CVA FIREBOLT ULTRAMAG 45

[Patrick McChristy]

So I couldn't resist a tinker project even after warning & picked up cheap 45 caliber. I am initially thinking about making a new breech plug & shorten the barrel. Any tips on figuring out how long the breech plug needs to be or any other tips? thanks

 

[Rick Dillard]

I have had a CVA Firebolt Magnum .45 caliber since 2003. I have successfully shot Blackhorn 209 powder using the existing breech plug. The trick is to use a small rubber o-ring in the primer pocket, and to use a saboted bullet that is fully seated against the powder. With this setup using Hornady SST 200 grain bullets and Harvester Smooth Blue Sabots and 90 grains of Blackhorn 209 powder, I have been able to get 1-inch groups @ 100 yards. I feel comfortable shooting to 200 yards. That being said, I plan to try a modified breech plug that uses a removable vent line this year.

 

[Patrick McChristy]

I plan to make 1 also with a vent liner. Came with the cross style breech plug. Been super busy lately. Thanks for your input

 

[dozer_xj]

I have a 45 cva hunter bolt. I did this
https://forum.gon.com/threads/hunterbolt-magbolt-cva-bolt-actions.563708/
Then I drilled it out for a vent liner. I was trying to do bullet to bore but the bore is so loose it never worked out for me. I haven't tried sabots. It just sits in my gun safe.

 

[sabotloader]

Here are a couple of old CVA plugs that I modified. Drilled out the flash channel the 5/32's and installed Lehigh Vent Liners. They shoot all powders very well.

 

[Patrick McChristy]

What determines how far to have the vent liner sit back from the nose or stick above it?

 

[MrTom]

I drilled mine 3/8 deep with I believe a 3/8" bit, then used a countersink to create the bevel for the liner to seat against. The 10 or so CVA plugs I've converted were all done the same. I've done four or five plugs for Kodiak rifles and I believe the plugs are the same as for your rifle Patrick.

At one time this site had a wonderful couple of pictorial posts done by Ron along with the directions and all the bit sizes/taps needed to do this conversion but I am not able to find it now. Using the information that was provided I picked up everything needed locally for about $35.00 and used the vent liners available at Badger Ridge.com... Tom is great to work with. Using some 1/4" steel strap I made a jig that holds the breech plug when drilling/tapping that bolts securely to my drill press table. It took more time to make the jig than to convert a plug. I've got my work area all tore apart right now or I'd offer to do the conversion for you but I believe Ron does this as well. The Lehigh Plug shown in another thread regarding a Firebolt will not work, so that avenue is out for you.

Can you take a picture of the primer end of the breech plug your gun uses? I think its the same plug as what a Kodiak rifle uses and they are very common. $14-$15 bucks.

 

[Patrick McChristy]

Thanks Tom, I just wondering as I have seen a couple different depths for the vent liners. I had pm'd Ron & he told me how he does them. Hopeful to nock this out in the next couple of weeks but man my to do list just keeps growing.

 

[MrTom]

but man my to do list just keeps growing.

As long as it's your list just move the plug job to the top, lol.

Let us know how the plug turns out.

 

[Patrick McChristy]

So I am getting ready to start tinkering with this project - which o-rings do i need to shim the pocket with? Also it has the cross slots in the breech plug - is this the plug i should get to start with? Thanks for any help

Cva Ac1678a

 

[MrTom]

So I am getting ready to start tinkering with this project - which o-rings do i need to shim the pocket with? Also it has the cross slots in the breech plug - is this the plug i should get to start with? Thanks for any help

Cva Ac1678a

If this looks like the plug then I am not too certain how well and o-ring will benefit you. Check to see if the primer end of your plug has the small grooves that are shown at the bottom of the removal tool slots. O-ring help if the bottom of the primer pocket is completely flat without those small grooves.

 

[GM54-120]

From my understand the 2009 Acurra NON QRBP will actually fit that rifle. The primer just wont hold in without modding the bolt forward. A few have done this. Using the vent liner mod and oring you can even get it shooting BH209.

Jon on the FML forum had a write up on this a few years ago.

 

[Rick Dillard]

No. That is not the breech plug you want. The slots on that breech plug allow sparks and powder residue (blowback) from the primer to escape which cruds up the bolt face and the firing pin. It also will put a burn spot on the bottom of your scope. This blowback makes it difficult to consistently ignite Blackhorn 209 powder. This is the breech plug you want to get: CVA AC1678 hex head. (Use at your own risk - Although the breech plug fits most CVA bolt action muzzleloaders, they have never acknowledged or promoted it for them).



A rubber o-ring (number 6, or 006) in the primer pocket should completely seal breech plug and prevent and back blow from the primer. The rubber o-rings are good for about 15 or 20 shots. They are cheap and easy to replace. I have had no problems shooting Blackhorn 209 powder in my CVA Firebolt after doing this. To insure proper ignition you MUST make sure that the saboted bullet is fully seated against the powder. However, you can go one step further if you like and have this breech plug modified to where it will accept a removable vent liner. This puts the powder charge a little closer to the ignition source, further reducing the possibility of a misfire or hangfire.

 

[GM54-120]

CVA AC1678

That part# comes back as the slotted plug
https://cva.com/product/replacement-breech-plug-for-standard-209-in-lines/
The plug ive seen mentioned to use for the "conversion" is this one. Its the same plug as a 2009 Acurra would use. (Pre QRBP break actions)
AC1678A
https://cva.com/product/hexhead-replacement-209-breechplug/
I had a 2009 Acurra 45 and BH209 ignition was not perfect until the vent liner mod. Enlarging the flash channel to 5/32 and adding a vent liner made it 100% reliable under any conditions.

The plug on the left in Sabotloaders pic works perfectly. Ron made me several to try. The best was shimming for a slight crush on the 209 primer. You dont want too much crush. Just about .003 or an oring.

 

[Rick Dillard]

My bad. You are correct it is the CVA AC1678a not the AC1678. Thanks!

 

[GM54-120]

IIRC it was Jon on FML that came up with the idea to convert the Magbolt type rifles. He shimmed the bolt head out a little with washers or something like that. Added the new plug and an oring. Looked like a pretty simple modification.

 

[Patrick McChristy]

Thanks for all the input! Is the elk horn stock any lighter than the fire bolt? Putting this together I thought man it’s heavy - maybe there is a weight in I can take out