Gamo Whisper tuning

[DWM]

Hi guys,

I’m another newbie to air gunning.  A year ago I bought a cheap bb/pellet gun for $50 bucks from the hardware store so I could smack the geese that crap on my lawn , which led to a neighbor showing me his new Gamo Whisper, which gave me gun envy, and led to my purchase of a Whisper with the venturi ram, then a GRT trigger when I got frustrated with my inability to hit a barn (as a kid I was deadly with a .22), then a Leapers 3-9X40 scope when I decided to dump the coke bottle glass scope that came with the rifle, and now after shooting 2000 pellets through the gun I’m actually getting in the grove. I now, with some consistency, can hit a beer bottle cap from 30 yards… I also get the wild shot that might bring down a low flying plane. I’m getting good results with Crow Magnums, RWS Superdomes, RWS Meisterkugelen wadcutters, and really tight groups with JSB Exacts, all of which are 8.4 – 8.6 gr. pellets. The JSB’s give the tightest groups, but the groups are 2” high and right of where the other three tend to land with the current sighting of my scope. Curiously, Eun Jin’s seem to hit in similar groups to the first 3 mentioned when shooting at 20 yards…. I know, I know… don’t shoot heavy pellets with a Springer!

I have a couple of questions for you experts out there. I haven’t done anything to the gun (With the exception of tighten up all screws, adding the GRT trigger, and the Leapers scope) to “Tune” the gun other than clean the gun with a RWS cleaning kit I got from Pyramyd. Is there anything I should be doing? Should I get some bore cleaning compound? My RWS kit came with a bore brush and cleaning pellets but no cleaning tip to put cleaning patches on… or patches for that matter. I know Bob and Gene don’t think much of cleaning pellets, so I will avoid them. Any hints would be appreciated.

I’m also thinking of getting some JBS Exact Heavy 10.2 gr. Pellets. Is that too heavy for a Whisper with a Venturi piston? I’ve burned through 500 Kodak 10.6, which also gave really good results, and I liked the impact of the heavy pellet, but I keep reading about not putting heavy pellets in springers.

Sorry for the long-winded entry to GTA. I look forward to more great reading about guns, ammo, and squirrel recipes!

Don

[Bob Fairchild]

Don:

Another new guy here.  I have the exact set up that you have - Whisper .22, Air Venturi ram, GRTIII, and Leapers 3x9 40mm.  I'm thrilled with the results so far.  Most of the posts I've found say to avoid really heavy and really light pellets since both can damage the gun over time.  I am slowly breaking the rifle in without cleaning the barrel as other posts also recommend.  And its working.  The groups are tighter, more consistent and more predictible after it has been 'shot in'.  Don't hurry it, enjoy the thrill of finding the right combination.  Mine is leaning toward Beeman's Silver Bear which is 15.74 gr.

A relaxed hold has been the key for me.  Once I'm set up on my tripod the only part of the rilfle I touch is the trigger and a very slight pressure on the butt of the stock.  I let the Whisper do the rest.  Truely amazing.  

If you haven't found it yet, go to the Library and look at the Pellet Chart by Ian Lamb - great reference.  If I knew more about this dang computer I could link you or whatever.  Also look around for the blogs on pellet weight - there are some good ones.

As for the tune - you bet cha.  I'm going to get one as soon as Gene is ready.  It is one of the things that is highly recommended here and I have seen the tremendous results with the GRTIII so far.  Whatever it takes to get better.

Give the gun a chance.  I am interested in how you do and will follow your updates.  Good Luck!
-----
Bob

[DWM]

Bob,

Thanks for the info. It is a process. I was initially frustrated by the gun, but then I read some blogs and realized that it was me, not the gun. Proper hold, pellet, and for me, a sandbag rest.

Don

[Jerrycup]

I was terminally frustrated with mine, as a result I traded it for some work done in my home. The recepient (who already owned a Big Cat) told me a week or two later that he was thrilled with the accuracy I had found so lacking, and that the secret was to grip that thing both hands vise-like, and it shot much better for him(?!). He said it shot way better than his Big Cat. Funny, that day I showed him the Whisper, my first shot at 25 yds was a dead center bullseye. I smiled, handed him the gun and said "give it a try"...

Welcome, Don. My Whisper shot the RWS Superdomes better than others.

As far as tuning, I suggest you put foam or "Great Stuff" in the stock to reduce the noise from the hollow plastic cavity, and make sure you have clamped your mount tight, pre-cleaning the rails and applying Loctite. Dano advises that you put polishing compound or a fine grit to the riser before you clamp, that this added friction improves the stability.

Watch out - that riser with the hole for the stop pin is an aluminum extrusion, and the pin can actually elongate the hole in the soft metal. Make a mark and watch to be sure you are not getting any slippage between the mount and the riser.

[CO_AirGunner]

Don,
First of all, from one newbie to another, welcome!  I have the Whisper with air-venturi (I added it myself) in .177 as well.  My factory Gamo scope crapped out last weekend, so I'm now sporting a CenterPoint 4-16x40 AO from Wally World.  Much better scope than the factory one!!!  I also bought a wooden Hunter 440 stock that I love (see my Nutter Down!!! post in Hunting Gate for pics), but need to do a slight fix to keep the rear pin from moving before I use it again.  When the rifle is on its game, it will stack pellets!

DWM and Bob F. - Could you two please do me a favor?  With your Whisper uncocked (cocked wouldn't really matter), FIRMLY grip the front of the action around the two screws that attach the receiver to the stock.  Now lightly grip the very end of your barrel "s!lencer" with a few fingers.  Do you notice ANY side to side play in your barrel when you LIGHTLY push it sideways in either direction (perpindicular to the direction that it moves when cocking)?  TIA.

[Bob Fairchild]

Guys:  

In answer to Jared's question about sideward torque at the tip of the barrel - yes I do get movement .  I was not aware of that and am somewhat surprised at how much movement is there.  I guess you have raised an interesting question for an expert, which I can assure you I am not.

Bob or Gene or another tuner or Gamo tech should be able to explain that phenomena to us.  Sorry I didn't respond sooner.  Stuff!
-----
Bob

[airiscool]

"In answer to Jared's question about sideward torque at the tip of the barrel - yes I do get movement . I was not aware of that and am somewhat surprised at how much movement is there. I guess you have raised an interesting question for an expert, which I can assure you I am not. "

I did the same as Jared asked with my 22 Whisper and yes, there was movement, but no 'perceptable shake' to use an old tolerance term.

Then, the question is  where is it moving?

To take my greasy-left-paw-holding-the-reciever out of the test, I clamped the reciever in padded vice jaws and got less deflection with the same moderate push-pull.

Then, to take any breach/reciever play out of the test, I clamped just at the breach and got just about the same amount of deflection.

To further test breach/reciever play, I measured the gap on either side of the rear most part of the breach in the reciever forks and got .007 inch on one side .009 on the other. I cut some .008 shim stock and put that on either side, repeted the reciever vice clamp deflection test and it was about the same as the first time.

Without using a standard force and measuring the amount of deflection each time, I think a major portion of the precieved movement is barrel deflection . The steel barrel is only 7/16 inch od inside the plastic. Not much meat for barrel ridgedity.

I have the gun apart now to install a gas spring and do a general inspection and de-burring.  The real test of reciever/breach play will come when I get this thing back together and see what affect the .008 shims have on shot groups.

Paul.

[DWM]

First off, sorry for the delay. I've been away from the computer for a few days. I love the wood stock! Really beautiful.

I also have a very slight shift in the front end of my in both directions. A little disconcerting! I wonder if other break barrels have the same issue, like a RWS 34. It must snap back into the same spot when shooting, otherwise you would have pellets all over the place.

I'm so impressed with this forum, like Paul's response to your barrel issue... measuring the variance to .007 inch! Anyway, thanks to you all for responding to my original question.

It's sunny and calm right now. Time to go shoot some paper.

Don

[gamo2hammerli]

Welcome to the two members DWM and Bob Fairchild to the GTA forum and family.  Just shoot the airgun a few hundred times...a 500 count tin of pellets at least to find out what she likes....and it'll settle down some and season the barrel.  After that you may consider a home tune or pro tune depending on the situation of the gun.  All my airguns have not been tuned in any way...except the Crosman Sierra Pro because I had to change the spring....since I had her opened up....I gave her a home tune.....and after 200 to 500 shots (Depending on which gun) everything settled down and they are pretty accurate out to 30 meters (average distance for an airgun).  If there's a miss.....it's most likely me.

[CO_AirGunner]

Interesting.  I am hoping we get some more people checking this.  My whisper now has about 2,000 shots on the clock.  I've noticed some accuracy issues lately, more specifically, two distinct groupings from the same pellet.  That's when I found that my barrel was shifting almost 3/16" either side of center.  

I am told that the pivot is sleeved (in other words - the pivot bolt rides inside of a metal sleeve pressed into the synthetic material).  That being the case, all I can figure is that the synthetic has worn out a bit from rubbing on the steel receiver forks during the cocking cycle.  I'm not sure if shimming is the answer or tightening the pivot bolt.

All I know is that I should be seeing worse spreads at the target than I am, so maybe the barrel kind of self-centers during the firing cycle; I don't know.  Doing the math, 3/16" of movement at the end of the barrel is about 3.75" at the target at 10 yards (which would be 7.5" spread between the two groups).  Since I noticed this, I typically nudge the barrel to the right after cocking.  If I nudge the barrel to the left instead, my groups move about 1.5" - 2" in that direction.  It is frustrating.  Unfortunately, my groups (when nudging the barrel in the same direction) have opened up a bit to about 3/4" 5-shot groups at 10 yards from less than 1/2".

I've been messaging with CDT about this, but I haven't heard back from him since my last message.  I'm wondering if this issue is reserved to the synthetic barrel Gamos or if the all-metal ones have the same problem.

[DWM]

I had some real accuracy issues this weekend. My gun is somewhere over 2000 pellets. The barrel shift is minimal with my whisper, but is is there. I had pellets in loose groups on one side of the bull, with occasional bull-eyes, then I would get shots on the opposite side of the bulls-eye. I was trying to finalize which pellet to use between Meisterkuglen, RWS Superdomes, and Crowmagnums. My best results ever with the gun have been with Kodiaks, so I'm considering going back to a heaver pellet. It was probably just my shooting, but if it is the barrel shifting after cocking I'll be chasing the right pellet forever.

Don

[airiscool]

Jared,
I got the gas spring and tins of Preditors  in from Pyramyd and installed the gas spring last weekend. It's not exactly like yours in that,
A. The nylon or Delrin guides are machined to a smooth finish (they must have read your post).  
B. It don't have the crimped  band near one end.

And, .....  I never mentioned which Gamo model I had when I ordered the gas spring ( plus I didn't get the gun from Pyramyd),  but this gas spring  had a red label on the end cap that said."Whisper". Wonder how they knew   Did yours have a label on the end ?

Before I tore it apart, I tried the preditors (.22) to see how well they group compared to the Super Domes which have been best so far. The pred's grouped about the same at 10 yards, just as expected, with a slightly differant POI.

After the gas spring was installed, as expected, cocking is smoother and no more 'twang',  but it definately takes much more force to cock it. It also has noticably more kick, and even after burning off any oil that got moved around in doing the spring swap, it is a bit louder.

Now, the Super Domes penitrate a bit deeper into a cardboard box of stacked-on-end news papers that I've been using to compare penitration.  For what it's worth, the Preds go 15 sheets of newspaper deeper than the Superdomes.  Both penitrate a bit more after the gas spring was installed.

I don't have a crony (unless you count the old guy next door   ) but all indications are that the Whisper seems to have more power than it had before. Original Gamo spring came out looking ok, and I never leave it cocked longer than it takes to get a shot off. Had good power from day one, but now it has a tad more.

The down side to all this 'possable increase' in power is  that  after shooting about 50 Preds, the Tasco World Class I was using, which has held up fine so far after about 1000 superdomes and Super HP's, finally started loosing zero. I guess with the combination of a 'possably' more powerful gas spring, plus the heavier Preds have taken their toll on it.   :emoticon:

Also, when I removed the scope mount, everything was still tight and no detectable loosness. All the screws were still super tight from the Lock-tite, but I noticed the scope mount pin hole in the reciever had a large burr worked up on the rear of it that never was there after checking for scope mount movement/gouging with the original spring. It had definatly taken an increase in  pounding.

Anyway, I broke down and ordered a ligit springer rated scope from Pyramyd.

Once the new scope is installed and dialed in and the variability of scopes going ka-flewy is no longer a factor, I can get back to test shots with the .008 shim stock saddle I made for the breach to see if it does anything for acuracy.

Paul.  

[CO_AirGunner]

Paul,
THANK YOU for the follow-up!!!  It is interesting that your Air-Venturi isn't quite the same as mine (esp. the crimp band).  I don't think the machining on the Delrin parts really matters much.  My Delrin spacers must have been the last ones made on a Friday...  

My Air-Venturi was shipped in a sealed plastic bag.  There was a red sticker that said "Whisper" on the bag (probably should read "Gamo" instead).

I have read that the gas springs are harder on scopes.  That's probably why my factory Gamo scope finally died shortly after adding my Air-Venturi.  It sounds like your power results are about on par with mine.  Did you hone your compression cylinder?

[airiscool]

Jared.
When I saw the physical differances, and how after installation it kicked more, I wondered if yours was as differant in power also ??

Mine came in a sealed  plastic bag too. And considering someone remembered to mark it before it went in the bag, plus how the delrin was so nicely finished......  I guess it pays to order earlier in the week !  

I didn't have a replacement seal on hand so I didn't take the piston out and get into honing. Plus I have to order some new finer grade stones for my brake hones. Wore them out doing  some shotgun barrels and chokes.  I figured that'll give me something to do next winter.  

Paul.

[CO_AirGunner]

FWIW, I replaced my breach seal this past weekend and it did help with the barrel movement problem!!!  The face of the old seal was pretty beat up for some reason.

I do still get some side-to-side barrel shift, but it is at least HALF of what it was before.  (I need to get the shim feelers out to measure it)  I don't notice the two different groupings like before.  As long as I cock the rifle the same every time, the only effect I see is that my 10-shot groupings are running about 1/2" c-t-c.  At least the shots overlap (I just wish the group was tighter)...