No issues here. Love my MM2K9.
No issues here. Love my MM2K9.
What length on/off pins is everyone using?
Did anyone have to adjust the clevis length?
Could anyone with a MM2K9 body please do the following:
1. State whether you can or cannot achieve 300fps in the MM2K9 setup using a valve that is verified to work in another setup.
2. Measure the following:
A to B. From center of rear field strip screw hole to bolt spring seat (without washer).
A to C. From center of rear field strip screw hole to aft edge of breech piece.
A to D. From center of rear field strip screw hole to aft edge of feed tube.
3. Place two balls in the feed tube (positioned vertically) without a hopper. Shoot the bottom one, and report what the top ball does (flies out of feed tube, feeds properly, jostles a bit, etc.). Try to quantify if possible. For example, it flew 2 feet out of the feed tube.
4. With a ball chambered, does the centerline of the ball line up with the centerline of the bolt and the centerline of the barrel?
Hypothesis 1: Bolt geometry is too far back relative to breech. Bolt releases power pulse too far back, losing much of the pressure up the feed tube.
Hypothesis 2: Air blast isn't centered on ball. It is concentrated above or below it.
The previous posts simply measure compression of the spring, which can be remedied by using a shorter or longer spring, using a thicker steel shim, or boring out some of the material at the bottom of the hole (depending on if your measured distance is shorter or longer than AGD spec).
Your data is greatly appreciated. Thank you.
Edit: Here's a link to the other relevant thread. Takes a while for us to figure out it's the body.
Last edited by nak81783; 08-05-2013 at 06:49 PM.
Last of the Salzburg Clan
Will do. Need to pick a proper caliper this week.
Well, the issue is exactly what I suspected all along. I even told the people at PTP when I sent my 2k9 back to them,mand they said the measurements were correct.
They had it over a year. I just got it back. They said it was fixed, and that it was an issue with some o-rings etc.
When I tried to get it over 170bps bps, it started leaking air again.
I order a caliper.
Well, the measurement is a whole half centimeter or a liittle over 3/16 of an inch short of what it should be.
From the center of the retaining screw to the edge of the breach, it measures 7 1/2 cm. vs 8 cm for a proper working Tac one.
So, the spring is already extremely compressed and too much force is needed to compress the bolt when firing the gun.
So the feedhole is too far back? See at least on mine, the hole for the valve is actually bored deeper than a standard mag, even with the steel insert installed. What is the depth from your quick strip screw to the front of the steel insert?
That's the measurement I'm talking about.
The breach wasnt drilled out deep enough.
The screw holes in the right place.
Interesting. My body is drilled .150" longer than a standard mag yet has similar problems. Yours should be a somewhat easy fix though. You would just need to have the hole bored a little bit deeper, assuming all other dimensions are ok.
I'm seeing similar variances with my Minimag, ULE and Xmag bodies.
I'll check more markers but they seem to have as much .185" variance in either direction with these stock AGD bodies.
However, there are certainly other issues with other bodies, as sniper42's also does not work, and the measurement you are talking about is longer on his body, not shorter.
I feel the only way to get to the bottom of this is to get the data I requested from working and non-working (for whatever reason) bodies alike. If you feel there is another measurement that can contribute, by all means, add it to the list.
I am certainly not the know-all, end-all, but I do feel it's time to let the data drive us. Let's get all the hypotheses out there, and collect whatever data may be necessary from as many members as are willing to contribute to prove or disprove each and every hypothesis.
Relevant thread: http://www.automags.org/forums/showt...l-RT-Pro-Issue
Last edited by nak81783; 08-02-2013 at 06:31 AM.
For measurements it may help if someone took a picture of a MM2K9 and used paint or something to highlight exactly what we are measuring. I can post up a closer pic of mine if needed or if someone has an unmounted body would probably be easier and that we are all measuring the same things.
I will say when I carefully lay my MM2K9 on top of my Tac body for comparison, the détents, FS holes, and feednecks seem to line up pretty spot on actually.
Last edited by OPBN; 08-02-2013 at 11:28 AM.
I'm planning on whipping up a print in solidworks once I have some time to sit down and sketch it.