Hw77 heavy cocking

[paul8932]

Hi all,

My hw77 is heavy to cock and I was wondering if there may be a solution to this.

It’s been modified with a venom silencer/ ball detent underlever catch ( silencer glued solid to barrel) and is stiff to release, I get the feeling that the ball detent is too close to the end of the underlever and is stiff/ annoying, but I think I can live with that.

After the stiff release is the heavy cocking cycle that causes me most concern...

The spring is standard length, round section, probably doing about 11ftlbs, but it is stiff to cock the gun, especially compared to my other standard 77 that cycles like a dream.

I did wonder if the barrel/ underlever has been shortened in a former life, hence causing the stiffness, but I can’t do anything about that now.

Anyway, is there a “softer” spring that I might be able to try?

Other than the faults listed it is a lovely action that’s worth some fettling I think

Paul

[deejayuu]

No expert but could the piston seal be tight so needing extra spring force?
Ours are slack fit and cock very easily.
Are both 77 same calibre and cocking lever length?

[TonyL]

"Probably" 11ft.lbs. Warrants a chrono check with a few likely pellet types to make sure it's not over.
Guessing that you obtained the gun second hand?
If the power is too high, a strip is mandatory anyway and I'd also be checking the piston seal isn't too tight and that the cocking lever pivot section hasn't been damaged. Then a sensible re-lube.

And, as above, how short is the lever?

[Rapid7Nick]

I had a venom tuning kit in my 77 and it eventually sheared the pin that holds the barrel into the tube. Barrel crept forward about 3mm.
I eventually pressed barrel back in and new pin welded in. Then a Reblue.
The venom Spring is harder to cock and loads up quite early. I ended putting a standard spring back in and the rifle shoots so much better.

Have you pushed the ball back and squirted a bit of oil in. I replaced mine, they are only a door ball catch.

[TonyL]

Also, thinking about it a little more........

Has a previous tinkerer short stroked it and then used a stronger spring / more preload to up the power?

Also, as the piston moves back with the compression tube on cocking, a tight fitting seal wouldn't increase the cocking effort. The tight seal would be more apparent upon returning the lever after cocking. I always polish the outside of the comp tube and inside of the main action body when fettling and apply a small amount of moly grease / paste.

If the "anti-bear" slide is still fitted, are there any clearance issues there?

Also check that the spring guide isn't too tight a fit on the spring and that the spring isn't too tight a fit in the piston.

[Mach 1.5]

If it's an early 77 before ser no. 144*** as someone put a 26mm seal on instead of a 25mm one? Mach 1.5

[piggy589]

I've heard it said that the early guns have seriously high preloaded mainsprings.

[Mach 1.5]

As per Piggy...had an early 77 and when I took it apart...38 coil came out..Beware. Mach 1.5

[TonyL]

I've heard it said that the early guns have seriously high preloaded mainsprings.

As per Piggy...had an early 77 and when I took it apart...38 coil came out..Beware. Mach 1.5

Yep, 'tis true, but, being a "softer and longer" spring doesn't equate to a heavy cocking effort.

Of course, what it does mean is that extreme caution is required when stripping and this will always apply if working on a gun that has been previously worked on and you don't know what spring has been fitted / preload amount.

In this case, I guess that the heavy cocking action will be a result of a very short cocking lever, too stiff a spring etc as above.

[paul8932]

Thanks for all the replies everyone.

On closer inspection, it does look like the underlever has been shortened, probably when the venom silencer was fitted.

Internally all is ok, no tight seals, lubed properly, spring kit is a wonky donky one.

So I’d guess that the problem is the shorter underlever

Don’t get me wrong, it’s not unusable and it shoots very well, it’s just a shame that it’s heavy to cock and it spoils it a bit...I wouldn’t want to plink all day with it if you know what I mean...

Would it be worth trying a different spring?, as mentioned before I don’t mind dropping power somewhat.

Paul

[Rapid7Nick]

Normally the venom silencer is just slip on and cocking lever doesn't need shortening. I fitted a venom silencer years ago. All what needs to come off is the existing catch block.

I found that having a silencer fitted, made the rifle too long and front heavy. In the end I cut 3 inches from barrel and cocking lever. Maybe yours have been cut.
Although if you measure the cocking lever, someone can compare against another 77.

[Mach 1.5]

Back in the day there were two types of Venom silencer for the 77. Short catch and long catch silencer. The short catch version meant they could shorten the barrel and leave the cocking arm std. The long catch was just a slip on job so leaving barrel and cocking arm as per factory. A friend of mine as long catch fitted to a 12 inch barrel and so the cocking arm would be around 10inch long so a bugger to cock. A venom cocking aid helps. Mach 1.5

[paul8932]

Normally the venom silencer is just slip on and cocking lever doesn't need shortening. I fitted a venom silencer years ago. All what needs to come off is the existing catch block.

I found that having a silencer fitted, made the rifle too long and front heavy. In the end I cut 3 inches from barrel and cocking lever. Maybe yours have been cut.
Although if you measure the cocking lever, someone can compare against another 77.

Good idea, I’ll have a look later when I get home 👍

[paul8932]

Back in the day there were two types of Venom silencer for the 77. Short catch and long catch silencer. The short catch version meant they could shorten the barrel and leave the cocking arm std. The long catch was just a slip on job so leaving barrel and cocking arm as per factory. A friend of mine as long catch fitted to a 12 inch barrel and so the cocking arm would be around 10inch long so a bugger to cock. A venom cocking aid helps. Mach 1.5

Thanks Mach, I’ll look at it again later and measure the underlever 👍

[paul8932]

Just measured the underlever and it’s 9.5 inches total length.

And if it helps, regarding the silencer type, the bottom tube that holds the ball detent is about 4.5 inches long.

Would that help explain the stiff cocking do you think?

Cheers
Paul