Need help with UMP barrel threads - pics - Page 2
Page 2 of 3 FirstFirst 1 2 3 LastLast
Results 11 to 20 of 27

Thread: Need help with UMP barrel threads - pics

  1. #11
    Gets the Shakes if No HK Contact in 24 Hour Period

    Join Date : Jan 2011
    Posts : 530
    Mentioned
    9 Post(s)

    Default

    You guys know the metric threaded pistol calibers seat on the muzzle right?

  2. #12
    Desperately Needs Treatment
    Renegade's Avatar
    Join Date : Aug 2001
    Location : Texas
    Posts : 1,183
    Mentioned
    10 Post(s)

    Default

    If your Obsidian is at your FFL, go get the piston shaft and try it for size.

    Also - Metric threads index off BBL, not shoulder.

  3. #13
    Unrepentant HKHolic
    gopherboy128's Avatar
    Join Date : Apr 2012
    Location : WA
    Posts : 2,363
    Mentioned
    12 Post(s)

    Default

    Quote Originally Posted by omega21 View Post
    I know, but I don't want to pay $65 plus shipping for a barrel I bought that was already threaded. Should have been done right the first time.
    Depends on what manufacturer you go by as far as "right" SilencerCo uses same thread spec for M16x1LH as HK uses on their pistol barrels. LikeNoScoE30 said, that muzzle seat is for oring seal. Your piston will mate to the face of the muzzle. If thats all you want- no problem.
    [Insert Witty Comment Here]

  4. Remove Advertisements
    HKPro.com
    Advertisements
     

  5. #14
    I Bleed Urban Gray
    omega21's Avatar
    Join Date : Feb 2011
    Posts : 2,072
    Mentioned
    91 Post(s)

    Default

    Quote Originally Posted by NoScoE30 View Post
    You guys know the metric threaded pistol calibers seat on the muzzle right?
    Quote Originally Posted by Renegade View Post
    Also - Metric threads index off BBL, not shoulder.
    Quote Originally Posted by gopherboy128 View Post
    ...that muzzle seat is for oring seal. Your piston will mate to the face of the muzzle.
    So what you are saying is the length of the threads doesn't matter since this is threaded 16X1 - which is metric - and that means the piston or fixed barrel adapter is going to index to the face of the muzzle not the shoulder? So there's no issue here? I really don't understand how this works. Could you educate me and explain eh concept of seating to the muzzle? Do I just screw the piston or fixed barrel adapter on until it stops and I'm properly seated?
    ________________________
    Omega21

    Keep your booger hook off the bang switch till you're ready to bring the hate

  6. #15
    Desperately Needs Treatment
    Renegade's Avatar
    Join Date : Aug 2001
    Location : Texas
    Posts : 1,183
    Mentioned
    10 Post(s)

    Default

    Quote Originally Posted by omega21 View Post
    So what you are saying is the length of the threads doesn't matter since this is threaded 16X1 - which is metric - and that means the piston or fixed barrel adapter is going to index to the face of the muzzle not the shoulder? So there's no issue here? I really don't understand how this works. Could you educate me and explain eh concept of seating to the muzzle? Do I just screw the piston or fixed barrel adapter on until it stops and I'm properly seated?

    Yes.

    When you get your piston and look inside of it you will see what we mean. It threads on until the muzzle of the BBL contact the inside of the piston.

    For USC, since BBL profile is so thick, you need longer threads to make sure piston does not bump up against shoulder before muzzle contacts inside piston. Yours looks fine.

  7. #16
    Gets the Shakes if No HK Contact in 24 Hour Period

    Join Date : Jan 2011
    Posts : 530
    Mentioned
    9 Post(s)

    Default

    The o-ring in his mount will become trash because the threads will cut it.

  8. #17
    Unrepentant HKHolic
    gopherboy128's Avatar
    Join Date : Apr 2012
    Location : WA
    Posts : 2,363
    Mentioned
    12 Post(s)

    Default

    Sorry Omega if I am not explaining this as well as I should.

    I know from personal experience that in order for SilencerCo pistons to mount "correctly" (meaning the O-ring seals and reduces gas blowback) you need to have the correct profile on the tip of the barrel, and not just straight threads, like shown in your photo. Because Rugged has come out and said that their products can use SilencerCo pistons, I *assume* they use the same thread spec.

    Different manufacturers have different specs for the same thread, for instance look at SilencerCo and YHM. Links posted below:

    https://yhm.net/media/pdf/COBRA_M2_M16LH.pdf

    https://s3.amazonaws.com/com.silence...s-16mmx1LH.pdf

    I don't believe you will permanently damage anything (aside from an O-ring) by threading your suppressor on to the barrel and shooting it, the way it is threaded now. Sorry if I implied the barrel was not usable in prior posts. Like NoScoE30 said, you will most likely cut up the O-ring inside the piston, which would lead to more gas. But as long as the piston bottoms out against the end of the barrel, you should be good to go.

  9. #18
    Desperately Needs Treatment
    Renegade's Avatar
    Join Date : Aug 2001
    Location : Texas
    Posts : 1,183
    Mentioned
    10 Post(s)

    Default

    Quote Originally Posted by gopherboy128 View Post
    Sorry Omega if I am not explaining this as well as I should.

    I know from personal experience that in order for SilencerCo pistons to mount "correctly" (meaning the O-ring seals and reduces gas blowback) you need to have the correct profile on the tip of the barrel,
    Yep. I do not have the SiCo piston, but though his BBL is correct threads, it is not threaded to typically BBL specs for silencers, as it does not have the relief on front. He needs to get his piston and check if this is an issue.

  10. #19
    I Bleed Urban Gray
    omega21's Avatar
    Join Date : Feb 2011
    Posts : 2,072
    Mentioned
    91 Post(s)

    Default

    I don't have the Rugged piston yet for this barrel. It's on the way. Sounds like my options are to A) leave as is and chew up o rings B) have the front of the barrel re-contoured to relieve the threads and create a "blank" unthreaded area right at the front (similar to the Sico and YHM diagrams above and similar to the USP barrel in my first post). Can option B be accomplished without "bubba-ing" the barrel up?
    At this point I'm inclined to return it to @Miacovet and just have my own USC 16" barrel cut down by ADCO.... thoughts?

  11. #20
    Desperately Needs Treatment
    Renegade's Avatar
    Join Date : Aug 2001
    Location : Texas
    Posts : 1,183
    Mentioned
    10 Post(s)

    Default

    Quote Originally Posted by omega21 View Post
    I don't have the Rugged piston yet for this barrel. It's on the way. Sounds like my options are to A) leave as is and chew up o rings B) have the front of the barrel re-contoured to relieve the threads and create a "blank" unthreaded area right at the front (similar to the Sico and YHM diagrams above and similar to the USP barrel in my first post). Can option B be accomplished without "bubba-ing" the barrel up?
    At this point I'm inclined to return it to @Miacovet and just have my own USC 16" barrel cut down by ADCO.... thoughts?
    You best Option is C, wait till you get the piston and then decide if it works or not.

Page 2 of 3 FirstFirst 1 2 3 LastLast

Sponsored Links

 
 

Posting Permissions

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