209 Breech plug whoas

[GM54-120]

McMasters lists a couple metal shims that might work. The 10mmx5mm would need a 8mm drill if thats possible. Its a bit thick at 40 thousandths.
https://www.mcmaster.com/98089A205/
This is 10x8ish and .005 thick
https://www.mcmaster.com/92927A150/

 

[BuckDoeHunter]

My shim kit from CVA consists of 6 shims, I'm no machinist but I think my measurements are accurate
2 at .0055, 1 at .008, 2 at .012, 1 at .022; OD of .375, ID of .324

 

[Travis299]

I use the O-Ring in the primer pocket to prevent blowback in my Accura V2 & MRs. I also make sure that the firing pin bushing is completely flush with the receiver with no protrusion or indention. This allows the action to be opened/closed without any problem. When I load a primer I keep the action pointed down, insert the primer and close the action with a firm snap. O-Rings last 10/20 shots for me. Fired primers come out clean.

 

[Far Sighted]

//

" " The fact is the nose of the CVA QRBP is the seal for the plug. That is exactly why you need a tool the first time to seat a new plug. If your OEM QRBP is leaking past that then you got a bad one. Very little should get past the nose of the plug and it should never need tape. Backing out a breach plug is a sure fire way to gas cut your barrel and plug. Once it starts there is no going back without resurfacing the barrel and more than likely a custom length plug.

DONT SHOOT A ML WITH THE PLUG BACKED OUT

GM,

With all do respect!

I thought about what you guys said about my suggestion. It came to my mind that you guys might be thinking of a different situation.

So this afternoon I took a close up look at my CVA Optima V2 BH209 breech plug and its relationship to the barrel area where it sets installed.

As soon as I pulled the plug and took a look it was clear the breech plug doesn't seal off the front of edge. That surface on the inward edge of the plug isn't designed to seal. See below photo. It is a surface about 1/64 wide at the most.
Then I looked inside for a possible mating surface to seal from. There was none. That surface close to the plug's end is a beveled area to allow the gases to flow out of the barrel.

The surface that is designed to seal the breech is the plug's large flange that seats against the barrel's end. Only it doesn't do a good job. I used a piece of aluminum foil to put between that flange and the barrel to determined there is direct contact. When I screwed the plug against it the foil was trapped on one side but not on the other. In this case the surfaces aren't matched or square to each other.

In the photos comparing the surfaces on the end of the breech plug to the possible mating seal surfaces. There isn't one. The inward end of the breech plug set out an open space almost touching the beveled surface. The discolor ring on that beveled surface was were I pushed a 9/16" rod against it to see where it hit. 9/16" (0.562") is the internal diameter of the plug. The rod was a slip fit to the threads.

Therefore I will continue to use my plug tuning method to seal the breech plug. it works very good.

 

[GM54-120]

Let me know if you can hand tighten a brand new plug and the action closes. If not it MUST be sealing on the nose of the plug. This is exactly why a new plug comes with the install tool. It mates the new plug to the barrel.

DONT SHOOT A ML WITH THE PLUG BACKED OUT

 

[deermanok]

I don't get the selling point of a quick release breech plug when they send you a tool to tighten it up? It seems like the better idea to use the wrench, no ?

 

[GM54-120]

Only use it once dont you?

 

[Mnt monkey]

Hopefully

 

[ronlaughlin]

I don't get the selling point of a quick release breech plug when they send you a tool to tighten it up? It seems like the better idea to use the wrench, no ?

No. No. No.


The wrench has one purpose, one purpose. The wrench is used to marry the plug to the barrel the first time the plug is installed in the rifle. It may perhaps be needed twice. There after, if the wrench was used properly, it will never ever be needed again.

If all is well, the plug makes a perfect seal with the barrel. The thin rim on the plug conforms to the barrel.

However, that thin rim is very fragile, and if damaged doesn't perfectly seal.

The idea of a hand removable plug may seem nice. However, a more durable plug that requires a wrench to remove may be a more realistic option.

The QRBP is a nice idea, and actually does work when 'new', but the slightest ding, and that is the end of that.




The fella believes it is correct to back out his plug seeking to stop blow by. He wouldn't believe this, if his plug/rifle was working as designed.

 

[Mnt monkey]

Breech plugs and ignition seem to be the most complex part of muzzleloading, I'm amazed how many gun builders and manufacturers just accept the dirtiness and inefficiency of 209 priming, I realize all the aftermarket plugs and little tweaking methods work,it's just still a shame to me from a business standpoint that there's not a better ignition system available to most people, I'm a big fan of the brass module Arrowhead -hankins type systems,,if installed properly the first time they need no tweaking at all, be nice to buy a CVA or a knight or a traditions or any other factory gun and not have to worry about ignition issues,leaking primers etc,I know many starting out are just bubba's like me that did not have a machineist background and they've had to figure things out for themselves,or just learn to clean after every session if shooting, which of course I do .I'm fixing to give a young man I've been teaching to hunt my cva accura mountain rifle, He's new to muzzle loading and to hunting,I put him in the deer stand with me last year and the very first time he had shot a muzzleloader he shot a doe at 100 yards sitting in the stand with me while I've verbally coached him,,, it would be nice to be able to give him a gun that I didn't have to explain plug issues too !!

 

[GM54-120]

You dont get the full benefit from LRMP though without the shorter flame path and to do that you need an action strong enough to handle it. Less fouling and cleaner is the main thing you will get for $6 per module with a limited life span.

I would imagine Arrowhead LLC CVA LRMP system probably works pretty well.
https://www.arrowheadrifles.com/product/cva_qrbp/

 

[Muley Hunter]

//
GM,

With all do respect!

I thought about what you guys said about my suggestion. It came to my mind that you guys might be thinking of a different situation.

So this afternoon I took a close up look at my CVA Optima V2 BH209 breech plug and its relationship to the barrel area where it sets installed.

As soon as I pulled the plug and took a look it was clear the breech plug doesn't seal off the front of edge. That surface on the inward edge of the plug isn't designed to seal. See below photo. It is a surface about 1/64 wide at the most.
Then I looked inside for a possible mating surface to seal from. There was none. That surface close to the plug's end is a beveled area to allow the gases to flow out of the barrel.

The surface that is designed to seal the breech is the plug's large flange that seats against the barrel's end. Only it doesn't do a good job. I used a piece of aluminum foil to put between that flange and the barrel to determined there is direct contact. When I screwed the plug against it the foil was trapped on one side but not on the other. In this case the surfaces aren't matched or square to each other.

In the photos comparing the surfaces on the end of the breech plug to the possible mating seal surfaces. There isn't one. The inward end of the breech plug set out an open space almost touching the beveled surface. The discolor ring on that beveled surface was were I pushed a 9/16" rod against it to see where it hit. 9/16" (0.562") is the internal diameter of the plug. The rod was a slip fit to the threads.

Therefore I will continue to use my plug tuning method to seal the breech plug. it works very good.

View attachment 10362

View attachment 10363

If that was true. Why do the threads stay clean? When using BH I clean the threads on the plug and barrel and never put anything on them again. Bone dry and the plug removes easily after being shot and are clean. It only works with BH though and I don't understand that part. If the threads are sealed what difference would powder make? Yet, the threads are clean after shooting. Maybe someone can explain this?

 

[GM54-120]

Like both me and Ron mentioned....When the plug is working as designed the threads stay relatively clean. Not sure changing powder is gunna make much difference in a rifle that has the plug correctly mated to the barrel. I would wager if Far Sighted's plug is very dirty when hand tight then something is out of spec. A brand new plug just hand tight would tell the whole story. If the action will close and hammer will cock then something is wrong, damaged or poorly machined.

Since he has been shooting it with the plug backed out, the area that creates the seal will need a very thorough cleaning before trying a new plug. Just the smallest amount of hard carbon will ding up a new plug when tightened down.

 

[ronlaughlin]

............Just the smallest amount of hard carbon will ding up a new plug when tightened down.

Yes it will.

 

[michiganmuzzy]

Breech plugs and ignition seem to be the most complex part of muzzleloading, I'm amazed how many gun builders and manufacturers just accept the dirtiness and inefficiency of 209 priming, I realize all the aftermarket plugs and little tweaking methods work,it's just still a shame to me from a business standpoint that there's not a better ignition system available to most people, I'm a big fan of the brass module Arrowhead -hankins type systems,,if installed properly the first time they need no tweaking at all, be nice to buy a CVA or a knight or a traditions or any other factory gun and not have to worry about ignition issues,leaking primers etc,I know many starting out are just bubba's like me that did not have a machineist background and they've had to figure things out for themselves,or just learn to clean after every session if shooting, which of course I do .I'm fixing to give a young man I've been teaching to hunt my cva accura mountain rifle, He's new to muzzle loading and to hunting,I put him in the deer stand with me last year and the very first time he had shot a muzzleloader he shot a doe at 100 yards sitting in the stand with me while I've verbally coached him,,, it would be nice to be able to give him a gun that I didn't have to explain plug issues too !!

I have a DIS lrmp system for my Accura. While it is clean and reliable, its a bit of a pita to use. Love it for hot loads of bh209. But for my hunting loads the 209 is just too easy and "clean enough"

 

[Far Sighted]

Let me know if you can hand tighten a brand new plug and the action closes. If not it MUST be sealing on the nose of the plug. This is exactly why a new plug comes with the install tool. It mates the new plug to the barrel.

DONT SHOOT A ML WITH THE PLUG BACKED OUT

The breech plug seals off the large flange not the end of plug. The supply wrench comes just in case it is needed like the orginal.

 

[Far Sighted]

If that was true. Why do the threads stay clean? When using BH I clean the threads on the plug and barrel and never put anything on them again. Bone dry and the plug removes easily after being shot and are clean. It only works with BH though and I don't understand that part. If the threads are sealed what difference would powder make? Yet, the threads are clean after shooting. Maybe someone can explain this?

Because you get a more complete burn with BH209.

 

[Far Sighted]

The breech plug seals off the large flange not the end of plug. The supply wrench comes just in case it is needed like the orginal.

Additional if the threads are a very smooth cut and mate well they seal good. In my case the barrel threads are torn and rough. That's why thread seal does the job.

 

[Far Sighted]

I apologize!

Guys there one thing I will do. I will admit being incorrect. I convinced myself this afternoon the CVA Optima Breech plug does indeed seal like you guys stated. That seal is off the very small enter thin rim of the plug against the chamfer enter surface.

I apologize for my incorrect statements.

This is what I did:

I applied thin .0005" thick tap to the end of plug. Then I inserted the plug to the breech until it matted with seat surface. The tip of the plug cut the tape when the seal was made.

I hats off to those that I questioned. You guys are awesome.
Have a nice day!

 

[Mnt monkey]

You're a good man I respect you