Discussion in 'Technical Articles - Discussion' started by ADMIN, Jan 21, 2013.

The Over-Rated Crown

  1. ADMIN

    ADMIN Administrator

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    This is a thread for discussion of the article, The Over-Rated Crown, By Alan Marshall. Here you can ask questions or make comments about the article.
     
  2. L-46

    L-46 Member

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    Alan,
    A facinating article to say the least!
    Many of us have had experiences about barrel crown and the like. We all see and do what we believe to be correct? at the time any way! This is an amazing 'trial' to get some factual answers. I would have never believed what your were going to write.
    Thanks for sharing
    L-46
     

  3. Whitesheep

    Whitesheep Well-Known Member

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    I have a confession. When I slugged the barrel of my 1 MOA .444 Marlin I used a wooden dowel to drive the slug notlightbulbnot. When it broke, the dowel was stuck good and I decided to insert a screw in the broken section so I could pull out the dowel. In drilling the hole for the screw I damaged the barrel across a grove about 0.25" below the crown. I kicked myself around the house for a week until I went to the range and found I still had a 1 MOA rifle.

    I feel better now. Thank you.
     
  4. Whitesheep

    Whitesheep Well-Known Member

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    I have a confession. When I slugged the barrel of my 1 MOA .444 Marlin I used a wooden dowel to drive the slug notlightbulb. When it broke, the dowel was stuck good and I decided to insert a screw in the broken section so I could pull out the dowel. In drilling the hole for the screw I damaged the barrel across a grove about 0.25" below the crown. I kicked myself around the house for a week until I went to the range and found I still had a 1 MOA rifle.

    I feel better now. Thank you.
     
  5. landcbeitner

    landcbeitner Well-Known Member

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    Great article! Thanks!
     
  6. kweidner

    kweidner Well-Known Member

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    Wow is the only word that comes to mind here. I do not doubt your evidence. My only thing is the amount of barrels I have recrowned that shot better after. It would be interesting to see what the test results would be like in a more run of the mill gun. It seems the ones that have been helped the most in my limited experience are those that are of the sporter non custom category. I'm with you in I now have more questions than answers. This is certainly interesting. I cannot believe the results from the carbide routing job! Just wow. Excellent article.
     
  7. L-46

    L-46 Member

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    Alan,
    I have seen, as others have, varing results with recrowning. I makes me wonder whether calibre, velocity, bullet jackets, BC, and other factors have an effect on the results.
    My story is a little different, maybe to the other end of the scale.
    I was given a .204 some months back, it was new, from a reputable manufacturer, out of the box, and did not shoot a 10 inch group!
    Long story short, my friend, the dealer asked me to take the rifle and see if could be fixed, I carried out a few basic tests to see if there was a simple solution.
    Upon visual inspection, all i could see was a small indent on the crown. I was sceptical that this was the trouble. Hey 10 inches at 100yds!!
    I took a tight patch and felt the bore for any variations, none where found.
    The rifle had fired an unknown number of shots, during the run in, by the owner, and it was returned to the importer for a warrantee claim, so i gave it the sweets and JB paste to be certain the bore was clean. it came up pretty good.
    I took the bore scope and had a good look inside, nothing was out of place for a factory rifle.
    I went to the range and fired 5 shots, I was also given the test target, the customers target was a good reference as the new target was similar, 10 inches! wow!
    now on further inspection i concluded that the group had in fact blown out, in favour of the damage to the crown ie indexed at 10 o'clock if you like in line with the damage.
    Not certain what to do next, and knowing my friend had just bought a cheap action, i proceeded to see if i could change the 10 inches down some what, to something less than an inch, on the target.
    Those of you who shoot 204's will know they are very capable, with less than half inch groups being obtainable out of the box.
    Not having the correct tools to recrown the barrel and not really troubled by the result i took the burr off the damaged part of the crown with a screw driver to see if the resultant target showed any improvement. To my surprise the consequent group was around 8 inches, not good but different.
    I knew if i was successful that a competant smith could take 1/8 of an inch off and reshape the crown so i was underterred. i took a drill and removed some more material trying to get below the damage part or the bore.
    I did this in stages as to see if i was getting any where. Another 5 shot group showed an improvement down to 6 inches, than 4 inches. At 4 inches some where landing in the bull, while others scattered out in a radius, I had achieved my goal. I stopped there as to not cause further damage to the barrel and it was time to let a machinist complete the work in a professional maner.
    The barrel was soon recrowned and now shoots as it should. I know we are not comparing apples here, but i was very taken by your findings.
    At any stage you are able to conduct more tests, it would be great to add some other calibres? To see whats really in a crown!
    Good Hunting!
    L-46
     
  8. gingerbreadman

    gingerbreadman New Member

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    This being my first post, I'm somewhat unsure/shy of sharing. I live in a state that limits the areas we can hunt with a rifle in, so for convenience I have chosen to hunt with shotguns. I have purchased used guns that had dented and banged up barrels and muzzles, and have cut down many. Some to get rid of an imperfection, but most to bring them to a cylinder bore choke.

    I've cut 'em off with a chop saw, a hack saw and a lathe. I've used a rat-tail file, a jewlery file, de-buring tool, and even a piece of Emory cloth to smooth the cut and try to true it up. But I've never had more'n an 8 inch spread at 50 yds!

    Right now I'm working on some 36 ga or 410bore shotties. I hope to be able to take Whitetail at 150 yrds, but we'll see what kind of projectiles I can get/design to accomplish my goal. GREAT article! Thanks.
     
  9. Mike 338

    Mike 338 Well-Known Member

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    Any chance you work in the Remington Custom Shop?
     
  10. gingerbreadman

    gingerbreadman New Member

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    That's a hoot, Mike 338! I don't even own a Rem, although, I wouldn't mind one of their shotties! I've got friends and relatives that swear by their 870's.

    Gingerbreadman
     
  11. ArtC

    ArtC Member

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    Hello;
    Very interesting info.; however, it seems to amount to much to do about nothing. One of my comp. rifles (DPMS 24" SUPER bull barrel AR15) shot in the 5's when new out of the box 13 years ago. I have over 7000 rds. through it as of last weeks 100yd competition. I shot 20 rounds for a score of 194-6X and a extra group bull of .541. This comp. was bench shooting from a bulls bag only (no back bag) I have the oldest AR in this competition by far, and certainly many more rounds through it. Over the past 13 years I have shot it in at least 300 competitions, and have won either first or second place against all comers ( AR's ). This gun has been undefeated in the last 5 yrs. winning "shooter of the year" in both group and score. Air Capital gun club, Whitewater Kansas, 20 mins. out of Wichita.
    I have done nothing to this rifle except clean it, (came with a JP trigger) I have went through three 308 Hunter class rifles and 3 Varmint class 223 bolt guns in that time because they had loss there winning accuracy. Go figure. Art Cheney
     
  12. ArtC

    ArtC Member

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    Sorry; ran out of room.
    That said; my crown is crap. However; I believe in a good crown being better than not! I have seen pics of open class gun crowns via a electron mic 400-500 and 600 power. They look like a old gravel road under construction at this power. But, still shoot great. In regard to the article; it is my contention, that if you were to put a tiny burr of metal in front of the bore where the meplat or front bearing surface of the bullet would strike it during flight, this pill would hit anything but the 10 ring.
    If you take a top and spin it on the floor it will bump into all kinds of things and keep on spinning. But if the tip of the top hits something on the floor, the yaw created will send that top crashing into everything in the room. I do know if you take a open class barrel that shoots in the 1's and after many rounds, now shoots in the 3's. A good crown job will bring it back into the 1's (all other things being equal) again, go figure. Art Cheney
     
  13. CB11WYO

    CB11WYO Well-Known Member

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    Great tests in this article! I myself couldn't believe what I was reading, I then showed it to my father who does custom rifle work/builds and he was astounded as well.

    I will say, as has been said already, just for peace-of-mind I'll still be careful with my crowns... :)

    Thanks for the article!
     
  14. greggc1960

    greggc1960 Well-Known Member

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    Very interesting. Now if just knew what type of crown to not worry about so much...