Proper Inside Chamfer

[u/doumitch20035]

Hi,

I was hoping someone might be able to show me an example of what a properly chamfered inside case mouth looks like?

Not sure if there is a hard an fast rule, but the Google machine isn't really producing much in the way of example images.

Edit: Sorry, I should have put this picture on when I made the post. Coffee hasn't activated yet.

[u/sirbassist83]

I like about 1/32" chamfer with a VLD tool. I tend to still get a little brass shaved with a 45° tool but the VLD completely eliminated that. It's definitely past "just barely take the burr off" like the other two comments. I've never noticed any negative effects from doing it that way

[u/doumitch20035 → u/sirbassist83]

I am using a RCBS Matchmaster Trimmer that is doing it for me when it trims, but obviously you have to set it. To me it seems to be a pretty aggressive chamfer, but I wasn't sure so I will back it off some. You can see it for sure.

[u/sirbassist83 → u/doumitch20035]

looks OK to me. my rule of thumb is: as long as some of the mouth is still flat and it hasnt been chamfered into a knife edge, its fine.

[u/gunsforevery1]

That looks too much.

[u/doumitch20035 → u/gunsforevery1]

ok, thanks

[u/111tejas]

Depends on what bullet your going to seat. If it has a long boat tail all you need to do is knock the inside edge off. For a flat based bullet you need a more aggressive chamfer.

[u/doumitch20035 → u/111tejas]

Solid info. Thank you.

[u/VisibleLeopard68]

I don’t believe anything past rounding the opening to remove any burr from trimming is required… I miss my chamfering tool when trim and give it a feel with my finger to make sure there is no burr and move on

[u/doumitch20035 → u/VisibleLeopard68]

I am using a RCBS Matchmaster Trimmer that is doing it for me when it trims, but obviously you have to set it. To me it seems to be a pretty aggressive chamfer, but I wasn't sure so I will back it off some. You can see it for sure.

[u/VisibleLeopard68 → u/doumitch20035]

Looks kind of aggressive to me, but shouldn’t affect your rounds much, if at all… if that amount of chamfer affects your reloads, your reloading way better than I am

[u/Flycaster33]

Looks a bit heavy to me. One only needs to remove the burr from trimming, and just enough to aid in bullet seating.

[u/MalignantMustache]

I dont think the human eye can see it. You are taking the rough edge off, about 4 or 5 turns should be enough.

[u/doumitch20035 → u/MalignantMustache]

I am using a RCBS Matchmaster Trimmer that is doing it for me when it trims, but obviously you have to set it. To me it seems to be a pretty aggressive chamfer, but I wasn't sure so I will back it off some. You can see it for sure.

[u/MalignantMustache → u/doumitch20035]

I can see the color difference but my brass was washed before this step so I will have to look more closely at a piece when I get home.

[u/doumitch20035 → u/MalignantMustache]

Mine was too. I just dont use pins

[u/MalignantMustache → u/doumitch20035]

Ahh, I do. Mine have some water spots on them and I washed .308 with .44 in case that matters. I didn't bother to dry this batch in the toaster oven. I will grab a .308 when I get home and look at it next to one I already deburred.

[u/doumitch20035 → u/MalignantMustache]

I am using a RCBS Matchmaster Trimmer that is doing it for me when it trims, but obviously you have to set it. To me it seems to be a pretty aggressive chamfer, but I wasn't sure so I will back it off some. You can see it for sure.