Canadian Airgun Forum

Hey guys! I have a previously detuned canadian Optimus 500, I ordered the new spring and swapped it out, I was wondering about the piston, I'm sure it is the longer version as the cocking is 90 degrees +/- . I know that the full strength piston is a 150mm and my current one should be 170mm, Is it as easy as taking a hacksaw to the back of the piston and trimming off the 20mm, deburring and cleaning up the edge and slipping it back into the gun? I'd rather not have to wait another 2 months for a part from the gravel agency, and I know that a fair amount of the Optimus stuff is now considered "obsolete" . I'm very much enjoying the new spring, it sounded a bit rough the first few cocks but after putting 70-100 pellets through it. The cocking effort is a little stiffer but that's alright. I'm a young guy

Not quite. You'll have to make a hole for the sear to catch, and the hole wall should be as straight as the stock one or you'll end up with a dangerous rifle that could fire by it self. Basically you do it exactly like the original one. The back end of the piston should be as straight as possible, you can use a square to check it. FYI, I measured 0.214'' (5.4 mm) from the back of the piston to the back edge of the hole. HTH

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If everything's so lovely yeah, then why don't I, why don't I, why don't I, why don't I feel lovely?

Damn.. I wish I had tools hahahah.. Looks like I"ll just order a piston from gravel agency then..

Have you checked with Eric at Scopes and Ammo?

Edit: You can also order a Phantom piston, they're the same

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If everything's so lovely yeah, then why don't I, why don't I, why don't I, why don't I feel lovely?

Why dont you email Eric at Scopes & Ammo? He sure as hell wont take 2 months to ship you something. I've probably placed 20+ orders with him, paid via EMT or sometimes CC and never once had a problem.

For me, I honestly Do. Not. Care. if his spring price is 25 bucks and gravel is 8 bucks. The advice and buying decisions he has helped me with so far are worth 10 times that to me and the more little guys that stay in business, the better for all of us.

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When the 425-hp "street Hemi" version hit the street in 1965, it was akin to taking an M230 chain gun to an arcade shooting gallery
Peter

I'll give him a try guys. thanks for the info.

You can use a hose clamp around piston as a cutting guide to stay square.Here is a pic I got from chevota's tuning guide.

another one.

Not sure if they are the same but seen a "vantage" piston for sale in For Sale section.

Chevota is a real class act. Not to mention the Springer tuning bible he's handing out has just about all the information one could need to tune or modify any Springer .

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I like air guns , and they like me

I agree.I have learned a LOT from the tuning guide.I still go back and re-read it

Many years ago I cut down a Quest piston with a Dremel tool and cut-off wheel. The project went great. I had to chop the piston, cut a new cocking notch, and lengthen out the cocking slot. These Quest pistons were even longer than the 170mm detuned Optimus.

I'm now shooting a tuned Optimus-495 with a 170mm piston. I replaced the spring with a 33coil .118" wire. With the 1.5" OEM guide spacer it was doing 755fps with 7.9gr pellets. This was more than I wanted so I reduced the spacer length to 3/4" and now it's about the same as a healthy HW30S or R7. It spits an 8.44gr JSB Exact at 620fps. This is exactly what I wanted for basement shooting and outdoor plinking to 30 yards.

I have a full power .177cal Optimus that has the regular 36coil .122" spring and 150mm piston. It was doing 960fps with 7.9gr out-of-the-box. I didn't like the behaviour so I installed a spacer that gave only about 1/4" of preload. The rifle now shoots at 800fps with a pleasant behaviour and good accuracy.

I know! I recently received his guide as well, have also had a few e-mails exchanged back and forth. What an amazing individual. A wealth of knowledge that is more than happy to share with anyone who asks. I unfortunately am merely a 30 year old in a one bedroom basement with 0 tools or access to them -_- I'm moving soon, hopefully will have a garage and can start tinkering slightly more heavily than at the moment.

You can prob do it with a hacksaw,drill and tape measure and a small file to clean up with.No special tools required.