Sunday, 20 May 2018

Crossbow Chrono'

I'm back from a weeks holiday on the Dalmation coast of Croatia, gorgeous scenery, lovely warm sea to swim in. A little too much sitting on a coach at a border crossing, but it was all organised so generally very relaxing.

I deliberately hadn't chrono'd the crossbow prior to going as I didn't want any disappointment hanging over me! I finally got round to trying it yesterday evening, it had already had about a dozen shots through it and has had time to settle.
Using a commercial alloy bolt (303gn)
First shot 196.3 fps . I'd been expecting 200 +/- 10 so that seemed about right.
The brace height was a bit higher than I'd used before so I took about 10 twists out of the string and tried again... It was slower, so I then added 5 twists and repeated, and then the same again.
It doesn't take too many twists on a short bow to bring the brace height quite a bit.
Here are the results starting from the slowest where I'd taken off 10 twists.
186.7 (+5 twists)
190.7 (+5 twists)
195.0 (+5 twists)
192.0 (no change to string)
196.8 (no change to string)
193.4 (no change to string)

I didn't want to twist the string up too much and risk over stressing the bow as it seem to be working within it's comfort zone. But I couldn't resist trying a lighter bolt (198gn)
229.7 fps which is ok. If I take it field shooting I'll use the 303 gn bolts.

 I couldn't resist going on E-bay and ordering a 'scope. I only went for a cheapish one as this is all just a bit of fun. I meant to order one suitable for an air rifle as they for some reason seem to shake scopes worse than fire arms!
In the search for a suitable scope with a decent size lens to let the light in, not too much magnification (x2 is prob enough) and the right mounts, I forgot to check it was suitable for air rifles... I also forgot to check where it was being shipped from.... yup, you guessed China!
 Still I'll find plenty to do around the house and garden while I wait on delivery, and the scope was pretty cheap as it had an 8% discount on it so only £26.03 !
* Reticle Type: Mil-Dot 
* Illuminated Type: Red and Green with 5 level brightness adjustment 
* Magnification: 2-6 x 32mm
* Material: Aircraft-Grade Aluminum Alloy 
* Field Of View(@100yds/@100mm): 15.71-41.96
* Eye Relief(mm): 75.0-95.0 
* Exit Pupil(mm): 4.6-14.0
* Length: 210mm 
* Battery: CR 2032 x 1 (Not Included)
I'll include a link to it just in case anyone is curious, but of course it will expire at some point.

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