My current build, now to replicate 5 times

[Riah_James]

This is the VM-68 I’ve been building out. It was modified for a phantom springpheed by BMC. I’m running a high pressure regulator on it, but I’m still having issues getting up to proper velocity. Can anyone help me with what I need to do to the springs, and does anyone possibly have some springs that would make the adjustment?

I do have the internal valve set to 12oclock so I’m pretty sure it’s turned up as much as possible. I’m only shooting around 260

[mooman978]

I love the stock

[Swedgin!!]

I love the stock

And the spring feed setup

[Riah_James]

Thanks guys

[Kit352]

On hpa you have to up the tank regulator pressure to get good velocity out of it, at least on both of mine. 900psi should get you close. Probably need to shim the stack. You can drill out the valve so one of the clock positions is massive, I generally pick the smaller winter position.
You can shim.the spring and make a poor man's velocity adjuster by trial and error or modify the stock back plug to accept a threaded bolt so you have an external velocity adjuster.
The automag spring conversion is great but I've found it's greatness is highly influenced by the gun it's on. One kit doesn't promise the same results on an identical gun. Almost certainly you would need the red and springs which are incredibly hard to find these days, almost impossible without help from someone's personal horde actually. The biggest issue seems to be the trigger mechanism. Some just can't handle the increased pressure from the agd conversion and so the sear won't release properly.
Looks like you have the stock barrel too. Mine was killing my velocity no matter what paint I put to it. I switch to an Armson and picked up 20 or so fps.
Check that your bolt is set to maximum velocity. Internal center screw turned all the way in with the ball bearing set in to the bolt, not pushing out into the oring.

260fps seems to be the defacto speed for these things once they are switched to hpa so at least your doing ok in that regard.

[DocsMachine]

Like Kit said, a good barrel will buy you a good bit. The stock tube is ballpark .693", way too big for any typical paint today.

If I might be allowed a bit of naked Capitalism, I have 'Bull' barrels for a VM that take 8" XL Freak inserts, as well as conventional VM Freak backs.

Either of those, with a tighter bore insert could probably buy you 30+FPS.

Doc.

[Riah_James]

I love the blatant self promotion. I already have your side panels on it. Do you have those barrels in stock, and if so how much are they?

[DocsMachine]

Somebody's gotta toot my horn.

Bulls are $90, for either 10" or 12", and a regular back is $56.
Doc.

[DocsMachine]

The other big thing is if you're using an aftermarket bolt, try switching back to a stocker.

You do NOT want a 'high flow' bolt. All a big bore bolt does is allow the gas charge to expand unnecessarily, before it contacts the ball. That wastes energy in the 'shot' of air, and you clearly don't have much to spare.

Doc.

[Riah_James]

I’ve gotten everything second hand, but I believe it’s the stock bolt

[Trbo323]

Take a look at the two you just grabbed from me to compare. As long as I'm remembering right they both had the same bolt in them so I imagine that's the stock one unless somehow 2 VMs both had the same aftermarket bolt.

Any particular reason you are replicating the build 5 times?

Sent from my motorola edge 2024 using Tapatalk

[Riah_James]

I want to be able to facilitate a 3v3 with these. They are so unique and inefficient I think it will be the most fun to play against itself.

and I’ll definitely do some comparisons on the bolts. I appreciate the advice.

[mmblake]

260 fps is the legal speed for most feilds. 280 is the max i see. if the vm is 260, you are good. You don't want to shoot above 270 fps with a vm68. You'll hurt someone shooting above that speed with a vm68.

my humble Opinion, there's a reason why vm68s were fased out of the sport.

[Riah_James]

I’m curious what the reason is? No shade or disrespect, just genuine curiosity.

Also, the fields around me in Oregon are 285, and I’m seeing a lot of bounces with this thing. Finally got it past lobbing though

[Riah_James]

One more note that I haven’t been able to get out of my mind. With what I know of physics, I can’t wrap my head around the idea that the same object (i.e. a paintball) traveling at the same speed would have a different force. I’ll admit I don’t have any sort of tested evidence in this case (VM-68 specifically) but it’s been tripping me up.

[DocsMachine]

You don't want to shoot above 270 fps with a vm68. You'll hurt someone shooting above that speed with a vm68.

-Sorry, but 260 FPS out of a VM is precisely the same as 260 out of an Autococker, a CS2, a Phantom, a PGP or a Splatmaster. The marker that fired it, has zero effect on the ball once it's left the muzzle- 260 is 260 whether it got there from being fired from a paintball gun, a slingshot or an Aboriginal poison-dart blowtube.

[In] my humble Opinion, there's a reason why vm68s were fased out of the sport.

-Of course there was: Because they were heavy, slow gas hogs, at a time when things like Autocockers, Automags and Illustrators were a fraction of the weight and far more gas efficient.

Doc.

[Riah_James]

The equation for force is literally mass x acceleration

[chplnstone]

IMHO, running hpa you'll need more volume to compensate for the lack of co2 expansion 'pop', i've heard of vmer's drilling out the smallest valve transfer port to slightly larger than the biggest stock one to increase flow

edit: reading previous replies, i kinda agree that 260-270 isn't bad, i was getting around 270 out of my pmi3 at supergame east a month or so ago, running hpa & hurricane labs/armson barrel