SR-25 Chamber Burr

[Dimp]

I fired my SR and noticed a deep ring just below the neck at the shoulder. I only noticed because I picked up my brass as I'm going to start reloading. When I passed it around, I was told it may be a burr in the chamber and may need to have it looked at. Big Bird level, can someone explain and should I worry.

[STJ]

Got a pic of the casing?

[Littlelebowski]

Contact KevinB (works for the manufacturer) on this site.

[KevinB]

Highly unlikely it is a burr, more likley the casing is banging off the ejection port during ejection.

If you had a chamber burr that size, it would impede feeding and function.

[Dimp]

A dent or dimple in casing from ejecting isn't the problem. A ring is imprinted in the case when it is fired around the circumference of the neck just below the shoulder. The gouge is uniform and forms a perfect circle.

[Dimp]

Not a great pic but best I could capture. Not an ejection issue at all. These rings are imprinted on the case during expansion in the chamber when fired. The pic doesn't capture the depth, but its a gouge around the neck.


http://m4carbine.net/attachment.php?...1&d=1240520446

[KevinB]

Dimp shoot me an email to kboland@knightarmco.com

I am very curious as this something I have never seen or heard of.

-Kev

[Mo_Zam_Beek]

Are these reloads? If so did you set your dies according to the die directions or according to your chamber specs using something like an RCBS Precision Mic?

[Dimp]

The deepest one's were reloads. I then fired factory FGMM, Win Supreme, & reg Win white box with the same results but not as deep and a little more faint.

[Mo_Zam_Beek]

The photos make it look like the ring is uniform. If it is it may just be the chamber deminsions.

Do you reload?

Do you have a Mo's Gauge or an RCBS Precision Mic?

Take 10 - 20 (more is better) once fired factory rounds and determine size of the chamber to the nearest 1/10,000 - see how that specs out against minimum chamber specs and to the specs as provided by Knight's.

Set your dies a couple 1/10,000's off of this and see what those reloads look like.

The other question - did it shoot tight with the factory stuff? If so, and the ring is faint and uniform, I wouldn't stress real hard about it. I'd put that energy into finding a load that shoots real tight and gives max velocity without pushing primers out the ass end.


One last question - do you know the history of the barrel since new? Was it ever set back?


Good luck