How do you tell if the crown is good or needs work? I suspect my Sav 11 LWH crown could be improved.
Printable View
How do you tell if the crown is good or needs work? I suspect my Sav 11 LWH crown could be improved.
There was a thread here few years back which demonstrated that a bad crown does not impact accuracy.
You can go around it with a cotton Q tip. If any cotton threads stick, it has burs. They can be removed by getting a brass, countersink, Phillips head screw, that has a head larger than the bore, cut the shank off at the base of the head, dab on some valve lapping compound, or other paste abrasive, and spin it in the end of the bore with a drill "in the direction that the lands exit". I don't know that it has ever helped that much, but it never hurt! ;-)
My cotton tip was shredded...Quote:
Originally Posted by FW Conch
The brass screw head may help you out?
+1 to above. Some guys over at snipers hide (I think) did a test. Basically cut off barrels with a hack saw and shot them and compared to before they were cut. What they found out was that it moved the POI but not the grouping as much.
One way is to shoot then look at the soot pattern on the crown end. It should be an even star like pattern.
It sounds like your crown needs attention. IT IS IMPORTANT!
I believe that when my model 93 rimfire was crowned, not enough material was removed to get rid of the 60 degree center drill recess that is put into the blank for profiling. None of my other rifles have it. So I am going to look at machining about 1/4" off and re-crowning it to see if accuracy improves. Right now 1.5" at 50 yards is the best it will do even with fully bedding the stock.
What caliber and what ammo ?Quote:
Originally Posted by Westcliffe01
22 magnum. Have 30gr CCI ammo that has shot nicely in other rifles. I have the stainless action/barrel with laminate stock.
Here is a picture of a proper powder burn pattern. Sorry it's blurry it was a quick cell pic one day during cleaning, but it shows enough to get the idea.
http://i46.photobucket.com/albums/f1...C86B7CE1BA.jpg
I've always thought of the crown to be important and know of many savage Rimfires that benefited from a recrown. Maybe it was a coincidence, but I know of many gunsmiths that include a recrown as part of their accurizing process. Hopefully sharpshooter will chime in with his knoweledge. In the mean time I'll continue to make sure mine are chip and nick free.
If the crown gets damaged so does your accuracy such as a dent,do you really think a speeding bullet being torn while exiting the muzzle will help accuracy,come on!If the crown gets a burr or dull for that matter,it needs proper crowning. The test on snipers hide is bogus,they probably were shooting full metal jacket or were deburring the crown after hack sawing.Ask any real benchrest shooter,if their crown gets dull or damaged they recrown and it shows on target period.These guys are the best shooters in the world accuracy wise and would laugh if someone claimed that a crown doesnt affect accuracy.The above picture is a perfect example of a carbon print of the rifling print,perfectly square.
My lgs is doing mine now, as well as threading the end of the muzzle. Cut, thread, recess and crown is only running me $50 can't beat that w/ a stick plus its good insurance.
Crown wasn't damaged, was like that from a brand new model 11.
I had to run to 4 different gun shops within a 75 mile radius in order to get 2-1lb powder and some primers. I then ordered the bullets online. Using my factory once fired brass for now and hopefully will hold me over until I find more.Quote:
Originally Posted by tammons
Not sure where the barrel crown discussion went, but I just finished redoing the crown on a barrel I had that needed it. I did the lapping compound/brass screw method and did a bunch of bench testing for the before and after. I'll shoot it again tomorrow with the new crown and compare groups.
back to the hijack...
Quote:
Originally Posted by Hotolds442
Thanks for the update! I'm no expert, but I have a hunch that a perfect crowned barrel will produce more consistent groups and POI from one type of ammo to the next compared to one with a bad or off-center crown.
The benchrest crowd say that if they set back a barrel that is part way through its life they cut off about 1" at the muzzle and re-crown and about 2" at the chamber end and re-chamber. They can supposedly get another half season out of it then. Saw a posting on a different forum of tests on AR rifles where they run 10k rounds through them. The ones shooting the steel cased surplus had no rifling left (in the entire barrel) within 6000 rounds. I believe the only cleaning the barrel got was at 5000 rounds...
My barrel is brand new but I think they did not remove enough material to clean up the muzzle to the rifling. In other words the blank was probably 1/16" short...