Quote Originally Posted by flatrajectory View Post
Matt,
I had the same problem. I re-profiled the grips at the top using a dremel drill ,where the knuckles of your thumb and index finger of your shooting hand tend to rub into the grip.
I added weight to the inside of the grip by drilling two holes and filling them with melted down lead pellets.
then just a smoothing out of the trigger/sear interface and an internal lube of mainspring and piston.
Shoots like a dream now.

Pete.
I ran all the tests and performed major tunes across a 12 month period after it first came out. I also purchased it due to its its less bulky appearance compared to the 45 i had but my conclusions realised it was not as good by some margin.
The main problem is the novel guide rod. The idea was to use a cross corners guide in the shape of an X in section, instead of round. Made from Black Nylon. It has a very tight fight, the idea being to grip the unwound mainspring, removing any twang at the end of the cyle.
While it did seem to work as a spring damper, it is tragic at returning top performance. There is not enough slip for the spring at these lower power levels. Also the nylon is not perfect, with high spots and the moulding is not perfectly straight ...as i found out when i ran it in a lathe.
I produced a replacement Blach Delrin guide but of round section. Front section was exactly similar to fit as forend plug of course.
I got a good improvement with no noticeable increase in twang.
However there are other problems. The breech washer never worked efficiently and even came out. There didnt appear much that i could do about it. Many reported similar problems but also struggled to come up with a fix.
Finally the barrel is too short. I wish BSA had not gone with the so called Plenum chamber in attempt to act as a small integral silencer. It may have had some slight effect but robbed a potential 2 inches of barrel length. Cardew did some tests many years ago where he concluded that a minimum of 7 inches would be required for the sub 6ftlb gun to perform to any reasonable accuracy. Suppose the Webley pistols just about made it at 6.75 inches but the Hw45 7.75 is a notable.