X39 ar pistol issues need gurus.

[bigken]

So i recently bought an ar pistol in x39 and have noticed a few issues, it doesn't want to feed properly, I'm noticing scraping on the rounds where it's dragging or catching on the mag, is it a crappy mag or something else and if I push up on the mag while in or two it it would feed? It was in a 28rnd duramag and a 30rnd asc. Also when it would feed as I tried to shoot it would fire one or 2 but mostly light strikes on the primer. Is that an ammo issue or is that a weak hammer spring possibly? This is a new unit and the only action it's seen was Saturday when I tried to test it out. It's a custom build with the m4 feed ramps and7.5in barrel if that means anything. Just looking for some advice on if it's possibly a manufacturing problem or something else. Thanks gurus.

 

[Rebel_Rider1969]

1st, welcome to the x39 club! While not a guru, I've had some experience with the pistol and rifle models. What lower and upper are you using? Bolt?
Some things you can try. If you have a 5.56 gi 20 rd mag load 5 rds in it and shoot, or you can use metal 30 rd mag. The poly mag lips dont hold the rounds good.
I use a 4oz buffer with carbine spring. H2 should work, remember its picking up loading a cartridge twice the weight now. You may need an "enhanced" firing pin, it's just a bit longer. X39 ammo for the most part has hard primers. If you can get some US made brass cased ammo and give it a shot. Scrubbing the chamber may help too.
I'm guessing its using a pistol lenght gas tube, hopefully it's not under powered. (Not enough gas) Maybe something I've mentioned helps, YMMV.

 

[bigken]

I'm using the steel 30rnd mag, just ordered a enhanced firing pin and hammer spring, maybe that will fix the light strikes, I didn't use American rnd I believe it was just the loose wolf and bear ammo I had from my sks. It did start feeding, I was able to get 3-4 rounds out back to back then light strikes and hang ups, I've been playing with the Dremel on one of the mags to see if it helps and it removed some of the metal and now rounds don't seem to hang up on the mag now but I didn't cycle through the pistol yet. I don't want to contribute anything to a gassing problem because it didn't fire enough rounds consecutively, I'd get a fire and light strikes and repeat and light strikes. After it fired a round it seems to cycle the next one fine but it usually turned out to be a light strike.

 

[Rebel_Rider1969]

Well hopefully the firing pin fixes the issue, along with the dremeling. On a new build I normally hose it with lube. New builds sometimes require some break in.

 

[FrankT]

The enhanced firing pin and CPD/duramag mags will fix it up depending if you have a good upper and lower.

 

[bigken]

 

[Rebel_Rider1969]

Ah, Moriarti Armaments LLC.

 

[bigken]

Yea, but it fired unlike the ar9

 

[bigken]

Plus if I knew their track record before purchasing I may not have.

 

[Rebel_Rider1969]

Plus if I knew their track record before purchasing I may not have.

Dont feel too bad, I tend to learn the hard way myself. This at least looks like a minor issue that will be corrected shortly.

 

[FrankT]

yeah I bought a Sanders Armory pistol side charging upper and it ran 100% out of the box

 

[Rebel_Rider1969]

Yeah, same with the Bear Creek Arsenal. Side charger.(rifle)Love their stuff.

 

[bigken]

Well I definitely have all the parts and honestly it seems like it's made pretty well, I think I just ran into a common problem based on research with the x39 in ar platform.

 

[FrankT]

yeah some manufacturers have the x39 down and some are still working on it, I generally go with those that have positive experiences. BUT you can get it working right, just takes some patience.

 

[bigken]

Yea I've been playing with it, so could the buffer tube spring have anything to do with the feeding? Just curious, as I was looking at it, the buffer tube seems like it's a little far back from the detent, but if I bring it forward a full rotation the tube sits to far out and cannot connect the upper, is it possible to sand down the buffer tube making it a little shorter this adding more umph to the spring to pick up the round? Or am I over thinking it?

 

[FrankT]

most likely it is the mag, what make are you trying?

 

[bigken]

A duramag 28 and asc 30.

 

[FrankT]

ok and never load them full 2 rds short especially when new, look for drag marks on the mag lips and tweek if necessary use a marker to reblack them. I hate those too short barrels, always gas issues. Mine is a 10.5"

 

[Zeroed in]

I'm not a x39 guy, but I don't think it'd be the buffer tube per se, but could be a weak buffer spring. If it's not strong enough to put the bolt into battery, you can get light strikes, can cause feed problems too by being out of timing.
If you have another carbine buffer spring, swap it out and test fire it with the known good spring. g/l

 

[Rebel_Rider1969]

I dont think a couple of turns on the tube would make any difference. Some company's V the end of the tube. Making an extended portion with a slot where it meets the retainer.
Hey frank, what buffer/ weight is in yours?? I'm running the 4oz. And having no issues.