Unburned IMR 4451 in barrel throat

[jim10801]

In my AI AT with a 6.5 Creedmoor barrel, 42.3 grains 4451 under Berger 140 VLD Match, once in a while after firing a round, will work the action to reload a round from the magazine and the round will almost, but not quite chamber.
It appears to be from an unburned kernel of powder getting wedged between the bullet and the wall of the throat.
Any suggestions on what to do to eliminate the problem?

 

[_Raining]

I may have had this problem. After firing around 30 handloads all of a sudden I couldn't chamber a round. Neither handloads nor factory ammo would chamber but once fired brass could chamber no problem. I fired 100 rouds of factory loads and no issue appeared. If I ran a mop through the throat then I could chamber the rounds.

These were my first loads for my 6.5 so it could have been something I did. The powder was IMR 4350. After this I switched to Reloder 16 and have not had that issue show up, but again: I was new to reloading.

 

[supercorndogs]

Could it be corn media from a primer hole or something?

 

[Milo 2.5]

I imagine you have a load, but if it is unburned powder, not getting a full burn, creed case is efficient, load 10 with a half grain more powder and fire, see if it happens then.
IME with 4451 in 6.5 creed, 140 hybrid, over 43gr was where I ran.

 

[GhengisAhn175]

Take out the piece of debris and see if it is actually a kernel of powder.

Do a flame test on it to see if it's energetic (burns like a kernel or burns like something else).

What primer and brass are you using?

Whats your barrel length?

IF you have had your rifle in field conditions have you cleaned out your magazine and chamber area? Since you have an AT im assuming you take your barrel off from time to time and at least clean the action / barrel area and take extra care at the chamber since it's easier to gain access to.

 

[Pakratt99]

What kind of neck clearance are you running on a loaded round? Could simple be not enough clearance and buildup from shooting a couple of rounds is preventing chambering?