Southern Brisbane Nerf Club

Monday, 27 January 2014

Tripple Spring Centurion Mod & Why You Shouldn't Even Try

Sigh. Oh Centurion. I want you to be good. You have the looks, but when it's time to perform... nothing. You're big and red and fire big red darts, but that's where all the fun ends.


I've recently figured out a way to add an extra spring to a Centurion. So I added another, so it had three in total.

MUHAHAHAHAAHAHAHAHAHA, right? Or so I thought. Here is the dual spring photo.

Here is what I did:

• removed the chamber return spring (it causes the second "thunk" when you fire)
• removed all trigger safety locks
• removed trigger catch safety lock
• removed air restrictor
• removed barrel extension (and made it removable)
• tied the dart chamber to the "sled" using fishing line (I explain why in the video)
• added a cut down Centurion spring and a Longstrike's spring

There is a handy bit of shell behind where the plunger sits when it's caught on the trigger catch. There is a space of about 19mm between the end of the plunger and a wall in the shell. There is about 140mm between the plunger tube and that wall when the breech is closed. I cut down the spare Centurion spring to a compressed length of 18mm and was pleasantly surprised to find it fit the 140mm gape nicely. While I had the plunger tube out, I removed the air restrictor.

Then I had to find a way to keep the spring straight as the blaster was priming. I found that some left over barrel tube form a Longshot barrel extension was a good size to fit inside the spring. so I cut a circular hole in the wall (on both sides of the shell) to allow the tube through, it had to be longer than 140mm so that it would poke through the hole when the breech was closed. Then there was a problem, the tube was too long for the blaster to prime because the tube was hitting the rear most part of the shell. I eventually settled on a shorter length of tube hot glued into the hole in the wall in one side of the blaster with a smaller spring guide that can travel through it. For the smaller guide, I settled for a balsa wood rod I found. I cut it so that it had 1mm clearance form the rear of the shell but when the breech was closed, there was a gap between the tube and the rod. I did a few tests and the rod was catching on the tube with every test. I overcame this by tapering the end of the balsa wood rod. After that, I looked at a Longstrike spring and realised, "I could put this in here", so I did.


I had to remove the chamber return spring because there was no point in having it. The spring behind the plunger was forcing the breech closed. There are locks attached to the prime indicators (the green plastic bits), removed the locks while retaining the prime indicator (watch vid to find out how).

To attach the "bolt sled" to the dart chamber, I drilled a small hole into the sled and cut some groves into the dart chamber and wrapped some fishing line around it (about 6 or 7 times) and then used a screw to hold it in place. It was surprisingly solid and held up to the pressure of the springs well. But to make it work I had to carve off some of the sled-rail's guides. (watch the vid to understand what the hell I'm talking about)

Then onto the gear box and aligning the bolts. Firstly I

and then I was able to finally align the bolts with the gears set at the right position.

Now I reassembled the blaster. Now, here is what I found. The mods I performed resulted in this blaster have the most difficult way of loading a clip ever. I had to hold the bolts forward to keep the breech open and then insert a clip, or, hold the breech closed and jam the clip in there. Either way, it was a nuisance. Priming the blaster was easy enough, you can really feel the extra resistance from the extra springs though. The gears and the fishing line held up to the pressure like champs.

Time for a test fire. WOW! This thing is loud! Aussie Centurions get only a 20 metre (65 foot) range. I was able to boost it to 28 metres (92 feet). What does this do about the accuracy or reliability? Nothing at all. I did nothing to the plunger tube, it still has those vents in there and a compression zone of about 25mm (1 inch). I was hoping that by compressing the air more rapidly the dart would launch at a higher speed and it did. In the range tests all of the darts nose-dived into the ground :(

Here is the video.

During this exercise. I came to a brutal realisation. Hasbro have won this one. How did I come to that conclusion? With three springs in the Centurion, it maxed at 92 feet I do feel this is the limit for the stock internals (grey trigger version at least) because any more force from any type of spring I could've used I think would've broken something. I could've just bought an orange trigger version from Amazon and it would perform the same and be a lot easier to use. And even if I did the same modifications to an orange trigger version, I don't think the outcome would've been much different. There would be an increase in performance of course, but, the boost is not worth the time spent on the blaster... trust me on this. Without completely gutting the Centurion and replacing the internals, the Centurion is mod proof.


  1. This comment has been removed by the author.

  2. i hate to say but the ar keeps the air compressed for a while then unleashes it making a ten foot difference


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