What are the symptoms of a bad crown?
- Thread starter pyscodog
- Start date
OldTurtle
Moderator - Deceased
Psychodog,,,,You might want to have a smith really look at that barrel with a good bore scope....When I got mine for Christmas and, like a little kid, started checking all my barrels, I was especially interested in my .308 semi-cuastom that had been giving me fits in the accuracy department..
Approximately 5 inches past the chamber, I found what appeared to be a stress crack running about 3/4 of the way around the inside, but wasn't visible on the outside...I took it to a local smith and just asked him to see if anything was amiss, since I was having accuracy issues and within a couple of minutes, he came up with the same observation...
While that doesn't explain the lack, or odd, pattern in the exit marks...There may be something going on away from the muzzle....
Approximately 5 inches past the chamber, I found what appeared to be a stress crack running about 3/4 of the way around the inside, but wasn't visible on the outside...I took it to a local smith and just asked him to see if anything was amiss, since I was having accuracy issues and within a couple of minutes, he came up with the same observation...
While that doesn't explain the lack, or odd, pattern in the exit marks...There may be something going on away from the muzzle....
Trip to the range today proved the "dots" on the crown were just imperfections in the finish. I shot 20 rounds and had no marks of any kind appear on the crown. With the loads I shot today, I had three groups that were well under an inch, two probably in the half inch range. Guess it may have been paranoia and bad loads causing my problems. Anyway, thanks to all for the suggestions and helpful info.
tnshootist
New member
Glad to hear it worked out.
DGW
New member
Good for you Pyscodog!
I have a decently sporterized 1903A03 with a very nice bore that I brought home from a gun show. Several trips to range later with it had me puzzled. Groups it shot were poor, dispite the variety of reloads I tried. Bullets always impacted target in a different spot, no pattern to them. Examined the crown numerous times, but couldn't see a darn thing wrong with it. Barrel had been shortened slightly and a nice round type crown done on it. Due to taper of barrel, couldn't figure out how to check if crown was level. Till one day, I had my Lee case trimmer on my work bench. Hmmmmm, if I find the right spindle for the case trimmer, perhaps I can insert it in the muzzle and check for low/high spots. Able to do this after inserting a piece of aluminum in bore that wrapped around the 7x57/.284 diameter spindle I used, which eliminated any wobble I had when I turned the case trimmer. Aluminum also protected the lands from the steel spindle. A turn or two later with the case trimmer with light pressure on it revealed the crown was not level. Curious, I continued to turn the spindle, applying pressure. Case trimmer will begin to shave off metal, leveling the crown. I would shave off the round crown, leaving me a flat muzzle. Would use a carriage bolt in a drill, coated with valve grinding compound to smooth/bevel the bore's edge at muzzle.
Next trip to range, after first shot, adjusted scope and then fired 5 more rounds. I was very pleasantly surprised. Had a 100 yd group I could almost cover with a nickle coin. Since then, I've used a Lee Case trimmer to redo several crowns on old rifles with decent results. This is not a technique I recommend, but its solved any crown issues I've had.
Guys at www.surplusrifleforum.com made a sticky in their gunsmithing forum about using a Lee Case Trimme to fix a crown when I posted pics of what I'd done there 4 or 5 years ago.
I have a decently sporterized 1903A03 with a very nice bore that I brought home from a gun show. Several trips to range later with it had me puzzled. Groups it shot were poor, dispite the variety of reloads I tried. Bullets always impacted target in a different spot, no pattern to them. Examined the crown numerous times, but couldn't see a darn thing wrong with it. Barrel had been shortened slightly and a nice round type crown done on it. Due to taper of barrel, couldn't figure out how to check if crown was level. Till one day, I had my Lee case trimmer on my work bench. Hmmmmm, if I find the right spindle for the case trimmer, perhaps I can insert it in the muzzle and check for low/high spots. Able to do this after inserting a piece of aluminum in bore that wrapped around the 7x57/.284 diameter spindle I used, which eliminated any wobble I had when I turned the case trimmer. Aluminum also protected the lands from the steel spindle. A turn or two later with the case trimmer with light pressure on it revealed the crown was not level. Curious, I continued to turn the spindle, applying pressure. Case trimmer will begin to shave off metal, leveling the crown. I would shave off the round crown, leaving me a flat muzzle. Would use a carriage bolt in a drill, coated with valve grinding compound to smooth/bevel the bore's edge at muzzle.
Next trip to range, after first shot, adjusted scope and then fired 5 more rounds. I was very pleasantly surprised. Had a 100 yd group I could almost cover with a nickle coin. Since then, I've used a Lee Case trimmer to redo several crowns on old rifles with decent results. This is not a technique I recommend, but its solved any crown issues I've had.
Guys at www.surplusrifleforum.com made a sticky in their gunsmithing forum about using a Lee Case Trimme to fix a crown when I posted pics of what I'd done there 4 or 5 years ago.