Best way to diagnose Huldra AR15 piston upper problem?

Question

Alright so far I have run about 125 brass rounds through my Huldra Mark IV complete upper. It has failure to feeds practically every round or three rounds and or failure to ejects as well. The bolt release it hates at times, only is okay pretty consistent with charging and if I recall sometimes the bolt hold may not work.

I know apparently the Huldra doesn't like steel but its not feeding brass. So far its been with both a Smith and Wesson M&p lower as well as a doublestar lower Ive put together. I have since tried to look at various factors and come up with this final test before I invoke the warranty and I was wondering if there is anything I could be missing.

1.Start with the Smith and Wesson lower with a newer buffer tube spring, standard buffer and an aluminum mag with 20 rounds in it. Fire off ten fairly rapidly and see how it does. (If it fires well switch to a pmag with 20 and record what issues).

2.Next switch to the double star lower with the newer buffer spring and standard buffer and fire 20 rounds with aluminum and pmag and record what issues.

3.Switch back to the Smith and Wesson lower with a more worn in buffer spring and standard buffer and repeat step 1.

4. Switch to Double star lower with more worn in buffer spring and standard buffer and repeat step 2.

5. Repeat the other four aspects but involve using an H2 buffer.

Do you guys have any suggestions or changes I should make? Im in college so when I go back up home this is when ill get a chance to test it. Previously I only had Pmags and I picked up aluminum mags to see if that would help. Ammunition wise its american eagle 5.56 and pmc xtac 5.56 that I would be using because its the only thing Ive been able to get my hands on.

I find it pretty stupid that it cant eat brass or that they think a break in period is required by todays standards possibly. My smith and wesson ate everything from the get go, hell i mixed brass and steel and stress tested it in dirt and it works awesome. Wonder if theyd let me switch it out for there new DI uppers haha

Answer 1

I'd send it back ... it may have a tight chamber (needs reaming) If you can find a set of "go/no go" gauges locally (any AR armorers nearby) they may be able to determine the issue.



Based on what your saying- I doubt the buffer is part of the problem.

Answer 2

Make sure that you clean the upper before using it. Run your bolt carrier group wet or greased. The other option is to trade it off on a DI upper.

Answer 3

Is the bolt carrier well lubed? If it's dry it's going to hang up. Try lubing it with some Breakfree CLP.