MVP shoot down help

[Brawcooi]

Anyone ever experienced shoot down with an mvp? Shooting 3-4 reds in quick succession results in the last ball barely making it out of the barrel.

The sound signature can be heard quite clearly getting weaker with each shot , anyone have any ideas of cause and how to solve the issue?

[river031403]

Sounds like it’s not recharging fast enough

[Brawcooi]

Umm k , kinda had that part figured out… hence referencing shoot down. lol , input appreciated , thank you … any ideas of what could and likely is causing the slow recharge?


little more back story …
I recently picked up the marker from a friend who’d owned it for the past 2 years and never fired it, because he attempted to gas it up and it leaked like crazy… he got it from a friend of his whom apparently was a bit of a collector , no idea how long he had it , or when the last time it was fired (previous to myself that is ) or when it was fully rebuilt or even maintained . I was able to fix the leak and did my best to give it a good cleaning and regrease, but only have Dow 33 at the moment, waiting for a parts kit and Dow 55 to arrive but did what I could with the Dow 33 for the time being .
only orings that I replaced were the few that were visibly Missing chunks which were the cause of the leak, I have a couple sizes of the smaller metric sizes ordered and arriving tomorrow but all of which are static seals , nothing on any moving parts … would the use of the Dow 33 cause recharge//shoot down issues to that degree? All of the orings on moving parts seem in good shape , and had a healthy amount of grease in them before I went through and cleaned it all seals on moving components are true, with minor drag as recommended per a couple teardown videos
on YouTube …

anyway . It was shooting 256+\- prior to cleaning it , but attempting to adjust the velocity from there didn’t have positive gain , clockwise turns resulted in lower velocity ~230ish . Figured it was due to to high of input pressure for the strength of spring so I back it out a turn or two and checked again, was still around 220. No real change. … which is why I opted to pull it apart and clean it all out and relube… now I hadn’t thought about it at the time but the first round of chrono was all with the pump handle free to move and not held forward, I Imagine that may have added 10-20fps to my first reading of 255ish which is acceptable to me , but after regressing and better choice of insert to match the paint I was shooting it still was shooting the same as it was in the first place … is this a sign the reg isn’t functioning as it should ?

[JohnB]

If you put the regulator on a gauge you can test recharge rates. Inception designs as the reg gauges along with other manufacturers.

[JohnB]

I would agree. No exp with mvp; but sounds like a regulator rebuild time. Maybe check recharge rates

[Brawcooi]

Regulator is inline , and both input and output are simply holes sealed with stationary orings sandwiched between bare flat aluminum surfaces… so there is no real way to separate it and put it on a bench gauge.. to check a recharge rate… there isn’t even a way to measure it while it’s on the gun either

[JohnB]

Didn’t think about that. lol, good point. I would rebuild the reg and put in a new reg seat and see if that fixes it. Otherwise wait for additional responses. I don’t think the Dow 33 vs 55 does anything material to the fps.

[JohnB]

The manual says check the spring stack orientation and make sure Dow 55 on reg, ram, and poppet orings

[Brawcooi]

Reg seat in the case of bob long refs is the schrader valve? , given the lack of a recognizable seat, that would make sense .
only thing is I’m not sure if they wear out , if they’re rebuild able or if their even available , I recall reading a post somewhere recently saying they’re sold out everywhere and the OP was asking if a valve produced by an alternate company would function as replacement as it appeared to be a 1/1 copy

[Chuck E Ducky]

What input pressure on your tank reg.

MVP requires 450 (Low Pressure)

You could have an over pressure situation and You need to hold the handle to get true velocity over the chrono.

Your reg seat is likely still good but it’s important to feed it the right pressure. If you feed them to much it would have likely blown out the frame to body oring first. Probably what was causing your leak. If I had to guess your feeding it to high input pressure.

[Brawcooi]

It’s 550 I believe . Its a fs hero 2 , with the lp spring pack in it ,so it’s either 450 or 550 so its jojos be fine

[Chuck E Ducky]

Have you tested it? Those First Strike / Myth style regulators are trash.

Did you use the right duro when rebuilding the reg 70’s I believe.

)()()()( shim stack in the proper order?

Both balls still in your reg? Large and small?

[JohnB]

Those tanks Regs are trash! Wanted to like the mini profile so much but just a bad design or materials or something. Could be shim stack or number of shims maybe. The input pressure was a good idea.

[Chuck E Ducky]

Yeah and they red locked the leaky fill nipples on the two I have. I snapped the first one off at the threads trying to replace the seal. 2nd one I heated but it’s probably not the best to heat them up like that. I like them for my small bottles because they only add 1/2” to the bottle profile length. I was wishful they improved the myth reg but it’s basically a copy of a terrible reg.

[Trbo323]

If it seals up and shoots the input pressure isn't the problem. There's no way the input pressure can cause shoot down, it would have to bypass the regulator and would show up as low velocity if anything. I've plugged high pressure tanks into g6rs which also say the same thing and never had a problem.

Dow33 isn't the problem, I've also used 33 on whole Bob long markers and not had a problem. Honestly I think the reason they want 55 in the markers is because the tolerances are crap so it helps take up the extra space.

Just replace the regulator o rings. Don't inspect and put them back in. You know this thing hasn't been rebuilt in at least 3 years and probably more, just rebuild the whole thing for that matter. I'm betting something has deteriorated and it's now causing more friction than it once was. Why bother trying to sort it out with questionable rings? Put fresh ones in and then you have a good benchmark.

Make sure you have all 8 bevel springs in the reg

For the Schrader valves, looks like a typical Bob long one from what I can see in the manual. Here check this out

https://www.mcarterbrown.com/forum/p...valve-sourcing

Don't buy from blast legacy. I used to work for that D bag.

Man. I forgot how bad Bob long manuals are

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[ChuckLove]

I'm going to echo replacing the Schrader valve and swapping the piston o-ring with some fresh grease.

[river031403]

Umm k , kinda had that part figured out… hence referencing shoot down. lol , input appreciated , thank you … any ideas of what could and likely is causing the slow recharge?


little more back story …
I recently picked up the marker from a friend who’d owned it for the past 2 years and never fired it, because he attempted to gas it up and it leaked like crazy… he got it from a friend of his whom apparently was a bit of a collector , no idea how long he had it , or when the last time it was fired (previous to myself that is ) or when it was fully rebuilt or even maintained . I was able to fix the leak and did my best to give it a good cleaning and regrease, but only have Dow 33 at the moment, waiting for a parts kit and Dow 55 to arrive but did what I could with the Dow 33 for the time being .
only orings that I replaced were the few that were visibly Missing chunks which were the cause of the leak, I have a couple sizes of the smaller metric sizes ordered and arriving tomorrow but all of which are static seals , nothing on any moving parts … would the use of the Dow 33 cause recharge//shoot down issues to that degree? All of the orings on moving parts seem in good shape , and had a healthy amount of grease in them before I went through and cleaned it all seals on moving components are true, with minor drag as recommended per a couple teardown videos
on YouTube …

anyway . It was shooting 256+\- prior to cleaning it , but attempting to adjust the velocity from there didn’t have positive gain , clockwise turns resulted in lower velocity ~230ish . Figured it was due to to high of input pressure for the strength of spring so I back it out a turn or two and checked again, was still around 220. No real change. … which is why I opted to pull it apart and clean it all out and relube… now I hadn’t thought about it at the time but the first round of chrono was all with the pump handle free to move and not held forward, I Imagine that may have added 10-20fps to my first reading of 255ish which is acceptable to me , but after regressing and better choice of insert to match the paint I was shooting it still was shooting the same as it was in the first place … is this a sign the reg isn’t functioning as it should ?

Mkay well it’s really that simple..that’s why I put it that way..rebuild the reg..also there is that mod that can be done to the MVP so that you can use higher pressure tanks if that’s all you have…I have mine modded and shoots great

[Chuck E Ducky]

Really… Do tell it’s the thing I despise about BL markers the most. Everything I have is HP but my MVP. I have tons of air systems options and swapping regs is such a pain in the starfish.

[Brawcooi]

Oh , so with the velocity screw backed out all the way when I turn the air on I can still hear the reg charge, just very slowly , is that a sign the valve is toast? Is there anything I can do to maintain it ? Or basically when it’s toast it’s toast?


Can someone please verify this is the correct valve ?

[Trbo323]

I can't say for certain since I've never ordered them like that but that does look like many of the BL schrader valves I've delt with in the past

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