CVA Accura MR-X Blowback

[weisenbu]

I have a CVA Accura MR-X that shoots well. I can get 2-3" groups at 200 yards, which is the furthest I've shot it with no intent to shoot further. I took a good MN whitetail last week at 180 yards.

My current load: 73gr by weight of BH209, Barnes 250 grain TEZ, Federal 209A primer - chrono'd at 2040 fps

However, I do get a fair amount of blowback. Should I consider installing the o-rings mentioned here? Will that solve my problem?

o rings?

I have seen threads where shooters where using O rings in there primer pockets.What size?where do you get them?How long do they last.

www.modernmuzzleloader.com

Should I bite the bullet and just upgrade to the Arrowhead breach plug, which is currently on sale for $150?

Arrowhead Gen2 LRMP CVA Replacement Breech Plug - Arrowhead Rifles

Converts CVA QRBP to Arrowhead Gen2 LRMP module system. Includes 20 reusable primer modules. If you want to shoot Blackhorn 209 in your CVA muzzleloader, this is the breech plug for you. Priming kit includes everything you need to prime and deprime modules (ASG189 universal deprime station and...

arrowheadrifles.com

Thoughts? Thank you in advance.

 

[ElDiablito]

I’d try an o-ring. There’re cheap.

The Fed 209As are about as long a 209 as you can get on average. Otherwise I’d recommend a longer 209 to see if that helps.



I wouldn’t mess around with modules in your set up. Not worth the hassle, IMO.

 

[weisenbu]

Thank you for the reply and advice! I'll likely try the o-rings first because as you state, they are cheap and won't require the extra cost and hassle of the modules. Will installing the o-rings change anything with my setup - velocity, POI, etc?

 

[ElDiablito]

They will change your headspace (obviously) - so the rifle should be stiffer to close.

With less blowback, you should see slightly more consistency in velocity. Will that translate into smaller groups? Probably won’t be noticeable if you’re already shooting 2-3” 200 yard groups. That’s better than average.

 

[ElDiablito]

Are you drilling the carbon out of the flame channel? Carbon build up can increase pressure on the 209 and blow-by.

 

[weisenbu]

They will change your headspace (obviously) - so the rifle should be stiffer to close.

With less blowback, you should see slightly more consistency in velocity. Will that translate into smaller groups? Probably won’t be noticeable if you’re already shooting 2-3” 200 yard groups. That’s better than average.

My rifle right now closes easily. I do ensure my firing pin bushing is completely flush with the face after every cleaning.

Are you drilling the carbon out of the flame channel? Carbon build up can increase pressure on the 209 and blow-by.

Yes, I use a 1/8" drill bit to remove the carbon after every session.

Thanks again for your advice and guidance! I plan to purchase a set of the o-rings and see how they do. I've seen mixed recommendations on the o-rings. Some prefer the Buna-N and some prefer the Viton. Thoughts?

 

[wyosam]

With o rings and keeping the flame channel cleanish my MRx stays squeaky clean, even with Cheddite primers which are pretty short. I’ve got a pile of them, so I’m glad they are working really well. I change the O ring every 20 rounds or so if if I’m shooting a lot, or every year when I’m not.


Sent from my iPhone using Tapatalk

 

[ElDiablito]

My rifle right now closes easily. I do ensure my firing pin bushing is completely flush with the face after every cleaning.


Yes, I use a 1/8" drill bit to remove the carbon after every session.

Thanks again for your advice and guidance! I plan to purchase a set of the o-rings and see how they do. I've seen mixed recommendations on the o-rings. Some prefer the Buna-N and some prefer the Viton. Thoughts?

Thats my post in the linked thread. I use the Buna-n o-rings. lol

I’ve got hundreds. I’d be happy to mail you a few if you don’t want to spend the ~$15 to try them.

 

[weisenbu]

Thanks again!!!

 

[cnelk]

If you were to guess, how much does the O ring reduce the blowback? Percentage wise.

 

[ElDiablito]

If you were to guess, how much does the O ring reduce the blowback? Percentage wise.

100% - if they work as desired. The 209 should come out looking like this.

 

[BPI_Outdoors]

I have a CVA Accura MR-X that shoots well. I can get 2-3" groups at 200 yards, which is the furthest I've shot it with no intent to shoot further. I took a good MN whitetail last week at 180 yards.

My current load: 73gr by weight of BH209, Barnes 250 grain TEZ, Federal 209A primer - chrono'd at 2040 fps

However, I do get a fair amount of blowback. Should I consider installing the o-rings mentioned here? Will that solve my problem?

o rings?

I have seen threads where shooters where using O rings in there primer pockets.What size?where do you get them?How long do they last.

www.modernmuzzleloader.com

Should I bite the bullet and just upgrade to the Arrowhead breach plug, which is currently on sale for $150?

Arrowhead Gen2 LRMP CVA Replacement Breech Plug - Arrowhead Rifles

Converts CVA QRBP to Arrowhead Gen2 LRMP module system. Includes 20 reusable primer modules. If you want to shoot Blackhorn 209 in your CVA muzzleloader, this is the breech plug for you. Priming kit includes everything you need to prime and deprime modules (ASG189 universal deprime station and...

arrowheadrifles.com

Thoughts? Thank you in advance.

There is a couple of reasons this take place. As I am going to guess this wasn’t the case when the gun was new. First let me say that when you use a 209 primers that during the firing the primer transfers carbon into your flash hole in your plug after a while it will shrink the size of the hole not allowing enough fire to reach the powder colon to ignite the powder. Prior to this happening you see primers sticking and black on the face of your gun where the firing pen strikes the primer. The fix is to get a small drill bit and service you plug by scraping the carbon by hand no drill. I have a set of pin gages that help me keep up with how much to clean and monitor the size of the flash channel. #CVAOfficial

 

[weisenbu]

Thank you for the reply! I am not sure if this issue was happening when the gun was new because I purchased the gun second-hand It has behaved this way since I've owned it. You are correct in that my spent primers do stick and the face of the breech plug (where it is stamped "Blackhorn") does get black after each shot. After each range session, I take a 1/8" drill bit and rotate it by hand (quite aggressively) in the flash channel to remove the carbon deposits. I also have some stiff wire that I use to clean out the flash hole. So, I think I am doing enough maintenance on the breach plug, but please let me know if I'm mistaken. The breach plug looks very clean and free of gunk/deposits after cleaning. ElDiablito was generous enough to send me some o-rings, so I'm going to give those a try. Please let me know if you have any additional feedback or suggestions for me. I'm relatively new to this and am still learning. I really appreciate the help received in these forums. Thanks again!

 

[ElDiablito]

First let me say that when you use a 209 primers that during the firing the primer transfers carbon into your flash hole in your plug after a while it will shrink the size of the hole not allowing enough fire to reach the powder colon to ignite the powder.

The “powder colon?”

Gasses and fouling residue also flow back through the flash hole into the flash channel upon ignition.