Omega flash hole size?
 

Does anyone know the drill size that would fit the flash hole on my omega z5? #55 #60? Not looking to enlarge, just to cut out the build up. It seems like the more I shoot, the more "back flash" I get around the primer. Solvent just isn't cutting it. I flop between 777 pelets and BH209 and a variety of bullets.

cabage

I really discourage you inserting a drill bit in the flash hole to clean it. You will cut it also.

If you must insert some thing in the flash hole get a set of Welding Torch tip cleaners and even them be really careful the tip cleaners are harder then the flash hole and can cause premature erosion of the hole.

I assumed that a drill bit of the correct size was safer than a torch tip cleaner (of which I already have) as the bit really only cuts on the tip and the torch tip cleaner is actually a file that cuts on the sides. Keep in mind that i'm not putting the drill bit in my b/o drill i'm just going to twist with my fingers.

I see a lot of posts about using a 1/8 bit to clear the fouling. Does the fouling just build up where the primer is placed and not down the flash hole?

I think I found that the flash hole is .028" which would be a #70 drill? Pretty sure that the average hardware store won't have this drill.

My guess is the 'back flash' you are experiencing is not happening because the flash hole is getting plugged up. It is probably due to the flash channel getting plugged up. The flash channel has a diameter of 1/8". Chances are you cannot get a 1/8" drill into your flash channel, because it is partially plugged with a very hard carbon. This is probably what is causing your 'back flash'.

What you should do is start with a smaller drill, and spin it by hand in your plugged flash channel, and move to larger drills until you can hand spin the 1/8" drill. Then you should be able to shoot your rifle without the 'back flash'.

The flash hole will take a #70 drill, and maybe even a #69 drill. If it has worn, and eroded, it will accept a #68 drill. However, you don't need to use any of these drill in the flash hole.

Keep the flash channel some open. Perhaps use the 1/8" drill every 15 or 20 shots or so. What ever it takes to keep the 'flash back' from getting too bad.

If you have experienced enough of the 'flash back' to flame cut the primer seat, you won't be able to stop the 'flash back' with a clean flash channel. You will need to repair the damage, or purchase a new breech plug.

I also think the twist of a drill bit can cut as well as clean the cutting from the whole. I have often used a bit to increase (ream) the size of a hole. And I knew you were talking about hand turning.

[quot]I see a lot of posts about using a 1/8 bit to clear the fouling. Does the fouling just build up where the primer is placed and not down the flash hole? [/quote]

I believe 99,6% of the fouling occurs from the primer pocket to the 'flash hole' or in the 'flash channel'. I wanted to say this in my first post but didn't but i personally have not seen a reason very often to clean the 'flash hole' with any thing more than a tooth pick, but there certainly could come the time.

I was going to guess .029 to .030...

So basically I go after the fouling from the primer side of the breech plug with the 1/8 bit? Forget about "punching it out" from the powder/bullet side.

From what I have read here it sounds like there should be a 1/8 channel leading to the flash hole? I must have not noticed this one day one with the rifle.
Thanks for the quick reply's!

Yes, and yes, and yes of course.

You are 100% correct with this thought - anyway that is what I believe

Make one of these and it really makes it easy..

yep, got it, thanks guys. I had no idea that the 1/8 channel goes that far into the breech plug before tapering/changing to the flash hole of .028"!!

OK complete newbie offering an idea....

since I didnt know much about cleaning the breech plug bore - I went to what I did know. Since I have been around cars, motors my entire life, when we rebuild snowmobile carbs the jets really get tarnished up. Easiest thing to use is copper wire, strip some wire and run it down there and great a little friction.

Thats what I did, no way would the copper wire damage the breech plug and it really cleaned it up. HOwever plug has to come out of course for this, so it may be an extra step to some.....