VM68 Detents and Tuning options?

[Chuck E Ducky]

My VM was a lil brutal on paint. Just snagged a new Venturi bolt that should help. But my detents are shot. What options do I have? I’m sure I could hand cut some but mine are so bad I don’t have the dimensions. I know some users have made some. Anyone print them with success? How do these things actually work it’s not like they enter the breach. I’m running a cocker laser cut detent between the body and barrel that worked great on my VM but I was clipping balls in the neck. Paint was a lil brittle for a blow back at the temp I was shooting it at. But I would like to enhance the performance as best I can and make it as useable as possible because it was a ton of fun to shoot.

Also I’m thinking of adding some more volume with an expansion chamber see if I can make it a lil softer on paint.

[Alexndl]

I have two 3d model
I can 3d print you some or if you don't want 3d printing can send you the dimensions.

[Chuck E Ducky]

Might just be easier for me to get the dimensions of one. They seem pretty simple I can probably hand cut some out of rubber or something. Mine are just so dry rotted I have no idea of the dimensions.

[netsurferdude2]

BretG made an assembly a couple years ago of a cam and a spring to take the place of the detent. I can't seem to find the thread but he fixed my VM-68 with it.

[Carp]

The "Charm"?

Edit...not much here, to bad the picture link is broken... https://web.archive.org/web/20180206...evolution.html

Edit #2...found this too.

https://web.archive.org/web/20180222133233/http://www.mcarterbrown.com/forums/vm-empire/307561-bretgs-vm-permanent-solution-detent.html

[netsurferdude2]

A couple years ago = 2018. Jesus my memory is failing

[Ecapnation]

Those are very worn down, normally they enter the breach...

Also ditch the between the barrel detent. Some vm's bolts enter the barrel a little bit and that could be wreaking havoc with the paint.

I say some because the pmi3 definitely does.

[Chuck E Ducky]

I ran an oversized freak back on docs barrel. I think I was having clipping issues due to the void created by the non existent original detent. I was getting more chops then barrel breaks. I used it both ways and II had less problems with the over bore and detent fingers.

[DocsMachine]

Two things about the VM detent:

One, I'm coming more and more to dislike rubber/urethane detents. They're not bad in something like a 'Mag, say, with one of my adapters, because the bolt's "at rest" position is open. The detent doesn't spend most of its time bent or compressed.

But in nearly anything else- PE guns with the rubber detent, most Tippmanns, VMs, many Spyders or clone blowbacks, etc.- you generally close the bolt on an empty chamber between uses. So the gun spends most of its time with the rubber detent folded over and compressed.

I have an Empire Sniper and a Ressurection- in both cases, any time I want to use them, which might be a year or more since the last time I used it, I have to replace the detents because the old ones have taken a set and don't hold right anymore.

On the other hand, the classic spring-loaded 'Cocker detents, or early Angels, etc. unless they get clogged with paint (which can be its own issue) work each time, every time. The chrome detent on my green 'Cocker was probably installed around 2001, and that gun hasn't even been cycled in over a decade- but that detent, I just checked, still works just fine.

I made a mechanical, spring-loaded, drop-in VM detent a couple of years back, but haven't bothered to produce it after finding out BretG was supposedly making a similar design. I feel a solid, spring-loaded option is a much better solution- a more or less permanent solution, as opposed to the rubber ones you have to replace twice a year. I can make a run of those if anyone's interested.

Second, part of the issue with the VM, bolt and detent is the breech chamber is oversized, the bolts usually "cupped", and the detents hold the ball away from the face of the bolt. All of that tends to promote breech breaks to various extents, or at least cracking balls that later blow up in the barrel.

I believe you need a detent that holds the ball against the bolt face, and the bolt needs to be both long enough and NOT cupped so the ball is positioned properly in the breech.

Just my 5¢.

Doc.

[Toestr]

For the Sniper, Ressi and similar; remove the bolt for storage. Simple enough to reinstall. That and/or remove the mainspring on guns with an RVA and cock the bolt back.

[Melrosejedi]

Chuck , i looked at mine before the blowback game and they appear to be the proper length fingers but fell apart when i touched them.dry rotted but still intact, i was thinking of trying to cut some from rubber. I like docs idea with the modern spring loaded detent myself,and are probably a necessity today as i never experienced chopping back im the day with larger paint. I’ll take a look this week at her and see what i can whip up.

[Chuck E Ducky]

Doc I would definitely be interested to see what you come up with.

[BretG]

This is the Charm. They have been in use for about 5 years or so and I've sent them to people all over. They really do work perfectly as a permanent replacement for the fingers.

[Chaos]

The last ball detent you'll ever need for the VM

[Ecapnation]

Didn't Carter slap cocker detents is some of his milled ones?

[Chaos]

You can't do 3d printed ones for it, I had good luck with the Freedummy ones on here. However, I highly recommend BretG's Charm detent.... You'll never need another detent after installing one of them

[The Inflicted]

I've only played with my VM once but the detents Palmer's sells worked for me, as did his hammer O-ring.
Don't suppose anyone has any leads on cupseals?

[DocsMachine]

Don't suppose anyone has any leads on cupseals?

-Those are on my upcoming to-do list.

Doc.

[Chuck E Ducky]

I will take a few when you do Doc that would be great. Good to have a few JIC.

[Matt’s In PA]

Anybody selling mechanical detents yet? Bret? Doc? I joined up just to ask this one question after years of lurking.

[Carp]

Bret's lil' "Charm" works well. I think it should be called the "Pick". Because, it looks like a guitar pick and well, you pick your own piece of material.😉

[BretG]

You can wear them on your charm bracelets.

[nicmauro]

I'm sure I'll catch grief for this but I just fold a couple of beefy orings and arrange them so they stick out about the same as the original detents. Obviously not an elegant solution but it works pretty well and it's not like anyone can see it 😂