As long as that groove in the breechplug is in line with the vent hole, It should not be that much of a problem. You do need a good vent pick, and I am not in love with those thin pieces of piano wire some use.
I make my own vent picks by forging them from coat hangers, or some other soft steel I find. I want the pick to be long enough that my big fat fingers, and hand can hold onto it, and find it in my possibles bag. About 4-5 inches long.
I flatten the round steel stock after heating it, then square the sides, then twist the steel to make interesting, but purely decorative designs to the shaft.
On one end, I form a loop- circle, or once, a heart-shape( just to see if I could do it) so that the pick is more like a latch-key.
The front end of the pick is filed to a point, and filed thin enough to enter the vent hole easily, and extend all the way across to the other side of the bore.
Then, I filed 2 flats on opposite sides, and rounded the "point", so I didn't have to worry much about stabbing myself with it. The two flat sides allows me to move granules of powder around to open a hole in the powder charge. The hole allows the heat from the burning prime to ignite many granules of powder all at once, which speeds ignition of the powder charge in the barrel.
When I am done making the pick, I heat it up red hotand quench it in oil. That gives it a permanent coat of black, that protects the pick from rusting, and leaves a nice surface that is easy to clean.
In your case, it will be perfect for keeping that groove clean during a long string of shots. If the vent is located at the end of the groove, you will get some gas "cleaning" of the groove as gases come back out the vent. Whether the gas will clear all the crud out of that groove depends on the gun.
Don't hesitate to put some soap and water down the barrel and shake it up to work out crud that builds up against that breechplug. It will build up, simply because of that groove. Pour the water and soap out, and then rinse out the barrel a couple of times, to remove the soap. Then dry the barrel with patches.
Finally, use Alcohol to flush out the back of that barrel, as that will help dissolve any oils and grease that may be part of that crud.
If you oil the gun for storage, ALWAYS flush the barrel with alcohol( inexpensive rubbing alcohol works fine), and use some patches with alcohol on them to clean all the oil and congealed grease out of the barrel before leaving home. If you store the gun muzzle up, no matter how fine an oil that is used to protect the bore, some of it will fall down to the breechplug and dry out partially, or " congeal".
Don't use petroleum based oils in the bore for storing the gun between shooting sessions, either.( Use vegetable oils, or mineral oils, instead) Petroleum and black powder don't mix well- and in fact produce Tars and solid residues that can't easily be removed with soap and water, unless the barrel is allowed to soak for more than 24 hours. :cursing:
I have had to use Acetone to clean out the crud that has built up in barrels due to use of petroleum oils, and inadequate cleaning attempts by prior users. Acetone is a very strong, and harsh solvent to use. Rubbing Alcohol is much nicer, and will do the job if used on a regular basis.
To clean the gun, you don't have to remove the barrel from the stock. Just use a gun cradle that lets you rest the barrel upside down-- ie, the top flat is at the bottom of the cradle-- when you are using your range rod and cleaning patches to clean and dry the barrel.
If you have one of those clamp- on devices( Track of the wolf sells them, as do other suppliers) that seal the vent hole, and a tube that can be run into a bottle or bucket of water, that is the best way to clean a flintlock without getting soap and water, or crud on your stock. If you don't have the device, or it won't work with your particular gun, then as long as the vent hole is on the bottom when you are pouring or forcing water or alcohol through the vent during cleaning, gravity will see that the fluids, and anything they carry, will stay off your stock, and out of the barrel mortise.
Now, plug the vent, with a toothpick, or a carved plug that fits tight enough to not leak, but not so tight you can't get it out again. Pour skin temperature(tepid) water and soap down the barrel and, with your thumb over the barrel, shake the barrel up and down. Pour the water, soap and crud out. Repeat the process until the water seems clear.
Now remove the plug from the vent hole, and with the gun rotated so that the vent is facing down- over a bucket or sink, wet a cleaning patch with water and liquid detergent, and pump it back and forth down the barrel. It will come out dirty- at least gray in color.
Holding the muzzle up at an angle, but with that vented down towards the sink or bucket, pour some water down into the barrel, and insert your cleaning rod, jag, and clean, damp( water only), patch and push that water out the vent as fast as you can by pumping on the rod. The damp patch should seal air between the jag and the vent, and the air will force the water out at high speed. This should scour the face of that breechplug, and the groove to clean out any remaining crud. Repeat this several times, until the patches come out clean.
Then dry the barrel with dry patches, and then use alcohol to do the final drying. It will get into any corners your cleaning patches can't reach.
Occasionally, you have to use a patch on top of a bore brush, to get down into the corners of the grooves, and I recommend you dampen that patch( sloppy wet) with the alcohol. It not only helps to dissolve the last bit of residue in those corners, but lubricates, and then dries the corners as you are doing it. The alcohol will be pushed out the vent, too, of course. Nothing wrong with that as long as it lands in the sink or bucket.
Wipe off the outside of your stock and barrel, removing the powder residue from around the vent, and clean the lock and flashpan. Set them aside to dry, and oil, while you dump out and clean that bucket of dirty water. This will give the alcohol time to evaporate, removing any last droplets of water from the barrel.
Now is the time to grease or oil the barrel, inside and out, to protect it during storage between shooting sessions. By using tepid water rather, than boiling or very hot water, you avoid the problem of flash rusting your bore. Flash rust occurs when the heat from the barrel causes the water to evaporate so fast that the steel actually corrodes from that action.
If you MUST use hot water when cleaning, then at very least, use cool water for rinsing the barrel to reduce that temperature of the barrel and prevent the flash rust. A little flash rust one time is not going to harm the accuracy of the gun. But, a lot of flash rusting over time is going to damage the lands and eat at the grooves, and then you will develop troubles that could have been avoided.
I use bore butter, but am testing Ballistol, in the barrel of my rifle. So far it seems to be working as well as bore butter works. I still use bore butter on the outside of the barrel to protect the barrel from the acids from fingerprints. The wax it leaves behind when the oils dry out gives that protection.
Always do a visual inspection of the gun's bore when you finish cleaning. I look down the barrel while having a bright light shine into the vent hole. There are also small lights available that can be slid down the bore to let you see the condition of the entire bore. And, I have a small reflective mirror that does much the same thing, that is dropped down the barrel, and then dumped out when finished inspecting the bore.
The problem with these latter approaches is they don't let you see the face of the breechplug very well, or not at all. If you are going to have rust that damages the gun anywhere, its going to start first at the face of the breechplug and in those few threads that may be exposed at the back of the bore.
That is why I use alcohol in final cleaning. The Alcohol gets in everywhere, and is a terrific solvent. If anything can clean out crud in those hard-to-reach corners, the alcohol will. Using alcohol will also insure that the groove in your gun is cleaned every time. Best wishes. :hatsoff:
