There are many spare parts and upgrade parts available on the market. A few years ago, the SHS brand surfaced and deservedly gained the reputation of an inexpensive brand of above-average quality and durability products. Later, it turned out that with this quality and durability it might vary. Is it the fault of the manufacturer itself or not completely fair competition? A subject for an endless debate and, probably, each individual airsoft player will have his/her own opinion about it. Today we took the most popular SHS main springs and compared them with each other. This test will not include any "it seems to me" nor "I know someone who knows". Just bare facts.

The conditions and the test platform

We conducted the test at the indoor sports shooting range in Myślenice. The temperature in the room was 23ºC, humidity at 41% and, obviously, no wind.

The test platform was the UAR carbine by APS which underwent a thorough upgrade.
Configuration:
- SHS 18:1 gears on ball bearings,
- SHS piston with 14 steel teeth,
- Ultimate silent piston head with a bearing,
- Ultimate cylinder head,
- APS stock nozzle with an o-ring,
- APS stock spring guide with a ball bearing,
- Element Ultra Torque motor,
- low-resistance 16 AWG wires,
- Gate Pico SSR3 mosfet,
- APS stock 363 mm barrel,
- G&G green elastic bucking.

During the tests, the carbine was powered by an 11.1 V 1800 mAh 45C battery by Brainergy.

The measurements were done using the XCORTECH X3500 chronograph, firing Specna Arms Core brand 0.2 g BBs.

The carbine was placed in the K-Zone shooting rest.

The was HopUp at zero.

Why UAR by APS? For convenience. Equally quick main spring replacement is probably only offered by a Steyr AUG replica, but those tend to leak air due to the gearbox moving away from the HU chamber. In the UAR the chamber is connected to the gearbox with a screw.

The M100 spring

<table style="width: 100%;"><tbody><tr><td colspan="10" style="vertical-align: bottom;text-align: center;background-color: black;" width="100%">M100 - nominal muzzle velocity: 328.1 fps</td></tr><tr><td style="vertical-align: bottom;text-align: center;background-color: white;">1</td><td style="vertical-align: bottom;text-align: center;background-color: white;">2</td><td style="vertical-align: bottom;text-align: center;background-color: white;">3</td><td style="vertical-align: bottom;text-align: center;background-color: white;">4</td><td style="vertical-align: bottom;text-align: center;background-color: white;">5</td><td style="vertical-align: bottom;text-align: center;background-color: white;">6</td><td style="vertical-align: bottom;text-align: center;background-color: white;">7</td><td style="vertical-align: bottom;text-align: center;background-color: white;">8</td><td style="vertical-align: bottom;text-align: center;background-color: white;">9</td><td style="vertical-align: bottom;text-align: center;background-color: white;">10</td></tr><tr><td style="vertical-align: bottom;text-align: center;background-color: white;">404.9</td><td style="vertical-align: bottom;text-align: center;background-color: white;">405.8</td><td style="vertical-align: bottom;text-align: center;background-color: white;">404.4</td><td style="vertical-align: bottom;text-align: center;background-color: white;">401.8</td><td style="vertical-align: bottom;text-align: center;background-color: white;">403.4</td><td style="vertical-align: bottom;text-align: center;background-color: white;">397.5</td><td style="vertical-align: bottom;text-align: center;background-color: white;">404.0</td><td style="vertical-align: bottom;text-align: center;background-color: white;">405.9</td><td style="vertical-align: bottom;text-align: center;background-color: white;">405.8</td><td style="vertical-align: bottom;text-align: center;background-color: white;">407.1</td></tr><tr><td colspan="9" style="vertical-align: bottom;text-align: right;background-color: white;">average:</td><td style="vertical-align: bottom;text-align: center;background-color: white;">404.1</td></tr><tr><td colspan="9" style="vertical-align: bottom;text-align: right;background-color: white;">difference   compared to the nominal muzzle velocity [fps]</td><td style="vertical-align: bottom;text-align: center;background-color: white;">76.0</td></tr><tr><td colspan="9" style="vertical-align: bottom;text-align: right;background-color: white;">difference   compared to the nominal muzzle velocity [%]</td><td style="vertical-align: bottom;text-align: center;background-color: white;">23.2</td></tr><tr><td colspan="9" style="vertical-align: bottom;text-align: right;background-color: white;">ROF:</td><td style="vertical-align: bottom;text-align: center;background-color: white;">24.7</td></tr></tbody></table>

In theory, the M100 spring should provide a muzzle velocity of 100 m/s, or 328.1 fps. We expected that the upgraded carbine will perform better, but the difference of 76 fps seems too much. It is over 23% more than the nominal value.

We also measured the rate of fire. The M100 spring had a ROF of 24.7 BBs/s.

The M110 spring

<table style="width: 100%;"><tbody><tr><td colspan="10" style="vertical-align: bottom;text-align: center;background-color: black;" width="100%">M110 - nominal muzzle velocity: 360.9 fps</td></tr><tr><td style="vertical-align: bottom;text-align: center;background-color: white;">1</td><td style="vertical-align: bottom;text-align: center;background-color: white;">2</td><td style="vertical-align: bottom;text-align: center;background-color: white;">3</td><td style="vertical-align: bottom;text-align: center;background-color: white;">4</td><td style="vertical-align: bottom;text-align: center;background-color: white;">5</td><td style="vertical-align: bottom;text-align: center;background-color: white;">6</td><td style="vertical-align: bottom;text-align: center;background-color: white;">7</td><td style="vertical-align: bottom;text-align: center;background-color: white;">8</td><td style="vertical-align: bottom;text-align: center;background-color: white;">9</td><td style="vertical-align: bottom;text-align: center;background-color: white;">10</td></tr><tr><td style="vertical-align: bottom;text-align: center;background-color: white;">426.3</td><td style="vertical-align: bottom;text-align: center;background-color: white;">427.9</td><td style="vertical-align: bottom;text-align: center;background-color: white;">426.5</td><td style="vertical-align: bottom;text-align: center;background-color: white;">432.9</td><td style="vertical-align: bottom;text-align: center;background-color: white;">429.3</td><td style="vertical-align: bottom;text-align: center;background-color: white;">429.2</td><td style="vertical-align: bottom;text-align: center;background-color: white;">429.8</td><td style="vertical-align: bottom;text-align: center;background-color: white;">430.2</td><td style="vertical-align: bottom;text-align: center;background-color: white;">429.0</td><td style="vertical-align: bottom;text-align: center;background-color: white;">432.3</td></tr><tr><td colspan="9" style="vertical-align: bottom;text-align: right;background-color: white;">average:</td><td style="vertical-align: bottom;text-align: center;background-color: white;">429.4</td></tr><tr><td colspan="9" style="vertical-align: bottom;text-align: right;background-color: white;">difference   compared to the nominal muzzle velocity [fps]</td><td style="vertical-align: bottom;text-align: center;background-color: white;">68.5</td></tr><tr><td colspan="9" style="vertical-align: bottom;text-align: right;background-color: white;">difference   compared to the nominal muzzle velocity [%]</td><td style="vertical-align: bottom;text-align: center;background-color: white;">19.0</td></tr><tr><td colspan="9" style="vertical-align: bottom;text-align: right;background-color: white;">ROF:</td><td style="vertical-align: bottom;text-align: center;background-color: white;">24.2</td></tr></tbody></table>

For the M110 spring the results show a similar tendency. Instead of the nominal 360.9 fps, we have an average of 499.4. That's 68.5 more. This gives a 19% difference.

We also begin to observe the difference between successive springs. Between the M100 and the M110 should (mathematically) be about 33 fps apart from each other regardless of whether the scale applied by SHS is shifted in relation to the "metric" scale. Yet, we do not have 33 but a 25 fps difference. That is not enough.

The M120 spring

<table style="width: 100%;"><tbody><tr><td colspan="10" style="vertical-align: bottom;text-align: center;background-color: black;" width="100%">M120 - nominal muzzle velocity: 393.7 fps</td></tr><tr><td style="vertical-align: bottom;text-align: center;background-color: white;">1</td><td style="vertical-align: bottom;text-align: center;background-color: white;">2</td><td style="vertical-align: bottom;text-align: center;background-color: white;">3</td><td style="vertical-align: bottom;text-align: center;background-color: white;">4</td><td style="vertical-align: bottom;text-align: center;background-color: white;">5</td><td style="vertical-align: bottom;text-align: center;background-color: white;">6</td><td style="vertical-align: bottom;text-align: center;background-color: white;">7</td><td style="vertical-align: bottom;text-align: center;background-color: white;">8</td><td style="vertical-align: bottom;text-align: center;background-color: white;">9</td><td style="vertical-align: bottom;text-align: center;background-color: white;">10</td></tr><tr><td style="vertical-align: bottom;text-align: center;background-color: white;">468.6</td><td style="vertical-align: bottom;text-align: center;background-color: white;">476.6</td><td style="vertical-align: bottom;text-align: center;background-color: white;">476.4</td><td style="vertical-align: bottom;text-align: center;background-color: white;">478.2</td><td style="vertical-align: bottom;text-align: center;background-color: white;">477.7</td><td style="vertical-align: bottom;text-align: center;background-color: white;">476.0</td><td style="vertical-align: bottom;text-align: center;background-color: white;">475.2</td><td style="vertical-align: bottom;text-align: center;background-color: white;">481.6</td><td style="vertical-align: bottom;text-align: center;background-color: white;">484.7</td><td style="vertical-align: bottom;text-align: center;background-color: white;">475.5</td></tr><tr><td colspan="9" style="vertical-align: bottom;text-align: right;background-color: white;">average:</td><td style="vertical-align: bottom;text-align: center;background-color: white;">477.1</td></tr><tr><td colspan="9" style="vertical-align: bottom;text-align: right;background-color: white;">difference   compared to the nominal muzzle velocity [fps]</td><td style="vertical-align: bottom;text-align: center;background-color: white;">83.4</td></tr><tr><td colspan="9" style="vertical-align: bottom;text-align: right;background-color: white;">difference   compared to the nominal muzzle velocity [%]</td><td style="vertical-align: bottom;text-align: center;background-color: white;">21.2</td></tr><tr><td colspan="9" style="vertical-align: bottom;text-align: right;background-color: white;">ROF:</td><td style="vertical-align: bottom;text-align: center;background-color: white;">23.2</td></tr></tbody></table>

The trend continues. The difference in respect to the "nominal" is 83.4 fps (21.2%).

Compared to the M110 spring, we have an increase of 47.7 fps instead of the expected 33 fps.

The M130 spring

<table style="width: 100%;"><tbody><tr><td colspan="10" style="vertical-align: bottom;text-align: center;background-color: black;" width="100%">M130 - nominal muzzle velocity: 426.5 fps</td></tr><tr><td style="vertical-align: bottom;text-align: center;background-color: white;">1</td><td style="vertical-align: bottom;text-align: center;background-color: white;">2</td><td style="vertical-align: bottom;text-align: center;background-color: white;">3</td><td style="vertical-align: bottom;text-align: center;background-color: white;">4</td><td style="vertical-align: bottom;text-align: center;background-color: white;">5</td><td style="vertical-align: bottom;text-align: center;background-color: white;">6</td><td style="vertical-align: bottom;text-align: center;background-color: white;">7</td><td style="vertical-align: bottom;text-align: center;background-color: white;">8</td><td style="vertical-align: bottom;text-align: center;background-color: white;">9</td><td style="vertical-align: bottom;text-align: center;background-color: white;">10</td></tr><tr><td style="vertical-align: bottom;text-align: center;background-color: white;">496.1</td><td style="vertical-align: bottom;text-align: center;background-color: white;">499.2</td><td style="vertical-align: bottom;text-align: center;background-color: white;">494.6</td><td style="vertical-align: bottom;text-align: center;background-color: white;">495.3</td><td style="vertical-align: bottom;text-align: center;background-color: white;">496.8</td><td style="vertical-align: bottom;text-align: center;background-color: white;">494.4</td><td style="vertical-align: bottom;text-align: center;background-color: white;">497.5</td><td style="vertical-align: bottom;text-align: center;background-color: white;">497.5</td><td style="vertical-align: bottom;text-align: center;background-color: white;">498.3</td><td style="vertical-align: bottom;text-align: center;background-color: white;">501.3</td></tr><tr><td colspan="9" style="vertical-align: bottom;text-align: right;background-color: white;">average:</td><td style="vertical-align: bottom;text-align: center;background-color: white;">497.1</td></tr><tr><td colspan="9" style="vertical-align: bottom;text-align: right;background-color: white;">difference   compared to the nominal muzzle velocity [fps]</td><td style="vertical-align: bottom;text-align: center;background-color: white;">70.6</td></tr><tr><td colspan="9" style="vertical-align: bottom;text-align: right;background-color: white;">difference   compared to the nominal muzzle velocity [%]</td><td style="vertical-align: bottom;text-align: center;background-color: white;">16.6</td></tr><tr><td colspan="9" style="vertical-align: bottom;text-align: right;background-color: white;">ROF:</td><td style="vertical-align: bottom;text-align: center;background-color: white;">22.8</td></tr></tbody></table>

497.1 fps on an M130! Almost like the heavily overrated Guarders!

Over 70 fps compared to the nominal value, but only 20.1 fps more than on the M120 spring.

The M140 spring

<table style="width: 100%;"><tbody><tr><td colspan="10" style="vertical-align: bottom;text-align: center;background-color: black;" width="100%">M100 - nominal muzzle velocity: 459.3 fps</td></tr><tr><td style="vertical-align: bottom;text-align: center;background-color: white;">1</td><td style="vertical-align: bottom;text-align: center;background-color: white;">2</td><td style="vertical-align: bottom;text-align: center;background-color: white;">3</td><td style="vertical-align: bottom;text-align: center;background-color: white;">4</td><td style="vertical-align: bottom;text-align: center;background-color: white;">5</td><td style="vertical-align: bottom;text-align: center;background-color: white;">6</td><td style="vertical-align: bottom;text-align: center;background-color: white;">7</td><td style="vertical-align: bottom;text-align: center;background-color: white;">8</td><td style="vertical-align: bottom;text-align: center;background-color: white;">9</td><td style="vertical-align: bottom;text-align: center;background-color: white;">10</td></tr><tr><td style="vertical-align: bottom;text-align: center;background-color: white;">532.2</td><td style="vertical-align: bottom;text-align: center;background-color: white;">530.8</td><td style="vertical-align: bottom;text-align: center;background-color: white;">521.6</td><td style="vertical-align: bottom;text-align: center;background-color: white;">521.0</td><td style="vertical-align: bottom;text-align: center;background-color: white;">533.3</td><td style="vertical-align: bottom;text-align: center;background-color: white;">527,7</td><td style="vertical-align: bottom;text-align: center;background-color: white;">531.8</td><td style="vertical-align: bottom;text-align: center;background-color: white;">530.2</td><td style="vertical-align: bottom;text-align: center;background-color: white;">532.7</td><td style="vertical-align: bottom;text-align: center;background-color: white;">534.1</td></tr><tr><td colspan="9" style="vertical-align: bottom;text-align: right;background-color: white;">average:</td><td style="vertical-align: bottom;text-align: center;background-color: white;">529.5</td></tr><tr><td colspan="9" style="vertical-align: bottom;text-align: right;background-color: white;">difference   compared to the nominal muzzle velocity [fps]</td><td style="vertical-align: bottom;text-align: center;background-color: white;">70.2</td></tr><tr><td colspan="9" style="vertical-align: bottom;text-align: right;background-color: white;">difference   compared to the nominal muzzle velocity [%]</td><td style="vertical-align: bottom;text-align: center;background-color: white;">15.3</td></tr><tr><td colspan="9" style="vertical-align: bottom;text-align: right;background-color: white;">ROF:</td><td style="vertical-align: bottom;text-align: center;background-color: white;">21.7</td></tr></tbody></table>

The carnival continues! 529.5 fps!

The difference between the M140 spring and the M130 spring  is finally as it should be - 32.4 fps.

The M150 spring

<table style="width: 100%;"><tbody><tr><td colspan="10" style="vertical-align: bottom;text-align: center;background-color: black;" width="100%">M100 - nominal muzzle velocity: 492.1 fps</td></tr><tr><td style="vertical-align: bottom;text-align: center;background-color: white;">1</td><td style="vertical-align: bottom;text-align: center;background-color: white;">2</td><td style="vertical-align: bottom;text-align: center;background-color: white;">3</td><td style="vertical-align: bottom;text-align: center;background-color: white;">4</td><td style="vertical-align: bottom;text-align: center;background-color: white;">5</td><td style="vertical-align: bottom;text-align: center;background-color: white;">6</td><td style="vertical-align: bottom;text-align: center;background-color: white;">7</td><td style="vertical-align: bottom;text-align: center;background-color: white;">8</td><td style="vertical-align: bottom;text-align: center;background-color: white;">9</td><td style="vertical-align: bottom;text-align: center;background-color: white;">10</td></tr><tr><td style="vertical-align: bottom;text-align: center;background-color: white;">560.1</td><td style="vertical-align: bottom;text-align: center;background-color: white;">556.9</td><td style="vertical-align: bottom;text-align: center;background-color: white;">559.0</td><td style="vertical-align: bottom;text-align: center;background-color: white;">556.9</td><td style="vertical-align: bottom;text-align: center;background-color: white;">555.2</td><td style="vertical-align: bottom;text-align: center;background-color: white;">559.7</td><td style="vertical-align: bottom;text-align: center;background-color: white;">557.1</td><td style="vertical-align: bottom;text-align: center;background-color: white;">559.2</td><td style="vertical-align: bottom;text-align: center;background-color: white;">552.2</td><td style="vertical-align: bottom;text-align: center;background-color: white;">559.0</td></tr><tr><td colspan="9" style="vertical-align: bottom;text-align: right;background-color: white;">average:</td><td style="vertical-align: bottom;text-align: center;background-color: white;">557.5</td></tr><tr><td colspan="9" style="vertical-align: bottom;text-align: right;background-color: white;">difference   compared to the nominal muzzle velocity [fps]</td><td style="vertical-align: bottom;text-align: center;background-color: white;">65.4</td></tr><tr><td colspan="9" style="vertical-align: bottom;text-align: right;background-color: white;">difference   compared to the nominal muzzle velocity [%]</td><td style="vertical-align: bottom;text-align: center;background-color: white;">13.3</td></tr><tr><td colspan="9" style="vertical-align: bottom;text-align: right;background-color: white;">ROF:</td><td style="vertical-align: bottom;text-align: center;background-color: white;">18.2</td></tr></tbody></table>

557,5 fps.
Again, below expectations compared to the weaker spring.
The motor finally noticed that the spring tension increased. The ROF dropped to18.2 BBS/s (from 24.7 BBs/s on the M100 spring).

Comparison tables

To make it easier for all of you interested in comparing and analyzing, we have compiled the values in separate tables.

The difference in fps in relation to the nominal value:

<table style="width: 100%;"><tbody><tr><td style="vertical-align: bottom;text-align: center;background-color: black;" width="16.666666666666668%">M100</td><td style="vertical-align: bottom;text-align: center;background-color: black;" width="16.666666666666668%">M110</td><td style="vertical-align: bottom;text-align: center;background-color: black;" width="16.666666666666668%">M120</td><td style="vertical-align: bottom;text-align: center;background-color: black;" width="16.666666666666668%">M130</td><td style="vertical-align: bottom;text-align: center;background-color: black;" width="16.666666666666668%">M140</td><td style="vertical-align: bottom;text-align: center;background-color: black;" width="16.666666666666668%">M150</td></tr><tr><td style="vertical-align: bottom;text-align: center;background-color: white;">76.0</td><td style="vertical-align: bottom;text-align: center;background-color: white;">68.05</td><td style="vertical-align: bottom;text-align: center;background-color: white;">83.4</td><td style="vertical-align: bottom;text-align: center;background-color: white;">70.6</td><td style="vertical-align: bottom;text-align: center;background-color: white;">70.2</td><td style="vertical-align: bottom;text-align: center;background-color: white;">65.4</td></tr></tbody></table>

The difference in percents in relation to the nominal value:

<table style="width: 100%;"><tbody><tr><td style="vertical-align: bottom;text-align: center;background-color: black;" width="16.666666666666668%">M100</td><td style="vertical-align: bottom;text-align: center;background-color: black;" width="16.666666666666668%">M110</td><td style="vertical-align: bottom;text-align: center;background-color: black;" width="16.666666666666668%">M120</td><td style="vertical-align: bottom;text-align: center;background-color: black;" width="16.666666666666668%">M130</td><td style="vertical-align: bottom;text-align: center;background-color: black;" width="16.666666666666668%">M140</td><td style="vertical-align: bottom;text-align: center;background-color: black;" width="16.666666666666668%">M150</td></tr><tr><td style="vertical-align: bottom;text-align: center;background-color: white;">23.2%</td><td style="vertical-align: bottom;text-align: center;background-color: white;">19.0%</td><td style="vertical-align: bottom;text-align: center;background-color: white;">21.2%</td><td style="vertical-align: bottom;text-align: center;background-color: white;">16.6%</td><td style="vertical-align: bottom;text-align: center;background-color: white;">15.3%</td><td style="vertical-align: bottom;text-align: center;background-color: white;">13.3%</td></tr></tbody></table>

The difference in fps in relation to previous, weaker spring:

<table style="width: 100%;"><tbody><tr><td style="vertical-align: bottom;text-align: center;background-color: black;" width="16.666666666666668%">M100</td><td style="vertical-align: bottom;text-align: center;background-color: black;" width="16.666666666666668%">M110</td><td style="vertical-align: bottom;text-align: center;background-color: black;" width="16.666666666666668%">M120</td><td style="vertical-align: bottom;text-align: center;background-color: black;" width="16.666666666666668%">M130</td><td style="vertical-align: bottom;text-align: center;background-color: black;" width="16.666666666666668%">M140</td><td style="vertical-align: bottom;text-align: center;background-color: black;" width="16.666666666666668%">M150</td></tr><tr><td style="vertical-align: bottom;text-align: center;background-color: white;"> -</td><td style="vertical-align: bottom;text-align: center;background-color: white;">25.3</td><td style="vertical-align: bottom;text-align: center;background-color: white;">47.7</td><td style="vertical-align: bottom;text-align: center;background-color: white;">20.1</td><td style="vertical-align: bottom;text-align: center;background-color: white;">32.4</td><td style="vertical-align: bottom;text-align: center;background-color: white;">28.0</td></tr></tbody></table>

The rate of fire on an 11.1 V 1800 mAh 45C battery:

<table style="width: 100%;"><tbody><tr><td style="vertical-align: bottom;text-align: center;background-color: black;" width="16.666666666666668%">M100</td><td style="vertical-align: bottom;text-align: center;background-color: black;" width="16.666666666666668%">M110</td><td style="vertical-align: bottom;text-align: center;background-color: black;" width="16.666666666666668%">M120</td><td style="vertical-align: bottom;text-align: center;background-color: black;" width="16.666666666666668%">M130</td><td style="vertical-align: bottom;text-align: center;background-color: black;" width="16.666666666666668%">M140</td><td style="vertical-align: bottom;text-align: center;background-color: black;" width="16.666666666666668%">M150</td></tr><tr><td style="vertical-align: bottom;text-align: center;background-color: white;">24.7</td><td style="vertical-align: bottom;text-align: center;background-color: white;">24.2</td><td style="vertical-align: bottom;text-align: center;background-color: white;">23.2</td><td style="vertical-align: bottom;text-align: center;background-color: white;">22.8</td><td style="vertical-align: bottom;text-align: center;background-color: white;">21.7</td><td style="vertical-align: bottom;text-align: center;background-color: white;">18.2</td></tr></tbody></table>

Summary

I am far from using pseudo-scientific gibberish. First of all, I do not have the proper knowledge and secondly, the amount of data is too small. However, it is obvious to me that the SHS springs are heavily undervalued. That is, they are stronger than the manufacturer says. The differences in relation to the nominal values are huge. Even considering that the reference rifle was previously upgrade.

A separate matter is their longevity, and precisely the time (number of shots) after which they apparently lose some of their properties. I have my won personal opinion on this subject, but I do not have any hard data yet, so I will probably come back to this subject in some time

PS

Immediately after completing the SHS springs test, I also measured the performance of the reference carbine on the M160 Tornado and the M170 Systema springs. Conditions, measurement method and measuring devices were the same as during the SHS test.

The average of 10 shots on the M160 Tornado spring: 454 fps.

Average of 10 shots for M170 Systema spring: 560.13 fps.

Will this turn into another set of tests?