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Posted: 9/7/2008 8:08:05 AM EDT
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Hello, iv been having some on going trouble with my POF*USA upper i took it to the range today and after 2-3 rnds the bolt did not go all the way forward. I dropped the mag and opened the bolt, the round did not extract but was sitting inside the barrel about 80% with the back end of the round sticking out a bit. I then closed the bolt and charged the action one more time and the round extracted. I then loaded another magazine with 5 rounds and racked the action paying extra attention to pulling the charging handle all the way back and letting the bolt slap forward, took 3 slow shots and the gun malfunctioned in the same manner as before with the bullet in the barrel about 80-90% and the bolt about half an inch from closed. After the second go at this with the same result i packed the rifle up not wanting to cause any damage I was using remington brand ammo and two different "GI syle" magazines that work fine in my other rifles. The POF upper is a 16 inch with the predator rail, i believe it is a 1st generation as it does not have the coated chamber and has the coated two peice bolt. I can not find anything visibly wrong or out of order on the rifle other then the piston is quite hard to remove and insert. When removing it, i tip the rifle and it falls about half way out of the rifle and stops, i then have to remove it by pulling fairly hard to remove it the rest of the way, the op rod falls out freely. when putting it back together the piston goes in about half and and then i have push it a bit to get it to fall into the rifle, when it does,it stops about an inch or two down and i insert the gas plug..i do not remember it being that hard to remove and insert the first time i fired it. I dont think its the mags or the ammo as i use them in other rifles and they work fine, this has happened with the POF upper on two different range trips with the result being the same both time and under the same conditions. I love the POF system and have recommended it countless times in forums and at the range to many different people and now feel quite silly that im having these problems  i did write POF an email both times this happened and they were very nice the last time and told me to make sure i had the piston facing the right way but it hasnt helped, im waiting on there reaspons to my latest email that i just sent so i will see what they think but i just thought id post on here and see if anyone has any information or has had the same happen to them or any idea of what it may be. thanks for reading and help  Dan |
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Most all the problems I have seen or heard about relate to the barrel/chamber. Yours sounds like it might be the same thing. Bushmaster uses their own barrels for their piston gun. Which might explain why you dont hear about the same problems with the Bushmaster piston even though it uses the same piston system. |
Is it possible that you can take some pictures for me of the "PISTON" the "OP_ROD" and into the chamber that the op-rod and piston operate in? I am one of the people that have a POF that had a barrel problem and sent my upper back to POF. They sent me a new upper with the updated barrel and it has not had a problem in the 3K rounds since. I dont think the barrel is the problem though! it sounds like something is going on either with the piston or the chamber the piston operates in! |
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yeah im pretty sure its the pison system thats the problem, the piston is VERY hard to get in the housing and i think its sticking in the rear possition not allowing the bolt to come forward. im taking the picters now and they will be up in a few minutes...i just hope my camera works weel enough so you can see something 
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Cool! hopefully the pictures will help. Do you ever clean the piston chamber? Do you lube the op-rod and piston? |
i did not run anything through it or oil the piston our housing at all intill this problem and only then to see if something was inside stoping it..i was told by many people not to oil the pistons and as a rule of thumb i try not to lube any piston housing in any of my rifles just dry patch them from time to time. these are the best pictures i could get with my camera.. when the piston is inserted it only sits about an inch or tow inside the housing and doesnt want to go back any further and i have to open the bolt and shake it to let the op rod knock the piston out to remove it       all i do for cleaning the piston is wipe them with a patch and they come pretty clean LMK what you think..i know there not the best pictures
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I know there is some debate on this issue of lubing the piston and op-rod but I think it was "Clint Smith" that said "If it moves, LUBE IT" Anyways, If I were you I would use a bore brush and a mop from a 45ACP and clean the SH!T out of that piston chamber than use a little bit of lube on the piston, the op-rod and the piston chamber and see if that helps at all. I know on mine ALOT of carbon builds up inside that piston chamber if it has accumulated for a while it could be causing some binding and friction. I clean the piston, op-rod and piston chamber about every other range session (which is complete overkill) and lube the piston and op-rod with some Mil-Comm TW25B grease and spray Mil-Comm TW25B aerosol into the chamber area and have put 1,200 rounds through mine over a weekend with no cleaning and no problems. It looks like the piston is pretty clean but are the gas holes in the piston clean? |
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OK I am going to go take a look at my POF and see if I can try and help you figure this out. Try a little lube! if it doesn't help you can always clean it back out. The piston system is different on yours than on mine. I think you have the older system that didn't have any barrel or piston problems that I have heard of anyway! Here's a couple pics of mine just for comparison purposes.     Sorry they are some older pics taken with the crappy camera I had at the time!!!!! 
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low and behold!!!! i spent the last half hour scrubing the crap out of the thing and oiling the @#%#, i tested it by locking back the bolt, taking a cleaning rod and bushing the piston rearward toward the op-rod and bolt..i got it all the way to the end of the housing assuring myself i was going to have to spend the next hour getting it out from way back there cuz theres no way alittle dirt messed up the piston system and wouldnt you know it, i hit the bolt release and the damn thing smacked forward!!!!!! i about sh^$ myself  ..the patches i used to swap out the gunk i just brushed out were pretty dirty..not anything TO TO bad but as if i just cleaned my pistol after firing 100 rounds through it =P im having a hard time believing a little dirt fouled up my rifle but then again it seems to be working ok now from my little test its still going in half way really tight but once it falls in it seems alot better, its worth mentioning that if i turn the piston around to the silencer setting if falls right in place but the normal setting is still alittle tight. now im just worried about shooting it and getting it dirty =P might just jam up again lol but perhaps i had gunked up powder that i didnt see ? anyone els have a dirty piston housing jam your rifle ? and i'll keep you guys posted if i get her to the range anytime soon =] |
and for the record i do have DI AR's and i like them both the same, i had a gas tube fail on my cmmg so i guess they both have there good points and bad, the piston system is WAY easier to clean and as i said that was the first time that i cleaned out the piston housing so we will se what comes of it.. hoping to hear back from POF tonight or tomorrow to get there take on it, they have always replied very fast to any question i send to them so it shouldnt be to long |
Cause they are way more reliable and can fire twenty bazillion rounds without ever needing a cleaning  On a more serious note though, not sure if your gen I model has it, doesn't look like it, but some have a coating that makes them more porous to help hold the oil. The 2007 model I had had it. If you use abrasive cleaners, they will strip the coating off, and then make you have to apply oil and clean more. To me, since this area of the gun is full of alot of pressure, I wouldn't advise sanding or grinding any of the surfaces to provide some give for it. You could have them sent off to be ionbonded, or even do some dremel polishing to provide a better surface area. Mine stuck after about 1000 rounds cause I believed that "CROSS doesn't require lubrication". They are running machines, just with more parts that can fail. |
I hope to hear that they help you out and make it better. I only called them once on something and wasn't too impressed with their attitude. Maybe I just got them on a bad day. And, for the record, I have a POF too and like it (18" barrel one). Mine was built in July of 07 and the piston system looks a bit different from yours. I only have 864 rounds through it, but it hasn't shown any problems in that time. And despite what I've heard about their lack of accuracy mine has been the most accurate AR I've ever owned and is probably the most accurate rifle I currently owned. Go figure  . Just got lucky I guess. 
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Those look like my Bushy Gas Piston / POF copy. |
yeah, bushmaster uses the POF system, i like the system as there are no springs and onlt the three parts.. |
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Let me know if someone has not gotten back to you yet. That is an earlier genration model. The fact it has a two piece carrier/piston key and the length of the piston tells me that. I run a nylon bristle brush down the piston tube from time to time to clean things out. |
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I was contacted by Chris with POF and after a few emails he asked me to send it in to have it looked at, He was very nice and helpfull and made me feel like he was going to get to the bottom of the problem.. nice to have a maker that will contact you and make you feel like they actualy care about there product working correctly.. im very pleased with how they handled it so far, We will see what happens when i send it in =] i'll keep you guys posted |
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***UPDATE*** got the upper back from POF a few days ago and it looks like they changed out the piston system and put in some of their newer parts. [shorter piston, longer op rod] everything seems to be working great...whole system drops out like its supposed to and it looks to be in great shape =] im fairly sure POF test fired it for function as there was aliitle GSR on the new op-rod so im hoping everything is fixed when i take it to the range in a few days. Chris at POF was great to deal with and he took care of me =] didnt cost me a dime and he had it back to me within a month. I couldn't be happier with how POF handled it and I will definitely be doing more business with them, infact I have been eyeballing one of their lowers =] just thought you guys would want to know how it all turned out.. i'll post a range report in a few days |
Hope it shoots for you... Let us know ASAP Mike |
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