Wild inaccuracy with CVA .50

Discussion in 'Percussion Rifles' started by ChrisPer, Dec 11, 2019.

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  1. Dec 11, 2019 #1

    ChrisPer

    ChrisPer

    ChrisPer

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    I have been very annoyed to find I cant hit a bull in the bum with my CVA, since the old ticking I used for patches ran out. I am talking six to ten inch groups at 50m benchrest, with flyers! Yet I had some years ago got six of thirteen into five inches at 100m! I use too many rifles, so have not paid attention that each was giving the best until now.

    Charges: 55 volume grains of Pyrodex, with 180gn .490 balls cast from roofing lead.

    Patches: I tested a bunch of materials, using a micrometer, and found several to try. Best was a Cotton Duck at .016". Shot with the .013 sworkshort (Hi-VIs!) a big and flyer-ridden group; the .016 tightened it a lot!

    I use hardware store soluble oil about 25% in water for lube, wet the patches before shooting a group.

    Tried pre-lubing and sun dried patches. Big groups.

    My Lee .490 2-cavity mold had a tiny burr, which made balls looking poor at the sprue. I weighed the bastards, and eliminated outside 3 standard deviations. (5%, mostly low side weights). The median weight was 179.1g, and the 3SD range I kept was 177.85 to 108.2g.
    The groups were still lame. I will weigh again. Next time, I keep those inside TWO standard deviations.

    (I also had three negligent discharges, from loose set trigger adjustment screw being turned in by fingers on the firing line. This rifle I had previously shown in this thread:
    Old thread about negligent discharges )

    I also need to figure out this patent breech; I believe my cleaning is not getting the inside part clean. I put a 9mm long jag on a rod and wrap a strip patch, but cannot feel that I get inside anything, or any lip. That doesn't bear on bad accuracy though.

    Then there is eyesight. I use +2 $20 reading glasses, with a 2mm knifed aperture in black electricians tape as an iris. The electrical tape adhesive gets old and mucky on the glass so I need to clean that and make it neat.

    SO what else could be a cause of bad accuracy? Sunshine on the sights? No, we are under a roof. I plan to open the notch on the rear sight, its a bit narrow.
     
  2. Dec 11, 2019 #2

    bang

    bang

    bang

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    Without looking at it it's hard to say. Did you let someone else shoot it?
    IMO 55gns seems low. 70-85 seems more prudent.
     
  3. Dec 11, 2019 #3

    flntlokr

    flntlokr

    flntlokr

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    I hate to say this, but is it possible that it is just shot out? Happened to my T C years ago. Suddenly wouldnt shoot a group beyond 25 yd, after about 10 K rounds. Usually only the last inch or so of rifling is responsible. I suspect ramrod abrasion in some cases, particularly with aluminum or fibreglass rods. I just rebarrelled the rifle, but some folks cut the barrel down to get back to sharp rifling.
     
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  4. Dec 11, 2019 #4

    Frontier's

    Frontier's

    Frontier's

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    Check the tang screw for looseness.

    Buy a new nipple as well.

    Flush the bore with HOT soapy water to melt out any patch lube thats built up in it over the years. Even go as far as wrapping some 000 steel wool around a bore brush and help work that fouling/lube out of the bore.

    Could even be old Pyrodex that has just gone bad, but replacing the nipple and doing a deep cleaning like i explain above is well worth the effort.
     
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  5. Dec 11, 2019 #5

    TFoley

    TFoley

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    100% for the above post. I helped a new shooter to clean out his new-to-him CVA Hawken - a fine-looking rifle indeed. It had been shot only with subs of some kind, and over the years the crud in the chamber had built up to an unbelievable level. It was shooting maybe one in three times, even with the Holy Black. Over a period of about three hours, with the rifle clamped in a Workmate, we removed, or rather excavated, around a heaped tablespoon of solid black/grey fouling from the breech. We then changed out the nipple, loaded up, and shot ten consecutive shots without a hitch.
     
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  6. Dec 11, 2019 #6

    Boomerang

    Boomerang

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    Yep, change out the nipple and also have you checked your patches after you shoot them to see if there are any holes in them?
     
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  7. Dec 11, 2019 #7

    dave951

    dave951

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    Give the gun a thorough cleaning and try real black powder.
     
  8. Dec 11, 2019 #8

    ChrisPer

    ChrisPer

    ChrisPer

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    Lots of good ideas here. I always use lots of hot water, but a subcaliber scraper would help I am sure. Black powder yes, I love the stuff but we have a lot of trouble getting enough so I switched to Pyrodex. Just wondering if I make up a lead taper slug would it show wear at the bore? I once had some Cerrosafe, but the chap I lent it to passed away. I feel a hacksaw in my future.
     
  9. Dec 11, 2019 #9

    bang

    bang

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    Good point. My 40+ years old Hawken just got a barrel replaced for that reason. Bored out the old 45 to a smooth 50.
     
  10. Dec 11, 2019 #10

    Carbon 6

    Carbon 6

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    What do your patches look like when fired ?
    Are you using Pyrodex RS ? if so, switch to pyrodex P

    Do you put soap in that water ? do you use the "pump" and submersion method for cleaning?
    Scrapers do not work well on CVA breeches .
     
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  11. Dec 11, 2019 #11

    Grenadier1758

    Grenadier1758

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    Use one standard deviation as the cut off for the weight criteria. You should have most of the balls weighing within one grain.

    When was the last time you changed the nipple? Change the nipple anyway.

    Use a round punch rather than a knife to make the pin hole for the tape aperture. Try using 1.00 reading glasses with the tape pin hole aperture.

    I would recommend Ballistol as the water soluble oil to use for your patch lubricant. I would use the solution of one part oil to seven parts water. I use it to dampen my patches before loading. JoAnn's cotton drill from the utility cloth section generally measures 0.017" after washing or the 0.022" cotton duck is also a choice.

    I, too, think the bore needs a good scrubbing using brake cleaner, maybe with 0000 steel wool on the jag to get out any possible fouling out of the grooves. Most of the time, a shot out barrel really has the grooves filled with fouling that builds up almost without notice because the Pyrodex fouling is noticeably less than real black powder fouling and can be left on the barrel and allowed to build up.

    If you can, check the barrel for pitting. Especially at the breech. That unevenness in the bore can grab patches and ruin accuracy.
     
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  12. Dec 11, 2019 #12

    Scota@4570

    Scota@4570

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    We should have a sticky about getting real BP via the mail. Posts bemoaning, "I can not get real BP in my area" happen every week. I have not bought BP at retail for 40 years. Mail order direct it is the best way. Just get on the phone and buy some powder. You can buy BP anywhere.

    Pyrodex will etch the bore. It has no redeeming value. Avoid using it.

    IF your bore is roughened by the use of pyrodex, polishing may help. Use some metal polishing compound on the steel wool. That may help of you are now cutting patches.
     
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  13. Dec 11, 2019 #13

    Britsmoothy

    Britsmoothy

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    So, it's been asked once....what do the shot patches look like?
     
  14. Dec 11, 2019 #14

    azmntman

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  15. Dec 11, 2019 #15

    longcruise

    longcruise

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    This should be the very first thing you check. If patches are torn or cut, you may have a rough muzzle and/or roughness in the bore.

    Might be a poor quality of patch material although duck is usually pretty good.
     
  16. Dec 12, 2019 #16

    ChrisPer

    ChrisPer

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    Don't know. I will get some next time!
     
  17. Dec 12, 2019 #17

    Desperate Lee

    Desperate Lee

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    You might want to check with Dr5x about his accuracy system. It is well worth the read and makes a hell of a lot of sense. CVA's usually have good quality, not excellent, barrels on them. Dont give up on it, you'll love it even more in the end when you solve this mystery. My $.02 worth.
    DL
     
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  18. Dec 12, 2019 #18

    SDSmlf

    SDSmlf

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    Any chance you have some of the old patch material when things were going better?
     
  19. Dec 12, 2019 #19

    Britsmoothy

    Britsmoothy

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    That is the first thing you needed to inspect.
    Any tiny holes by the rifling marking on the patch and that is the problem.
    If there is add a firewall first like sending a patch down first on its own or cream of wheat maybe.
    If your still getting holes in the patches polish the barrels crown with 1000 grit and finger rotating not just your finger in the barrel but you also around the rifle.
    Still getting holes, you need to lap the bore with wire wool mop.
    If that don't work don't buy any books, buy a chicken and sprinkle it's blood about while chanting " bubba Janna jibba jabba" instead.
    Bye.
     
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  20. Dec 12, 2019 #20

    Treestalker

    Treestalker

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    -bubba Janna jibba jabba- Got it!
     
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