View Full Version : mr1 popcorn , chopping, and misfire?

05-19-2010, 05:26 PM
I definitely need help on this one.

I have changed springs, adjusted the velocity, used 2 types of paint (using Weapons Grade right now), switched barrels, switched valves, switched strikers, and I still have the same 3 problems:

- First it misfires once and awhile which I thought would be the spring providing too much tension on the striker. The trigger will not go back to its original position, but moves forward just enough to create a misfire.

- Second thing that happens after about 10-25 shots is the marker popcorns like it is out of air, but I have a 20 oz tank that is mostly full so I'm not our of air. And of course at that point I have to cock the bolt to start shooting again.

- Third after awhile I get a chopped ball right as it is about to fire.

Always in this order. When it is shooting properly it is pretty accurate (1 out of 15 does a 90 left or right). Unfortunately I do not have a chorono so I have no idea what the fps is right now.

Anyway, most of you know the mr1 way more than I do. I have fixed up a used TL with no problem because I used to own a few in the early 2000s. If anyone can help then I will take a look at all of the advice. I don't know ... maybe I have to many parts that don't work together. This is what is on and in the marker right now:

- gravity feed hopper
- rap4 12" recon rifled barrel w/ frostbite muzzle brake
- stock air line, trigger, and grip
- clamping feed neck
- New Designz NDZ valve
- stock cup seal, cup seal guide, and valve pin (having problems with the NDZ valve pin, but the stock one is working great)
- stock valve spring
- ACP low blow bolt
- ACP slim style lightened stainless steel and delrin striker
- yellow Trinity spring (have used stock spring, blue, red, and yellow - haven't used green because I was having trouble with the spring not allowing the striker to back off of the valve pin)
- Serial #01100739 (if it helps as far as the year of the marker)

Thanks for your help.

slim and shady
05-19-2010, 07:22 PM
First you really should go to a paintball feild and get your marker chronographed. Since you switched to a different striker you should experiment with different valve springs, this could be the reason for the burping, especialy since you mentioned with some springs not allowing the striker to get off the valve pin. But its hard to even look at any of that without chronoing as your doing it. Chrono services are free at any paintball feild I have ever went too. It is something that could help you out alot.
For the popcorn and chops get a cheep revy or electronic hopper to feed the balls properly and defeate blowback. As for the misfire your triger is sticking take the grip off and clean it up and lightly oil it as you put it back together in some cases there is a part (I cant remember what its called right now I will have to find the manual) that may need to be slightly filed or bent ahead. We see this alot with out rentals. Since you have the trigger frame off make sure your sear is in good condition and not wore out or burred. If it is you could try fileing it the burs back flush. If it has a bur somethimes it causes it to burp but more out of controle.

hope some of this can help you.

05-20-2010, 08:40 AM
I am having trouble finding a valve spring kit. Do you have any suggestions?

05-24-2010, 04:28 PM
Found one.

slim and shady
05-24-2010, 08:13 PM
I use the 32degrees spring set comes with main springs and valve springs.

05-31-2010, 06:50 PM

Fixed popcorning ... Tried Maddman spring kit ... nothing worked after much frustration. Removed the NDS valve and ACP slim style lightened stainless steel / delrin striker. Put back in the stock valve and striker. Also removed Trinity springs and installed green Maddman spring. Now I have no more popcorn.

The NDS valve must only work with low pressure ... I don't know. Anyway, I put back on the 14" barrel that came with the marker (purchased used so I don't know the make of the barrel) and now I am waiting on a better hopper. I think I will just stick to changing the asetics of the marker and modifying the shoulder stock. This is my mr1 now:

- viewloader revolution hopper
- 14" barrel (with rifled porting along most of the barrel)
- stock air line, trigger, and grip
- clamping feed neck
- stock valve
- stock cup seal, cup seal guide, and valve pin
- stock valve spring
- ACP low blow bolt
- green Maddman spring

I picked up a mr3 that I am having fun with. I think I will turn it into a low pressure marker or at least use HPA instead of co2.