Old CVA Optima Pro modified to QRBP

Status
Not open for further replies.

Snidely70431

Member
Joined
Mar 10, 2018
Messages
417
upload_2019-7-15_12-44-34.jpeg

One of the test beds I use when trying out new versions of of breech plugs is an old CVA Optima Pro. I noticed that the standard breech plug in this rifle is only supported by threads in the barrel; the 209 primers just barely contact the receiver. Looking at it, I decided that I could modify it to take a quick release breech plug.

upload_2019-7-15_12-45-46.jpeg

Using a hacksaw, some files and a couple of grinders I removed about 10mm (400 thousandths of an inch) at the back of the barrel behind the barrel threads, and enough of the piece to which the barrel is welded to allow the new breech plug to clear. I then built a new QRBP to fit the modification and accept a primed 32 H&R Magnum case. I chose to remove this much material from the barrel because the head of the bolt from which I make my breech plugs is about .450" thick.

upload_2019-7-15_12-46-28.jpeg

upload_2019-7-15_12-47-2.jpeg

upload_2019-7-15_12-47-45.jpeg

I tested the modification and it performed with no apparent problems. I will make some more QRBP's and do more testing.
 
Very nice.
It looks like a tricky operation that you only get one shot at performing the modification perfectly or the barrel could end up being toast.
I'm glad that the gun survived. ;)
 
Very nice.
It looks like a tricky operation that you only get one shot at performing the modification perfectly or the barrel could end up being toast.
I'm glad that the gun survived. ;)

Actually, there is a lot of room for error. The most difficult part is getting the QRBP right, but I've made a lot of those.

The part of the barrel one is cutting into is not at all important to the functioning of the rifle except that it encloses the 209 primer. If one wanted to use the old breech plug one would just have to put something over the hole. Lots of older muzzleloaders expose the primer at least that much.
 
Now you will need to index the breech plugs each time that either of them are installed to get the "head spacing" for the firing pin correct?
 
Now you will need to index the breech plugs each time that either of them are installed to get the "head spacing" for the firing pin correct?

Nope. Head spacing is a problem for cartridges that are rimless. Rimmed cartridges head space on the rim.

No more than one would have to with any sort of QRBP. Once I have the breech plug close to sized, I just have to shave 5 or so thousandths off before each trial until the action just closes and the hammer will stay cocked. As the sizing gets close, the action first locks closed but the hammer will not stay back, then finally the hammer stays back and it is ready to go.
 
Status
Not open for further replies.
Back
Top