Classic Automag - Shootdown

[jrod]

I had my mag rifle out today. Overall it worked great. I did have some instances where balls kind of plopped out (maybe 150 fps). It didn't happen during long strings, and didn't happen often, just kind of at random. Any ideas?

[secretweaponevan]

I had my mag rifle out today. Overall it worked great. I did have some instances where balls kind of plopped out (maybe 150 fps). It didn't happen during long strings, and didn't happen often, just kind of at random. Any ideas?

Make sure your nubbin is in good shape.

All I can think of right now.

What is your setup?

[Coralis]

Perhaps you have a small power tube leak so if you do not shoot for a few mins you are getting a weak first shot?

[jrod]

Power tube is good, no leaks there. I'll check the nubbin. But, how would the nubbin affect anything?

[deathbypaint1213]

Check the reg piston and make sure it is clean. The regulator seat can also contribute to some erratic velocity problems. Make sure to pull and release the trigger completely when you are firing the gun.

[Biz Kizzle]

referring to the nubin comment, i'm thinking if you had a weak/bad nubin occasionally a ball could slip past it making velocity variable, but this would only work if your mag rifle didn't have a springfeed, otherwise it would double feed and you'd notice that so idk what wrong.

[secretweaponevan]

referring to the nubin comment, i'm thinking if you had a weak/bad nubin occasionally a ball could slip past it making velocity variable, but this would only work if your mag rifle didn't have a springfeed, otherwise it would double feed and you'd notice that so idk what wrong.


Yeah, I was drunk and tired and figured that a bad nubbing and a powerfeed plug with flat spot could do the same thing as a closed-bolt gun with too large a bore.

[jrod]

I think I discovered what was happening. Remember, this is a classic valve mounted on a classic rail, mounted in an SKS stock. The trigger is moved back behind the sear.

Anyway, with all the strange torquing and what not, I noticed that if I put some slight pressure on the trigger, I can sometimes hear a leak from the on/off (RT on/off). I think this slight leak, followed by a full trigger pull resulted in a lower velocity shot. I swapped the entire valve out with another classic valve, with classic on/off, and the problem seems to have gone away. Since it works now, I'm not going to mess with it anymore. However, I do wonder if the thicker on/off pin of the classic assembly is more forgiving than the rt on/off pin.

I did place the valve with the RT on/off into another marker, and it shoots fine. No leaks when slight pressure is applied to the trigger.

http://home.comcast.net/~jimrodriguez/valve%20and%20stock.jpg

[Dend78]

the rt is eaiser to pull, that little bit of pressure is causing it to unseat just a bit, not enough for a full shot but just enough that air escapes it sounds like. the classic with its harder pull doesnt notice that little bit of initial pressure it feels a full trigger pull.

[jrod]

the rt is eaiser to pull, that little bit of pressure is causing it to unseat just a bit, not enough for a full shot but just enough that air escapes it sounds like. the classic with its harder pull doesnt notice that little bit of initial pressure it feels a full trigger pull.

Yep, I can faintly hear the oil bubbling and gurgling sometimes. Now that the classic on/off is in, I think it's all good.