Rap4 T68 gen 5 velocity adjustment

[oats944]

Hey guys, wondering if anyone has or had one of these? Just picked one up to give magfed a try. Velocity tops out at 220 fps with the strongest hammer spring. I read after purchase these aren’t so popular, but thought it would be a good starter with the low price I paid.

It appears very A5-ey inside. It has a screw on the passenger side that looks like it restricts air like the A5 which is backed all the way out. I found an old instruction manual that says velocity is adjusted down the barrel. I attached a picture of the barrel side of the valve housing. There’s a semi circle opening to let air to the bolt, and a 14 mm brass screw that seals that side of the valve. I’m not seeing anything that can be adjusted down the barrel though.

Internals are clean and well oiled. Hammer was polished. Tank output pressure was tested between 800 up to 1100 with no change in velocity.

If you have any idears please let me know. Thank you in advance!

[Arthur]

Welcome to Magfed! That’s NOT the gun you want to start with though my dude. I don’t know how to get a t68 to velocity but when you finally do, your next problem is jams, flips and chops. This gets you waxed in today’s MFOGs, super frustrating.

You can pick up used EMFs on the cheap nowadays. I highly recommend buying or saving for one.

One idea about T68 since I don’t want to just goon on your post: Is your paint super small? Barrel might be overbored.

[oats944]

Thank you sir, yeah I kind of saw that these aren’t that great after I already bought it lol. But it was complete, came with mags and extra parts, and was $50 so I said what the heck.

It came with the stock barrel with shroud and everything which I took off to save some weight and put on my A5 to Spyder adaptor to run a smaller bore barrel. It very much didn’t like the adaptor and broke every ball. Stock barrel shoots fine though, just the low velocity now.

Reading about the issues with these makes me want get rid of it, but on the flip side the fact that a marker that I own is not 100% right is driving me nuts lol.

[Arthur]

Oh yeah, thats exactly what this marker is worth. T68 is the dinosaur of magfed too.

[Trbo323]

Ok. Where's your bolt?

Rap4 has a terrible manual but yes it does say to adjust down the barrel with a common nelson valve velocity adjuster. I'm not even certain which valve style this things uses because rap4 has changed the platform so many times. My father in law used to have a t68 but it was based around a stacked tube blowback so velocity adjusted at the rear like normal

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[oats944]

Just throwing this out there if it helps someone down the road. Only place to adjust velocity is a screw on the side like an A5, which really doesn’t change anything if it’s all the way in or all the way out. I reached out to MCS and they suggested their extra long, extra heavy hammer spring for the A5. It’s a little too long as I couldn’t cock it, but after cutting off maybe 6 coils it fit and the velocity is at 300.

Between my first post and now I picked up a used emf100 so this ol’ girl will be on the shelf, but now I can sleep at night knowing a marker I’ll probably never use is up to speed lol. Thanks again everyone!

[Trbo323]

Between my first post and now I picked up a used emf100 so this ol' girl will be on the shelf, but now I can sleep at night knowing a marker I'll probably never use is up to speed lol. Thanks again everyone!

That was a very good decision

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