Discussion about rifles in 300 AAC BLACKOUT (7.62x35mm), hosted by the creator of the cartridge.
Yea ok, I have been shooting 208's subs in my blkouts for couple years now without any cycling problems at all. I switched to Mobil 1 oil back last spring to try it. In the summer it was great, oil the BCG and it stayed wet after shooting couple hundred rounds suppressed quiet well. The other day I tried to fire a few subs and had some feeding problems. I didnt have time to play with it and see what the problem was. So yesterday I got it out and tried fireing some more with same feeding problems. I switched the BCG out to see if that might be a problem, nope same thing. Its like the BCG is dragging or not enough mass to load and lock a round in the chamber. I dropped a live round in the chamber by hand with the mag out of the lower and same thing, was like the BCG was in slow motion it still didn't go all the way forward and lock the bolt. Now, iv had no problems at all this sommer while the temp was up, now that its like 20 degrees outside the oil is much thicker and draging my BCG. I tried this in both my 16" and 8" blkout. Both the same thing. So I know its not a mag or BCG problems. Its got to be the Mobil 1 in cold weather conditions.
What viscosity are you running? I run 0W-40 European extended wear because it meets BMW 15k oil change specs. What kind of powder are you using? What speed did it chrono at in the summer?
Humm.. dont remember what weight it was, ill check when I get home. I know I got the heavy stuff though. Im using 10.6gn of A1680, chronied at 1050fps. Here is the funny thing is they do the same thing in my 8" pistol. Both will fire and eject the brass but not load another round, short stroke. It take a few cycle of the BCG to even get a round loaded from a mag or single feed in both guns. Its not the ammo, once you get one to chamber correctly they extract easly, no binding or anything. I know it the oil, even when you let the bolt go with the bolt release with no mag or round its really slugish. I checked the buffer spring in both and they are fine. The only common denominator is the oil. Thats the only thing I have changed. Fine when its warm, bad when its cold. Now it cycles supers fine, but they heat it up.
Hahaha... yea, its a freezer here outside, was about 10 here lastnight. I was hunting with it Saturday, came to the house at lunch and the boys want to shoot it, it had been out in the cold all morning and I wanted to try the subs so this is how it come to be. Leason learned. Im gona try to strip the oil off today or tomorrow and see what happens. Im sure some has gotten down in the buffer tube to.velo555 wrote:I think your right about the oil. I would think a lighter viscosity should be fine all year round. Now I may have to stick mine in the fridge or freezer to simulate your failures.
Mobil 1 or another brand? I have been using Brakefree for years. I have a huge jug of it, but I read about Mobil 1 awhile back and wanted to try it.AR-300 wrote:run 0W20, it is what the wife's Honda runs!!
pretty much the only 0w20 you an find is mobil 1farm use wrote:Mobil 1 or another brand? I have been using Brakefree for years. I have a huge jug of it, but I read about Mobil 1 awhile back and wanted to try it.AR-300 wrote:run 0W20, it is what the wife's Honda runs!!
works great, low viscosity even at low temps
PSA 10.5" & 16'' FN CHF CL 300 AAC Blackout