Author Topic: Factory replacement barrel fitting  (Read 491 times)

0 Members and 1 Guest are viewing this topic.

Offline Hutehund

  • Jr. Member
  • **
  • Posts: 64
Factory replacement barrel fitting
« on: July 27, 2017, 04:43:45 PM »
I decided to replace the 18x1 thread pitch barrel on my Scorpion EVO 3 with a factory 1/2x28 barrel.  I had already done the SBR conversion, and the adapter for the suppressor was bugging me.  Should be easy, right?  I watched the videos on YouTube... Piece of cake.  And it was - right up until the time that I went to reinstall the lower.  It seems the block on the bottom of the trunion of the new barrel (which serves the dual purpose of feed ramp and disassembly pin retainer) is .030 wider than the block on the trunion of the original barrel.  And about .015 wider than the opening on the lower.

Has anyone else experienced this?  I expected a drop-in replacement, and otherwise it was.  But now it's starting to look like I may need to make a trip to a gunsmith with my tail between my legs.  I definitely don't want to widen the lower, in case I ever want to reinstall the original factory barrel.  I'm hoping the width of the block on the bottom of the new trunion/barrel can be reduced to fit.
« Last Edit: July 27, 2017, 05:16:22 PM by Hutehund »
Take responsibility for your actions.

Offline SouthernScorp

  • Hero Member
  • *****
  • Posts: 861
Re: Factory replacement barrel fitting
« Reply #1 on: July 27, 2017, 05:48:00 PM »
pretty sure the trun is different between gen 1 "18x1" and gen 2 "18x1 and 1/2x28 dual thread" barrels.
CZ Scorpion Evo S1 Pistol:

SLR Synergy Mini comp
SBT-EVO Brace
PMM Safety Levers
Dual HBI Prostock Charging Handles
Gearhead Mag Release
HBI Trigger Spring
HBI Delta Trigger
PMM QD Front & Rear
Magpul MS1 + QDs
Holosun HS515cu on ADM low mount
Vendetta VP-17-A AFG

Offline Destructo6

  • Full Member
  • ***
  • Posts: 136
Re: Factory replacement barrel fitting
« Reply #2 on: July 27, 2017, 06:09:23 PM »
Yep, do a search for the barrel fixation feed ramp issued and related.

IIRC, HBI had a fix for this.

Offline OpusXJ

  • Newbie
  • *
  • Posts: 34
Re: Factory replacement barrel fitting
« Reply #3 on: July 27, 2017, 09:03:25 PM »
Your gun is a gen 1, your new trunnion is gen 2. Either machine the feed ramp/pin area to match your gen 1 trunnion, or use the gen 1 trunnion on your new barrel. You'll probably have to machine the extractor notch into the new barrel after installing into gen 1 trunnion, as they're not timed to each other.

Offline OpusXJ

  • Newbie
  • *
  • Posts: 34
Re: Factory replacement barrel fitting
« Reply #4 on: July 27, 2017, 09:11:05 PM »
ILWT sells micro barrels already set up in a trunnion
https://www.inleadwetrust.com/products/scorpion-evo-micro-3-lug-1-2-28-tpi-custom-barrel-trunnion

HBI can swap your new barrel into your gen 1 trunnion and machine the extractor notch for $50

Offline Hutehund

  • Jr. Member
  • **
  • Posts: 64
Re: Factory replacement barrel fitting
« Reply #5 on: July 28, 2017, 07:35:53 AM »
ILWT sells micro barrels already set up in a trunnion
https://www.inleadwetrust.com/products/scorpion-evo-micro-3-lug-1-2-28-tpi-custom-barrel-trunnion

HBI can swap your new barrel into your gen 1 trunnion and machine the extractor notch for $50

Great info... Thanks to everyone.  Ideally, if the width of the feed ramp is the only difference between the Gen 1 and Gen 2 trunnions, I'd prefer to have that width reduced on the Gen 2 trunnion to match the original Gen 1 trunnion without removing either barrel from either trunnion.  At that point, I'd have two factory timed barrels, which was my original intent.  I'm going to call HBI today to see if that's possible.

Hey, if nothing else, at least I learned how to spell "trunnion."  :)  Thanks again for your help!
Take responsibility for your actions.

Offline ShootersElement

  • Sr. Member
  • ****
  • Posts: 394
  • www.ShootersElement.com
    • Shooters Element
Re: Factory replacement barrel fitting
« Reply #6 on: July 28, 2017, 10:41:45 AM »
Trunions from the gen 1 to gen 2 scorpions are different. It's not a direct swap, if I remember correctly the feedramps would have to be machined down to fit the older gen scorpion.

You might be better served just taking the barrel to a local smith or machine ship and having them thread the end for 1/2x28, that's what I did for my SBR'd gen 1 scorpion. Well actually it's one of my FFL dealers in the area that stocks my parts so we did some horse trading :).
CZ Scorpion accessories

www.ShootersElement.com

Like us on Facebook:www.facebook.com/ShootersElement
Check us out on Instagram:https://www.instagram.com/shooters_element

Offline Hutehund

  • Jr. Member
  • **
  • Posts: 64
Re: Factory replacement barrel fitting
« Reply #7 on: July 28, 2017, 11:07:03 AM »
Trunions from the gen 1 to gen 2 scorpions are different. It's not a direct swap, if I remember correctly the feedramps would have to be machined down to fit the older gen scorpion.

You might be better served just taking the barrel to a local smith or machine ship and having them thread the end for 1/2x28, that's what I did for my SBR'd gen 1 scorpion. Well actually it's one of my FFL dealers in the area that stocks my parts so we did some horse trading :).

Thanks!  That's plan B, if I can't get the replacement Gen 2 barrel/trunnion ramp machined to fit and function flawlessly.  I emailed HBI to see if they could do the machine work to make that happen.  I'd like to keep the original serial numbered barrel unaltered, if possible.  That's just my own OCD... There's no sound reasoning for needing to do that.  Regardless, I'll post the results of whatever I end up doing.   :)
Take responsibility for your actions.

Offline OpusXJ

  • Newbie
  • *
  • Posts: 34
Re: Factory replacement barrel fitting
« Reply #8 on: July 28, 2017, 11:26:22 AM »
You could also buy a gen 2 lower for $69 or however much CZ sells them for, swap all your parts over to it and file down the nub on the back so it fits your gen 1 upper. This may be the most economical way.

Offline Hutehund

  • Jr. Member
  • **
  • Posts: 64
Re: Factory replacement barrel fitting
« Reply #9 on: July 28, 2017, 01:49:16 PM »
You could also buy a gen 2 lower for $69 or however much CZ sells them for, swap all your parts over to it and file down the nub on the back so it fits your gen 1 upper. This may be the most economical way.

Absolutely correct, OpusXJ.  Pat from HBI just replied to my email agreeing with that method.  He even sent pics of the lower differences for the modification.  HBI has the best customer service I have ever encountered.  As always, I'm grateful to all of you for your expertise, and to Pat at HBI for his immediate help in resolving this issue.  Here's the response from Pat at HBI:

Sorry.... I had to remove the email message from HBI.  After I had included it in this post, I realized that the email had a confidentiality clause, and the last thing I want to do is post something that HBI might not want shared.  Suffice it to say that Pat at HBI was more than helpful!
« Last Edit: July 28, 2017, 03:44:05 PM by Hutehund »
Take responsibility for your actions.

Offline OpusXJ

  • Newbie
  • *
  • Posts: 34
Re: Factory replacement barrel fitting
« Reply #10 on: July 28, 2017, 03:24:55 PM »
I believe you could also widen the pin/trunnion area of your existing gen 1 lower if you wanted to.

Offline Hutehund

  • Jr. Member
  • **
  • Posts: 64
Re: Factory replacement barrel fitting
« Reply #11 on: August 07, 2017, 12:05:26 PM »
Just a quick follow-up as to how the issue was resolved... I located a local machinist (who also happened to be a gun guy), and he shaved the Gen 2 trunnion to match the original Gen 1 trunnion.  And he did that using the original bore to trunnion edge as his reference - not just equal millings off each side.  Of course it assembled perfectly, and I took my father out to the range on Friday to help me sight-in and test it.

One hundred and fifty hiccup-free rounds later, both unsupressed and suppressed (Rugged Obsidian 45), I am very pleased to say it was worth the effort.  Thanks to all for your support and advice.
Take responsibility for your actions.

 

anything