Several months back, someone posted a thread regarding their normal shot groups going to hell.
This happened to my Knight Wolverine after I around 200ish shots & I found an article by Randy Wakeman discussing the erosion, thus, widening of breechplug flash holes as an apparent cause of this problem. Anyone else experience this?
He suggested changing the breechplug as often as every 100 shots. So I changed mine, and behold... my groups came back together.
However, at 100 shots, per BP, this could become a bit expensive at $40 per breechplug for my new Mountaineer. Love to hear anyone else' experiences or opinions here.
THX jimsmokepole

It seems you have stumbled upon one very good reason to have a breech plug with a removable vent. The vent can also be removed for easier cleaning. Replacing the vent instead of the whole plug will save you $$.

Photo show the plug from my mountaineer after it was converted to utilize a removable vent.







I cannot comment on accuracy, because i have never ever shot through a breech plug with a orifice larger than 0.035".

I take what Randy says with a grain of salt. That's just crazy, no one should have to replace there BP after every 100 shots. I've yet to wear out a BP pr even come close, not that it cant happen but it would take way more than 100 shots IMO.
I make sure after every shooting session that my BP is cleaned throughly so it looks like new. I also use Pyro RS and Pellets so this may or may not be one reason that mine have lasted so long, I dont use any other subs as they may wear more than Pyro so someone else ca reply.
(BP)

thanks Ron. Can you tell me how to convert my BP into the one like your photo? Thx jimsmokepople

Jimsmokepole:

Ron can most certainly tell you how to convert your breech plug to a removable/replaceable vent.

There are many good threads up in the help section, one is about breech plugs, that may answer many of your questions. It is full of good info on reworking breech plugs.

+100!!!!! I've put over 3000 shots on one plug in my original accura and that sucker still was clipping shots at 100 yards. If the gun isn't shooting worth a darn after 100 yards, take a look at the shooter and see what broke down on him.

i agree.

Bought a cheap CVA StagHorn in 2000. Converted it to use 209 primers. The current breechplug has been in that gun since 2004. The gun has been fired at least 800 times since then, most likely a lot more. The plug is giving a lot of blowby now and needs to be replaced.

You would do the job in similar fashion to the way described in the thread about cva breech plug modification. It won't be near as easy, because the brazed in vent is hard, which makes it difficult to drill compared to normal breech plug hardness. It can be done. I've done it three times. Non was easy. The work damaged and dulled tools.

It may be easier to modify an fpj plug to fit the Mountaineer, and install a vent whilst making the modification.