO2, I would highly recommend an expansion chamber.

The FLAC Sniper rifle, is basically like the TF above, but, In my opinion it shoots tighter, the
above shot groups are reduced by 2" per stated range, head shot at 90-100'.
I think the barrel/receiver interface, and barrel quality are MUCH better in the FLAC. The down
side of the FLAC is that of all cockers, When they are timed right, there is not a better shooting
marker on the market, BUT, you have to know how to time and futz with cockers to achieve this.
If your not a cocker mechanic, stay away from this gun, or you will cry a lot.
I am a cocker mechanic, and I like to fiddle with it, both are needed to use it.
I use my TF as my back up marker, when I have major probs with the FLAC, since with a
Tippmann these markers are low maintenance, and sometimes when the FLAC is acting up I just
go with the simple, reliable TF. For speeds of less than 250 ft/sec I use a straight barreled marker.

when firing the marker for the first time after seating the barrel/receiver, make sure the barrels curve is at Top Dead Center, there is a mark on the tip that notes that, lightly tighten the clamp. Place the marker on a gun rest, and sight in, (use iron sights), I also recommend a target at 20 yrds. fire off a few rounds see where they are striking the target. (make sure gun is perpendicular to the level ground). watch how the balls are flying, if they are drifting to the left, rotate the barrel clockwise as viewed from the firing position, only 2-3 degrees, until the balls trajectory does not drift, (use quality balls), If it drifts right, turn the opposite, make only SMALL adjustments!!, tighten the clamp screw on the barrel. Once drift is corrected, and velocity is at 280 ft/sec, (no ball float, with Flat line trajectory). Note: use a metal scribe to mark the position of the barrel in relation to the barrel clamp and marker body, "Witness marks". That way the next time you take it apart and put it back together you can just line up the marks and be at zero. That being done, you can now mount the your scope, and zero it, on your target at whatever range you like to shoot at. An adjustable gun rest and stable shooting platform really helps the initial marker barrel adjusting, (you can make a home made gun rest with sand bags). once the barrel rotation is set, tighten the barrel clamp screw. Now you can really reach out and touch some one...hee...hee.

The article parallels the experience I have had with the Flatline and my testing was indoors. As I have said in previous posts about both the Flatline and the Apex, at those long ranges, though still flying with a nearly flat trajectory, the paintball has been in-flight so long that any little wisp of air movement has time to impart motion to the ball.

What this and my test information says is that nothing about the barrel design degrades its accuracy. The point is that you can make shots with a Flatline that you would not attempt with a conventional smooth bore barrel. At such extended ranges wind drift becomes the prevailing factor in accuracy...not some inherent defect in the design or function of the Flatline.

A smooth bore barrel trajectory is, in-fact, effected more at such long ranges due to its lack of stabilizing spin on the ball (a knuckle ball thrown by a pitcher has similar flight characteristics). But, we seldom take those long shots because it requires such high angles of elevation of the barrel to even reach those distances. At best, such high arching trajectories make it difficult to align with the target. And  such curved trajectories make it difficult to see the fact that the ball was moved left or right by the wind. The extremely flat trajectory of the Flatline or Apex barrel makes it easier to actually see that the shot moved left or right...missing the target.

The rumors of Flatline inaccuracy make people believe that a conventional ranges the Flatline misses more than most smooth bore barrels. The fact is, from test firing nearly a thousand rounds indoors, 50 to 100 foot accuracy is equal to or better that with most smooth bore barrels. I have attributed this to the gyroscopic stabilization that back spin gives to the ball.

In my controlled tests using industrial warehouse fans, I found the back spin actually seems to improve close range accuracy when it is windy, preventing drift from every whim of the air currents. (again, the knuckle ball drifts up, down, right and left due to lack of stabilizing spin)

With "bad" paint a Flatline will give you some spectacular flight paths. I have been amazed at some of the almost beautiful corkscrew spiral flight paths when using old dimpled or oval shaped paint. But, with fresh uniform paint I have found the Flatline to provide superior accuracy at any distance.

Snake6 wrote: Overall, it is a good article. However I believe that the accuracy tests seem a little skewed. It is quite possible that these tests were conducted indoors where there is no wind, under ideal range conditions but none of the flatlines I have ever bench-tested outdoors have had groups like that. On every flatline I have every tested (all correctly installed) I have never gotten anything better grouping wise than 15-20" at 150ft(measured with a 100 yard tape), with about one ball in ten going stray due to wind. The wind effects the Flatline alot more than the fact other barrels due to the fact that the balls move rather slow once downrange. IMO these tests were not conducted in a way that would show proformance in-game, they were conducted in a way to make the barrel seem more accurate than it really is.

I totally agree with you.  I have a flatline for my a-5(which i don't use anymore) and my brother and friend both have a flatline for their 98c.  We all know how to install our barrels and knew about the whole leanning effect and we also used marbs. There is no way you can get a 4"-6" grouping at 100ft.  My backyard is 90ft wide so i've done alot of tests from that range.  At that range, its more like 14"-24" grouping.  4" is about the size of a closed fist, thats hard to do with a barrel that shoots straight. I'm thinking the measurements must be off or way over-exagurated.

hey,

   I have a flatline and I haven't used it in months because it shoots crazy curve balls.  I'm going to hope this is just from the paint, but I don't have the money for marbs so what tipe of cheeper paints work well in this barrel????

P.S I have found out that the A-5 stock barrel is worse at any given range, by far.

A-5Mitch wrote: hey,    I have a flatline and I haven't used it in months because it shoots crazy curve balls.  I'm going to hope this is just from the paint, but I don't have the money for marbs so what tipe of cheeper paints work well in this barrel???? P.S I have found out that the A-5 stock barrel is worse at any given range, by far.

The a-5 stock barrel is more accurate than the flatline.  I'v been using the flatline for almost 2 years and then finally i took it off to see how it was like to shoot a normal barrel.   So, i put the stock barrel back on and a noticably difference in accuracy.  It was way more accurate.  I compared it to my brothers lapco bigshot 7.5" and it was about the same, but seemed as if the stock barrel shot a little more accurate.