[Old Man Dave]

Been doing some more testing. Fitted my 140cm x 6.5mm diameter spear in place of my 125cm x 7mm diameter spear. This spear was now rigged with 160lb mono to the rear hole rather than with a line slider. This was the set up from my original Beuchat gun and the one which was so inaccurate when I fitted 20mm rubbers. So I was keen to see if my new wood hybrid stock with rail would sort out the problem. Bear in mind that the hybrid with the 7mm and line slider + 20mm rubbers was within 2 inches at 8 foot.

Right, well results were crap. At 8ft the spear hit 9 inches low and 1 inch left. Just about the same as the beuchat. Even at 6 ft and with the rubber on the front notch it was 6 inches low and 1 inch left. Hopeless for hunting.

So what's going on. Well I think Foxfish might be right about the line slider. It doesn't seem to be the problem. The 6.5mm spear doesn't seem to handle the power of the 20mm bands. Also the Mamba, as Mart mentioned, uses a line slider and is very accurate. However next step will be to target shoot both spears with no line and see what the results are. Will need to find somewhere suitable so I don't loose the spears.

All this got me thinking and so I decided to test the flexibility of both spears. De-rigged them and in my shed set them up spanning 2 concrete blocks. I hung a 4lb weight mid span and measured the deflection. I was really surprised at the result. The 7mm diameter spear bent 2.5cm while the 6.5mm diameter spear bent nearly 6cm. Even under its own weight the thin spear bent noticeably where as the thicker spear was dead straight. Incidentaly I checked both for true as I could hardly believe how innacurate the 6.5 had been. Both were good.

Need to try the no line target shoot to definitively sort out the line slider issue but what I'd really like is to try a 7mm spear without a line slider but rigged with a rear hole. Unfortunately my 7mm spear is not equipped as such so maybe have to get the drill out.

Dave

Had a further though that maybe some spears are stiffer than others irrespective of diameter. Ed's got a big selection of fancy spears so maybe I can test some of his?