Olympic Arms 10mm Upper Just Landed...


October 21, 2010, 12:26 PM
...and a day early, to boot. Gotta love the folks at Midway!

I was expecting an A2 upper for some reason. Turns out it's a flat top upper. I've got a Low-Pro upper coming from Brownell's (we don't need no FA, we don't need no stinking dust cover) tomorrow anyway, but interesting nonetheless.

I also didn't realize they were using SS barrels. Painted black, but stainless. Cool.

The new Olympic magazines are impressive! Looks like a longer version of the straight 20-round AR15 magazine. Only 19 rounds, but VERY hefty. Appears to come apart by removing 8 socket head cap screws on the side (and another up under the follower). Seems significantly heftier than a PMAG.

Last thing I noticed was the lack of a gas tube. Straight blow back design, from the looks of it.


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October 21, 2010, 12:32 PM
Matt do pictures if you know how; I don't!

But please let us know how it works out for you after a few rounds down range.

October 21, 2010, 01:06 PM
My camera's at home. I will be taking pics as soon as I get home and will post them here. Can't wait to get it all stripped down and built back up into the configuration I want.


October 21, 2010, 10:01 PM
BCG goes first. Interesting stuff:




Oly added a firing pin spring:


I prefer the original style firing pin retainer, so I added one:


Notice the buffer tube end of the bolt carrier. Lot's of extra mass there. I'm guessing that's at least part of the reason for the firing pin spring.



October 21, 2010, 10:04 PM
The upper itself looks pretty much standard issue, save for the little hole used to mount the ejector.




October 21, 2010, 10:09 PM
Here she is all put together for now:



I need to add a spacer for Ace stock, and mill some sort of adapter for a QR sling loop somewhere up under the gas block. The UPS guy should be bringing a Yankee Hill Machine gas block/folding front iron sight, a 3 pound Timney trigger, Lo-Pro upper (I don't care for forward assist or the dust cover), an aluminum hand guard similar to the one on the .223 upper in the last pic, and a Miculek compensator, which I'm going to have to bore out 10 .40".

I hope to get a chance to take her to the farm this weekend. Of course, rain is now in the forecast.


October 21, 2010, 10:29 PM
Awesome build. That is gonna be a hog killing machine

Pappy John
October 22, 2010, 05:55 AM
That's pretty cool. Me want.

I don't think my Dillon could keep up with that thing. It's hard enough keeping my G20 fed.

October 22, 2010, 06:17 AM
That is down right nasty! Really makes me want one... I would like to know the ballistics with the carbine barrel. Could easily be a hog killing machine in brush country. Super nice build. Hope you reload for the 10. Expecting a range report!

October 22, 2010, 10:46 AM
Yeah guys, I do indeed reload. This will be a companion to my Delta Elite that I had worked over at Heirloom Precision last year. I loaded PLENTY o' rounds whilst waiting for that puppy to come home to me, so I'm all set.

If I can dodge the rain I hope to get up to the farm tomorrow and run a few rounds through.


October 22, 2010, 12:56 PM
Remaining goodies from Brownell's just landed. Hehehehehehe...


October 22, 2010, 01:10 PM
I researched doing this exact same thing a while back. If I remember correctly the muzzle energy of a 10mm with a 16in barrel was around 1000-1300 ft lbs depending on the load. The 100yd energy was in the 500-650 ft lbs area. That does not tell the whole story however, because a 10mm 180gr hollowpoint can provide a whole not more knockdown/penetration that the #s would lead you to believe.

October 22, 2010, 01:36 PM
I purchased a user 10mm upper of gunbroker last year. It had some kind of (old) gas piston conversion which either wasn't done properly or more likely was repaired by someone who didn't know what they were doing. I was able to take a few shots with it before returning it.

It seemed a bit anemic. Those were very tame target loads, though. Not really sure what to expect. My only real goal was to have a little fun, and I'm sure it will provide that. :)


October 22, 2010, 02:10 PM
Very cool. I assume that since the bolt is fixed to the carrier, and the firing pin can protrude at any time instead of only in a locked position, the spring keeps everything nice and separated until the hammer says so.

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