PredatAR problem:
Total I have approx 1000rds through this gun. I have mainly shooting M118LR, Mk316/319 and various Federal and BH 175/168gr rounds. The problem started at about the 200rd mark. When the bolt is heavily oiled the weapon will run smooth and extract flawlessly. However after 40-60rds and the large quantity of oil is sprayed/burned off the weapon will fail to extract on almost every round until more oil is applied. The weapon will fire, bolt goes to the rear, but the extractor did not maintain a bite on the rim of the spent case. So the bolt then tries to feed another live round on top of the spent case in the chamber. Once the live is cleared and the bolt is sent forward again on an empty case, you can then extract the spent case with the charging handle. The case is not stuck. It comes out freely when hand cycling the bolt. The spent cases show no signs of rupture, torn rim or any deformity.
You mention shooting several types of ammo, which exact type/s are having issues?
Does the brass show signs of pressure or sizing issues?
I’m not drawing a parallel between lube and extraction. Unless… you have got excessive lube in the chamber, coking up, increasing adhesion, raising pressure, impeding extraction.
Possibly an extremely tight extractor isn’t moving w/o being wet?
I would check the extractor for:
free movement, debris
tension of spring
profile of extractor working surface/edge aka “kittens teeth”
If nothing remarkable shows. I would have a new extractor & spring sent out.
ASSuming properly sized ammo/brass. One would suspect a tight chamber or extractor lacking enough tension or bite. Easiest cheapest component switch 1st…
I personally was stunned by an OBR’s reliability, having run a 16" OBR 700+ rds, suppressed, w/o cleaning or lube having no issues (7.62LR mil ammo). Being suppressed, the BCG was filthy… The last magazine or two it started to get a bit sluggish, slowed reciprocation, but worked fine.
I don’t have experience with the PredatAR, but I do know that my 7.62 MWS definitely prefers grease more than an oil type lubricant. I experienced malfunctions using SLiP 2000 oil type lube, and switched to the SLiP 2000 EWG (grease), and she runs like a top. The guys that I worked with who used KAC MK 11’s also stuck with grease, mostly TW 25. Hope that helps.
Have you called Mark? Maybe I’m spoiled by being only a few hours away, but I find him frequently willing to go above and beyond to support his products.
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