Here is the 30 cal slug tuning report.
If you want spec of my gun, reed my first post, its all there.
1. I did notice that when I was loading slugs, as specially smaller, shorter 44gn NSA slugs every few loads they did not chamber as easy as others, after looking in to it I figured out that smaller shorter slugs, do grind on the hole in the barrel transfer port, the stock one with one round hole and they get scraped off, deform and later don't fly as good as others, to solve that I got myself Huma high flow dual port with bridge in the middle to support loading shorter slugs and that made loading smoother, port size did not effect speed, I still get same FPS, FYI.
2. I upgraded my hammer. After tuning I figured stock Crown hammer maxed out at 140BAR reg. and about 830FPS on 44gn slugs, so I got me 8.5 gramm hammer, stock spring and I got my speed up to 900fps, and I was able to get up to 940FPS with 155BAR but I also wanted better shoot count, so I scaled down to 150BAR and 900FPS, thats where I am at now.
3. I installed carbon fiber sleeve on my liner, I believe all my issues with flyers was due to the liner vibration "harmonics" and also when I took my liner out and rolled it on the flat glass it was not straight, on 600mm liner I had bow in the middle about 1/16", I needed to straighten the liner and get rid of that harmonics mixed with bowed liner, also I don't think liner supports from the factory are not ridged enough to compensate vibration produced from slugs with more contact surface to the liner VS pellets, thats why pellets shoot better, because they produce less friction and less harmonic note, thats just my train of thought. So liner needed some rigidity and I got carbon fiber sleeve from ebay, 2MM thick wall, I had to sand it down some inside to get it to fit snug but results was amazing, liner bow was straighten and after clocking barrel my spread was only 1/2MOA VS 6" before sleeve, so that killed two birds with one shot
I am only using one liner to shroud support now at the muzzle, rest of the liner is free float.
4. As I mentioned above UTAH airguns confirmed my 30 cal 600mm 1:22 twist liner is a heavy liner (later they released 1:18 and recently 1:16 heavy liners) but my lined still considered slug liner medium to light slugs, so I got me NSA slugs of all sizes from 44gn to 65gn and started testing.
5. Here are the results. Gun shut awesome (see pictures below) I shot 3 shot groups with 44gn NSA slugs and 47gn NSA slugs. ignore red X group, that was me zeroing. Top 8 groups are 43gn and bottom row of 4, 47, seems like 43 did slightly better.
I shot this at 50 yard. I consider this a huge improvement over all, same time I shot off of the bag, so there is some human factor, I am sure if I put my gun on the stand I can get better results.
More to come...
