AR Build Question

[OC13]

I'll apologize now, as I'm sure this has been asked before... but I haven't found the answer yet, so I'll ask it again.

I'm building an AR/M4 16" 1:7, Carbine-length DI gas... fairly standard parts; it's a budget build. Checked torque specs, headspace, etc...

Bought a Del-Ton Full Auto BCG, but a commercial CAR stock assebly... the buffer weighs just under 3 oz

Tested it twice, and am having a cycling issue.

testing went as follows:

1 round in mag to test for BHO after last round = good

loaded 10 rnds, cycled two rounds (3 shots fired), then FTF... rounds ejected & cleared, but failed to strip the next round off the mag (BTW newer mags, never a problem in my match rifle)

Pulled semi-auto Double Star BCG from my match rifle, tested in new M4 CAR build... loaded 10 rnds, fired smooth until end of mag w/BHO at the end...

Conclusion... heavier BCG does not cycle properly, lighter BCG cycles perfectly...

Aside from buying a new semi-auto BCG i nliue of the F/A BCG, what can be done to help the cycling issue? Heavier buffer? New buffer spring from Sringco?

Any advice from those more knowledgeable than I, would be greatly appreciated

 

[ugaarguy]

Aside from buying a new semi-auto BCG i nliue of the F/A BCG, what can be done to help the cycling issue? Heavier buffer? New buffer spring from Sringco?

Check the gas port diameter, but with a standard CAR buffer it sounds like the spring is weak. A heavier buffer wouldn't help, since the lighter BCG did help. Maybe lube the BCG heavily, and see if that combined with some more firing will wear everything in.

 

[gotigers]

ugaarguy gave good advice. Also check the gas key and bolt gas rings. Did you try other mags?

Edit: check gas block alignment.

 

[madcratebuilder]

What ammo did you use to test with?

Run the SA BCG to break in the rifle then try the FA BCG.

Conclusion... heavier BCG does not cycle properly, lighter BCG cycles perfectly...

Under gassed?

 

[Zerodefect]

Shoot more.

Pull gas block. Look inside gas block for the carbon pattern. Was the gas block crooked? Gas Block hole too small?

What buffer are you using? H buffer with FA carrier should be fine.

 

[Tirod]

Is it wet with lube? Especially in the upper cam track, per the TM?

What ammunition?