Adams Arm Piston noncompatible with Wylde chamber?

[WxWatcher]

Was looking over Armslist trying to help a buddy find a good, relatively affordable AR. Came across a posting sold as-is, as the wylde chambering doesn't build enough pressure to cycle the AA piston reliably. Anybody ever hear of this? Curious since I was thinking of running an AA with the Rainier Match barrel in 223 wylde I ordered the other week. Portion of the post is copied below:

"Problem: in building this and working with the engineers at Adams Arms we have found that the kit is incompatible with the .223 Wylde chambering. This chambering does not create the pressure needed to fulling activate the the piston and leads to short stroking. Rifle will fire first round but fails to auto load the 2nd round. Rifle was dead on at 100 yards. Local Gunshop/Ar15 armorer inspected and saw no other issues other than what Adams Arms engineers were stating. "

 

[smschulz]

Re: Adams Arm Piston noncompatible with Wylde chamber?

Yes it is.
I have two AA piston guns ~ both with Wylde chambers.
First is a 14.5 mid length and no issues at all.
Second is a 20" SDM WOA rifle length.
It initially had problems with not enough pressure.
Though trial and error it was resolved by:
a) slightly enlarging the gas port to .095
b) used an Endine (rifle buffer in PRS)
c) used Wolff reduced power buffer spring.


I think the main thing was the reduced power spring but I stopped experimenting after it starting working.

 

[WxWatcher]

Re: Adams Arm Piston noncompatible with Wylde chamber?

Thanks, smschulz. For as relatively small of a difference between a 5.56, 223 wylde and 223 rem chamber, I was pretty skeptical of his explanation of the problem. Good to know your mid length ran with no problems, that's what I'll be running too.

 

[NYresq]

Re: Adams Arm Piston noncompatible with Wylde chamber?

the wylde chamber is a happy medium between the Nato chamber and the saami spec 223 chamber made to try to accomidate both types of ammo without having pressure and chamber issues. The difference is measured in thousandth of an inch and the pressure difference is not so different as to not produce enough pressure to cycle a piston system. It is still more then ample pressure to cycle the bolt as most of the gas is bled off anyway as soon as the piston starts moving...

 

[Wolfish365]

Re: Adams Arm Piston noncompatible with Wylde chamber?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: smschulz</div><div class="ubbcode-body">It initially had problems with not enough pressure.
Though trial and error it was resolved by:
a) slightly enlarging the gas port to .095
b) used an Endine (rifle buffer in PRS)
c) used Wolff reduced power buffer spring.

</div></div>

Very informative, bookmarking this with my post here. Thanks for sharing!

 

[smschulz]

Re: Adams Arm Piston noncompatible with Wylde chamber?

My two Wylde chamber Adams Arms piston AR's

20" that required some buffer experimentation

14.5" that did not