GTA
All Springer/NP/PCP Air Gun Discussion General => Air Guns And Related Accessories Review Gates => Air Gun Review Gate => Topic started by: mikeyb on April 18, 2022, 06:18:23 AM
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Got a couple $40 Airtact refurbs when they first came out and I promised myself I would not get another one, but I caved last week.
The recent Hatsan deal was too good to pass up. An Airtact refurb, free 3-9x40mm AO scope & rings with any refurb rifle purchase, a refurbished AT44(180cc) air tube, and free shipping.
Package arrived late Friday and everything looked good. The AT44 tube came fully charged so it's holding air. Scope looks nice but will NOT go on a springer because I don't think it will survive. I have a still-boxed PCP that will be a perfect match for this scope... and that is a post for another day.
I started testing the Airtact Saturday morning.
Still not a fan of all the new plastic parts but the rifle feels light, solid, and shoulders well. Target groups using the open sights started large but quickly tightened up as I (re)discovered the best hold/grip/pellet for the rifle. Trigger seems better than I remember. Not great, but maybe more "broken in" being a well used refurb? I decided not to make any trigger mods... for now.
While shooting I became aware that the rifle made some pretty loud (IMO abnormal) crunchy sounds during cocking. The shot cycle also seemed much harsher than the typical Edge rifle it is based on and I could feel significant extended spring vibrations (twang) after each shot.
With the stock removed I could see through the cocking slot that the unsupported spring was heavily preloaded, canted, and dry. Decided to go inside and check piston seal since I've seen several damaged piston seals in my Hatsan refurb collection. Piston seal was actually in very good condition this time so I refocused my attention on the tiny spring guide.
IMO the factory plastic guide 3.875" total length is inadequate for this design. I made a new spring guide from a 1/2"x 8" partially threaded steel bolt (<$2) very similar to the one I made for a Mod85 here
https://michaeljbernard.wordpress.com/2021/10/23/2021_10_23_hatsan_mod85_spring_177_refurb_mods/
Total guide length for my Airtact version spring guide measured 6.125" and it uses only the one thin steel washer from the original Airtact guide. Bolt-guide was a very snug fit into the "fully relaxed" spring and exactly what I wanted. Spring preload was nearly identical to factory setting and, if I measured correctly, there should be less than 1/8" gap between new guide end and the back of the piston head at full cock/triggerlatch. Now spring is fully supported along its entire length by either the guide inside, the piston outside, or BOTH. No spring canting allowed and longitudinal vibrations significantly/completely suppressed (no-twang).
I wish someone at Hatsan would read these GTA posts and consider making this relatively simple design change.
Deburred cutouts and cleaned out all the old crusty factory lube. Burnished Moly paste inside the compression tube, on piston tail/skirt, and in piston cocking slot. Tacky grease painted on new guide, spring, and spring ends. Reassembled and sent about 50 pellets down range. No supersonic pellets on this one so my relube technique seems to be improving(?).
As received the rifle was shooting 7.9grain CPHP ~950 fps mv. It is now shooting ~910 fps mv, but "may" be gradually increasing? I'll need to track the chronograph data to determine if that is real or just my imagination. Groups are about the same. Open sight 10 shot groups are ~3/4" at 30' and slowing shrinking with practice. Hoping to be able to get them down to ~3/8" which is pretty much the best "I" can shoot with any of my budget springers.
There are no more odd crunchy sounds during the cocking stroke and the shot cycle is noticeably less harsh with "0" felt spring vibrations. I think the shot cycle will always be a bit sharper for the Airtact over the Edge because the Airtact is just a lighter (lower mass) rifle. The new longer spring guide and fresh lube has made shooting this Airtact more enjoyable and I have no problem trading ~40 fps mv for the smoother operation.
If I place a value on the scope of $25 then this Airtact was a $25 refurb. I'd have to pay $25 for one factory or aftermarket coil mainspring so NO regrets on this purchase!
Note:
I think this rifle is a very good candidate for conversion from coil spring to Crosman NP power. My piston has the dimple which centers the shaft of a Vortex air spring or Crosman NP and the trigger-group/endcap-assembly has a ready made recess to hold the body of an air/gas spring. The only variable is how thick a spacer is needed to properly preload an NP. I don't know that dimension yet but will update this thread if/when I attempt that conversion.