What is the type & size screw people use when touching up their crown on a 22cal? What is the procedure/process and aside from using a drill, is there anything else needed/used? Thanks in advance.
Cross posted
Cross posted
Recrowning
- Thread starter josh3rd
- Start date
There are several ways of doing this other than using the correct crowning tools. I used whatever screw I had around that had a round head and would not fall through the crown and into the barrel. One can decide on the angle of the crown by the size and shape of the screw head and how much material is removed. I used a small square of #600 wet dry sandpaper, taped under the screw head, when I did my crowns back in the day. This made short werq of the job. Some others prefer the paste type polishing compounds to do the same job. This takes allot longer. Make sure to rotate the drill evenly at an angle to your werq while doing this so that you get a well centered crown.
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It would be easier for you to look up the YouTube video. The one I seen the guy was using a button head brass bolt In a hand drill.I myself would prefer to do it In a lathe but I heard people get good results by using the bolt method.
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If you can’t find the video I will try to explain it to you. He puts a button head brass screw in a cordless drill. Then he put some lapping compound on the head. Then he takes the drill and goes straight into the crown area. And then he turns it on at about medium speed. Then he twirls the top of the drill around in circles so the drill is always at an angle As he goes around with it.
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Try this at 5:14 for one way of doing it. Proper technique for a fairly even crown.
https://duckduckgo.com/?q=recrowning+an+airgun++barrel&t=ffab&atb=v180-1&iar=videos&iax=videos&ia=videos&iai=https%3A%2F%2Fwww.youtube.com%2Fwatch%3Fv%3D5Y9fr-3Wy5M
https://duckduckgo.com/?q=recrowning+an+airgun++barrel&t=ffab&atb=v180-1&iar=videos&iax=videos&ia=videos&iai=https%3A%2F%2Fwww.youtube.com%2Fwatch%3Fv%3D5Y9fr-3Wy5M
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Scroll down see video how to disassemble the P17 he recrowns the barrel.
https://www.airgunnation.com/topic/beeman-p17/
https://www.airgunnation.com/topic/beeman-p17/
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Josh, I'm going to include an excerpt from a guide I wrote a while back...
What you will need is a round head (not pan head) brass machine screw. #6-32 is good for .177 cal and a #8-32 is good for .22 and .25 cal. Whereas most everything that has been discussed thus far should be done with the barrel removed, you can do this procedure with the barrel installed. Secure the barrel in an upright position so you can have both hands free. Stuff a small piece of cotton into the muzzle to keep debris from falling down into the barrel. Chuck up the screw into a handheld drill. Coat the head of the screw in polishing compound and hold it against the muzzle and operate the drill at low speed, moving it in an irregular circular or figure 8 pattern. I use the term "pattern" loosely; you expressly want to randomize the movements. If you try to hold the drill in one position, invariably more pressure will be applied to one side which will abrade an irregular bevel into the crown.
Do not apply downward pressure to speed things along. If you do, a wire edge will get pushed into the bore. I don't even use the full weight of my drill; I support it to limit the pressure to something between 0.5 and 1 pound. The idea is to let the abrasive slowly do the work. Refresh it often and keep at it until you see a clean, polished ring appear. A good crown will also have a distinct cog-like appearance when viewed under magnification, owing this to sharp, burr-free lands and grooves. Here's a before and after for reference...hopefully your before won't be this bad:
When you think you've done enough, check that there is no burr remaining. The usual way is to very gently drag a cotton swab over the crown (from inside the bore and onto the bevel) and see if it snags. If it does, you still have a burr that needs to be worked down. When dealing with an unchoked barrel, I like to check by pushing a pellet through from breech to muzzle. I find it easier to detect a slight burr this way. I know it's right when the head of the pellet slips out the end with no more resistance than it takes to push it down the barrel.
What you will need is a round head (not pan head) brass machine screw. #6-32 is good for .177 cal and a #8-32 is good for .22 and .25 cal. Whereas most everything that has been discussed thus far should be done with the barrel removed, you can do this procedure with the barrel installed. Secure the barrel in an upright position so you can have both hands free. Stuff a small piece of cotton into the muzzle to keep debris from falling down into the barrel. Chuck up the screw into a handheld drill. Coat the head of the screw in polishing compound and hold it against the muzzle and operate the drill at low speed, moving it in an irregular circular or figure 8 pattern. I use the term "pattern" loosely; you expressly want to randomize the movements. If you try to hold the drill in one position, invariably more pressure will be applied to one side which will abrade an irregular bevel into the crown.
Do not apply downward pressure to speed things along. If you do, a wire edge will get pushed into the bore. I don't even use the full weight of my drill; I support it to limit the pressure to something between 0.5 and 1 pound. The idea is to let the abrasive slowly do the work. Refresh it often and keep at it until you see a clean, polished ring appear. A good crown will also have a distinct cog-like appearance when viewed under magnification, owing this to sharp, burr-free lands and grooves. Here's a before and after for reference...hopefully your before won't be this bad:
When you think you've done enough, check that there is no burr remaining. The usual way is to very gently drag a cotton swab over the crown (from inside the bore and onto the bevel) and see if it snags. If it does, you still have a burr that needs to be worked down. When dealing with an unchoked barrel, I like to check by pushing a pellet through from breech to muzzle. I find it easier to detect a slight burr this way. I know it's right when the head of the pellet slips out the end with no more resistance than it takes to push it down the barrel.
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Nervoustrig, dude I literally just read a post of yours on GTA about this,lol. Question, what if my barrel has a non removable or very hard to remove muzzle brake that's about 2.5" deep? Just use a longer #8 screw?
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If it had a muzzle brake Installed by the factory, the crown should still be good. Not unless they goofed it up At the factory.
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I'll take a pic of it tomorrow morning, well it's 0237 here in SE PA. Anyway, it looks lopsided and has a noticable dent/flaw that's easily seen.
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Sorry man, I can't help you there. I haven't tried working a crown deep down in a narrow space.
My thinking is that it presents two handicaps. It limits how much you can orbit the drill and will make it difficult to inspect your work. Maybe a third thing...a long screw will magnify the drill’s runout, causing vibration and chatter. Personally I would look into how to remove the brake.
My thinking is that it presents two handicaps. It limits how much you can orbit the drill and will make it difficult to inspect your work. Maybe a third thing...a long screw will magnify the drill’s runout, causing vibration and chatter. Personally I would look into how to remove the brake.
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Well I looked at the crown and got the muzzle brake off by cutting it close to the tip of the muzzle and didn't touch the barrel whatsoever, lol.
So now I'm looking at it with a loop and I can see that it is deeper/wider on one side than the other. Deeper/wider than what a number eight screw can go. Meaning if it's let's say the crown is a inch wide all the way around okay? Well on the upside(where the front sight would be) of the crown, it's bigger, wider/deeper than the rest of the crown. I'll take a picture if that doesn't make sense to you guys.
So I guess my only option now is to have it cut and crowned. and I'm not sure if a regular gunsmith can do this because I cannot remove the barrel from the rifle.
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Hard to tell from pix, but it looks considerably off! Non concentric and that is no good at all. If you do the recrown, I'd expect a noticeable improvement. I'd get a #10 brass screw and some lapping compound, watch the videos posted above and have at it. I've done 3 or 4 and it has always significantly improved my accuracy (when I did it to a barrel with a messed up crown like yours). I don't think you need to take a dremel/stone to it, just some medium grit compound and a drill / screw and some patience. Actually it probably won't take you 20 minutes. Just keep checking it by cleaning and examining with your loop.
You'll still need to find the best pellet, but you'll be a long ways better off. I hope you can find a way to do it yourself and post back.
I just recrowned a Diana 430L and did not do a great job of it (Quick one with a dremel, and then a screw/paste, intending to come back and do it properly when I get some more lapping compound) and it radically improved things. My crown was a bit more nasty than yours, but yours is messed up for sure so I'd expect it to improve significantly.
Good luck and Keep us updated.
John
You'll still need to find the best pellet, but you'll be a long ways better off. I hope you can find a way to do it yourself and post back.
I just recrowned a Diana 430L and did not do a great job of it (Quick one with a dremel, and then a screw/paste, intending to come back and do it properly when I get some more lapping compound) and it radically improved things. My crown was a bit more nasty than yours, but yours is messed up for sure so I'd expect it to improve significantly.
Good luck and Keep us updated.
John
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Start out slowly until you feel comfortable. Then I still take it slow and easy. I feel less prone to damaging my barrel and I check my progress often.
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I've cleaned up a few crowns over the years. Personally, I like using brass srews and valve grinding compound. As others have said, take slow, not much pressure, check often.
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