Would like some opinions before I install one.
Forum member "randy_68" recently tried both the Maccari Pro Mac Kit and the Twister spring in his FWB 124. He said the velocity was just about the same with both, but that the Pro Mac Kit gave him a more-pleasant shot cycle. That is, he was getting right at 840 fps. or so with the 8.44 gr JSB Exact pellets with both the Pro Mac Kit and the Twister spring.
If you didn't know it, that's a nice increase compared to what you get with a factory spring, and both ARH options are easier to install than a factory spring. Both of them also do-away with the spring 'twang' or 'buzz' that is pretty evident when you're using the factory spring.
I replied to his post that I thought the Twister spring might be almost the same in the way of smoothness if he left it cocked inside the rifle for 12-24 hours, fired 15-20 shots to allow the velocity to re-stabilize, then retested (he only tried 2 hours total of leaving it cocked). But, since he already had both kits at hand, he elected to re-install the Pro Mac Kit and be done with it. Hence, I haven't seen the actual proof yet that my 'leaving-it-cocked' approach will yield the same results in the way of smoothness with with the Twister spring.
The Pro Mac kit is $89, while the Twister spring (on close-out BTW) is only $20. I have a Twister spring here that I can't wait to try as soon as I get an FBW 124 in here to tune/test and compare.
To compare the differences between the 'stand-alone' spring approach and the multi-part spring kit, you can read about the Pro Mac Kit here:
http://www.airrifleheadquarters.com/catalog/item/251483/8265467.htm
In case you didn't read about it already, the Twister spring requires a little spring-prep before you install it compare the spring in the Pro Mac Kit--not a lot, though, just a little. I know you obviously already saw the listing itself, but in case you didn't read those spring-prep instructions, I'm posting the link here as an easy reference:
http://www.airrifleheadquarters.com/catalog/item/251483/10335554.htm
Finally, here's the complete post thread about randy_68's experience with both the Twister spring and the Pro Mac Kit, with more details, comments by others, and several nice photos:
https://airgunwarriors.com/community/airgun-talk/3-tunes-for-my-fwb124d/
HTH.
Thanks ekmeister for your input...it is great to see the sharing of info on the forums. One question regarding the promac kit. Is the "white front guide " just a top hat? Also because the FWB manfacturing tolerances are so good is there much value in installing delrin buttons or a delrin piston ring? Thanks
Thanks ekmeister for your input...it is great to see the sharing of info on the forums. One question regarding the promac kit. Is the "white front guide " just a top hat? Also because the FWB manfacturing tolerances are so good is there much value in installing delrin buttons or a delrin piston ring? Thanks
You're welcome. My ability to help with your first question will be limited, because I've never seen the Pro Mac Kit in person, or even a photograph of it. My comments regarding the second question will be my opinion based on personal springer tuning experience.
I'm guessing that the front guide is 'just' a top-hat type, because JM usually calls the piece that drops into the piston first only a 'bushing', if it's a simple, flat piece with no insert on the part to fit down inside the spring.
But, your use of the word, "just", takes me aback a little. I say that because the top-hat design is an excellent way to make a front guide as long as the fit is correct, and I can guarantee you--even without ever seeing the kit--that the fit of the guide he provides is perfect, like his other tuning parts. Let me say this another way: when you say, "just", do you have some issues or reservations related to using that type of a front guide? If so, I invite you to please state those reservations here, and perhaps I or someone else can possibly help you address and resolve them.
Now, as far as buttons, I've done a lot of reading and studying about them over the years. The theories and experiences seem to fall over the playing field among those who have installed them, including myself.
Did you notice?: randy_68 showed photos of the work he did to install the buttons, plus photos of the piston once the buttons were installed. It looks like he did a great job IMO, and I'm sure he'll get good results with the way he did it when it comes to minimal friction in the cocking stroke, AND some degree of reduced vibration in the shot cycle.
(This space is being intentionally left blank to drop him a hint to tell you exactly his results in that regard, since he shot his rifle when he was done and I didn't!).
I've installed both Delrin and nylon buttons on both ends of a piston--not just one end--and I've installed a Delrin ring all the way around the skirt of an HW80/R1. Even though I used very-low-friction Delrin to make the ring, I went even further and machined an indentation into the ring at its midpoint to hold some appropriate lube.
And, when it was done, although the cocking stroke was indeed smooth, I really couldn't discern an appreciable difference in the cocking stroke from doing what I usually do. That is, to perform a very-thorough cross-hatching of the receiver tube, then use the best possible lubes on the parts. I'm not talking about using a low-powered spring here, either, where it probably wouldn't matter. I put a high-power spring in that HW80. Although it turned out well and will last many years, IMO/IME it wound-up being a lot of extra work for what didn't give anyone all that much in the way of a discernible benefit. (Opinions vary and this is just mine).
(Edit regarding buttons or a ring--VERY-Important. I can't believe I left this out--my apologies and embarrassment. It's the first thought that popped into my head when I woke up this morning) :
While buttons or a ring are a nice option on a springer, they may be A NECESSITY and YOUR ONLY HOPE for saving your pistol/ rifle if your receiver and or piston have become badly galled and the internal tolerances/ dimensions have been lost...
If, due to galling, the ID of the receiver and/ or the OD of the piston are no longer their original size, appearance, and smooth texture, and you thus feel harsh grinding when you attempt to cock the gun, new buttons or a ring can be made and trimmed to a new correct size, so the parts fit, galling is no longer an issue, and smooth operation is once again restored. Before you complete that work, any galling of the receiver should be smoothed so the new buttons don't get chewed-up by the rough, galled surface.
Now I'll address the normal situation where there is no galling whatsoever of those parts, and no reason to expect they will occur, such as might occur in the future, as when using a VERY-HIGH powered spring, to the point where you have concerns that the design of the springer might not be able to handle the stress of the cocking effort...
So, now, under normal circumstances and looking at the other side of this coin, does it HURT anything to use buttons or a ring?? No, it doesn't. However, that said, it's not always a case of one size fits all. You still need to look at the particulars in question to see what the best way is to install the buttons, or possibly a ring.
An example of what I'm referring to: If we're talking about the RWS/Diana rifles like 34/36/48/etc, the standard installation of a button at the 12 O'clock position may need modified (the others at 4 O'clock and 8 O'clock are still OK). You'll be better-served by installing buttons at 2 O'clock and 10 O'clock instead of a single button in the 12 O'clock position. That's because the sharp factory indentations in the receiver tube at 12 O'clock will pretty-quickly scrape-off any 12 O'clock button(s) that were on the piston.
As to the shot cycle, buttons or a ring do reduce the space in-between the piston and the receiver. The less space you have, the less vibration you'll have--there's no denying that. But, pretty-much as you said, it tends to be more-noticeable on sloppily-built guns. I've found the tolerances of the 124 to be tight-enough that adding buttons or a ring isn't necessary to get a mostly-vibration-free shot cycle. The largest improvement you'll get in reducing vibration is to use a mainspring that fits the spring guide(s) well, and either of the ARH options will do that for you. I've found the same thing to be true with most of the other Euro-made springers I've ever worked on, as long at the spring was a good fit on the guide(s).
BTW, I should mention a couple of things about the ring I put on the Weihrauch piston, as shown in the pics:
1. I have a machinist-also-a-friend who does just about any lathe work I want done to my exact specifications. That usually only means making some custom spring guides if I want to use a spring for which ARH doesn't have a complete spring kit. I do all the final measuring and fitting of those parts here, where I have a small set-up to do such things. Of course, I also do the rest of the actual tuning work. But, I elected to take-on this job of putting the ring on the piston myself, at my place, feeling it was sort of a challenge I might enjoy. All of it was done using an electric drill, a Dremel tool using assorted cutting wheels and grinding stones, and some files and sandpaper. That's how I machined the groove in the piston for the ring, and that's how I machined the groove in the ring for holding some lube. It came out just right.
2. The first thing I had to do when it came to modifying the piston was to turn-down the OD of the piston skirt, so I'd have some room to leave the Delrin sufficiently-proud (above the steel) to eliminate any chance of the steel piston skirt contacting the receiver tube. I mention it because I smoothed-out the surface of the skirt again once I had it machined to the right size, so you wouldn't be able to tell that I performed that essential step from the pic.
3. I glued the Delrin ring to the piston only for turning the piston while machining the indentation into the ring. Once the piston and ring were back in the rifle, even if the glue let go, the ring can't go anywhere so it will still work right. Both the groove in the piston skirt and the receiver wall keep the ring in-place.
4. The indentation you see at the midpoint of the ring isn't a mistake, and neither are what look like 'scratches' across the ring. Look closer and you'll see those scratches are in a near-perfect cross-hatch pattern. Both the (larger) indentation, and the (smaller) cross-hatches are there to hold some lube, like I said. Without something to hold the lube, it will soon be rubbed-off of smooth-surfaced buttons or rings. We can't have that! But, the majority of where the lube is held is inside the indentation around the circumference of the ring. Those minor-by-comparison cross-hatches are probably either wishful thinking, overkill, or both.
5. Many people use moly paste for lubricating buttons or a ring, but I mix a different lube here that's better-suited to lubing both the Delrin and the metal IMO. That is, moly paste with an oil/grease carrier base is really great for steel-on-steel applications, but things like graphite and Teflon particles in the right oil/grease base probably do a little better job of lubing BOTH surfaces. I DO add some moly particles to the mix, too, just to cover all the bases.
6. The bottom picture showing the piston inside the receiver was literally a 'dry run', not the final assembly. When I put the pieces back together for their final assembly, you could see some of that special mix of lubricant inside the groove around the Delrin ring, colored black due to the graphite and moly particles in the mix.
FWIW, the owner of the HW80/R1 in question still has the rifle and it's still doing very well for him. But he owns several other rifles that I've tuned without either buttons or rings, using the receiver cross-hatch method, and he's still perfectly happy with those, too. That is, he's never mentioned either a friction or a vibration problem with any of the dozen or so springers I've tuned for him over the years that didn't have buttons or rings. A couple of them are heavy-hitters with very-powerful mainsprings, so I think both he and I would know by now if it was a problem.
Bottom line on buttons (or a ring): Install the buttons if you'd like to give them a try, and see what YOU think. But, you'll probably do well using the aforementioned ARH parts and his off-the-shelf lubes, even if you don't.
IMO a ring or rings--like the ones used on the Air Arms TX-200--makes/make for a superior end-result compared to buttons when it's/they're done right, if the situation allows. But, that's IF the design of the rifle and the piston allow for ring installation. Depending on the application/design of the parts involved, buttons may be the better way to go.
(Before long, they're going to kick me off of here for using all this space, I just know it).
Hi Ed, thanks for the mention and kind words on my work.
On my original piston it had a very small area on the top rear of the piston that had wear marks from cocking so that is one reason I installed the buttons. It is now very smooth cocking with that satisfying click when it latches.
I never shot this gun before tearing it down as I knew it needed re built when I bought it so I dont know how much it changed the cocking but I'm sure it is smoother.
However as I stated in my original post the Promac kit is the clear winner in my eyes over the Twister. They have very similar power but the promac is much tamer on firing which I really like. I dont think the buttons do much for the firing cycle, as far as "feel" goes but are there to smooth the cocking cycle and eliminate the wear or galling on the piston and tube.
Proper lubes on the piston would do the same but apparently at one point this started to gall slightly. I did do a light crosshatch but failed to mention that in my other post.
I believe the top hat also helps with a smoother shot cycle as that is the main difference in the kits other than spring length. The twister is longer without a top hat.
I haven't shot much since then as it was deer season but now that I'm done with that I'm gearing up to go squirrel hunting and farm pesting. I'll post again after I get to do some more shooting. I must say though that after the last rebuild on my gun it is just a very nice shooting springer and it is just what I wanted out of it.
Hi Ed, thanks for the mention and kind words on my work.
On my original piston it had a very small area on the top rear of the piston that had wear marks from cocking so that is one reason I installed the buttons. It is now very smooth cocking with that satisfying click when it latches...
...Proper lubes on the piston would do the same but apparently at one point this started to gall slightly. I did do a light crosshatch but failed to mention that in my other post...
Yes, alleviating or repairing a galling situation is a very good application for a synthetic ring or buttons. I went back and edited that comment into my post.
Just like the way you did it, a light cross hatching of the receiver ID is also a good idea when you have a ring or buttons.
It seems you may already know this next item, but I'll mention it for the sake of others who may not.
You can use deeper cross hatching when the steel receiver tube will be directly against the steel of the piston. But you can't use simple, deep cross hatching if the cross hatches will be directly against Delrin, nylon, etc. If you do, the cross hatching will act much like a file and soon start to wear-down the synthetic material.
The right way to do it, and the way I did it but didn't mention it, is to use a shallower cross hatching depth in a direction that is diagonal in relation to the receiver tube, then lightly smooth over the area with finer sandpaper in a line that's parallel to the receiver tube. That way the cross hatching still holds some lubricant, but it won't be rough enough to hurt the ring or buttons.
I should have stated something about doing cross hatching even if you have a ring or buttons, so I'm glad you brought it up.
Thanks!
Thanks to all...great in-depth info! I think I will hold off on the twister spring. I have another that I will try with only a delrin top hat. I will put together the specs for this spring and also the measurement details of the top hat. When I get some results I will start a new post.
