209 Breech plug whoas

[deerlessbob]

My Accura had the primer sticking problem, but my new Optima with a Lehigh plug does not. Shooting the Win Blue box with 66.5 weighed grains of Blackhorn and 300 XTP’s in black crush rib sabots.

 

[MrTom]

How do I go about that? Bore polish on something?

I'd chuck up a .22 or .25 cal cleaning mop in a drill with variable speeds and coat the tip with some bore polish and give it a minute of polishing at a lower speed. Then wash as per cleaning.

 

[deermanok]

I have the original QRBP that comes with the Optima V2 pistol. I might switch back to it just to see if it will stay cleaner. I'm shooting Swiss 3f powder.

 

[ronlaughlin]

If one can close the action with a primer in place; remove the primer, and measure the same length, one's rifle has too much head space. This is the normal cause of blow by.

To stop blow by, the primer should fit tight in the rifle, when the action is closed.

One can decrease the head space of a CVA rifle by backing out the firing pin bushing. If one cannot cock the hammer, the bushing has been backed out too far.

The primer should come out of a properly head spaced rifle a little bit shorter, say 0.004" or so, shorter. One may have to 'snap' the action closed to achieve this 'crush'.

Once the bushing has been located in the desired place, it can be held there by using loc-tite on the threads.

If one changes the primer of choice, one will probably have to reset the location of the firing pin bushing.

 

[MrTom]

In looking back at each of my inline cva guns, The Accura had sooting and sticking issues with the original factory breech plug and 209 powder. The Western replacement 209 plug in the Accura had no sticking, but shot dirtier than the original plug. My Optima pistol shoots a vent-liner converted plug and primers pop out easily and clean, as they also do my .45 cal Kodiak rifle with a converted plug. The Accura uses a converted standard plugs [actually I have converted two for all of the CVA in-lines] and the primers pop right out after shooting but both will soot up without an o-ring. Both of these Accura plugs are slightly shorter in over-all length after fully seating them as per cva instructions than the 2 randomly purchased plugs for the Optima and the Kodiak. Both of those plugs for the Accura were ordered at the same time so it could be factory run thing if they came from the same machining lot. I think some of the issues with CVA plugs that required the initial seating to seal comes from an inconsistent overall length prior to the sealing process. Think the Wolf, Accura and Optima models. I have three plugs for the Kodiak and they all measure identical. If there's a slight deviation in length, there can also stand to be a slight deviation in primer pocket width as well which could come into play on sticky spent primers.

Ron's suggestion on the firing pin bushing above can address the shorter plug issue, but it the primer pocket itself is too narrow they'll likely hang up after firing. That said, a person will need to find a primer with a working diameter, then adjust the bushing mentioned to achieve their headspace.

 

[Muley Hunter]

If the primers are sticking and you can't use an o-ring. You need a smaller primer. I normally use the Federal 209A primers because they're the hottest primer. They're also the smallest and usually will allow an o-ring.


Federal 209A .239-.242 dia. not stepped

CCI 209 .240-.242

Rem. 209P .241-.242

Cheddite 209 .240-.243 stepped, most consistent in size

Win. 209 .240-243 stepped

Fiocchi 616 .243-.244 *

Rio type 209/G600 .244 *

Nobelsport type 209/686 .243-.244*

 

[I beagle]

I dont understand why but the only ones I can find locally are the Winchesters. thanks for all the help.

 

[RDReed]

Interesting info here.

I noticed my primers were quite dirty the other day but they popped out easily. Sounds like adjusting the firing pin bushing could create a tighter seal and in turn keep things a little cleaner?

 

[Far Sighted]

So I shoot a CVA Accura and I have to pry out the primers after every shot. Clean rifle, dirty rifle, don't matter .Win blue box, CCI's feds , all the same. I tried a New factory breech plug, same thing. tried the O ring thing, nope. Any tosuggestions ?

I tune my primer seal to keep the area clean by adjusting the plug engagement.
After screwing the plug in until it stops CW back it out CCW about 15 degrees. With a spent primer in plug try closing the action. Check for resistance. If none turn plug CCW a few degrees. Check again for resistance. Repeat until you get resistance closing the action.
When you get enough resistance you notice you are the point where will get a good seal around the primers. Too much resistance and you will not be able to close the action
You should find a fine point that does well.
You can also adjust the firing pin housing the same way if more tuning is needed to stop the gas from blowing back.
Once you learn the amount needed it will be easy to maintain the right settings.
What is accomplished is squeezing the primer head to seal off.

 

[HC]

Not a good practice. The breech plug needs to be seated firmly against the barrel to prevent gas cutting of the breech plug and the barrel.

 

[RDReed]

Not a good practice. The breech plug needs to be seated firmly against the barrel to prevent gas cutting of the breech plug and the barrel.

I'm new to the theory but I think you might be misunderstanding to conversation. We're not moving the breech plug, were moving the firing pin bushing toward the breech plug.

 

[HC]

Was referring to post #29.

 

[Far Sighted]

Not a good practice. The breech plug needs to be seated firmly against the barrel to prevent gas cutting of the breech plug and the barrel.

Thanks
That is a good thought.
If that is the case then why did gas pass back between the barrel and plug before I made this adjustment?
The fact is it never seals of the end of the plug . It will when I apply pipe thread seal compound on the first few threads.
Each of my CVA rifles stay clean in the action doing this. Never did before.

 

[GM54-120]

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

 

[GM54-120]

Ron's suggestion by adjusting with the bushing has merit but using Loctite to secure it in place could be problematic. Maybe using Green Loctite for pre-aasembled fasteners may be the ticket. Set the bushing as needed and put a couple drops along the thread. It will seep into them.

Shimming the firing pin bushing for the primers you plan to use is the ticket.
Using a fatter primer like the NSI/Nobels will help with primer fit. The NSI 209/686 or 688 are both long and fatter than most USA primer. (These fit CVA plugs but may be too fat for others)
Set your primer up for about a .003 crush with the longest primer you will use. That way you wont ever get one too tight. After about .005 you can run into problems crushing a 209 in a break action.

If you want to try a short fat primer with an o-ring....Try Fiocchi primers but check them first if possible. I know mine are very short. Like .294ish long and about .243 OD with virtually no taper.

 

[Muley Hunter]

Adjusting the firing pin housing is what we used the shims for. That way you can still tighten down the housing. It works good as long as you stay with the same brand of primers. I don't know why CVA stopped offering the shims. I suppose the proper size shims could be found. I like the shims better than the o-ring because once you have the proper shim installed you're done forever. The o-rings always need to be replaced and I never liked the way it made the primer stick out more. The primer can fall out easier. Plus, the action needs to be slammed shut. I didn't need to slam it with the shims unless you used one too thick.

 

[GM54-120]

Might be able to use a medium hard plastic or Teflon washer as a bushing shim but most are probably too thick. McMasters has a selection of them too.

 

[Muley Hunter]

It seems we typed at the same time but we both had the same message.

 

[ronlaughlin]

One can make shims. Before CVA offered the shims; one made them.

One can purchase 0.005" shim stock at Ace.

 

[RDReed]

Ok so after some adjustments I was able to get a clean primer. The bushing is a bit more proud than I would like and it takes a bit more enthusiasm to lock it up but I guess that's the price you pay.

Now I need to find or make some shims.