Having tried different approaches to pistol caliber carbines Blow back, DI etc.. Just bought a new Olympic Arms .40 S&W upper and put it on my AR45 lower with modified grease gun mags. Result best running upper I have used to date. Bolt and chamber design are excellent, instead of just a feed ramp it has a feed funnel, almost impossible for rounds not to chamber, accuracy was very good.. Now I come to material and workmanship. Hand guard is cheap and did not even have a heat shield lining, rest of upper average. The upper did mate very well with my AR45 lower. I will probably purchase one in 45 ACP based on this experience. Hope this is some help for members .

 

Over the years I've tried a lot of Olympic Stuff. I have one lower that I will never part
with. As your upper, it must have been made on a Wednesday. Treasure what you've gotten
from Olympic as they are few and far between.

Shooting with Ron Williams, I have loads of experience with his DI Pistol Calibers. From
9mm through the 50 Cals he makes, the accuracy, reduced recoil and extreme attention to
detail and quality is unsurpassed by any of the other manufacturers that I've done testing
for. He personally does pre shipping tests himself and if anything needs tweaking it gets
done before he will release it. I'm hooked on the rifles he builds. So far I've had a 9mm,
two 45's and a 45 WinMag. We are working on a few new calibers that I'm not mentioning at
this time but I do see a 357 SIG and a 40 S&W RMWXtreme in my future.

Dave / SpecOps-13 in Florida

I to have used RMW upper, good product, I also have a D.I. 45 ACP upper by Rudy from Macon,ga. runs well. My expreinece with D.I. uppers is that they won't function well with low power loads and are powder fussy. Blow backs will run with anything, and proper buffering can reduce recoil to a minimum. Different stokes for different folks.

That's really what makes the world go round....


Dave

Could you elaborate on what is proper buffering for a 45??  I have an Oly 45ACP upper......it needs something....not sure what......but it's no fun to shoot in it's current  set up...which is completely stock.  I assume the Slash Heavy Buffers and springs are a starting point



 

That's it, heavy buffer 9 oz. with extra power spring, and if you reload your own go with lighter loads. I shoot my .40S&W with a rifle buffer and a Wolff extra power spring,with a A2 butt stock. With my D.I. 45ACP it's just the opposite, you have to lighten buffer and spring so low gas presure can operate bolt carrier. I have used expensive hydraulic buffer with results that are not worth cost in my opinion. Hope this is some help.

 

Very Good Explanation.

Dave

Excellent info, Thanks so much for your help

 

My blowback .40 S&W runs well with a heavy Spikes ST-9X buffer w/ a standard carbine spring.