Webley Viscount 177 trigger modification

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Joined: Mon Jul 13, 2020 10:54 pm

Webley Viscount 177 trigger modification

Post by Normkel » Thu Jul 16, 2020 6:23 pm

If anyone is interested, I just acquired a Webley Viscount 177 cal which had a horrible trigger so some study revealed the problem, too much sear engagement, and some possible strategies. I have competed in bench rest rim fire & centre fire, metallic silhouette in 22 rifle, centre fire sporting rifle, centre fire silhouette, and other classes so am quite familiar with both good equipment and high quality triggers. <this for context>

We considered making pad to allow an adjustment screw to bear against the sear (SRO17) to which the trigger mates but the need for the sear to "over-travel" during engagement seemed to make this less practical .

Considering the configuration of the trigger, one will notice that there is a pronounced notch at the top end of the trigger sear surface (orange label). I determined to wrap wire across the notch (which locates the wire) and experimented with some copper wire of about 1 mm which improved the trigger engagement and release. After using the rifle in that mode for some time, I determined to increase the wire size in search of further improvement.

We attempted to measure some of the pre-modification and post-modification trigger qualities and will try to report those later.

The trigger engagement moves from the trigger sear surface which engages with the sear (green label), to the sear engaging with the curve of the wire (purple arrow).

Steel wire wrapped across the notch and crimped around the trigger will remain in position by virtue of the "V-shapped" groove and that the thrust forces it rearward. The sear engagement area moves from the green area of trigger and sear, to the (purple arrow) curved area of the wire. Engagement and sear creep are very much less, very much improved. Crimping the wire snuggly allows it to pass into the stock without interference.

A previous owner has obviously been less than concerned about the surfaces, given the scratches.

I don't know if the diagram will appear after posting, but if it does not, I will need advice as to how to include a photo in a post.

https://www.dropbox.com/s/b4616rgobu1t0 ... n.jpg?dl=0

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