Need help with UMP barrel threads - pics - Page 3
Page 3 of 3 FirstFirst 1 2 3
Results 21 to 27 of 27

Thread: Need help with UMP barrel threads - pics

  1. #21
    Unrepentant HKHolic
    gopherboy128's Avatar
    Join Date : Apr 2012
    Location : WA
    Posts : 2,363
    Mentioned
    12 Post(s)

    Default

    ADCO can fix what you have now without taking additional length off the barrel. That's what they did with mine. I wanted the "HK Pistol Profile " on my M16x1LH threads, as I figured if suppressor companies designed them to seal at that point, I wanted them to function as designed.

    Does your SOT let you shoot cans before stamps come back? Your piston will index off the muzzle but that wont really tell you how much gas you'd be dealing with.
    [Insert Witty Comment Here]

  2. #22
    I Bleed Urban Gray
    omega21's Avatar
    Join Date : Feb 2011
    Posts : 2,074
    Mentioned
    92 Post(s)

    Default

    Quote Originally Posted by Renegade View Post
    You best Option is C, wait till you get the piston and then decide if it works or not.
    If the threads are going to cut/wear the o ring prematurely, then I'm gonna skip that option. Thanks @Renegade

    Quote Originally Posted by gopherboy128 View Post
    Does your SOT let you shoot cans before stamps come back? Your piston will index off the muzzle but that wont really tell you how much gas you'd be dealing with.
    My SOT is a pawn shop that agreed to only charge me $125 for a NFA transfer as opposed to the $200 typically charged by people in Maryland! So no associated range @gopherboy128

    Quote Originally Posted by NoScoE30 View Post
    The muzzle is critical for the o ring seal. I can fix that.
    @NoScoE30 has agreed to reprofile the threads to be more like the design on a USP barrel so I can mount my Obsidian and not chew up o rings or have a sub-par seal. He has some fancy lathe (see picture below) that he's going to do this on and he's charging me next to nothing. This is why I love this forum! I'll post pics when the barrel comes back for the sake of comparison.

    My thanks to all of you for helping me solve this problem and especially to those who reached out and offered to do the work for little or no cost.

    Need help with UMP barrel threads - pics-lathe-garage1.jpg
    ________________________
    Omega21

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

  3. #23
    Desperately Needs Treatment
    Renegade's Avatar
    Join Date : Aug 2001
    Location : Texas
    Posts : 1,192
    Mentioned
    10 Post(s)

    Default

    Quote Originally Posted by omega21 View Post
    If the threads are going to cut/wear the o ring prematurely, then I'm gonna skip that option. Thanks @Renegade
    How you gonna know that until you have the piston?

    Here is a Pro-Tip, next time you get your BBL threaded, give the machinist the piston you want it to work with. Measure twice, cut once. Or do it your way cut the BBL several times.

  4. Remove Advertisements
    HKPro.com
    Advertisements
     

  5. #24
    I Bleed Urban Gray
    omega21's Avatar
    Join Date : Feb 2011
    Posts : 2,074
    Mentioned
    92 Post(s)

    Default

    @Renegade Next time I buy a barrel I know what to look for or I send the barrel with the spec sheet for the threads I want now that I have spec drawings/sheets that folks gave me. After this thread I am better educated. It was a worthwhile investment. Question now is, are you better off with cutting and threading an HK barrel or buying an HDPS barrel? I'll ask that in a separate thread.

  6. #25
    Desperately Needs Treatment
    Renegade's Avatar
    Join Date : Aug 2001
    Location : Texas
    Posts : 1,192
    Mentioned
    10 Post(s)

    Default

    Quote Originally Posted by omega21 View Post
    @Renegade Next time I buy a barrel I know what to look for or I send the barrel with the spec sheet for the threads I want now that I have spec drawings/sheets that folks gave me. After this thread I am better educated. It was a worthwhile investment. Question now is, are you better off with cutting and threading an HK barrel or buying an HDPS barrel? I'll ask that in a separate thread.
    Yeah, if you cannot have the actual piston the spec sheet is the next best option. I send everything to Adco myself.

  7. #26
    I Bleed Urban Gray
    omega21's Avatar
    Join Date : Feb 2011
    Posts : 2,074
    Mentioned
    92 Post(s)

    Default

    @Renegade do you have a picture of the threads on an Adco barrel? Just curious what that looks like. Thanks!

  8. #27
    Gets the Shakes if No HK Contact in 24 Hour Period

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

    Default

    Quote Originally Posted by Renegade View Post
    How you gonna know that until you have the piston?

    Here is a Pro-Tip, next time you get your BBL threaded, give the machinist the piston you want it to work with. Measure twice, cut once. Or do it your way cut the BBL several times.

    A machinist might just thread it m16x1lh just like this barrel was. Bing bada boom, piston fits...done deal. NOT! Metric pistol threads and the profile are unique. I follow the AAC muzzle thread dimensions that are widely regarded as the industry standard. Fitting pistons to barrels is sort of backwards. Parts and barrels should be made to industry standards, NOT fit to components.

    For example,

    I had a Sig P226 Combat Threaded Barrel. I got the barrel, and it had m13.5x1lh threads on it. Only problem was, the pitch diameter of the threads was .002" OVERSIZE! Nothing I had would fit the barrel because it was not threaded properly. However, the thread protector fit. Sig said since the thread protector fits, it is in spec. The barrel took two trips back to sig before I was sent a new barrel with threads in tolerance.

Page 3 of 3 FirstFirst 1 2 3

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
  •