Evanix Tactical Sniper

[QVTom]

dogwood,  I don't know your crony string but it seems that you could back out your hammer tension a few turns.  It would lower the velocity of your first shots and conserve some air pressure for the last two.  Might even the vertical stringing some.

Are the major grid lines one inch?

[dogwood]

Thanks Tom, yes the major lines are 1"

I haven't gone back to trying to tune it better yet. This is just where it was when my pump started acting up.

[QVTom]

Pull up the two lower shots up and you have a decent group with some horizontal stringing possibly due to wind conditions.  Your are getting close.

Interesting about the barrel band, shroud and tube alignment.  I happen to be working on a rainstorm receiver today, before fitting the new barrel I decided to spend some time checking the geometry on the CMM (coordinate measuring machine).  The bore of the barrel and valve block are in perfect alignment with the bottom surface of the receiver.  The barrel bore has and angular misalignment  of 0.0001 per inch with the sides the receiver (horizontal) which is very very good for a commercial product.  The method of threading the shroud to the receiver is very rigid, I really don't see  a need for a barrel band in their design and will probably open up the shroud clearance of the band on on this rifle so it does not touch the shroud.  The Sniper may be different but the overall design seems very similar.  I guess my point is, with the rigidity of the shroud I don't see the flexible barrel forcing the shroud out of alignment. More the other way around.

Tom

[dogwood]

Sounds like you have access to some fun tools Tom 

You make a interesting point about the shroud and barrel and most likely I will do what you plan on doing and open up the barrel band. Right now it's just hang in off to the side out of the way.

C.ALLS did seem to have success shimming, which means he was able to bend the shroud with the barrel, doesn't seem like he should be able too but he did 

[QVTom]

I just found this, It may shed some light on C.ALL's and your's issue.  It may not be the barrel that needs shimming but the shroud is not square like mine.

http://www.gatewaytoairguns.org/GTA/index.php?topic=63424.msg611144#msg611144

[dogwood]

interesting find, went and checked mine, nope not my problem.

My barrel slopes downward at the muzzle, the gab between the reservoir and barrel gets smaller. 

[C.ALLS]

Sounds like you have access to some fun tools Tom 

You make a interesting point about the shroud and barrel and most likely I will do what you plan on doing and open up the barrel band. Right now it's just hang in off to the side out of the way.

C.ALLS did seem to have success shimming, which means he was able to bend the shroud with the barrel, doesn't seem like he should be able too but he did 

Pretty sure you don't get what I'm saying which is understandable as it's hard to explain. See if this post from the other thread helps.

"When you screw down your barrel stops on top of the breech you're pushing the barrel down to rest on the bottom of the breech bore. I put my .1mm shim at the end of the breech bore between the barrel and the breech which raised my barrel end and aligned it with the shroud. You'll notice when the barrel set screws are loose the barrel to breech clearance is rather large and seems to get tighter down towards the transfer port. My shim raised my POI down range as well and allowed my scope to be adjusted closer to it optical center. "

[dogwood]

forgot what I was doing and replaced the spring - shot some over the crony and tuned it up a bit.
Much windier today with swirling winds thrown in. 
Tuned it to spit JSBs out a bit faster  - little over 800 fps



shot at 50 yards, last shot (7) is in the lower right, not sure what happened there. really seeing a difference with the barrel band removed.

[dogwood]

ran a last minute before dark grp.  backs up the previous grp I do believe
I did all the adjustments before shooting, 2" up and 1/4" left - which in my book means things are getting very repeatable.
I think I missed labeled the outlier - 6 I think is really 5.  Not sure what happened but I'm going to blame it on me, same for 1, that was a  quick shot.
Still really windy, these guys buck the wind pretty good - shot 7 is out of frame - but I was aiming at something else and the pellet went right where I was aiming

[Fur-n-dirt]

You've got a lot of patience!

[Nomadic Pirate]

You've got a lot of patience!

LOL, been thinking the same

[rkr]

Looks like your gun is starting to group, is this without the barrel band and shroud now - free floating barrel? I also got some fliers on my 20 yard tests, 4 shots in about 1mm ctc / 10mm hole and then suddenly a flier that opened up the hole.

[dogwood]

NO barrel band, but is with shroud and my extension.

[dogwood]

well it's trying my patience 

cooler today but little to no wind. Groups were bigger and I had more fliers.....

looked at the barrel and it was leading pretty good, so I decided to clean it, this is what I found:


Mind you this is the second patch through, the first had even more on it but was so dark I couldn't get a clear picture, those are lead shavings. I had found them on the previous cleaning and rounded the edge of the port inside the barrel, apparently I either didn't do it enough or there is someplace else shaving the pellets.
I rounded the port some more and polished the heck out to the leade in. I then ran several patches with grit from my fire lap kit, med. then fine and finished with JB - much smoother and shiner  - we'll see if it stays that way.

[rkr]

well it's trying my patience 

cooler today but little to no wind. Groups were bigger and I had more fliers.....

looked at the barrel and it was leading pretty good, so I decided to clean it, this is what I found:


Mind you this is the second patch through, the first had even more on it but was so dark I couldn't get a clear picture, those are lead shavings. I had found them on the previous cleaning and rounded the edge of the port inside the barrel, apparently I either didn't do it enough or there is someplace else shaving the pellets.
I rounded the port some more and polished the heck out to the leade in. I then ran several patches with grit from my fire lap kit, med. then fine and finished with JB - much smoother and shiner  - we'll see if it stays that way.

Have you tried loading those pellets straight to the barrel and not using a magazine? That would eliminate one potential source where pellets could get shaved.

[dogwood]

Good idea rkr, i'll use my load tray tomorrow and then check it after shooting a few rounds

[rkr]

Good idea rkr, i'll use my load tray tomorrow and then check it after shooting a few rounds

Post some results, I'd like to see what effect the barrel cleaning and polishing had. If it groups well with the tray try some groups feeding from the magazine to check if that's your problem, I just realized that I was feeding JSBs from the magazine when I had those flyers ... come to think of it - a simple reason could be that the magazine is just not centered right in the middle.

[dogwood]

 made a new spring and shot some over the chrony... 200 BAR fill, JSBs
805.1
821.3
825.6
819.5
809.3
805.7
790.7

then shot a grp at 50 yards - tad over 1" on the vertical and with the flier just under 1.5" horizontally


I didn't find any shavings after shooting with the tray, haven't check yet after shooting with the mag again.
need to shoot a grp with the tray and see if anything changes.

[dogwood]

Doesn't seem to like being tray feed 

[dogwood]

put a coat of black ceramic on the shroud extension today