Page 2 of 7 FirstFirst 1234 ... LastLast
Results 11 to 20 of 65

Thread: Adams Arms/VLTOR A5 fail to eject

  1. #11
    Join Date
    Apr 2009
    Posts
    637
    Feedback Score
    0
    Magazines either empty or loaded create drag on the bottom of the bolt carrier. The fact that you can extract and eject an expended casing without a magazine in the firearm tells me you are on the cusp of functioning. The questions that are not answered without the magazine in the gun is whether or not the bolt carrier is traveling far enough to the rear to pick up a fresh cartridge or lock the bolt to the rear if it did have a magazine.

    Lighten your buffer by adjusting the weights as jaxman7 pointed out and I believe your gun will cycle.

    You can check the gas block alignment on your Adams Arms by laying the top rails flat on a piece of glass. Between the flat top upper and rail on top of the gas block they should sit flat without any rocking side to side. Next take your piston rod out and remove the spring and "spring cup." Reinstall the rod without the spring and spring cup. With the muzzle pointed up and the tip of the piston rod resting on the bolt carrier, push the bolt and carrier forward (into battery) with your thumb. When the bolt and carrier are in battery, there should be .015 - .025 clearance between the piston rod and back of the gas block. (Measure with a feeler gauge or if you do not have a feeler gauge a business card will get you close.) If the rails are flat and you have the required clearance the gas block should be aligned.

  2. #12
    Join Date
    Feb 2012
    Posts
    407
    Feedback Score
    44 (100%)
    Do you have another functioning AR available to test the upper and lower separately? Preferable one with a carbine buffer and spring. Two complete and working ARs would be even better.

    Try your AA upper on a known-good lower, and your lower with a known-good upper. Isolate which half is causing the problem. It could be both, however.

    If I fire without the magazine in the mag well, it spits the brass out just fine, about 3 or 4 o'clock.
    Honestly, I don't think the A5 is your problem. Assuming your ammo is full-power 5.56 and the gun works fine without a mag, messing with the buffer system is not going to fix things. The A5 is actually a good idea to run with piston ARs and confers the same advantages as with a DI upper.

  3. #13
    Join Date
    Apr 2009
    Posts
    637
    Feedback Score
    0
    I own two uppers with Adams Arms kits installed. I experimented with buffer weights because I also use a 9mm upper on the same f/a lower. I was trying to find a buffer that would work well with both. If your buffer is too heavy the AA upper will not cycle.

    Try Jaxman7's suggestion about changing the buffer weight.

    Call AA and speak to them about buffer weights.

  4. #14
    Join Date
    Dec 2008
    Location
    Where the 2nd Amendment still lives.
    Posts
    2,729
    Feedback Score
    5 (100%)
    I have seen this issue before with the AA piston Middy upper and the VLTOR A-5 and you need to reduce the buffer weight to 3.8 oz's for solid function with 5.56/.223 factory brass pressure loads and down to a 3.0 oz's if shooting weaker steel cased.

    Now another issue I have also seen on piston guns is bolt carrier tilt which can be exaggerated if the bolt receives to much up-ward pressure from magazine contact. This will cause the charging handle to feel as it is dragging during cycling but the real contact is the bolt trying to aligning its self into the buffer tube.

    Look at your buffer tube and see if there is any abnormal wear occurring in the first few inches. If you find none then it maybe be just simple drag on the bolt from the magazine and to much weight in the buffer.
    We are all inclined to judge ourselves by our ideals; others, by their acts.

  5. #15
    Join Date
    Nov 2010
    Posts
    669
    Feedback Score
    18 (100%)
    Either keep the AA Upper and ditch the Vltor A5 buffer system for a standard carbine buffer system in the weight that AA recommends. You could also look into and anti-carrier tilt type buffer. It doesn't sound like it is worth the trouble of hacking up an A5 buffer to get it to work with an AA piston upper that it was never intended for and visa-versa (AA piston was not designed to work with the Vltor A5).

    ... or, ditch the AA upper for a good quality DI upper that will work well with the Vltor A5 system.

    My recommendation would be to unload the AA piston upper. I don't understand the attraction of the piston kits when a good DI upper works fantastic with the Vltor A5 system. The piston system just seems to complicate things and introduce new problems such as carrier tilt.

  6. #16
    Join Date
    Apr 2009
    Posts
    637
    Feedback Score
    0
    There is nothing wrong with your setup other than your buffer weight. Just like carbine buffers, A5 buffers are sold in various weights. An A5 H0 buffer is what you want. You can either purchase one, or convert yours. Personally, I would convert mine because that way I can experiment with varying weights until I find the weight that works best. PA Patriot's suggestion of 3.8 oz sounds right on the money. An A5 H0 weights 3.8 oz. No need to change your entire upper or receiver extension...

  7. #17
    Join Date
    Dec 2008
    Location
    Where the 2nd Amendment still lives.
    Posts
    2,729
    Feedback Score
    5 (100%)
    I see there are some folks who recommend the OP dump the AA piston upper but I have to disagree with that opinion. Why dump any single platform without the very simplest of trouble shooting measures. I understand there is always resistance to going outside the established norm's which is the DI system but if you look at the latest offerings from Colt and HK they seem to be focusing on the piston driven system. I run both DI and Piston guns and found they each have their own strengths and weaknesses which I use accordingly for the mission at hand to capitalize on the capability I need at the time.

    Currently I like the piston design to run steel cased at courses were the round count is high and in colder weather during three gun. My DI guns are set up for serious use both SD and ranged engagement but if I had to run a piston gun for the same mission I would not hesitate.
    We are all inclined to judge ourselves by our ideals; others, by their acts.

  8. #18
    Join Date
    Apr 2009
    Location
    FL -Where it's summer 10.5 months out of the year
    Posts
    4,114
    Feedback Score
    17 (100%)
    Quote Originally Posted by PA PATRIOT View Post
    I see there are some folks who recommend the OP dump the AA piston upper but I have to disagree with that opinion. Why dump any single platform without the very simplest of trouble shooting measures. I understand there is always resistance to going outside the established norm's which is the DI system but if you look at the latest offerings from Colt and HK they seem to be focusing on the piston driven system. I run both DI and Piston guns and found they each have their own strengths and weaknesses which I use accordingly for the mission at hand to capitalize on the capability I need at the time.

    Currently I like the piston design to run steel cased at courses were the round count is high and in colder weather during three gun. My DI guns are set up for serious use both SD and ranged engagement but if I had to run a piston gun for the same mission I would not hesitate.
    I understand what you are saying, but if a gun won't run with the A5 and a standard buffer, which successfully emulates the most reliable buffer system extant, then I say the educated troubleshooter has to start asking the question "why won't my gun run with a rifle buffer/A5?"

    I have a buddy who bought a CMMG piston AR back in 2008. It had been nothing but problems for him using all types of factory ammo until he sent it back to CMMG. They replaced the entire upper and sent it back....now it runs OKAY. It still NEEDS a a BCM extractor spring WITH the o-ring and insert to extract properly, but yet will malf with anything heavier than a carbine weight buffer.

    Why deviate so far from the original design, only to have slightly more muzzle rise, a sharper recoil impulse, and no more resistance to dirt/carbon?

    I'm all for troubleshooting the OP's gun in a practical manner instead of immediately demanding that he trash it (I doubt he's made of money), but let's be honest about this: he would likely be better served in all aspects by a Colt 6920's upper half or another quality upper from BCM/DD/LMT etc.
    Last edited by BufordTJustice; 08-05-13 at 05:16.
    "That thing looks about as enjoyable as a bowl of exploding dicks." - Magic_Salad0892

    "The body cannot go where the mind has not already been."

  9. #19
    Join Date
    Apr 2009
    Posts
    637
    Feedback Score
    0
    Quote Originally Posted by BufordTJustice View Post
    ...then I say the educated troubleshooter has to start asking the question "why won't my gun run with a rifle buffer/A5?"

    Because it was not designed to. It was designed to function with a H weight carbine buffer.

    I have a buddy who bought a CMMG piston AR back in 2008.... It still NEEDS a a BCM extractor spring WITH the o-ring and insert to extract properly, but yet will malf with anything heavier than a carbine weight buffer.

    Several DI guns need buffers of varying weight and an extractor spring...

    Why deviate so far from the original design, only to have slightly more muzzle rise, a sharper recoil impulse, and no more resistance to dirt/carbon?

    I would say it is good advice if he did not already own a piston upper that he can get functioning properly for little or no money by changing weights in the buffer. I would even advise converting it to DI by buying a gas tube, gas block and bolt carrier before I told him to dump the whole upper. He could sell the piston kit and pocket some money instead of laying out more money.
    Responses in red.
    Last edited by az doug; 08-05-13 at 10:34.

  10. #20
    Join Date
    Apr 2009
    Location
    FL -Where it's summer 10.5 months out of the year
    Posts
    4,114
    Feedback Score
    17 (100%)
    Quote Originally Posted by az doug View Post
    Responses in red.

    "Because it was not designed to. It was designed to function with a H weight carbine buffer."


    It wasn't designed with any consideration of the sort. All first gen AA piston systems were replacement uppers and carried no such caveat. I have seen several. Their original product was simply a piston conversion kit that could turn a DI upper into a piston upper....which incorporated an amalgam of the design features found in the then-new LWRC/POF systems. Again, no such requirement for buffer weight was made. I've seen the original AA manuals.


    "Several DI guns need buffers of varying weight and an extractor spring..."


    Yes, but you didn't state the reason. The piston guns need uber-power extractor springs and heavier buffers because of their far-faster-than-EVER-INTENDED extraction. This is why many piston guns cannot digest steel cased ammo. CMMG (which started with an AA piston setup) specifically prohibits the use of steel cased ammo in their piston guns.


    "I would say it is good advice if he did not already own a piston upper that he can get functioning properly for little or no money by changing weights in the buffer. I would even advise converting it to DI by buying a gas tube, gas block and bolt carrier before I told him to dump the whole upper. He could sell the piston kit and pocket some money instead of laying out more money."


    If he modifies the upper, it turns into a franken-gun and the resale value is destroyed. Piston conversion kits run for ~$175-$250 retail. For maybe twice that he can buy an all new quality upper (BCM, HELLO?). Instead of trying to put lipstick on a pig, he would be better off not dumping a ton of cash into this project.

    If the OP can alter the buffer weight and get it to run, fine. Spending much more than that doesn't make fiscal sense. Especially since there are tons of Arfcommers who would have to fight the urge to rub one out before handing over their money ("Piston! Yay!").
    Last edited by BufordTJustice; 08-05-13 at 14:34.
    "That thing looks about as enjoyable as a bowl of exploding dicks." - Magic_Salad0892

    "The body cannot go where the mind has not already been."

Page 2 of 7 FirstFirst 1234 ... LastLast

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •