OA-93 Recoil Spring, Help requested. . .
Hello All,
My name is Dave and I live here on the west coast in Portland Oregon.
I am 53 years old and a long time Gun Enthusiast/Collector.
I own half a dozen AR's in various configurations.
Recently Joined this Chat board in hopes of getting some input to
resolve a problem I have been having with an OA-93 pistol upper.
Just after the AWB expired a group of us ordered a dozen AR Lowers
and had them all registered as Pistols.
From one of these I assembled an OA-93 using Olympics Upper.
This firearm would not cycle reliably when first assembled.
Experimented with many different types of ammo and found that
only the Federal Lake City Brown box would cycle more or less reliably.
None of the ammo tested would Lock the action open after the last round.
Emailed Olympic's Support people and never received an answer.
So now I am on my own. Dissassembled the Upper and found the following.
The Gas port was set at .0625" (1/16) and it had the straight gas tube.
The recoil spring seemed way too stiff. It's dimensions were as follows:
OD=.440" OAL=7.5" Wire Dia.=.047" Coil Pitch=.1875
Opened the Gas Port just slightly to .070" and added a pigtail Gas tube.
I have Inquired all around and spent Hours searching the web to find a
spring with a little softer rate and have had no luck.
So I started cutting off coils and retesting, I now have a spring that is
just barely 6.0" long. The Federal Lake City ammo now reliably Locks
the action open every time. The other ammo now cycles But they
will not Lock the action open.
At least now the OA-93 functions, But it is not the optimum situation.
I would still like to find a spring that will allow a wider variety of ammo to be
used while still functioning correctly.
Anyone that has any thoughts on this subject please respond.
Dave
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