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Old 08-14-2012, 03:50 PM   #527 (permalink)
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Join Date: May 2008
Location: Eureka, California

Originally Posted by CCMachinist View Post
I have done most of my shooting with 12 gram and paint just to make sure the gun works. The set up has been very reliable and really consistant for 12grams. The FS is much better than the paint within about 7fps

But if you want really close consistancy, hpa remote has been the best.
each time we tried it over the chrono its been within 3fps. Trinity can chime in here. We did this on saturday.
I have been watching the discussion over 12 grams for awhile now and Bill and I talked a lot about them this past weekend. I have a lot of experience using them with first strikes. In fact, for the past two years that's all I used with first strikes in the T8, T9, and T9.1. There are a couple of reasons for that. First, I desperately wanted to be done with remote lines, whip lines, and refilling HPA tanks so I jumped at the chance to use 12 grams.

Second, the T8 and T9 were my entry point into using first strikes and the T9 didn't have an easy, convenient way of using a remote line. Using 12 grams meant that every mag in my vest was interchangeable with both guns. When the T9.1 came onto the scene, I simply continued doing what I was doing. Continued, that is, until the Tiberius/Lapco .683, rifled barrel came along.

The new small-bore barrel required a major increase in the reg pressure to force a first strike down the barrel. Using 12 grams, I began to see some wild swings in the velocity of the T9.1 In my experience, swings in velocity clearly impact vertical accuracy and I was seeing the results of those swings on the field in the form of misses that should have been hits. Misses that were dead-center accurate but impacting higher or lower than they should have been for the range I was shooting. I started checking the gun against the chrono more carefully. I found that 10-15 FPS swings were pretty common using 12 grams with the small bore barrel. In large part, that was probably because the Tiberius regulator was probably outside of its optimum pressure level, but the 12 grams were also a contributing factor.

Guys like uv_halo on this forum and Chicago on the Tiberius forum were doing some parallel testing that seemed to verify my own work. The remedy to the swings was to double reg using an HPA tank. Using a 3000 CI Ninja reg set at about 400 PSI, my swings in velocity dropped to 5-7 FPS (so about a 50% improvement). It got even better when I dumped the small bore barrel and went to the .688 rifled Hammerhead barrel.

Similarly, I have shot both HPA and 12 grams through two different SR1s. I have nothing that I would characterize as definitive test, however, I have put about a dozen rounds over the chrono with both prototypes using both HPA and 12 grams. I believe that there is a definite consistency difference between using 12 grams and HPA with a second reg.

My initial impression is that the SR1 is more consistent out of the box. With 12 grams and first strikes is about as consistent as the Tiberius gun is when it is shooting first strikes and using the appropriate HPA tank - maybe about 7 FPS on average.

The SR1, shooting first strikes, using HPA has velocity swings of only about 2-3 FPS. In fact, two weeks ago when I first started using HPA I thought my chrono was broken because for the first three shots with the SR1 using HPA, the FPS was exactly the same. Then it varied by 1 or 2 FPS with one swing of 3 FPS.

I am calling this up from memory but I think uv_halo posted a ballistic graph for first strikes dealing with the vertical drop between first strike rounds travelling at different velocities. As I remember, that chart reflected that at 25 yards the difference between two first strikes travelling at 5 FPS difference was about 1 1/2" and 3" with a 10 FPS difference.

The ultimate question for anyone using either Tiberius rifles or the SR1 is whether the difference in vertical accuracy is important enough to you to go through the bother of using a remote line with HPA. Remember though, that the ballistic chart I mentioned above was measuring the differences at just 25 yards.

Last edited by Trinity; 08-14-2012 at 04:42 PM.
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