.177 JSB 10.34

Thanks Shutik,

I found that prior to me tuning the magazine and polishing the lead in of my barrel I couldn’t push the 10.34 past 890, 870 seemed the most stable.

I suspected that the pellets were getting a little deformed or that they were getting scratched on entry to the barrel, so I broke out the micro files for the mag and the 3m fabric abrasive for the barrel.

I hit the lead with about 50 strokes and the the entire length to the twist about 10 strokes and finally the twist for about 5 strokes.

There was a noticeable difference when loading pellets, feels like it isn’t pushing a pellet in at all now, accuracy is now achievable at a higher speed, and at longer ranges.

I read a post of a wildcat shooting them at 920+, so I wanted to see if this was the norm or the exception. I am now getting 180 shots down from 200 at 875fps, about 1mag less, but at 180 shots per fill I don’t think that I should be too concerned as that’s a lot of shots for 1 fill!

So I removed the barrel oring and secured it in my gunrest, I then plugged the barrel with a pellet and filled it with Eezox, I suppose Ballistol or other suitable solvent would work..

I let it soak for about 5 min, during this time I prepared lengths of cotton packing string that I fold over 4 times and use as patches, lots of them...

Take a dowl, carbon rod or cleaning rod and push the plug out over the bin and drain. Next is to clean the barrel with pull throughs until they come out clean, I mean until there isn’t a trace of grey, you need as pristine of a surface as humanly possible. The tighter the patch the better...

Once clean you need to sacrifice a nylon brush to create an undersized jag by carefully trimming the bristles down as much as you can, you could use an appropriate punch jag but one really needs an undersized jag that you can wrap patches around not spike with a single patch. I thought about turning down a jag but picked up a three pack of nylon brushes for a third of the price of an aluminium jag.

The last part is to mount said brush on a rod and wrap 1.5 to 2 layers of 3m abrasive fabric around the brush, creating overlap at the points where metal joints are, I.e. the top tip of brush and bottom mount.

This wrapped brush is then inserted into the barrel and passed back and forth a few times in the areas I mentioned.

There are three grades of 3m fabric, get them all, use low grit first on the lead and transfer port hole, medium on the smooth bore part and finally the fine on the entire barrel including twist.

I had some JB paste and passed a saturated patch 5 strokes after I had finished the 3m.

Finally removed all solvents, polishing compounds and potential filings with a saturated Ballistol patch and buffed the interior with a pristine bore snake.

I like to wrap the little sting around my foot while holding the loop in one hand and the barrel in the other, then move barrel up and down over the snake about 100 times.

For the mags I used a dremmel polishing compound embedded wheel on the aluminium exit hole, and on the lip that guides the pellet in and I used 1000 grit sand paper wrapped around a 4mm drill bit on the carrousel grooves.

My reg is at about 108, as indicated by my Wika gauge, the valve adjuster is at 3.5 bars and my spring tension slider is at the default.25 distance, 18 mm.

When shooting.177 I only use setting min to A and min to 5, using max is too much force for the reg set point, results in no speed increase but much larger blast of air.

I feel that having the correct hammer tension range for a specific reg set point is important and sometimes overlooked with Impact tuning, the troubleshooting guide really helped in that regard.