Is there a company other than Olympic Arms that makes a 10mm upper?
If not, then is anyone out there that has any first hand knowledge of the 10mm upper from Olympic?
Is it good?  Bad?  

Thanks in advance
Mike

Ron Williams of RMW extreme.



Do a search for member ronaldmwilliams on here. Send him an IM. He makes an excellent product at a good price.



ETA: Ron Williams



Ron's uppers are DI, not blowback.  The only other option I know of for a blowback gun would be a RRA .40 upper reamed out to take 10mm.

I had a 10mm upper from Olympic for a full auto AR-15 SP-1 that worked OK.  I had to get a stronger recoil spring for the Norma 10mm loads and on full auto it was a handful, but shot great.

Guys, Olympic Arms has about 20 years of experience working with .22lr, 9mm, 40SW, 10mm, and 45 ACP pistol caliber rifles and AR pistols.

I have an Olympic Arms 10mm 16" carbine.  It shoots flawlessly and I get 1-2" groups at 50 yards if I do my part as a marksmen.  I have several of the 45 acp Uzi mags with a block welded on that Oly manufactured years ago.  Fits like a glove.

The key advantages to running an Oly system:

1.  Use any old lower you want - no special hammer or mag release modifications

2.  They have the most experience with all of the the pistol caliber conversions (357 sig has been abandoned in the blowback design and must be DI)

3.  They are the largest AR manufacturer west of the Mississippi

4.  They manufacture their own accessories such as flash hiders with the correct tpi for 10mm and 45 ACP

5.  They have a lifetime warranty and when I was building my 45 ACP pistol - they helped me and helped me with some Sten mag malfunctions when I was getting FTF in my 9mm carbine;

5.  And they continue to innovate with new pistol caliber mags in 9mm, 40SW, 10mm, and 45 ACP all well designed and eliminating the mag blocks:

I just ordered some 9mm and 45 ACP pistol caliber mags:



Nobody else in the industry is developing 10mm AR15 pistol caliber rifles as an AR manufacturer.  RRA does not appear to be able to make the 40SW rifles promised to a federal LEA.  Others in the industry only seem to be making 9mm and .22lr uppers - good products but only two calibers.

I have several ARs from different makers but I do have a 9mm carbine, 10mm carbine, and a 45 acp pistol all AR pistol caliber conversions from Olympic Arms.   They also have a .22lr conversion kit too.

The only thing you'll need with any 10mm upper is extra power recoil spring to save your BCG from the harsher loads as an earlier poster stated.

10mm is still somewhat considered an exotic or reloader's caliber so if you want a company experienced with 10mm including making brand new 10mm magazines that don't require a mag block, Oly is it.

It's a special caliber and no one else is running units in a production fashion - just one offs.

Oly is your answer.  Here is mine - 16" carbine with YHM free float tube, EoTech red dot, Magpul ACS stock - my pig and deer rifle: