Weird range experience today with my RRA 9mm

[Alaskapopo]

The temperature when I showed up at the range was about 32. The gun was well oiled prior to shooting. I was getting failures to eject about 1 in 15 rounds or so. The empty case would be wedged up on top of the next round trying to enter the chamber. Anyway as I shot more the temperature also went up and the gun started to run better. I went through the last few loaded mags with no problems at all. I use this gun as a trainer because 9mm ammo is cheaper. I am still trying to work the bugs out.

Anyway how do you get these things to eject properly. I also got a weird malfunction where the gun cycled but did not cock the hammer.
Pat

[Azrael2004]

Sounds like it may be short stroking.
Has it been previously reliable with the same lube and same ammo at higher temperatures?

[Alaskapopo]

Sounds like it may be short stroking.
Has it been previously reliable with the same lube and same ammo at higher temperatures?

Yes more reliable at higher temperatures never quite 100%.
pat

[Azrael2004]

Sounds like it worked better when the lube warmed up a bit.
What ammo and mags are you running in it?

[MarshallDodge]

Was the ammo cold? The powder in the ammo could be temperature sensitive.

[Puffy93]

Was the ammo cold? The powder in the ammo could be temperature sensitive.

What would that have to do with it not ejecting?

[MarshallDodge]

What would that have to do with it not ejecting?
Certain powders are sensitive to low temperatures. When the temp drops so does the energy from the burning powder.

With the reduced energy, the bolt does not come back as hard or as far as it normally would which would create a short stroke condition. The ejection phase would never happen because the bolt does not come back far enough.

[Puffy93]

Oops I was thinking of a plunger style ejector
My mistake

[Alaskapopo]

Sounds like it worked better when the lube warmed up a bit.
What ammo and mags are you running in it?

Mags were a mix of Colt 32 rounders, C Products 32 rounds and Uzi 25 rounders. Ammo was my own reloads which I know is part of the problem as the load is a bit lighter than standard nato ball. I was using a 147 grain plated bullet over Tight Group.
The gun runs better on more stoutly loaded 124 grain reloads but I don't want to pump them up too much as I have broken my bolt stop in the past. I got one of Slash's buffers but the gun would not run reliably with it and would short stroke more often. He has been nice enough to take it back and agreed to lighten it a bit to see if that helps. When I was shooting I was running the standard buffer and spring.
Pat

[Alaskapopo]

Was the ammo cold? The powder in the ammo could be temperature sensitive.

The ammo had been sitting in the back of my truck for about 2 hours. But prior to that it was room temperature. So I am not sure if 2 hours in the truck would give it enough time to get that cold because the truck was parked in my garage before I went into work. So the interior of the truck would have had to cool down as well.
pat

[Azrael2004]

The weak loads are the most likely culprit. I can run WWB aamo all day long and it runs 100%. If I run UMC I get short stroke failures. My solution is not to run UMC.

The bolt stop breakage is really not from the pressure of the round but a result of the bolt travel before it slams into the stop when it is raised.
You can get a buffer that is longer or put spacers ehind the recoil spring.
I used a couple nylon spacers in mine that I found at Lowe's.
Some folks use quarters as a spacer. IIRC it was about $1.75 in quarters. Add more or less as needed.
Just drop them in the empty buffer tube then reinstall the spring and buffer.
Assemble the gun then pull the bolt all the way back. Look in the ejection port and see how far it is from the bolt stop when all the way back.
You want it to be about 1/8" from the stop.
Try it before the spacer and look how far it goes back. This is why they break the stops.

[Alaskapopo]

The weak loads are the most likely culprit. I can run WWB aamo all day long and it runs 100%. If I run UMC I get short stroke failures. My solution is not to run UMC.

The bolt stop breakage is really not from the pressure of the round but a result of the bolt travel before it slams into the stop when it is raised.
You can get a buffer that is longer or put spacers ehind the recoil spring.
I used a couple nylon spacers in mine that I found at Lowe's.
Some folks use quarters as a spacer. IIRC it was about $1.75 in quarters. Add more or less as needed.
Just drop them in the empty buffer tube then reinstall the spring and buffer.
Assemble the gun then pull the bolt all the way back. Look in the ejection port and see how far it is from the bolt stop when all the way back.
You want it to be about 1/8" from the stop.
Try it before the spacer and look how far it goes back. This is why they break the stops.
I have a longer heavier buffer from slash but the gun will not run reliably with it and I have sent it back to Slash to lighten it a bit.
Pat

[Azrael2004]

Longer is good, but it would be nice if they stuck with the standard 9mm buffer weight. They all seem to want to make them heavier. :rolleyes:

[redtazdog]

I have a longer heavier buffer from slash but the gun will not run reliably with it and I have sent it back to Slash to lighten it a bit.
Pat
.
I have the same slash buffer and had the same problems until i installed a
wolff reduced power buffer recoil spring and now its a 100% runner.:D

[Alaskapopo]

.
I have the same slash buffer and had the same problems until i installed a
wolff reduced power buffer recoil spring and now its a 100% runner.:D

Thanks for the tip. I will order one. SLash also reduced the weight of my buffer for me and I am going to test it on my next RDO's.
Pat

[CarlosDJackal]

What kind of lube were you using? I ask this because if you happen to be using a lube that likes to gel up in lower temps, this may be the culprit. Also, did you have the "Roll of quarters" installed behind your action/buffer spring?

[Alaskapopo]

What kind of lube were you using? I ask this because if you happen to be using a lube that likes to gel up in lower temps, this may be the culprit. Also, did you have the "Roll of quarters" installed behind your action/buffer spring?

Standard buffer and spring at the time of the shoot. I have a Slash longer buffer now. The lube I used was machine gunners lube from Larue.
Pat