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HW97KT177 Chrony Concerns

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Winged

Winged

Member
Sep 30, 2015
57
0
Ca, United States
I shot my HW97KT in .177 with JSB 8.44 over my Chrony, 20 rounds, the results were an average velocity of 770.0 fps, a spread of 59.63 fps with a SD of 24.16.

​Just got my Chrony, so I don't have a feel for it, but 11.14 Ft lbs seems low, the velocity variance of 59.63 fps feels large and a SD of 24.16 is???

Vibration feels more than normal too, but I just got a PCP and have been shooting it a ton, so that may be a misperception.

​Accuracy at longer ranges is off, but I have had a bad tins before.

Could I get some insight from some more experienced folk?

​
 
Just went through 3 different tins and couldn't group 5 shoots less than 1" at 25 yards, my baby is broken.

I would like to have my beloved HW97 tuned, new spring kit and generally given attention from an expert, AOA are the only folks I know who does this type of work. Is there someone else I can trust to fix/tune my favorite gun? Any input would greatly be appreciated, I shoot this gun ALOT and it is my favorite, not to mention it's body count is unreal!

Thnx again,

​Ken
 
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I don't have any names for you but if you post this question on the yellow forum there are a few guys who can tune that puppy up no problem. Of course you will have to ship it to them. If you are the least mechanically inclined just look on youtube for some disassemble vids/tuning instructions, get a JM or Vorteck kit for the gun and off you go.
 
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On an average day, my HW97K and I can easily put 5 rounds within a 3/8" group at 25 yards, 1" is exceeding atypical. Bore is clean, all screws tight, scope is springer rated, have approx 200 rounds from 4 different tins and all shoot exactly the same. Is there something else I can check to explain this loss of accuracy?

​Dieseling effect on Chrony, interesting point. Correct if I am mistaken, but doesn't dieseling occurs in springers that have not been shot very much or if one has recently lubricated or replaced the piston? My gun is 7 years old, I have never opened it up or lubricated it, has MANY thousand of rounds through it and I don't see, hear or smell any evidence of dieseling as I understand it.


Thank you for your input,

Winged

 
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Seems to me an HW97 with a 7 year old spring and shooting 11 fpe and 1" at 25 yards can't be in too bad shape. StraitShooters lists the 8.4 JSB from the '97 at 812 fps. By slowly cocking it and carefully listening for scratchy or "sproing" noises you might be able to determine if you have a broken spring. Put a piece of tissue paper over the breech and fire the gun and see if the tissue is being blown upward indicating a bad breech seal. You can check for dieseling by blowing a puff of air up the barrel immediately after firing and watching for smoke emerging from the muzzle. 
No matter what, a seven year old springer could probably benefit from some attention. The 97 is not a difficult rifle to work on. Check the web to see what a respring or reseal and relube might involve. You could probably do it yourself or do a search to find someone to do it for you.
I'm assuming you have chronied your PCP and determined that your new chronograph is working well. If you could provide the chrony string w/ 59 fps spread it would help. The extreme spread is the only thing I would judge to be unusual with your gun. . 
Good luck.

https://www.straightshooters.com/ourtake/ourtakehw97.html

PS: I just found some chrony results from my lightly used 20 year old 25mm HW77 from two years ago: Shooting 8.4 Exacts 764, 764, 762, 761, 763 for 10.83 fpe. Pretty tight sd! This gun has never been serviced.
 
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"scrane"Personally,I have never had much luck with my Chrony on a springer. They seem very sensitive to any smoke generated by dieseling. I think you'll find your problem lies with the Chrony.


Also, 1" @ 25 yards sounds pretty typical for a springer.
Click to expand...
This is not typical for any decent springer. Half inch or much better is VERY typical for any properly working quality springer. If 1 inch groups were typical, how would anybody ever compete in field target with one?
 
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When is the last time you changed the breech seal? These guns need a new one from time to time. And they can go bad from sitting in the safe not being used since it's always under compression. 11fpe is a touch low for a HW97 sold in the states originally as an FAC powered gun.

Are the "4 tins of pellets" you tried all JSBs? I ask because I have several tins here that are undersized at 4.49mm and shoot terrible in guns that love JSBs. They give wide ES numbers over the chrony too.

Concerning the chrony, set the rifle on bags so that it shoots level in somewhat the same spot across the thing. As long as the gun is a foot away, no amount of dieseling will skew the reading. Smoke over the front sensor will throw an error message on my chrony. It's an old piece of crap though lol!

Check your breech seal out, and if that don't fix it then try a different pellet. 

If you need a kit put in, I'd recommend the Maccari GSX-OS kit if you are mainly target shooting. It's a little more mellow and softer shooting than the full power Vortek kit. 

 
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Order a spring kit from www.airrifleheadquaters.com or www.vortekproducts.com. Make sure to get breach seals. Change those out right away. As said above it may be that simple and would be a common problem on a rifle of that age with the original breech seals. If not just swap in a new spring kit. It's not a big deal and once you have done it you will realize how easy it was.
 
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Winged, I just bought a HW97K off the yellow 2 weeks ago. It has the Vortec kit in it and here were my results over a Pro Chrony when I got it..

JSB 8.44 Avg Vol 845 FPS ES 86 SD 24 for 13.32 FPE Still it puts 5 shots at 15 yards in a ragged hole and under a dime at 30

JSB 10.34 Avg Vol 741 FPS ES 16 SD 5 12.61FPE Better results for these pellets. and the same performance. Now I am not a springer guy, just wanted to get one in case I want to try it at our club. I shoot a Styer LG110Ft in the grand prix's around the Southeast so I don't know what is good for a springer over the chrony. my Styer's ES is 9 and SD is 2..... Compared to the Styer, the results for my HW seems alarming. However, it really shoots well dispite the funky looking results. 

I just wanted you to see the difference between the 2 pellets I tried. It made a huge difference. Also the 10.34 and the 8.4 were washed and lubed for my Styer and pistol i use inn comps...

I did have the HW's POI go a little off yesterday and found the rt front stock screw about 1/4 turn loose and the bolts on the trigger guard were 1/2 turn loose. I took it out of the stock and shimmed the rear in the stock with a plastic shim as when it was loose the action/barrel would move slightly front to rear.This causing the POI to jump around. After putting the stock back on and putting Blue Locktite on the bolts it is back on.

I did not see what state you are in but there are several guys who specialize with the springers. David Slade in Tenn and Hectore Medina at Connecticut Custom Airguns. These fellows can give you advice on what to do to get yourself right.

Also try Jim Stanis at Precision Airguns, He is the one who worked on my rifle prior to my getting it. If not he will definitly have a source to got to...Good Luck
 
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