300BLK not picking up the second round. Could use some help.

[popper]

OK, my guess, try a standard BGC. Side chargers use a bolt screwed into the front of the BGC and if too deep, would prevent the bolt from moving in the carrier. Second, check the tail of the bolt! It is the back seal of the 'cylinder'. Leakage there and no worky. The rings are the front seal. 147 gr @ 2k fps is a pretty hot load. Would work fine in my 16" carbine. Other thing to check is the length of the spring. Can you easily lock back the bolt, in the gun? GK had a 308 with a too long spring, wouldn't cycle properly - almost had to use 2 hands to lock it back as the spring got wonky and bottomed in the tube. Cut off a couple turns to make it fit. Of course the normal staking gas key check and length of the tube into the key. Use a pipe cleaner to check the key isn't clogged - I did have that problem once. Heavy buffer is to slow down bolt speed so it locks back. I use a heavy weight in a 10" pistol port BO. I've not used anything but 'proper' standard spring in any of my ARs.

[Outer Rondacker]

Spring is 10.25 inches. I thought the same thing about the bolt so I took out the charging lever off for one shot. Wasn't that. I did clean and relube everything one more time and hand cycle the bolt about a 1000 times. Honestly does feel smoother and softer but like I said. I am out of ammo and I can not find load data for the short fat 125g oldschool speers I have.

[Outer Rondacker]

Here is the last update. Thank you all I think I figured it out.

Grabbed a box of Winchester white box 125g running 2100 ish at the muzzle this morning at the not so local gun shop. Last night I stripped it entirely. Drilled out the gas tube and cleaned it all once again. Lubed the entire rifle with summit racing assembly lube. Plopped my butt in the chair and watched some TV just working the action over and over and over. Took it all apart this morning and cleaned it, applied the proper lube where needed.

Stepped outside, Loaded one shot in the mag and let it fly. Brass fell at 3 oclock and the bolt locked back. Then like a school kid I loaded two more giddy as I could be and dumped the two back to back with the final shot locking back the bolt. Repeated this test until I ran out of ammo. Box only had 20 rounds. I think I got it. Ran flawlessly. Now I can work on casting some projectiles for this baby.

I will also not buy another Armscor box of ammo ever again or Magtech. Not sure it was the problem but I am a happy camper. Called the kids and told them dad popped off a few 300BLK today and couldn't be happier.

If you guys have any suggestions of cast bullets and loads I'm in the market. Don't need smokers just plinkers.

[imashooter2]

Glad you got it sorted.

The Lee C312-155-2R is my choice. 6 cavity mold makes a pile quickly. I size to .310 and lube with White Label Carnauba Red. Feeds great, no issues binding in the magazines. My load is 14.5 grains of IMR 4227 and it gets 1,733 fps average.