CVA Paramount Update

[Brad7348]

I finally got around to measuring my Variflame adapters today. The clean adapters measured between .300 and .301 in OAL, .7790 to .2795 in diameter. The adapters that leaked measured in the same range for both OAL and diameter so the problem is definitely not an out of spec adapter. I left just a little residue on the top rim of the ones that leaked so I could ID them later. I have a raw wood top bench that I use for reloading so I rubbed the dirty primer face on the top of my bench until they were clean and smooth, basically polishing out a little of the machine marks without taking off any real amount of material. I will reload and shoot them again soon. It may be that those adapters were from a different lot and had just a tiny bit deeper machine marks on them allowing the initial leak to occur? I would think once the gas initially gets under the primer it is easier for it to push it back allowing a larger gap. Kind of like prying the top off a paint can with a screw driver. With the new stiffer bolt spring coming in this week, and 20 clean adapters, I would hope that everything stays nice and tight this time. Anyone else try the new spring yet?

 

[ENCORE50A]

I finally got around to measuring my Variflame adapters today. The clean adapters measured between .300 and .301 in OAL, .7790 to .2795 in diameter. The adapters that leaked measured in the same range for both OAL and diameter so the problem is definitely not an out of spec adapter. I left just a little residue on the top rim of the ones that leaked so I could ID them later. I have a raw wood top bench that I use for reloading so I rubbed the dirty primer face on the top of my bench until they were clean and smooth, basically polishing out a little of the machine marks without taking off any real amount of material. I will reload and shoot them again soon. It may be that those adapters were from a different lot and had just a tiny bit deeper machine marks on them allowing the initial leak to occur? I would think once the gas initially gets under the primer it is easier for it to push it back allowing a larger gap. Kind of like prying the top off a paint can with a screw driver. With the new stiffer bolt spring coming in this week, and 20 clean adapters, I would hope that everything stays nice and tight this time. Anyone else try the new spring yet?

Brad, I'll admit I'm totally in the dark having never actually seen the rifle or adaptors. From my past experiences with brass cases as primer carriers, the head thickness really matters.
For instance.... my old BP Xpress using Starline brass had a head thickness that could vary up to .005". Now the Remington Ultimate brass is known to vary in head thickness up to .020". No way can one get a solid head space with that variance. Might measure that just for giggles???

 

[antman]

Ive used the new spring. Same issue some leakand some don't. I'd say 4 out of the 10 don't leak. Also it seems the 1st shot never leaks, so maybe the breach plug getting dirty contributes to it.

 

[45-70]

barrels fouled more pressure

 

[GM54-120]

Ive used the new spring. Same issue some leakand some don't. I'd say 4 out of the 10 don't leak. Also it seems the 1st shot never leaks, so maybe the breach plug getting dirty contributes to it.

Can you put a washer or two in WITH the new spring? I assume the firing pin runs through the spring? Get that puppy set so the spring has just a tiny bit of room left to compress and the bolt closes without too much effort.

 

[ronlaughlin]

My experiences with the adapters began in 2014.

What i did was modify a few Omega breech plugs to use the adapters, and a couple Optima plugs. What happened is the adapters/breech plugs worked perfectly when new, but after about 75 shots on the breech plugs they started leaking, and wouldn't quit. For some reason, i cannot live with blow by.

Because i am unable to live with blow by, i modified breech plugs to allow the use of o-ring under the primer. This entails making the primer socket deeper so that the rifle can go into battery. One wants the socket to be deep enough to allow the rifle to go into battery, but not so deep there is light primer strike.

























Neither the Optima, nor the Omega are bolt action. It is possible there is no way to use o-ring when one rotates the bolt to close the action. Chances are rotating the bolt will booger the o-ring. This information may have no value for the Paramount rifle, but it is all i know..........my rifles have zero blow by, using the adapter with o-ring. Zero blow by is a wonderful thing, yes it is. After many many uses, each adapter is dirty looking; no longer bright, and shiny. Dirty adapters don't leak when using o-ring. The adapters are very well made, and very durable.


Another thing done to the breech plugs was to enlarge the flash hole to 0.034". The adapters fit a 22 Hornet shell holder, so they can be easily primed, with any standard priming tool. Spent primers are easily removed in any standard press.

The large rifle magnum primers were tested in sub-zero weather more than once, and there never was a problem igniting Blackhorn powder, after the loaded rifle was left out over night. Unlike shotgun primers, the magnum large rifle primers do not erode flash holes. After 700 shots, measured flash holes were exactly the same as they were at zero shots. It seems like the adapters, and the breech plugs will last forever. ☺

 

[lwh723]

When the seal is just contact between two metal surfaces, everything has to be perfect for a consistent seal.

 

[Brad7348]

Brad, I'll admit I'm totally in the dark having never actually seen the rifle or adaptors. From my past experiences with brass cases as primer carriers, the head thickness really matters.
For instance.... my old BP Xpress using Starline brass had a head thickness that could vary up to .005". Now the Remington Ultimate brass is known to vary in head thickness up to .020". No way can one get a solid head space with that variance. Might measure that just for giggles???

The Variflame system headspaces off of the OAL of the adapter itself, so I am not sure how head thickness would make any difference, but maybe I am overlooking something. How did your BP headspace?

 

[Brad7348]

Ive used the new spring. Same issue some leakand some don't. I'd say 4 out of the 10 don't leak. Also it seems the 1st shot never leaks, so maybe the breach plug getting dirty contributes to it.

Was afraid this would be the case. CVA should have looked at a system more like the one used in the UML. Never owned one but I suspect that the flexibility of the brass adapters forms and seals the breach a bit better under pressure.

 

[ENCORE50A]

The Variflame system headspaces off of the OAL of the adapter itself, so I am not sure how head thickness would make any difference, but maybe I am overlooking something. How did your BP headspace?

Both the UF and RUM rifles have this breech plug. The bolt compresses the case head to the nipple creating the seal. The OAL of the brass case has no bearing on the seal and only guides the case onto the nipple.
As one can clearly identify, if the case head thickness varies, the seal is compromised and it will leak. When they start to leak, they start gas cutting the nipple and the breech plug will require replacement. Imagine if you will the brass cases for the RUM, varying up to .020" in head thickness.....

Fortunately, Luke created the Gen2 replacement plug that completely and permanently fixes leaking, gas cutting, or ever having to replace it.

 

[Brad7348]

There are a few other unrelated things I am still trying to figure out. Any advice would be appreciated. First I will say that this is my second muzzleloader (first was a break action) but still its my first venture into a bolt action ML. So I am familiar with, but no pro when it comes to the ML sport. I do however shoot several precision rifles so I am very familiar with precision shooting, loading, cleaning, etc, and I have built/head spaced my own rifles. But still the ML is quite a bit different.

My first question is, how are others cleaning their rifle? I have been cleaning it like I do my precision rifles, from the breach end, but I feel weird not using a bore guide. Do they make such a thing? I want to say that the folks with a UML say that they clean from the muzzle end without removing the breach plug. That sounds weird to me, like you would leave a bunch of solvent and crud in the powder chamber and up against the breach plug. Is everybody removing the breach plug every time they run a patch through the bore? With my precision rifles the bore guide serves two purposes, protect the lands/bore from wear from the cleaning rod, and keep solvent out of the action. Is this not as important with a ML and 209 solvent? Lastly, the loading jag is nearly bore diameter so it is super difficult to start a bullet without getting it slightly crooked and touching the rifling. My jag has some scratches on it from this. Is the jag soft enough that this is no concern, or is there something I should be doing to keep this from happening? With my precision rifles I am super careful about anything abrasive touching the lands or muzzle end rifling.

 

[Brad7348]

Both the UF and RUM rifles have this breech plug. The bolt compresses the case head to the nipple creating the seal. The OAL of the brass case has no bearing on the seal and only guides the case onto the nipple.
As one can clearly identify, if the case head thickness varies, the seal is compromised and it will leak. When they start to leak, they start gas cutting the nipple and the breech plug will require replacement. Imagine if you will the brass cases for the RUM, varying up to .020" in head thickness.....

Fortunately, Luke created the Gen2 replacement plug that completely and permanently fixes leaking, gas cutting, or ever having to replace it.

View attachment 5069

Ahh, got it. That makes sense.

 

[GM54-120]

Any chance we can get some good pics of the bolt internals and how the spring is installed? OD, OAL of the spring and OD of the firing pin shaft would be interesting also.

I may have an idea.

 

[Brad7348]

Any chance we can get some good pics of the bolt internals and how the spring is installed? OD and OAL of the spring would be interesting also.

My replacement spring comes in this week. I will take some pics/grab dimensions when I pull my bolt apart.

 

[antman]

Couldnt get pics to work but the measurements are as follows:

11.33 od spring 11mm tall

7.88 inner diameter spring recess

15.2 outer diameter spring recess

8.89mm outer bolt variflame
interface

5.66 mm inner bolt variflame
interface

 

[Busta]

Unfortunately, metrics are still like a foreign language to most of us from the US still. Even though they used to tell us is in school back in the 60's, that we would be fully converted to the metric system by 1980. They converted the gas pumps from gallons to liters back in the late 70's, and it just pissed off the people that didn't like change. Might have lasted around a year, or less, and it's been gallons again ever since. the only thing that really stuck from the 70's is 2 liter bottles of pop. The 1 litter bottles went from 16.9 oz to 20oz.

Hope you don't mind, but I converted your measurements so people can visualize the dimensions on their heads, without scratching all the hair off.

Thanks for posting that.

11.33 (0.446") od spring 11mm (0.433") tall

7.88 (0.310") inner diameter spring recess

15.2 (0.598") outer diameter spring recess

8.89mm (0.35") outer bolt variflame
interface

5.66 mm (0.2228") inner bolt variflame
interface

 

[GM54-120]

Thanks and as it turns out CVA has a Paramount manual online now. That manual has semi detailed pics of the bolt internals and how to take it apart.

Im fairly certain the idea has potential as a band-aide solution. Shim the spring or use a bushing and/or a compressible material like a nylon washer/bushing. There are several "plastics" used in washers and bushings so nylon might not be the ideal choice but you get the idea.

While im not a huge fan of adding stuff to a primer pocket, the SS modules are a bit different. They dont need the same amount of support to prevent bulging. A thin Nylon/PTFE washer might just work in the breach plug and last longer than an oring. PTFE and Nylon MDS have far less friction than a rubber oring. They might just handle the camming action of the bolt just fine. After all they are made to be used with fasteners like nuts/bolts.

 

[Brad7348]

 

[Brad7348]

Just saving everyone a little time. I forgot I had the manual saved already.

 

[Brad7348]

I don't know about you guys, but based on the picture, it seems to me like a proprietary precision wrench is needed to take the bolt head off. Man that's gonna be pricey.