With the 9.1, I instantly upgraded to the Rifled Barrel (LAPCO manufactured, Tiberius Sold) and I faced some serious issues. The first major problems I faced were Barrel Jams and Velocity Consistency. I sent the gun into Tiberius Arms for them to check out. The found that the o-ring (factory supplied) between the body and the ASA was of the wrong durometer (hardness), resulting in it getting squished and restricting the air path. They returned the gun to me, and I still had problems but, they were slightly reduced. I later found the barrel jam problem to be the result of heavy use (100+ shots) between barrel cleanings. Once I got past that, I dubbed it "Totmacher 9.1SD" and I started using the marker regularly (to include LL4).
However, one problem always remained- Velocity consistency. This gun has never felt to be anywhere near the consistency of my 9.0. I've had the suspicion for awhile now that the cause of the inconsistency was the gun's reg. The T9x regs are 'un-balanced' meaning that a rise in the input pressure will result in a rise in the output pressure. When it comes to unbalanced regs, better regs have a better ratio. For example, Palmer's regs are claimed to have a 72:1 (input:output) ratio so, it would take a 72 PSI change on the input to register a 1 PSI change on the output. Regs also often have an optimal adjustment range (# of turns) and if you adjust outside of this range (i.e. all the way in, or out), you begin to see output inconsistency.
When you switch to the Rifled Barrel, you have to increase the output of the reg usually by two or more full turns, to get your velocity back up. I suspect that this adjustment puts the reg out of it's optimal adjustment range, leading to a decrease in consistency. To confirm this, I also tested a Ninja 45ci tank with an SHP reg. The higher input pressure to the gun means I don't need to have the gun's reg turned as high so, it should be closer to it's optimal adjustment range.
That's all the theory behind the test, now let's get down to it. The test setup:
Tiberius T9.1 with
- Polished "firing pin/bolt"
- Ported ASA/Body oring (increased flow between ASA and body)
- Ninja 45ci (standard- 850PSI)
- Ninja 45ci SHP (~1100PSI)
- LAPCO STR8Shot First Strike Ready T8.1/T9.1 - 16" .690
- Tiberius Arms (LAPCO) 9.1 FSR 14" Rifled Barrel - 0.683
My Lovely Assistant (Girlfriend) and I would chrono the gun into the 270s and then, I'd fire a shot, she'd write down the FPS for a 20 shot string. We did this all within the span of an hour (10-11 am) and there no significant changes in the weather. We shot the following configurations:
- T9.1 with .690 Barrel and Ninja 45ci (standard)
- T9.1 with Rifled .683 Barrel and Ninja 45ci
- T9.1 with Rifled .683 Barrel and Ninja 45ci SHP
- T9.1 with .690 Barrel and Ninja 45ci (standard) FPS Standard Deviation: 4.68
- T9.1 with Rifled .683 Barrel and Ninja 45ci FPS Standard Deviation:12.72
- T9.1 with Rifled .683 Barrel and Ninja 45ci SHP FPS Standard Deviation: 8.36
The gun is clearly less consistent when using the rifled barrel. The decrease in the rifled barrel's SD while using the higher output SHP seems to indicate that the problem does in fact exist in the gun's regulator. Further testing with an even higher output tank reg would confirm this.
Now, maybe those numbers don't quite speak to you. Well, let's see what these SD's mean in regards to trajectories:
In the following graphs, The blue line indicates the perfect 280 FPS trajectory. The red line shows the upper edge of where 68% of your shots will fall while the Grey line shows lower edge. Keep in mind that this is only the 'majority' of your shots. To get a rough idea of where all of your shots will spread to, double the widths of the tracks. These tracks continue to get wider, at the same rate all the way out to the maximum range.
T9.1 with .690 Barrel and Ninja 45ci (standard)
T9.1 with Rifled .683 Barrel and Ninja 45ci
T9.1 with Rifled .683 Barrel and Ninja 45ci SHP
So, with the rifled barrel, and my regular output Ninja tank, firing at a target 50yds away, I could see my first shot fall 10" low, and then I compensate by aiming 10" higher, only to have my shot go over the target by 20". In real world situations, I have had this happen.
Edits: Fixed Links, and spelling
Edited by UV Halo, 27 November 2011 - 07:28 PM.