Tuning Springer Tuning: More spring or more spacers for power?

[nobody1]

Power and accuracy don't mix well in a springer.

Adjustability is also not easy with a springer.

To reduce velocity cut the spring, half/one coil at a time, reassemble rifle, shoot, measure velocity and start again until you get the velocity as low as you want it.

To increase velocity, buy a new spring, or preload spring with many washers.

Or buy a PCP, and adjusting velocity is much easier.

 

[AirShot]

Make sure those spring ends are smooth and preferably polished, keep in mind that spring needs to rotate smoothly thru the shot/ cocking cycle! Also heat and make flat the last coil or an uneven surface will cause the spring to cant quickly.

 

[Sqwirl57]

Power and accuracy don't mix well in a springer.

Adjustability is also not easy with a springer.

To reduce velocity cut the spring, half/one coil at a time, reassemble rifle, shoot, measure velocity and start again until you get the velocity as low as you want it.

To increase velocity, buy a new spring, or preload spring with many washers.

Or buy a PCP, and adjusting velocity is much easier.

I'm just going to assume you just made this comment so that you could get your 10 comments over with so you could post to the classifieds because you clearly didn't read the post at all.

 

[gonzav71]

I prefer having more spring than washers. With Vortek springs after several tins of pellets , I usually get a velocity drop as the spring sets and shortens in length as much as 1/4”. I set my springers under 12 FPE as a starting point. Over the years of shooting my HW97K, LGU and TX200HC, sometimes going down to 10 FPE makes it even more consistent and easier to cock and shoot accurately. Power is not everything even at 12 FPE but a smooth shooting (minimal vibration) rifle should be the goal.

 

[austin870]

Im pretty new to springer tuning and had a question for the more experienced tuners out there. Given a set power that you are aiming to tune for (let's say 12ftlbs) do you prefer a longer spring or a shorter spring with some spacers to add preload? Does it matter? Does it affect shot cycle at all? Aside from coil count/OAL, let's assume both springs are otherwise identical.

To clarify what I'm talking about here. Assume you're starting out with a 14fpe spring. Would you prefer to cut away at it until you're sitting at 11.7ftlbs or would you rather cut it all the way down to 10fpe and then add some shims to the spring to bring it back up to 11.7fpe?

Get the correct spring from the beginning. I would advise Macarri when you are going down in foot pounds and Vortek when going up. The gun will be smoother and have less recoil if the spring is left its maximum length. A more compact shorter spring will have a different sort of shorter stroke feel as well.

It is like comparing the HW50 and HW35. Although very similar foot pounds, velocity etc they feel quite different. The HW50 with the longer spring and tube is noticeably smoother. The HW35 has a short choppy kind of stroke with slightly more recoil. The HW35 also has a shorter and harder cocking effort with the HW50 having a longer softer one. They are both quite successful shooters and fun as heck. It is a matter of which type you like. After having both I am just not a short stroke springer guy. Of course this example would be somewhat exaggerated compared to some spacers but it will be noticeable.

Getting the correct spring also means taking the gun down once and only one opportunity to bugger things up. Doing the spacer thing and hacking springs etc the chances of a scratch in the bluing, losing things, things going flying etc goes up considerably.

 

[thumper]

Im pretty new to springer tuning and had a question for the more experienced tuners out there. Given a set power that you are aiming to tune for (let's say 12ftlbs) do you prefer a longer spring or a shorter spring with some spacers to add preload? Does it matter? Does it affect shot cycle at all? Aside from coil count/OAL, let's assume both springs are otherwise identical.

To clarify what I'm talking about here. Assume you're starting out with a 14fpe spring. Would you prefer to cut away at it until you're sitting at 11.7ftlbs or would you rather cut it all the way down to 10fpe and then add some shims to the spring to bring it back up to 11.7fpe?

Get the correct spring from the beginning. I would advise Macarri when you are going down in foot pounds and Vortek when going up. The gun will be smoother and have less recoil if the spring is left its maximum length. A more compact shorter spring will have a different sort of shorter stroke feel as well.

It is like comparing the HW50 and HW35. Although very similar foot pounds, velocity etc they feel quite different. The HW50 with the longer spring and tube is noticeably smoother. The HW35 has a short choppy kind of stroke with slightly more recoil. The HW35 also has a shorter and harder cocking effort with the HW50 having a longer softer one. They are both quite successful shooters and fun as heck. It is a matter of which type you like. After having both I am just not a short stroke springer guy. Of course this example would be somewhat exaggerated compared to some spacers but it will be noticeable.

Getting the correct spring also means taking the gun down once and only one opportunity to bugger things up. Doing the spacer thing and hacking springs etc the chances of a scratch in the bluing, losing things, things going flying etc goes up considerably.

The stroke is only about 5mm different between the two. A negligible and basically unnoticeable difference at the most.

The 50 is smoother and less recoil because the piston is smaller *lighter* and the powerplant is more efficient. Smaller piston takes less spring to push and resists bounce. 

The 35 is more harsh because the piston is much larger *heavier* and the powerplant less efficient. Larger piston takes more spring to push.

 

[JayJay]

Your question boils down to how spring rates affect cocking and recoil.

When you cut a spring, the main thing you're changing is its spring rate. A shorter spring is always stiffer. Think of beard hairs, they are stiffer they shorter they get.

You also make the spring shorter which reduces its preload and thereby the initial compression. This explains why a cut spring delivers less power, even though it's stiffer. You have to shim to regain that lost preload. 

A stiffer spring has a steeper compression slope. Cocking effort may start easier, but it will increase faster. On the other hand, power delivery to the piston will start higher but drop off sooner. The piston will accelerate faster, but may have less resistance to bounce at the end of the stroke.

I suspect gasrams have higher spring rates than metal springs. That may explain why they feel so different.

So in your scenario, the shorter spring will be stiffer, even if you shim it back up to the same net power level as the other spring. 

 

[Teber66]

I had the Maccari adjustable tune kit put in my HW97K. He polished everything and used needle bearings and none of the spacers that came with the kit. Haven’t chrono’d it since I first got it but it was as at 11.7fpe with H&N Baracuda FT 9.57gr. I’ve got close to a 1000 pellets through it now and I’ll check the velocity in the next day or two.