AA HFT 500 (or similar) tuning resources

[acorneau]

Howdy folks,

I'd like to get my HFT 500 running a bit better than it does now and I'm having a very difficult time finding any resources with information on tuning this or any similar Air Arms rifle.

Right now a full 190 bar fill starts at about 735 FPS (with AA 10.3's) and the power curve peaks around 770 around 70 shots later. I get about 25-30 shots at 770 before it starts to drop off.

I'd like to get it to run the heavy pellets at at least 800 FPS, preferably 850 or even 900, but if I increase the "power adjustment" screw it exaggerates the power curve even more than it is right now.

I'm ok with loosing a bit of overall shot count if I can get the speed up and a little more consistent. I've looked into some regulator options but would like to see if I can accomplish the goals with adjustments of the firing pot, power adjustment, and striker spring before having to commit to an irreversible modification like adding a regulator.

If anyone has a lead on a thread, website, video, or any other resource that would help me figure this puzzle out I would be very appreciative.

Thanks.

[Motorhead]

I've REGULATOR converted and then retuned / modified valve and transfer path to get them at @ 18 fpe ( 10.3 @ 880 ) and make @ 70 or so shots while under regulation.

There really no different in basic layout to any AA 410/510 - 400/500 series rifles.  Small specs are different, hammer & springs etc.

Its doable absolutely.

Good luck & enjoy the tuning journey

[acorneau]

Circling back around to this old post of mine.

I ended up finding a good combination of the adjustment choke screw and shimming the striker spring with a washer to get a decent enough power curve and consistency.

It's not shooting above 800 FPS, more in the 765/775 range, but a fairly flat power curve with a velocity spread around 5 FPS. Pellet testing has confirmed over and over that it prefers the AA Field Heavy pellets (10.3) over anything else I've tried so far.

For those interested, I wrote up a full article on all the modifications I made to make it my favorite air rifle to shoot for Silhouette. Go to "nassasilhouette" dot org and use the search bar for "HFT 500" to get to the article in the technical blogs.

I may eventually get this thing worked on by a professional tuner like Motorhead, but at the moment it's running pretty darn well for me.

Also, for those interested in Silhouette, NASSA is the new focal point for air rifle, small bore, and high power silhouette covering all of North America including the USA, Mexico, and Canada. Check it out!