Crown Touch Up wiith piloted PTG Center Reamer ?

A round headed screw in a battery drill and valve grinding compound works just fine, too--screw head should be about 1.5-2x bore size.
 
I can tell you what I did one boring Sunday afternoon. I was shooting the ppc there at home, and I started thinking about crowns, and there importance on accuracy. My rifle that afternoon was shooting extremely well even though the barrel had 7-800 rounds on it. none the less I decided to give the crown a re-sharpen. I wanted to see if a sharp crown would improve the group sizing. I knew it might be hard to see any real improvement as the rifle was shooting solid .200's anyway. Long story short. when I went into my machine shop, I noticed dad had the 3 jaw chuck on the lathe. My big machine is a 16" and the chucks are heavy, so I didn't feel like changing the darn chuck for 10 min of work. I wasn't even going to mess with the crown after seeing the 3 jaw on the lathe, but something hit me, and I could help but wonder. could I crown this barrel without indicating anything in??? I thought what the heck!! I chucked the barrel up in the 3 jaw the best I could, and faced the crown with a sharp ground HSS tool bit I have. After I re cut the crown, I checked the run out. My barrel was out .007 TIR . I didn't know what to expect? I took the barrel back over to my range, and screwed the barrel back on my rifle. With the same load I had been shooting before the re-crown I shot 5, 4 shot groups. average group size was a .208. I still indicate all my crown in like we should, but I cant help but really wonder if this is really needed.
I don't want to draw any major conclusions from one experiment, but the results from my "boring" sunday afternoon, we really interesting. Lee
 
done it lots . Go in only as far as to clean up the lands and grooves . (just break the edge)
Chris
 
skeetlee said:
I can tell you what I did one boring Sunday afternoon. I was shooting the ppc there at home, and I started thinking about crowns, and there importance on accuracy. My rifle that afternoon was shooting extremely well even though the barrel had 7-800 rounds on it. none the less I decided to give the crown a re-sharpen. I wanted to see if a sharp crown would improve the group sizing. I knew it might be hard to see any real improvement as the rifle was shooting solid .200's anyway. Long story short. when I went into my machine shop, I noticed dad had the 3 jaw chuck on the lathe. My big machine is a 16" and the chucks are heavy, so I didn't feel like changing the darn chuck for 10 min of work. I wasn't even going to mess with the crown after seeing the 3 jaw on the lathe, but something hit me, and I could help but wonder. could I crown this barrel without indicating anything in??? I thought what the heck!! I chucked the barrel up in the 3 jaw the best I could, and faced the crown with a sharp ground HSS tool bit I have. After I re cut the crown, I checked the run out. My barrel was out .007 TIR . I didn't know what to expect? I took the barrel back over to my range, and screwed the barrel back on my rifle. With the same load I had been shooting before the re-crown I shot 5, 4 shot groups. average group size was a .208. I still indicate all my crown in like we should, but I cant help but really wonder if this is really needed.
I don't want to draw any major conclusions from one experiment, but the results from my "boring" sunday afternoon, we really interesting. Lee
Click to expand...

Its all in what kind of crown you cut. Let it run out .010 then throw an 11deg on it and see what happens. Id love to see the results of that
 
dusty
If I can find some time this coming weekend, ill give it a try. im sure your right though. ill document some before and after groups and post my findings. Im not real sure how I will do the .010 out, but I do have a really crooked barrel with several rounds on it. I will chuck it up in the 3 jaw, and measure the run out on the end. im sure it will be more than .010. the weather here sucks and I don't have much to do, so this will be interesting.
here is another one for you. This one will really blow your mind. I no of a fella who swears by running his chamber reamers in the crown. He says you have to stop about .040 before the neck shoulder junction. After him telling me about this, I thought I would give it a try. I didn't really see anything special after doing so, but I didn't see any accuracy loss either. Anyone else hear of this, or try this? Lee
 
Sounds like lunacy. Back to the offset crown id like to know also if it changes impact area if it doesnt hurt the groups
 
Ball Mill

Always carried a small ball end mill and small tap handle in my loading box in case I dinged my crown. I used it on mine and couple of other guys crowns and it seemed to work very well. I always placed a small piece of the blue paper shop towel between the ball mill and crown to stop any chatter.
 
Started reading this and thought should I! Well here goes, Years ago I got an 11 Deg. crown reamer from Hugh Henriksen that has a pilot. While using it one day at the range, One of the Gunsmiths seen me and asked what the Hell was I doing? Well I ended up kicking some butt's that day so I say, Works For Me. So know when my Smith Chambers my rifles I give him my reamer and ask him to please us this to Crown the barrels.

Joe Salt
 
A friend bought the wrong twist in a barrel (engineers always know best!) so he decided to cut off six inches just to see the velocity difference. Cut it off with a hack saw and crowned it with a counter sink in a battery drill. I don't remember what the velocity difference was but it really did shoot better.
 
IanRobertson said:
A friend bought the wrong twist in a barrel (engineers always know best!) so he decided to cut off six inches just to see the velocity difference. Cut it off with a hack saw and crowned it with a counter sink in a battery drill. I don't remember what the velocity difference was but it really did shoot better.
Click to expand...


Years ago........after reading a true story Harry Pope wrote .....
I`ve done similar tests... hacksaw/file.....with same results......hacksaw alone will surprise you..... did one ...filed it smooth.....didn't check it... shot it..... it shot great...back at shop noticed how out of square the muzzle was...trued it up.....still shoots great...
My belief is rimfires require a better crown than CF`s
bill larson
 
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