How much to debur flash hole

[Naterater]

I just got my Lyman flash hole deburrer in and the instructions say set the set (locking) ring so the deburrer trims 1/100 of an inch of the primer pocket. This seems like a lot.

I don't want to weaken any of my brass by removing too much brass around the flash hole. All I want to do is deburr, right? What is enough? too much?

I am reloading .308 brass if this helps in anyway and I can see inside the case how much I trim.

 

[EddieNFL]

The K&M tool cuts to a pre-set depth. Just enough to put a slight bevel on the flash hole.

 

[243winxb]

Lyman Flash Hole Uniformer Instructions.

Leave a gap of .010" between case mouth
and cone shaped adapter. Set it using a feeler gauge. Instructions > http://www.lymanproducts.com/lyman/case-prep/pdf/LyC_CPT_Tool_FHU.pdf The K&M BR Inside Flash-Hole Uniformer looks like the best one to buy. It does both the large & small flash holes. Plus it is self-adjusting. Oh well, i will just have to keep using my Lyman. :banghead:

 

[Naterater]

I understand... But I don't have a feeler gauge... any suggestions besides buying one??

 

[dagger dog]

Look inside the case to see if there is a burr, most cases have punched flash hole which can leave a "hanging chad", (remember that debacle?), if it does, you only want to remove just the chad, all punched cases will have cratering of the edge of the punched hole in the direction that it was punched.

SUPPOSEDLY, the "chad" can block the primer flash to a portion of the powder charge causing some unequal burn that affects accuracy, or send the chad down the barrel causing a problem.

I dechad the flash hole but leave the rest alone if I can't see a "chad" hanging.

 

[243winxb]

But I don't have a feeler gauge... any suggestions besides buying one??

The thickness of a soda can is about .004" Cut 2 or 3 strips with Scissors and use as a gauge. This will get you in the area. Plus you can feel when it stops cutting. Full lenght size and trim brass to the same length before using the tool.

 

[GP100man]

I trimm until it`s even all the way around the hole .

Trial & look until ya see a small bright ring all the way around the hole .

 

[Walkalong]

Yep, that's how to do it. Easy peasy.

 

[243winxb]

The K&M BR Inside Flash-Hole Uniformer looks like the best one to buy. It does both the large & small flash holes. Plus it is self-adjusting.