Those that know me know I am kind of particular. On October 29th, I drafted a post regarding the purchase of a new HW97 from Krale as a "project rifle." And while the experience was great in all regards, and the tuning results were very good, up to now, I just wasn't quite satisfied.
I hated to tear it back down after just getting it together, but while shooting it on Friday, it all of a sudden developed a "dieseling" condition, and it wasn't just one shot, it was routine. It bumped the Predator GTO 6.79 grain pellets from about 970 to +/- 1050. It cracked like a .22.
This was all of the excuse I needed to tear it back down - completely - every power component. While I didn't find anything that would cause the dieseling in the power plant, the barrel had a heavy black sludge come out of it. It took a half hour and several patches to get it clean. I have no idea where it came from as I cleaned the barrel right out of the box, and I only use Balistol to clean with, but however it got there, I think the sludge must have been the culprit.
I wanted to shorten the stroke up slightly, so I sanded off the stem guide of the top hat about the thickness of the two 10MM stainless steel spacer washers I inserted ahead of the top hat upon reassembly. The Vortek seal appeared as new. I relubricated everything very lightly with Air Venturi's tune-in-a-tube, a product I have had very good luck with.
Upon completing the reassembly, I installed a Rowan Engineering cocking handle, which made a very nice difference in the cocking effort.
Once I had everything back together, all of the stock screws coated with Vibratite and locked down, and the Vortex 6-24x50 Diamondback scope back in place on top of the Sportsmatch fully adjustable mounts, I spent about 15 shots getting it zeroed back in.
The final results can be seen below. They are about as pretty and round of a group as I could hope for - no evidence of vertical or horizontal stringing. FYI, I did try the 2nd best performing pellet of the dozen or so I tried with the original rifle acquisition, and while very respectable, nothing like what you see below. If you haven't tried the GTO series pellets, while twice as much as a conventional pellet, I have had very good luck with them, especially in .22 caliber.
Good luck, and thanks for taking time to review this information.
I hated to tear it back down after just getting it together, but while shooting it on Friday, it all of a sudden developed a "dieseling" condition, and it wasn't just one shot, it was routine. It bumped the Predator GTO 6.79 grain pellets from about 970 to +/- 1050. It cracked like a .22.
This was all of the excuse I needed to tear it back down - completely - every power component. While I didn't find anything that would cause the dieseling in the power plant, the barrel had a heavy black sludge come out of it. It took a half hour and several patches to get it clean. I have no idea where it came from as I cleaned the barrel right out of the box, and I only use Balistol to clean with, but however it got there, I think the sludge must have been the culprit.
I wanted to shorten the stroke up slightly, so I sanded off the stem guide of the top hat about the thickness of the two 10MM stainless steel spacer washers I inserted ahead of the top hat upon reassembly. The Vortek seal appeared as new. I relubricated everything very lightly with Air Venturi's tune-in-a-tube, a product I have had very good luck with.
Upon completing the reassembly, I installed a Rowan Engineering cocking handle, which made a very nice difference in the cocking effort.
Once I had everything back together, all of the stock screws coated with Vibratite and locked down, and the Vortex 6-24x50 Diamondback scope back in place on top of the Sportsmatch fully adjustable mounts, I spent about 15 shots getting it zeroed back in.
The final results can be seen below. They are about as pretty and round of a group as I could hope for - no evidence of vertical or horizontal stringing. FYI, I did try the 2nd best performing pellet of the dozen or so I tried with the original rifle acquisition, and while very respectable, nothing like what you see below. If you haven't tried the GTO series pellets, while twice as much as a conventional pellet, I have had very good luck with them, especially in .22 caliber.
Good luck, and thanks for taking time to review this information.
