.40 cal Barreled uppers vector vs. bmp.

they're more or less both exactly the same thing. BMP or special weapons or cohaire or tactical arms or what ever company Todd Bailey has decided to sell his products from this week manufactured the .40 caliber receivers and parts kits for Vector Arms under a marking varience when vector was first in the HK clone buis.

ALOT of barreled .40 cal VECTOR receivers you see for sale online were made from a parts kits BMP/SW was selling a while back and is most likely built by a home builder who is looking to unload a bad project on someone else. some were sold by special weapons as barreled uppers. its kind of a crap shoot on exactly who built the gun. even the best builders have problems making those crap parts kits work right out of the box without replaceing or drasticly fixing most of the parts in them.

if your not looking for a complete gun right off that bat that was built by an experienced builder i would reccomend starting with a NEW SW receiver and sourcing all of the parts separately either German ones or parts from KNOWN good companys then have a reputable builder put it together. you'll be much happier with the results.

DAS said:

"Stress relive the trunnion on any SW and/or Vector kit also add to the front portion due to inaccurate position of the barrel pin. Big write up in Weaponsguild concerning the trunnions. Written on facts not hear say."

Paul123 - Are you recommending to avoid BMP/SW trunnions or is it the way they pin them. I have a BMP trunnion for a build, should I use an RCM instead?

Dave

Click to expand...

Right now the only show in town for a .40 cal trunnion is either SW or factory German. i have not been on weapons guild to see what info they have provided on the trunnions but in my experience out of the 8 SW .40 cal trunnions i have used ALL of them ended up cracking across the barrel pin hole on the face of the trunnion. i have pinned quite a few trunnions in my build experience and those are the only ones that did it. its kind of a crappy feeling to walk over to the parts rack and see all of them cracked and then miss 2 in a gun that you just finished building only to have to tear it back apart.

here is a pic of what the cracks looked like.


im not saying they all do it, they may have been just the crappy ones SW put in the vector kits. i know that they ALL dont crack there are ALOT of people out there with Coharie guns and Vector guns that didint crack. but my expensive experience in using them has put a sour taste in my mouth. now if i build a .40 cal gun its either German core parts or i wont do it.

even worse on a .40 cal barrel is that once you set the barrel and drill the barrel pin hole thats it. the breech face is milled a little bit to allow clearance for the .40 cal extractor in the bolt face and unlike a 9mm barrel which you could press out clock 90 degrees and repress and redrill and pin. you cannot do that with a .40 cal barrel because once you clock it the 90 deg. the extractor relief in the breech face will no longer be in the right spot and it will not work. so if you end up with a bad trunnion you either have to scrap the barrel too or try using an oversized barrel pin but on a trunnion with an alredy known weak area drilling an even bigger barrel pin hole means even less support material so it would be even more prone to cracking!!!

Factory HK trunnions have the fronts of the trunnion where the barrel pin go's Annealed after the heat treating process this means softer metal not quite so brittle and prone to cracking. it also helps when you go to press the barrel in (all factory HK guns get their barrels pressed in from the front by the way) the trunnion will give ever so slightly and allow the barrel to start its path into the trunnion. the SW trunnions that came in the Vector kits may not have had this done, or the barrel pin hole was drilled in the wrong spot (IE: too low in the trunnion center line) which doesent provide enough material to handle the stress of a press fit barrel pin. if you've ever pinned a barrel you know the little buggers go in and come out extremely tight.

just my observations im sure other builders have had very different experiences.