Unusual RT Pro Issue. . .Now confirmed as micromag 2k9 problem!

[OPBN]

Probably be easier to take the feed neck off and just cover it?

[athomas]

Load a single ball in the breach. Make a feed tube blocking device to prevent blowback and stick it in the feed tube far enough to use up any space but not far enough to interfere with the bolt. Fire the gun and see if the velocity is any higher without the blowback.

[OPBN]

Does post #34 answer that question?

[nak81783]

Beats being called Mr PoopyPants....

I would still like to know the detent questions.

Does post #34 answer that question?

[OPBN]

Crap. Running out of ideas.

With a ball chambered, does the centerline of the ball line up with the centerline of the bolt and the centerline of the barrel? Perhaps the air blast isn't centered behind the ball? I'm assuming yours is fine, since you can hit desired velocity, but it's something to check on Sniper42's.

I posted similar questions in the thread Sniper42 referenced earlier. Hopefully, all those people are still subscribed, and we can get more data points. Worst case, I have more people call me Mr. Snippy.


-Nathan

Beats being called Mr PoopyPants....

I would still like to know the detent questions.

[nak81783]

Crap. Running out of ideas.

With a ball chambered, does the centerline of the ball line up with the centerline of the bolt and the centerline of the barrel? Perhaps the air blast isn't centered behind the ball? I'm assuming yours is fine, since you can hit desired velocity, but it's something to check on Sniper42's.

I posted similar questions in the thread Sniper42 referenced earlier. Hopefully, all those people are still subscribed, and we can get more data points. Worst case, I have more people call me Mr. Snippy.


-Nathan

[OPBN]

No you didn't miss anything. I misread Sniper42's post. I thought he meant his bolt face was sitting back .150" from the forward face of the body (largest piece, not the removable breech). This is why I want to verify who's measuring what from where.

Can you answer some questions if they don't involve taking the thing apart, please?

1. Look at this post. It's the best picture I've found to use for my understanding thus far. Other than the breech being backwards (detent holes should be forward of the feed tube), I think it is fairly accurate. Is the breech keyed, so it can only go in one way? It is keyed, but I cannot honestly remember if it is both sides or only one side of the breach. Is it a straight-shot diameter all the way through, or is it stepped? Appears to be the same size to me. If push comes to shove, I could take it apart and use calipersI'm wondering if they're not keyed and have a stepped diameter, if some of them got machined backwards.

http://www.automags.org/forums/showthread.php?264765-MM2K9-for-sale&highlight=mm2k9

2. Can you hand load two balls into the feed tube without a hopper? When you fire the bottom one, does the top one shoot out of the feed tube as Sniper42 described?Yup. Second ball in the stack shot up and out.

3. With a ball all the way forward against the detent, you have about a .300" gap from the back of the ball to the face of the bolt as well?Yes. Approx.

As far as slightly higher velocity with your hopper off, the only thing I can think of is you don't have the forcefeed pressure on the ball stack. This makes it ever so slightly easier for the Level 10 to complete its stroke. Any bit of less resistance lets it complete its stroke slightly faster, losing slightly less pressure through the bleed hole in the shorter cycle time. I would think this would be negligible, but it hypothetically could translate into higher velocity.Kinda my thought. Which made me think perhaps there was something wrong/weak about the detents being used. Perhaps the loader was pushing past and causing the low FPS? But Sniper said he had the same issue with hand feeding. What about taking the detents out and hand feeding?

Anyway, I'm sure I'll come up with some more questions.


-Nathan

Questions answered.

[nak81783]

Except, that I just measured my body using a very scientific method of sticking a wooden kabob skewer flat side into the breach from the front, marked it and measured it and my bolt face is sitting at approx .15" from the feed hole as well.

Did I miss something?

Edit* I had a stupid idea about trying to test the FPS by just dropping a ball in to see if it made a difference and it didnt. I hand fed 4-5 balls and the FPS oddly went slighty higher than with the hopper on.

What detent are you using Sniper? I am using Check it detents which are pretty weak to begin with, but I made them stronger by putting an additional spring from a pen in.

No you didn't miss anything. I misread Sniper42's post. I thought he meant his bolt face was sitting back .150" from the forward face of the body (largest piece, not the removable breech). This is why I want to verify who's measuring what from where.

Can you answer some questions if they don't involve taking the thing apart, please?

1. Look at this post. It's the best picture I've found to use for my understanding thus far. Other than the breech being backwards (detent holes should be forward of the feed tube), I think it is fairly accurate. Is the breech keyed, so it can only go in one way? Is it a straight-shot diameter all the way through, or is it stepped? I'm wondering if they're not keyed and have a stepped diameter, if some of them got machined backwards.

http://www.automags.org/forums/showthread.php?264765-MM2K9-for-sale&highlight=mm2k9

2. Can you hand load two balls into the feed tube without a hopper? When you fire the bottom one, does the top one shoot out of the feed tube as Sniper42 described?

3. With a ball all the way forward against the detent, you have about a .300" gap from the back of the ball to the face of the bolt as well?

As far as slightly higher velocity with your hopper off, the only thing I can think of is you don't have the forcefeed pressure on the ball stack. This makes it ever so slightly easier for the Level 10 to complete its stroke. Any bit of less resistance lets it complete its stroke slightly faster, losing slightly less pressure through the bleed hole in the shorter cycle time. I would think this would be negligible, but it hypothetically could translate into higher velocity.

Anyway, I'm sure I'll come up with some more questions.


-Nathan

[nak81783]

Sniper first. lol. Post up some pics of what you are measuring and I'll confirm. Seriously, its a pain to take apart and every time you do there is a risk of cross threading and stripping the front block. That and I might scratch my baby.

Understood. Thanks for your input.


-Nathan

[OPBN]

Sniper first. lol. Post up some pics of what you are measuring and I'll confirm. Seriously, its a pain to take apart and every time you do there is a risk of cross threading and stripping the front block. That and I might scratch my baby.

[nak81783]

Sniper42 and OPBN: I can't tell if we're all measuring the same thing. Could you both please remove the breech, and measure the distance from the face of the bolt to the nearest flat surface of the body (nearest surface to the OD of the bolt, perpendicular to the axis of the bolt), noting whether it is recessed or protruding from this surface?

Now my head is starting to hurt.


-Nathan

[OPBN]

Lol. I've been called much worse. Thanks for the info.

What does everbody think? Time to employ a machinist? The custom bolt would be cool, in my opinion. I wonder if PTP could whip these out to remedy the faulty bodies.

What is involved in making a Level 10 bolt? While changing a foamie last night, it looked like the center portion is brazed in. I feel a lathe with offset boring tools (or trepan tools), a basic mill, and some stainless bar stock would work though.

How many of these bodies are faulty? Enough to get a machinist to do a run of custom bolts or repair work?


-Nathan

Except, that I just measured my body using a very scientific method of sticking a wooden kabob skewer flat side into the breach from the front, marked it and measured it and my bolt face is sitting at approx .15" from the feed hole as well.

Did I miss something?

Edit* I had a stupid idea about trying to test the FPS by just dropping a ball in to see if it made a difference and it didnt. I hand fed 4-5 balls and the FPS oddly went slighty higher than with the hopper on.

What detent are you using Sniper? I am using Check it detents which are pretty weak to begin with, but I made them stronger by putting an additional spring from a pen in.

[nak81783]

Okay, Mr. Snippy.

Lol. I've been called much worse. Thanks for the info.

What does everbody think? Time to employ a machinist? The custom bolt would be cool, in my opinion. I wonder if PTP could whip these out to remedy the faulty bodies.

What is involved in making a Level 10 bolt? While changing a foamie last night, it looked like the center portion is brazed in. I feel a lathe with offset boring tools (or trepan tools), a basic mill, and some stainless bar stock would work though.

How many of these bodies are faulty? Enough to get a machinist to do a run of custom bolts or repair work?


-Nathan

[OPBN]

Any chance you could answer these questions, please?


-Nathan

Okay, Mr. Snippy.

OPBN: Does the bolt face sit recessed in your body as Sniper42 describes? Yes. Appears to actually sit right up to the breach

OPBN and Sniper42: Please measure, if you can, the distance from the face of the body material on the aft inside edge of the breech slot (actual breech piece removed) to the aft surface of the steel insert.Not going to lie, taking this thing apart is a PITA. I can say that the bolt face seems to sit right at the seam of the breach.

[nak81783]

OPBN: Does the bolt face sit recessed in your body as Sniper42 describes?

OPBN and Sniper42: Please measure, if you can, the distance from the face of the body material on the aft inside edge of the breech slot (actual breech piece removed) to the aft surface of the steel insert.

Any chance you could answer these questions, please?


-Nathan