Gunsmithing  Expert opinion wanted on New barrel freebore (pic)

mdesign

Gunny Sergeant
PX Member
Minuteman
Nov 2, 2004
2,124
8
Nebraska
So I have looked at a lot of barrels (factory and custom) with my bore scope and this is much more common than people probably think. It is also one of the first things I look at for a barrel that will not shoot. My experience is that barrels that look like this (usually worse) often do not shoot as well with the bullets close to the lands but can shoot very well with significant jump.

I will say that I see this very common on factory and not unusual on pre-fits but is very rare when the chambering is done at a quality shop. Most of the those places do some pretty amazing work and manage their quality very well. It all comes down to technique and attention to detail when indicating everything into place.
 
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Rubicon Precision

Sergeant of the Hide
PX Member
Minuteman
Feb 21, 2018
170
184
I've seen several barrels lately by a manufacture (that I won't mention) that look similar to this. I will still see rifling in the freebore as if the grooves were cut too deep, or see some undercut at the toe of the lands still showing in the freebore. It may even look eccentric in a bore scope, but I know my setup is sound, and they look just fine on the DTI while still set up in the lathe. I batch calibers together when I can, and I may do 6-8 barrels in a day with the same reamer, same set up . All other manufactures look perfect, except some of the one manufacture's barrels. Different reamers, different flute count, doesn't matter.

That said, I think a 90 degree bore scope would give a better idea of the reality of the situation in the OP's barrel(s). I think it was mentioned earlier, the bore scope photos could be a bit misleading.
 

Supersubes

Heathen
PX Member
Minuteman
  • Sep 6, 2006
    5,984
    5,314
    Rural Nevada
    I've seen several barrels lately by a manufacture (that I won't mention) that look similar to this. I will still see rifling in the freebore as if the grooves were cut too deep, or see some undercut at the toe of the lands still showing in the freebore. It may even look eccentric in a bore scope, but I know my setup is sound, and they look just fine on the DTI while still set up in the lathe. I batch calibers together when I can, and I may do 6-8 barrels in a day with the same reamer, same set up . All other manufactures look perfect, except some of the one manufacture's barrels. Different reamers, different flute count, doesn't matter.

    That said, I think a 90 degree bore scope would give a better idea of the reality of the situation in the OP's barrel(s). I think it was mentioned earlier, the bore scope photos could be a bit misleading.
    I encountered an xcaliber that was big in the groove. The reamer only just kissed a portion of it. Maybe it would have shot but I sent it back and they replaced it.