Jump to content
Sign in to follow this  
Gunfighters808

Initial Impressions of the TM PX4 GBB Pistol

Recommended Posts

I just got a PX4 and it is a lovely gun but I keep having feed issues.

The follower in the magazine seems to get jammed every few rounds causing me to dry cycle.

Is this a known issue and if so has anyone come up with a fix for it yet.

I bought three magazines with the gun and have this issue in all three.

Share this post


Link to post
Share on other sites

Yes, I've seen this reported before.

 

Just to get this out of the way: I assume you are filling mag with the bottommost bb down on where the follower is at an angle, and that there are no voids in the rest of the bb stack.

 

Some people have reported just changing bb brand did the trick.

 

Others have lubricated inners of the bb slide, follower, lips, etc. with the tiniest drop of silicon, and also reported that this helped.

Share this post


Link to post
Share on other sites
The follower in the magazine seems to get jammed every few rounds causing me to dry cycle.

Use quality BBs that run freely against each other. Matte BBs are generally a bad idea: They can cause the above problem, leave dirt inside the gun and fly worse ;)

 

I'd recommend G&G BBs.

Share this post


Link to post
Share on other sites

Here's a thing. Recently installed a tbb and new hop rubber, everything went back together seemingly fine. Afterwards the fps had almost halved, first bb fired but gave the impression it was under protest, the rest would nonchalantly trundle or roll out of the barrel.

Stripped it down again, hop platform not putting any hop on at all but seems to be functioning correctly. Re fitted original parts again, still doing the same? What have I done to it?

Fitted new barrel / hop rubber to a G-17 and all as it should be? Any ideas ?

Share this post


Link to post
Share on other sites

Here's a thing. Recently installed a tbb and new hop rubber, everything went back together seemingly fine. Afterwards the fps had almost halved, first bb fired but gave the impression it was under protest, the rest would nonchalantly trundle or roll out of the barrel.

Stripped it down again, hop platform not putting any hop on at all but seems to be functioning correctly. Re fitted original parts again, still doing the same? What have I done to it?

Fitted new barrel / hop rubber to a G-17 and all as it should be? Any ideas ?

 

Brand of tightbore/BB's you're using? Also, brand of hop rubber? I had slight fitment issues with the Nineball rubber in my PX4 back when I had it..

Share this post


Link to post
Share on other sites

Now that is odd. I found with the Nineball rubber, it was just half a mm or so too long to seat correctly in the hop unit; Trimming it solved that, but it doesn't sound like your issue.

 

Is the leaf spring that applies hop definitely seated correctly? It took me a few attempts to get that back in the right place, and that could well be causing the issue if it's not correctly installed.

Share this post


Link to post
Share on other sites

See I found there were 2 places it'd happily 'sit', one of which being incorrect obviously - Any chance of a decent picture of how you're seating it? Chances are it could be something else causing the problem, but it'd help rule it out. I figure it's engaging with the adjustment wheel and moving up and down correctly?

 

I'm assuming the BBU is all functioning as it should - Pulls itself back into the correct position and everything? All clean and lubed I'm guessing is an obvious one... Definitely sounds like a hop unit issue though.

Share this post


Link to post
Share on other sites

Im having a little trouble with mine recently, well more with the metal slide that was released for it some time back.

 

The gas effiency is crazy bad 1 mag and its out. Also it seems to be spitting a little gas out of the ejection port, after every shot which would acount for the gas effiency problem.

 

The piston head appears to be in good shape no damage, the nozzle seems fine too.

 

Anyone know why?

Share this post


Link to post
Share on other sites

I thought that could have been the reason and spent an age with it. All seems well and as it should be?

With the inner barrel and hop-up unit out of the gun, look down the barrel from the opposite end to where the hop-up is, and gradually turn the hop-up adjustment wheel. What do you see? Go, gradually, from minimum to maximum.

Share this post


Link to post
Share on other sites

Not very much really. When checking with no hop rubber the platform rises. With it assembled no matter which hop rubber the platform seems to rise but make no impression on the hop. Bb's roll out of the barrel when re assembled.

Share this post


Link to post
Share on other sites

I haven't seen a PX4 hop-up, but if it's anything like other TMs, there's a tiny L-shaped piece of metal that fits into a groove on the adjustment wheel, and on the other end sits on top of the bucking and is supposed to exert downward pressure when the wheel is turned.

 

I feel that the L-shaped piece may have got bent out of shape. Try bending the two "arms" of the L in towards each other--slightly!--so that they form a slightly more acute angle. The top part of the L should therefore press down on the bucking more, making the mound on the inside of the bucking be more visible as you adjust up the hop.

 

BBs dribbling out the barrel is a sure sign of insufficient hop. It's the bucking and the internal mound in the bucking that holds the BB there awaiting the next jet of gas.

Share this post


Link to post
Share on other sites

Not very much really. When checking with no hop rubber the platform rises. With it assembled no matter which hop rubber the platform seems to rise but make no impression on the hop. Bb's roll out of the barrel when re assembled.

 

It sounds like the little tab on the hop leaf spring might not be engaging with the hop wheel itself - When re-assembled, there's a line cut into the adjustment wheel, that this 'tab' slots into, thereby moving the leaf spring up and down when the wheel is moved.

 

Still, if it's moving without the hop rubber, that sounds like it's adjusting correctly... See if any other PX4 owners have any pictures of the hop unit handy, as it really does sound like something isn't installed right. And unless the L shaped spring is really quite significantly bent, it shouldn't be performing that badly if that's the cause of the issue.

Share this post


Link to post
Share on other sites

A big thank you to all who gave their time and advice. Managed to look at another it seems the platform had bent down, probably when I took all apart to replace barrel and rubber. After gently re shaping it, fingers crossed its now back to its fantastic old self.

Thanks again!

Share this post


Link to post
Share on other sites

Nice to see this pistol doing so well. Not too many complaints or issues being posted. It's a solid "piece" and continue with a fair following. Everyone who shoots mine seems to be impressed. It really is made quite well. In the top 3 of my Marui collection.

Share this post


Link to post
Share on other sites

It does seem that the hop unit has failed on mine though. It moves and adjusts but does nothing to the round, tried 2 different TM rubbers & a Nineball nothing.

Share this post


Link to post
Share on other sites

I thought I'd update with another upgrade part on the market :D

 

http://www.uncompany.com/pageproductdetails.asp?prodid=32400

 

I dunno if the SD gaskets for the Glocks did any good for the Glock crowd but if they did I guess those willing to spend cash to milk every bit of performance from the gun can consider getting those for their mags :D

Share this post


Link to post
Share on other sites

What are you guys using to holster your PX4? Neither of my holsters, a Blackhawk Omega dropleg and an Bianchi M12, work as it is slightly fatter than the M9/Glock/P226 Ive run in them in the past.

 

Cheers

Edited by starburst

Share this post


Link to post
Share on other sites

Ive not seen this mentioned anywhere but thought I would check, has anyone run their PX4 in a Serpa holster and have you had any issues? Asking as obviously their Glock is oversized for 17 so you need the holster size up. Cheers

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this  

×

Important Information

By using this site, you agree to our Terms of Use and the use of session cookies.