Taming the HW45 Beast

[Lynx]

Thanks WildCJ5 for the suggestion, this goes opposite to what is expected and would also probably means that you have steady hands and good technique that shot well even with slowly advancing pellets. Will try them

Gary, amazing craftsmanship and marksmanship!

[Rakin]

I've owned a P1 for close to 20 years. I've done a little work to it including tuning it up. I love them. They are accurate and a joy if you know how to hold and shoot them. 

[clarky]

I have been tuning the annoying (to me after doing about 30 of them) HW45 since its advent in the 80s.
My very last one was the best I have ever done which may be of interest to some of you.

I have gone down several routes with efforts at improving it but you will not do much better than cleaning, or shooting out the oil that HW...or pre owners have put in it.
The reason is the restrictive TP design (to keep it compact) requires a massive mainspring/stroke to overcome the restriction and this induces heat. Any oils in it will simply flash over and cause erratic shots. Just when you think you have it all cleaned out, it will still flash over and emit smoke.....Why...because oil has found its way below the seal and you did not see it!... 
Once cleaned out (you will never wear the gun out for lack of oil its too well built) You need to machine an opposing top hat for the opposite end of what you normally expect. Placing it at the opposite end of the piston and shortening the guide rod. Better still machine up a solid guide rod, and benefit from retaining all the weight down in the piston, for being 2/3rds the length of the original. You need the weight inside the piston, or the gun will return a slowed cycle from the massive cushion of air, reducing power. Forget light weight, Delrin top hats in these, offered by the Tinbum kit.
The light Top hat will lower the power, ruining the only reason why you purchased this pistol in the first place...plus I have removed 2 broken ones in this gun, caused by the lack of a central latch rod which normally shores up the strength of such top hats in air rifles. Don't waste your money.
The second reason for keeping the weight in the gun is damping recoil. Adding a sighting aid can also help with this.
My final best effort with this gun was a pair of solid Phosphor bronze guide/ Top hat offering plenty of slip similar to Delrin but even more weight than steel.
With maximum weight in the piston and the base of the mainspring supported by a small Top hat/guide, you will access all its power and remove the inconsistency of a normally flailing mainspring at the muzzle end. Plus it help with the life of the mainspring by keeping it straight and remove any torque.
Once here, we can then select the RWS Hobby pellet. The 45 likes Hobby because the Hobby has a soft spreading skirt, which quickly seals in the first inch of the barrel, realising 600 fps velocities.
The accuracy of the Hobby is pretty good also almost matching R10 but more velocity.
Hobby not so good in SSP like the FAS as this easy expansion causes reduced velocity due to lower available power but makes the most of the available power in the 45.

Finally, get on and learn to shoot it. I have known some practised shooters out shoot SSP with them due to learning how to shoot it. I have done similar with a modified LP53. Learn your rig being the best advice.
If you do not have access to tune the gun as above, just insure you have your mainspring guide down inside the piston and make sure its nice and clean. Hobby pellet and get shooting.

 

[DIABOLO]

I need a video showing the entire teardown of the gun including using a spring compressor to fully disassemble.  I wanted to completely disassemble because I am tired of the dieseling that never seems to end. 

[byhsu]

RWS Basics and RWS Meisterkulgen 7.0gr work really good on the HW45, accurate and good power, i get about 575fps with the basics and 585fps with the Meisters.

I consistenly hit dime size targets at 5 meters distance, very accurate.