Repairing "SAHot Out" CVA Blackhorn BP

Just curious why one couldn't repair the factory CVA Blackhorn BP with the following method.

Drill through flash channel with 5/32" drill bit.

Tap with 10-32 threads about 8 threads

Use 10-32 SS set screw 3/16" -1/4" long drilled through with .028" bit

The drilled set screw becomes the flash hole removable vent liner

Seems to me this would be a way to "save" a "shot out" factory Blackhorn plug. Just thinking on the keyboard.

Please excuse my fat fingers on the thread title, don't know how to correct it

Some members here have been doing that for years.

Yep

They have been converting the standard CVA breach plug. You will shorten the flame channel even more if you modded the BH209 plug. Maybe not a lot but its short already.

You really want some kind of shouldered screw, not a "vented" set screw. You can buy vented screws but the holes are too big on all the ones i can find.

vaguru said:

Just curious why one couldn't repair the factory CVA Blackhorn BP with the following method.

Drill through flash channel with 5/32" drill bit.

Tap with 10-32 threads about 8 threads

Use 10-32 SS set screw 3/16" -1/4" long drilled through with .028" bit

The drilled set screw becomes the flash hole removable vent liner

Seems to me this would be a way to "save" a "shot out" factory Blackhorn plug. Just thinking on the keyboard.

Please excuse my fat fingers on the thread title, don't know how to correct it

Click to expand...

Why not just buy the leihigh vents and be done with it ??? Then you can play with that pile of batterys !!! Lol

GM54-120 said:

They have been converting the standard CVA breach plug. You will shorten the flame channel even more if you modded the BH209 plug. Maybe not a lot but its short already.

You really want some kind of shouldered screw, not a "vented" set screw. You can buy vented screws but the holes are too big on all the ones i can find.

Click to expand...

I was just thinking of a way to "salvage" a factory CVA Blackhorn BP once shot out. I have other ideas as well, but all involve more "work".

I have read where they shoot out in as little as 250 shots. Never had a problem with flash holes in any mz I ever had, what makes this bp different?

So what is the "optimum" flame channel length? Does it really make a difference, the length? Why a shouldered screw?

Yes I can mod the original bp that came with the gun and use Lehigh vent liners, easy enough to do.

If I had known about the plugs "shooting out", I would have bought the Lehigh instead.

Just curious what others have found and experienced.

Sideshow said:

Why not just buy the leihigh vents and be done with it ??? Then you can play with that pile of batterys !!! Lol

Click to expand...

I don't believe there is enough material left in the CVA Blackhorn plug to cut the proper chamfer and use the Lehigh vent.

What pile of batteries?

vaguru said:

I don't believe there is enough material left in the CVA Blackhorn plug to cut the proper chamfer and use the Lehigh vent.

Click to expand...

Seems there is. The flame channel would be quite short. The Lehigh plug has a very very short flame channel. Basically you would be making your own Lehigh plug.

The shorter the flame channel, the hotter the flame to the powder, and the higher the pressure on the primer. Direct ignition plugs eliminate the flame channel completely.

And i think we already had someone mention they had sticking primers in the Lehigh CVA plug. You can increase pressure on them if you want to take the time to get everything else just right. More primer in the pocket, tighter tolerances ect ect. That huge slot though in the CVA firing pin bushing is the killer. They need to rethink that and make the firing pin smaller too.

GM54-120 said:

And i think we already had someone mention they had sticking primers in the Lehigh CVA plug. You can increase pressure on them if you want to take the time to get everything else just right. More primer in the pocket, tighter tolerances ect ect. That huge slot though in the CVA firing pin bushing is the killer. They need to rethink that and make the firing pin smaller too.

Click to expand...

That's the only thing I would change about the Accuras, the firing pin and bushing.

vaguru said:

I was just thinking of a way to "salvage" a factory CVA Blackhorn BP once shot out. I have other ideas as well, but all involve more "work".

I have read where they shoot out in as little as 250 shots. Never had a problem with flash holes in any mz I ever had, what makes this bp different?

So what is the "optimum" flame channel length? Does it really make a difference, the length? Why a shouldered screw?

Yes I can mod the original bp that came with the gun and use Lehigh vent liners, easy enough to do.

If I had known about the plugs "shooting out", I would have bought the Lehigh instead.

Just curious what others have found and experienced.

Click to expand...

I have the Lehigh, a converted cva plug, and a Hankins DIS LRMP plug. They all work well enough. The Lehigh and converted cva (standard) plugs are nearly identical and both have an issue with sticking into the firing pin bushing when using heavier loads. The DIS doesn't but it's not nearly as user friendly. It is such a clean system tho and works flawlessly with bh209. It's expensive too.

michiganmuzzy said:

That's the only thing I would change about the Accuras, the firing pin and bushing.

Click to expand...

I imagine making that bushing would be easy for a machinist and turning the fire pin down to match it would be simple also. I would use something like a spanner wrench instead of a slot. That way there is no slot going through the firing pin hole. Just 2 holes on either side. A socket type would be simple enough to make also.

GM54-120 said:

I imagine making that bushing would be easy for a machinist and turning the fire pin down to match it would be simple also. I would use something like a spanner wrench instead of a slot. That way there is no slot going through the firing pin hole. Just 2 holes on either side. A socket type would be simple enough to make also.

Click to expand...

I like the spanner wrench. I may buy a spare pin/ bushing and have it modded like you say.

I rarely take it out since putting an oring into the primer pocket. It stays plenty clean.

One could make a spanner to fit the existing slot and then fill the balance with JB Weld just leaving the ends open. Easy enough to try, and if it didn't work out could always revert back to factory. JB Weld is machinable so should be stout enough.

I may try that. If i i can find a suitable spanner first. Or make one.

GM54-120 said:

I imagine making that bushing would be easy for a machinist and turning the fire pin down to match it would be simple also. I would use something like a spanner wrench instead of a slot. That way there is no slot going through the firing pin hole. Just 2 holes on either side. A socket type would be simple enough to make also.

Click to expand...

Now you got me thinking that if i have one made, instead of shimming it out, i can have it made to correct headspace for my Fed primers or to my DIS.

A spanner could be made out of a screw driver with a blade wide enough, just file out the center portion. If the blade is too wide, just file to fit the bushing. Not that difficult.

Lotta ways you could make some kind of spanner "bit". Its not like it needs to apply much torque. You could grind down a socket like guys did to make DIY Savage breach plug (old style) tools.

This works. Just fill in around the firing pin hole in the bushing, and file a little more out of the center of this tool.



It wouldn't be needed if CVA would go back to the 0.030" slot instead of the 0.050" slot on the newer bushings. I've never had a problem with the 0.030", and now they even have that tool, which they didn't back when they made the 0.030" slot.