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Crowning humor

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20 May 2014, 09:05
SR4759
Crowning humor
This is the group at 90 yards.



This is the crown



And this


20 May 2014, 11:57
eagle27
Wow that is amazing, who would have though the rifle would shoot like that. I think I'll get out my 6.5-06 with a Douglas Supreme barrel and take to the muzzle with a centre punch, might improve my groups Big Grin

What condition is the rest of the rifle in?
20 May 2014, 14:30
srose
That is amazing. I've always thought the crown was the most important part of a barrel. Recrowning usually fixed most accuracy issues. Myth Busted I guess.
20 May 2014, 19:26
tek4260
Both the crown and the ammo are "aged to perfection" I suppose
20 May 2014, 21:06
dpcd
Crowns are important but as long as they are uniform, you are good. So, uniform rust and pits works.
20 May 2014, 22:01
Bobster
That bore seems to be a bit big for a 6.5 in relation to the general muzzle diameter of military rifles. Perhaps it is counter-bored and there is a nice crown deeper in the tube?
21 May 2014, 04:00
ssdave
You ought to be able to tighten that group up a bit if you use a more precise aiming point.....

I've had some amazingly bad looking barrels shoot well, and some pristine ones that wouldn't. But, usually there's a direct correlation between condition and accuracy.

dave
21 May 2014, 09:18
delloro
quote:
Originally posted by Bobster:
That bore seems to be a bit big for a 6.5 in relation to the general muzzle diameter of military rifles. Perhaps it is counter-bored and there is a nice crown deeper in the tube?


HA! I missed that altogether. good catch.
22 May 2014, 10:05
SR4759
There is no catch.
That is all there is. If you have a Dutch M95 carbine you will know that they have a small diameter muzzle. There is little point in making a carbine with a fat heavy barrel.


quote:
Originally posted by delloro:
quote:
Originally posted by Bobster:
That bore seems to be a bit big for a 6.5 in relation to the general muzzle diameter of military rifles. Perhaps it is counter-bored and there is a nice crown deeper in the tube?


HA! I missed that altogether. good catch.

26 May 2014, 07:09
ted thorn
Saeed did a hacksaw crown test years ago and found the crown to be over rated


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26 May 2014, 08:09
Bobster
What exactly is the diameter of a Dutch carbine at the muzzle? If it is .600 or larger, that is at least a .30 cal hole. My Swede carbine with a 16 in bbl is .605.

quote:
Originally posted by SR4759:
There is no catch.
That is all there is. If you have a Dutch M95 carbine you will know that they have a small diameter muzzle. There is little point in making a carbine with a fat heavy barrel.


quote:
Originally posted by delloro:
quote:
Originally posted by Bobster:
That bore seems to be a bit big for a 6.5 in relation to the general muzzle diameter of military rifles. Perhaps it is counter-bored and there is a nice crown deeper in the tube?


HA! I missed that altogether. good catch.

26 May 2014, 08:32
SR4759
Mine are .550, .551 and .552.

One is a 1917 Hembrug rifle that was converted to a carbine. The last 7 inches of the barrel is turned to a smaller diameter leaving a step that the beginning of the turned down section. .552

One is a 1900 Steyr that began life as a carbine.
It is the version called the OM #2. .551

The last is a new arsenal carbine barrel that has never been installed at .550.
27 May 2014, 03:54
Fjold
quote:
Originally posted by SR4759:
Mine are .550, .551 and .552.

One is a 1917 Hembrug rifle that was converted to a carbine. The last 7 inches of the barrel is turned to a smaller diameter leaving a step that the beginning of the turned down section. .552

One is a 1900 Steyr that began life as a carbine.
It is the version called the OM #2. .551

The last is a new arsenal carbine barrel that has never been installed at .550.


I stole those pictures to send to a couple of gunsmith friends of mine and they're calling me a liar.

I think that it's hilarious!


Frank



"I don't know what there is about buffalo that frightens me so.....He looks like he hates you personally. He looks like you owe him money."
- Robert Ruark, Horn of the Hunter, 1953

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27 May 2014, 06:22
roughone
I ran a test once under lab conditions on 5 heavy bbl. 700's in 308. The rifles were benched to establish the baseline accuracy. Then various violations were visited upon the barrel muzzles. After each mistreatment, accuracy was check under the original conditions. Then the muzzles were faced off and re-crowned. Then they were damaged in a different way. All 5 rifles were treated in the same manner each time. Based on the target results, crown has almost no effect on accuracy. The only damage that gave any degradation in accuracy was center punching metal into the bore. Even that was not as bad as expected.
Several years ago a lady gunsmith wrote an article for Precision Shooting magazine and her findings mirrored my own.

The crown is not very important.


(You can't fix stupid)
Falls of Rough Ky University
Our victory cry is FORK U!
27 May 2014, 19:36
ELeeton
This is curious. There is a long thread about Sabatti using a Drexel to "regulate" double rifles ie altering the crown to shift the point of impact. This posting indicates accuracy is not severely affected but what about point of impact? In the various tests referenced in this thread was the point of impact changed though grouping remained the
same?
I can understand that the crown may not significantly impact group size but if it does not shift the point of impact with any significance how was it used to regulate the Sabattis?


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Brno ZP-149 45-120 NE

27 May 2014, 19:49
roughone
An uneven crown will definitely affect the point of impact. This is evident on both rifled and smooth bore barrels. Altering the angle of the crown has been used to change the POI since the days of muzzle loaders.


(You can't fix stupid)
Falls of Rough Ky University
Our victory cry is FORK U!
28 May 2014, 04:27
Dulltool17
Check this thread, for giggles:
http://www.mausercentral.com/f...022&p=349838#p349838

If this isn't counter-intuitive, I don't know what is, but as some have suggested, this might be a counter-bored barrel, sufficient to take care of the poor crown


Doug Wilhelmi
NRA Life Member