Canadian Airgun Forum

I have an HW77k, which I had recently sold (for a short time). The colleague who bought the gun had a change of mind (his wife didn't approve of it) and I gave him his money back. He shot the gun only once and I was with him, so the problem I have with the gun has nothing to do with the other guy. When originally bought this gun, my first HW, in the winter of 2013 from a major dealer that no longer sells HW, I didn't chrony the gun. In fact I didn't chrony it until late last month and I found that it shot its favourite pellet, FTT 4.50, with a MV of 825 fps. JSB 8.44 gr pellets did 835 fps, while Express pellets did 876 fps. At the time I thought the velocity was on the low side.

Today I had some time on my hands so I rechecked the rifle. The FTT were in the mid-780s, the JSB 8.44 gr pellets in the low 800s, and the Express were in the 830s. The MVs I got today are considerably lower than they were one month ago. The MV figures were consistent, with the ES between 12 and 16 fps, depending on the pellet. In terms of muzzle energy, the gun has gone from a high of 13.5 fpe a month ago to 12.23 fpe (based on the Express) and 13.08 fpe with the FTT last month to now 11.8 fpe. The originally full power rifle now has the power of a 12 fpe gun.

What would be the likely cause of such a power loss?

Was it possibly left cocked for any period of time? It could have compressed the spring and caused a loss of power.

The gun hasn't been left cocked for any length of time (and the other fellow who briefly owned the gun was strenuously advised to never do this and he can be counted on to have followed that advice).

I've been researching for information about possible causes and came across the notion that the breech seal on 77s and 97s can be an issue related to a loss of power. Will anyone with any knowledge about breech seal problems with HW77s please comment?

Yes breach seals are a culprit when it comes to the 77/97. Get one of the Vortek seals. They are top notch.

I think he meant breech seal not piston seal?

I bought 4 extra breech seals when I just got my 97, just in case I need one down the road

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Weihrauch HW97KT .22 + Hawke Varmint 4-16x44 SF
Crosman357 .177
Crosman Phantom .22
Crosman 2240
Daisy 953
Ruger Green Mountain Laminate 10/22+Hawke Airmax 3-9x40 AO
1950 Russian SKS
Remington 783 30-06 Hawke Vantage 6-24x44 SF

Mike ....Mulby is correct vortek also sell breach seals, and are by far one of the best seals you can get

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"A candle loses nothing by lighting another candle"

Sorry, my bad
I got mine from SSSO, which ones would they be?

_________________
Weihrauch HW97KT .22 + Hawke Varmint 4-16x44 SF
Crosman357 .177
Crosman Phantom .22
Crosman 2240
Daisy 953
Ruger Green Mountain Laminate 10/22+Hawke Airmax 3-9x40 AO
1950 Russian SKS
Remington 783 30-06 Hawke Vantage 6-24x44 SF

Thanks for the confirmation and recommendation about Vorkek seals. Any tips for changing a breech seal on a 77/97?

Get a set of "Picks"... http://www.princessauto.com/pal/en/Hobb ... /8212862.p

OR... http://www.princessauto.com/pal/en/Hobb ... /8450389.p

Self Explanatory..Just take it nice and slow and no "Gouging" Or No Gorilla moves.

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President and CEO of Procrastinator Unlimited.

Arsenal..
Kraft Marshmallow Pump and Shoot Rifle.
GoodYear Gatling Gun rubber-band shooter.
PEI Potato PCP Rifle.

Glass ..12" Dobsonian Reflector.
Shooting for the Stars.

click the link.
http://vortekproducts.com/ourstore/Seal ... duct_id=93

_________________
"A candle loses nothing by lighting another candle"

Thank you, gentlemen. I'm going to order a Vortek breech seal (or two) and get the picks from PA.

Mine are white, not blue, so they are probably a stock type
Ill have to order a couple extra Vortek seals, breech and piston

_________________
Weihrauch HW97KT .22 + Hawke Varmint 4-16x44 SF
Crosman357 .177
Crosman Phantom .22
Crosman 2240
Daisy 953
Ruger Green Mountain Laminate 10/22+Hawke Airmax 3-9x40 AO
1950 Russian SKS
Remington 783 30-06 Hawke Vantage 6-24x44 SF

Mike they/Vortek sell white seals as well, just so happens that those are blue I'm sure your white seals are fine

_________________
"A candle loses nothing by lighting another candle"

Sorry to threadjack but typically how long should breech and piston seals last?

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Weihrauch HW97KT .22 + Hawke Varmint 4-16x44 SF
Crosman357 .177
Crosman Phantom .22
Crosman 2240
Daisy 953
Ruger Green Mountain Laminate 10/22+Hawke Airmax 3-9x40 AO
1950 Russian SKS
Remington 783 30-06 Hawke Vantage 6-24x44 SF

A breech seal can last for years -- many thousands of shots. Sometimes they don't last as long. Underlevers are sometimes prone to go through them sooner than others.