New PDI barrel for PTW

[SBranson23]

Any one else get one or try to fit one on the hop-up yet.
Got my barrel the other day and PDI used the wrong sized cutter for the slot that takes the pin that holds the hop-up assembly on the barrel.
I managed to file it down to get it to fit but man this is one serious F*%K up!

I've written them and they said they haven't heard of that problem but would get back to me after looking in to it.

There's a discussion here too:
http://www.systema-europe.com/Forum/...s.asp?TID=1622

[Ronan]

Yeah i saw that, sorry mate... i guess i'll have to grab those $250 Duff one's >.>

[wey ferro]

they are only 250 cad?
i thought they were 300 something

[SBranson23]

$309 according to the website.
http://www.systema-europe.com/Sales.aspx?c=7

[SBranson23]

PDI responded. I think they basically they say the undersizing is on purpose so the fit will be tight. Then essentially blames the tolerances of the aluminum pieces for the mismatch. Lame excuse as far as I can tell as I've worked on about 5 PTW barrels, both older gen3 and newer max ones and they've all fit together very well and don't need any undersizing to assure a tight fit. They told me to file the piece down. Lame.

"Dear Sir.

Sorry for late reply.I'm Sales Manager of PDI
We answer your question instead of X-FIRE because X-Fire is a just
retailer.
We set that a depth & width become a bit smaller than Standard.



--------------------------------------------------------------------------

If that slot is a little larger as same as standard,it seems to be
difficult to fix the 3 parts(chamber ,Brass one & barrel) completely.
That block made from Aluminum by mold.It has larger tolerance than all
machined.Now we know that width is 3.5mm around.But if that is made
with negative tolerance,like a under 3.5mm,a barrel slot is too large &
can't fix completely.
So We think this block need to be larger compared to slot.
Please rasp the block a bit.

These days upgrades are very loose fit as anyone can use it,but PTW is
a very expensive rifle.That customer doesn't want that easy kit.We
guess every pro player want more serious setting.So we made that to be
tight fitting.

But you know,this is not perfect answer cause the other parts are not
precise like a die-cast, or mold.So we found the final answer to make
PDI original chamber & sleeve(brass) laser-welded to inner barrel.

Thanks

PDI Co.,Ltd.
Sales Manager"

[mcguyver]

Nice. Next manufacturer, please?

[SBranson23]

Thing, is is that filing the piece down is not only tough because the damn piece is so small but it can also get off centered and cause the hop-up to cant to one side which will cause the bb to veer off to one side. This isn't hypothetical but actually happened while I was filing and "eyeballing" for the straightness of the hop-up.

What pisses me off is the attempt to make it seem like Systema users are pro-airsofters and demand such precision. Way to sell your mistake buddy... How about an precise fit, not a imprecise modification?... Geez.

[mcguyver]

Tell them what you really feel. Unless they are likely to take the barrel back. If not, let them have it, and tell them you'll spread the word worldwide to avoid PDI PTW barrels.

[Lakonian]

Originally Posted by SBranson23

What pisses me off is the attempt to make it seem like Systema users are pro-airsofters and demand such precision. Way to sell your mistake buddy... How about an precise fit, not a imprecise modification?... Geez.

+1.

These guys are goofs.

[SBranson23]

I've got the draft email already saved. I just want to be sure that someone else doesn't get one that drops in no problem. I'd feel a little stupid berating them for a one off misfit... I'm not anticipating that from PDI's response though...

[MadMax]

Originally Posted by SBranson23

PDI responded. I think they basically they say the undersizing is on purpose so the fit will be tight. Then essentially blames the tolerances of the aluminum pieces for the mismatch. Lame excuse as far as I can tell as I've worked on about 5 PTW barrels, both older gen3 and newer max ones and they've all fit together very well and don't need any undersizing to assure a tight fit. They told me to file the piece down. Lame.

It's called tolerance analysis. I met PDI and talked to them about their bushings not press fitting into mechboxes consistently because they were attempting to acheive a dual press fit at the through and shoulder bores on the holes on cast TM mechboxes. Dual press fits on economically cast parts aren't a very good idea because you are hoping to nail precise press fits on two features instead of one. It's hoping that two planets are in perfect alignment when you pledge your AEGs soul to the perverted bat god of the of inanimate things. I got the same goofy response that their loopy customers demanded an extreme press fit so they were unwilling to give up on their shoulder press fit dream.

PDI obviously does not do a statistical tolerance analysis of TM (or other manufacturers for that matter) mechboxes as it works out that many of TM mechboxes will see some bushing fitment issues in at least one of the six bushing holes.

Designing a mass produced aftermarket part around measurements of only one example of a host machine is a mistake typical in the airsoft aftermarket. I see in slide fitment, mechbox fitment, metal receiver fitment etc. About the only parts that go together without any filing are the complete parts set of a TM AEG or GBB. I think they're the only company making assemblies that are robust for the tolerance of parts that they make.
Even the SystemA PTW has some fitment issues. I have noted that nearly every PTW I've come across benifits from some magazine catch adjustment. They've thrown the CNC'd manufacturing accuracy hammer at everything they could, but they missed it on the one sheet metal thing that they don't get to control so tightly.


Sorry. /end gripe

[Ronan]

Nice fail from PDI...

Btw what freaking tight fit are they talking about? Didn't you mention it didn't fit at all??....

[MadMax]

Engineering douchbaggery typical in aftermarket airsoft. PDI doesn't realize that the round ends of the aluminum barrel block and the significant axial preload on the barrel exert a self centering force which does not require a tight press fit in the lateral direction.

Think about how the barrel pocket loads against the rear of the barrel block. The round contact causes a self centering if the barrel block has a close fit in the hop up body.

Achieving tight fits in between barrel pocket, barrel block, and hop up requires close fits in three parts which is statistically difficult.

[SBranson23]

Originally Posted by MadMax

Achieving tight fits in between barrel pocket, barrel block, and hop up requires close fits in three parts which is statistically difficult.

And yet every Systema barrel I've looked at has done so very handily.

Still waiting to hear of someone else even trying one.

Originally Posted by Ronan

Btw what freaking tight fit are they talking about? Didn't you mention it didn't fit at all??....

Yup, not even close.

[MadMax]

SystemA does not achieve a press fit in any of those parts. The friction comes from the preload in the hopup assembly, not intentional interference between parts.

It's not very wise to manufacture with intentional interference involving cast parts that aren't finish machined especially if they're non round. Precise machined round holes are easy to manufacture for interference fits. Obround stuff that's cast is much less consistent.