HK91 vs PSG1 Trunnion
Page 1 of 2 1 2 LastLast
Results 1 to 10 of 13
Like Tree3Likes

Thread: HK91 vs PSG1 Trunnion

  1. #1
    Junior Member

    Join Date : Jul 2014
    Posts : 4
    Mentioned
    0 Post(s)

    Default HK91 vs PSG1 Trunnion

    Working on a hybrid build due to the scarcity of some (PSG1/MSG90) parts. While the differences in appearance are obvious I"m not familiar with the dimensions of the two different trunnions. So my question is; Can a standard HK91 forearm (hand guard) be used with the PSG1/MSG90 trunnion. Also, is the HK91 bolt locking piece compatible with the PSG1 trunnion?

  2. #2
    HKPRO PREMIUM PARTNER
    HKaltwasser's Avatar
    Join Date : Feb 2009
    Location : Dripping Springs, Tx- Just west of weird.
    Posts : 2,187
    Mentioned
    9 Post(s)

    Default

    I believe the standard wide 91 handguard will work. It will slide over the trunnion, I just don't have a wide 91 on me right now so I checked it with a G3K length one. The slim forearm won't work with it.

    Yes, you can use a standard locking piece. On the bolt head, I believe the recesses in the trunnion will accept both standard rollers and half moon but I'm not positive. Maybe JFK will chime in. What kind of PSG1 trunnion are you talking about? If it's an RCM , then it should be fine .....75 Bronco can confirm that too (RCM owner).
    eddypaul likes this.
    A voice from the past whispers in my ear, “Brethren, keep your powder dry.”

  3. #3
    Supporting Vendor

    Join Date : Apr 2002
    Posts : 1,241
    Mentioned
    33 Post(s)

    Default

    91 HG will NOT work.
    Lots of PSG1/MSG90 parts available.
    MM
    eddypaul likes this.

  4. Remove Advertisements
    HKPro.com
    Advertisements
     

  5. #4
    HKPRO PREMIUM PARTNER
    HKaltwasser's Avatar
    Join Date : Feb 2009
    Location : Dripping Springs, Tx- Just west of weird.
    Posts : 2,187
    Mentioned
    9 Post(s)

    Default

    I'm not trying to go against MM , but I'm not sure how it wouldn't work.

    Correction, I mean the triple tree. If you want this to work as a free floating barrel with a 91 handguard, you will have to modify\cut down your triple tree so it doesn't wrap your barrel.





    Last edited by HKaltwasser; 01-10-2020 at 02:44 AM.

  6. #5
    HKPRO PREMIUM PARTNER

    Join Date : Oct 2011
    Posts : 1,107
    Mentioned
    22 Post(s)

    Default

    Quote Originally Posted by eddypaul View Post
    Working on a hybrid build due to the scarcity of some (PSG1/MSG90) parts. While the differences in appearance are obvious I"m not familiar with the dimensions of the two different trunnions. So my question is; Can a standard HK91 forearm (hand guard) be used with the PSG1/MSG90 trunnion. Also, is the HK91 bolt locking piece compatible with the PSG1 trunnion?
    When your post counts gets up, PM me. I might be able to help you out.
    Own: HK91, SR9, PSG1 clone, SP5k, G36k, HK416, P30L, 2x P8, 2x P8A1, USP9, USP9 FDE
    Future: SP5 inbound

  7. #6
    Junior Member

    Join Date : Jul 2014
    Posts : 4
    Mentioned
    0 Post(s)

    Default

    hk21man...Agreed. I have found numerous PSG1 parts on the web, I'm having trouble locating the forearm. They are listed on HK Parts($230) and Numrich($180) however both have been out of stock for quite a while. Found one on Gun Broker, I'm thinking $475 is a bit too much.Considering the AIM Sports Inc Extended M-Lok Hand guard...

    HK91 vs PSG1 Trunnion-31.jpg
    Last edited by eddypaul; 01-11-2020 at 10:28 PM.

  8. #7
    jfk
    jfk is offline
    Desperately Needs Treatment
    jfk's Avatar
    Join Date : Jan 2001
    Posts : 1,221
    Mentioned
    2 Post(s)

    Default

    Quote Originally Posted by HKaltwasser View Post
    I'm not trying to go against MM , but I'm not sure how it wouldn't work.

    Correction, I mean the triple tree. If you want this to work as a free floating barrel with a 91 handguard, you will have to modify\cut down your triple tree so it doesn't wrap your barrel.







    My SR9 converted to PSG1 from RDTS did not include a PSG1 trunion or trunion extension. The PSG1 foream floats on the receiver end but locks up tightly on the cocking tube. With a specific PSG1 cocking tube or converted 91 tube, it is cut to fit. If you add a 91 forearm with or without the PSG1 trunion or extension, the hanger location on the 91 will be slightly too long. A PSG1 cocking tube is slightly shorter. Not much but enough for the front pin not to fit. Hope this helps. OP HK Parts has a PTR forearm that free floats similar to the HK factory forearm.
    I sold my HK's and bought a whole bunch of Century C93s. The best rifles on the planet bar none. I love the C93 pistols with the 12 o' clock slot!

  9. #8
    HKPRO PREMIUM PARTNER
    HKaltwasser's Avatar
    Join Date : Feb 2009
    Location : Dripping Springs, Tx- Just west of weird.
    Posts : 2,187
    Mentioned
    9 Post(s)

    Default

    I believe he is keeping his 91 cocking tube from the way I understood it. So the only way to free float is to cut down the triple tree and everything would be the same. It's hard to understand what he's trying to accomplish here. Really I don't see why he would need the PSG1 trunnion to free float his barrel if that's the angle he's going for.

  10. #9
    HKPRO PREMIUM PARTNER
    HKaltwasser's Avatar
    Join Date : Feb 2009
    Location : Dripping Springs, Tx- Just west of weird.
    Posts : 2,187
    Mentioned
    9 Post(s)

    Default

    Quote Originally Posted by eddypaul View Post
    hk21man...Agreed. I have found numerous PSG1 parts on the web, I'm having trouble locating the forearm. They are listed on HK Parts($230) and Numrich($180) however both have been out of stock for quite a while. Found one on Gun Broker, I'm thinking $475 is a bit too much.Considering the AIM Sports Inc Extended M-Lok Hand guard...

    Click image for larger version. 

Name:	31.jpg 
Views:	22 
Size:	54.2 KB 
ID:	249194
    What are you trying to accomplish by adding the trunnion? Are you planning on changing the cocking tube or keeping the 91 tube? All of this is relevant for whether or not this will work.

  11. #10
    Junior Member

    Join Date : Jul 2014
    Posts : 4
    Mentioned
    0 Post(s)

    Default

    Thank you for all the feedback! I've decided to go to a full MSG90 clone. I took the leap and purchased a PSG/MSG forearm, going with a PSG1 trunnion from RCM, now I'm on the hunt for the correct cocking tube. HK Parts is out of stock, any leads on one would be greatly appreciated...
    Last edited by eddypaul; 01-13-2020 at 01:52 AM.

Page 1 of 2 1 2 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
  •