We might as well keep the hot topic going
It's starting to look like the stroke length on the HW45 is not a factor with the low velocity examples. I'm pretty sure that the cylinder diameter is not a factor either. This means there is another area to look for a difference between a 6.0 FPE pistol and a 4.5 FPE pistol. We know that the 6.0 FPE HW45 is available in Canada in .22cal. Many of us have them. Is there a .22cal model with a low power spring... or should we be looking for something else to change/fix?
Here is a list of things to check if you are not getting full power from your .22 HW45. Please post other experiences that have increased power. We can keep this for a reference for others who may have underpowered pistols. 1 - Clean your barrel, pull an oily patch through and follow with one dry patch. I have seen this improve velocity.
2 - I always lube my pellets with a spray wax lubricant. I have some old furniture wax that works but bicycle chain lube works well too (wax based). Let the wax dry overnight before shooting.
3 - Check your breech seal for nicks and gouges. Change it anyway, just to see if velocity improves. Sometimes seals can be on the small side of an acceptable tolerance. Seals are cheap. Also try out a 009 quad seal.
4 - Try shimming the breech seal with dental floss. Sometimes this trick will tighten up the barrel-to-seal fit and improve velocity.
5 - Check your mainspring. I'm not yet convinced that we have a weaker version here in Canada but it's possible (for .22cal). Compare your spring measurements to one that is know to produce full power. Mine has .094" thick wire, .653" OD, and a coil count of 34. Sometimes springs get weaker before their expected time. A replacement isn't too expensive.
6 - Expand your piston seal by dry firing one shot. This is a suggestion by Mac-1 Airgun. Apparently the flat faced teflon seal will expand when spanked.
7 - Change the 009 seal that is located under your "cylinder saddle". I call the part a "transfer port".
8 - Change your piston seal. Possibly your seal is worn or damaged from installation or may be slightly undersize.
9 - Try different pellets. When going from Crosman Premiers to RWS Super-H-Points I get an additional 30 fps. These pellets are the same weight but the RWS fits my barrel better. Try a variety of pellets to see if one does better.
10 - Try adding some internal lubrication. I prefer a mixture of moly paste and spring oil. Every few thousand pellets, I apply a bit through the cocking slots. Even plain chamber oil or spring oil will be better than nothing. Use 3 drops total.
Parts Diagram -
http://my.tbaytel.net/coopers/HW45Revie ... TS_DIAGRAMDon't forget to add to the list if you have experienced something that works to improve velocity.
Cheers,
Todd