I have a vulcan armament upper with sten mag block that I currently use on my carbine.  Am I correct in thinking this is similar to the olyimpic system?  Is the barrel extension the same?.  I've got a registered pistol lower and want to build a 9mm pistol.  Are there any already made short 9mm barrels available, or should I just get my current barrel cut down.   I'm currently considering building a Colt/RRA type 9mm rifle, or getting an Oly. Glock carbine to compliment my Glock 19.

Try Garrison in Ohio, as I recall. They had an ad in S.A.R. with good $$$. OTTO. But, All COLT system.

Quoted: I have a vulcan armament upper with sten mag block that I currently use on my carbine.  Am I correct in thinking this is similar to the olyimpic system? I think it is a somewhat copy of the Olympic system Is the barrel extension the same?.   The Oly is different than the COLT style. The chamber end of the COLT style is flat and chambered, where as the OLY is back-bored and chambered up -inside the end of the barrel... I've got a registered pistol lower and want to build a 9mm pistol.  Are there any already made short 9mm barrels available, or should I just get my current barrel cut down. TROSUSA has 5' & 9" 3 lug barrels he makes, and Henry @ Title2.com has them usually,  WA Tom makes barrel, Randall Rausch here makes barrels,  M60Joe.com will cut/modify existing barrel, ADCO modify, tell us what you want, and we point in right direction.  I'm currently considering building a Colt/RRA type 9mm rifle, or getting an Oly. Glock carbine to compliment my Glock 19.

COLT  style -


Typical Olympic - fuzzy pic by KKF

Wow!  Thanks for the great info and especially the pics!  I'll compare those with my gun... I may still build a whole new gun.  Mine seems to like only 124gr and higher ammo and that makes my ammo options alot smaller.  I've heard that both the Oly and the Colt style aren't as picky.   Is that true?  Those 32rnd sten mags sure do deplete my ammo stores.

Story is the Oly will eat anything you feed it, due to the center feed mag (Sten), and the large cone/funnel  at end of barrel into chamber..

The Colt pattern is finiky about hollow point ammo, as it has to ride up a ramp and hit the chamber right on.  Colt pattern is 100% with ball ammo.

I have had good success with hollowpoints in my Colt 9mm.  Colt magazines work quite well, though others do indeed perform best with ball.

The only exception to this rule is for cartridges that are relatively short.  If the LOA is correct, then they feed fine.