Primers sticking in Metrics Unlimited breechplug.

[LittleGump72]

So for the first few years I didn't have any issues with primers sticking, but the last couple of years primers will stick after firing a load.
After reading and learning different things here, I am questioning if maybe the flash hole has eroded too much causing excessive back pressure.
Tonight I have sent an email to Metrics Unlimited to see if I can find out what the flash hole size was originally. Hopefully I will get a response within the next few days.
I checked the flash hole size with pin gauges at work and came up with. 041-.042.

Do any of you have any thoughts?

 

[Jitterbug]

I suspect that you have found your issue, with the flash hole size.

A commonly mentioned figure related to flash hole size is .036. That size is what’s often considered the limit of normal wear… anything larger is typically considered excessive wear.

I’ve not heard of Metrics Unlimited, so I’m completely ignorant of your setup.

There are a number of threads here regarding “vent liners.” Basically these are a treaded insert, made of a very hard material. You drill and tap a breech plug to accept a vent liner, and for practical purposes it functions as a brand new flash hole.

If/when the vent liner wears, you just replace it, for a couple of bucks. Also a great help for folks who are having a hard time finding new breech plugs, for whatever reason.

Perhaps this thread will help you visualize the vent liner:
https://www.modernmuzzleloader.com/threads/breech-plug-vent-liner.36759/
Get that brech plug squared away, and keep shooting!

 

[MeatMachine]

I bought one of those breech plugs years ago and talked to the guy who designed and made them and he told me they made the flash hole at .040 for better ignition with bh209.

 

[LittleGump72]

I bought one of those breech plugs years ago and talked to the guy who designed and made them and he told me they made the flash hole at .040 for better ignition with bh209.

Thank you, I was thinking that is what I had read once before but couldn't remember for sure.

 

[Jitterbug]

I bought one of those breech plugs years ago and talked to the guy who designed and made them and he told me they made the flash hole at .040 for better ignition with bh209.

Wow- “I stand corrected.”

Sounds like the flash hole was larger than some, when it was new…

You can learn something new here, every day!

 

[LittleGump72]

Wow- “I stand corrected.”

Sounds like the flash hole was larger than some, when it was new…

You can learn something new here, every day!

I was thinking that the flash hole was bigger. I do know that the breechplug made by Metrics Unlimited was a different design than most. Unfortunately I heard they no longer offer it anymore.
And yes, you can always learn something new here. That's what I enjoy about this forum.