Opinon's on crowns

T

ta6ppc

New member
I was thinking about cutting my new 26" remington 700 sps V down to 20"

I know what a pain it can be breaking the barrel loose.

How adverse would it be to leave the action on the barrel while I indicate and part and re- crown the barrel?
Have any of you done this?

I have also seen these hack crowning kits like midway sells that you use a drill motor hand held.. It seems to me that once you get it indicated there is no need in haveing the barrel seperate.

I will be turning it slow so that there is no wobble or in-balance on the big end...

so break it loose or leave it in what do the expert's think ?:eek::eek::eek:
 
I just recrowned my Savage Model 12 LRPV. Just recrowned, nothing else. I took the barrel off when I did it. If it's worth doing, it's worth doing right.

Fitch
 
If you are going to cut a flat or a flat recessed crown the barrel does not have to be indicated in. If you are able to get it close just do it. Finish it with a 60 degree piloted reamer and don't worry about it.

Far more importance is placed on the set up for crowning than is required in my opinion. When it is finished a uniform smooth burr free crown is more important.

Cutting that much off a barrel you will probably find the bore is not concentric with the outside diameter.
 
I've crowned with my small lathe by running the barreled action thru the headstock spider and out the chuck. At the outboard (action) end I had just enough room to slip a dial in and indicate off the outside of he barrel at the chamber and the inside at the crown. I've had no problems with this method on factory rifles.

Another way to crown through the headstock is to turn an AL plug for the muzzle with an indicator ring OR use a long indicator OR the "range rod" that's featured on Gordie Gritter's vid..... something to allow you to adjust the muzzle only, letting the rear end wobble if need be.

I use 80-100rpm and wrap a towel around the action, duct taped in place. This is to keep it from tangling in someone walking around the lathe.


hth


al
 
ta6PPC,

I see where you're cutting clear down to 20", doubt that'll fit thru the headstock...... In your case I'd chuck the action and use a steady. I can't imagine any sort of problem as long as you dial in the crowned end.

Unlike Dennis I feel that it's vitally important to dial in the GROOVES of the muzzle to be perfectly concentric to centerline and square to the axis of the bore. When using a plug or pin for dialing in the bore I'll always watch my beginning cut closely to ensure that it bottoms on the grooves evenly as the cut starts.

I cut by pulling out from center.

al
 
I was going to cut from inside out that always leaves the best finish...

The head stock on my lathe should allow for a 20" barrel.

What do you guy's say about a 20.5" barrel length for a 223 rem.
If my memory is correct it burns all the powder in 20" so the way I see it, It is a waste to have another 6"
 
ta6ppc said:
What do you guy's say about a 20.5" barrel length for a 223 rem.
If my memory is correct it burns all the powder in 20" so the way I see it, It is a waste to have another 6"
Click to expand...
Depends on what you mean by "burn." As long as the gas pressure is higher than the force of the friction of the bullet against the barrel, you'll pick up velocity. For a .22 long rifle, which uses a powder faster than Bullseye, it takes about 16 inches for that to happen. In a 6mm BR, you'll still pick up about 12 fps per inch around the 30-inch barrel mark.

I rather doubt that a .223 runs out of gas pressure in 20 inches. As a guess & only that, I'd guess you will lose about 125 to 150 fps by cutting of 6 inches of barrel. Depends somewhat on the powder & bullets used. You may prefer the shorter barrel, but likely will lose some velocity.
 
ta6ppc said:
What do you guy's say about a 20.5" barrel length for a 223 rem.
If my memory is correct it burns all the powder in 20" so the way I see it, It is a waste to have another 6"
Click to expand...

Not necessarily. It's a trade off. Most everything in the physical world is.

It is true that increasing barrel length decreases in effectiveness as the total length gets longer. It is also true that if the barrel is made long enough, in the extreme case the bullet will never exit having dissipated all in's energy in friction before it gets to the muzzle.

A shorter barrel is better handling in brush and stiffer for the weight, the compromise is muzzle velocity and energy. Energy decreases with the square of velocity decrease. A bullet at 90% speed only has 81% of the energy. Punching paper, and some other fire missions, it doesn't matter. Other times, it does. As I say, it's a trade off. But the useful length limit for a .223 is a lot longer than 20" depending on what the rifle is to be used for.

With regard to poweder burning, a quick simulation for my favorite 40g varmint load in my .223 shows that it is picking up about 40 fps per inch between 20 and 22" of barrel length and that I'm getting 90% of powder burn (28.0g of AA2460 which is a compressed load well below max pressure) when the bullet leaves the barrel at 22". I use that load because it is with out question the most accurate load for the 40g Nosler BT (my favorite .223 varmint bullet) in my rifle.

Powders that finish burning a lot earlier, like by 16", are quite a bit faster, AA4100 for example, but only fill the case about 72% so may not be as good a choice in terms of accuracy because of combusion variation. The slower powders tend to deliver more MV at the same peak pressure because their sustained burn tends to maintain pressure better as the bullet goes down the barrel.

You pick your pony, you take your ride.

Fitch
 
It has never occurred to me to take an action off to recrown the bbl. I have been indicating the outside of the breech and inside of the muzzle.

Of course, my headstock is short.

I say you should make a spider for the spindle of your lathe.

Or take it to someone who has one, as Butch says.

Ben
 
same as bnhpr

and if it was custom barrel's i do it befor i fit it to the action !

is custom actioned rilfe i take it of as they useally come of easy

i dont like the hand held type but they do work !!!!
 
Opinions on crowns

If the muzzle is set up using Deltronic pins or range rods and two .0001" dial indicators, the action removal would not only not be required, it would be foolish to do so. Additionally, the crown would benefit from being truly concentric and perpendicular to whatever strange and wonderful wandering path the bore is taking at that point. I've been doing them that way for years and consider it superior to just dialing in both ends and crowning. I also use range rods for setting up for muzzle brakes.
 
I was considering doing some recrowning on the new lathe we just installed in our shop ... A Haas TL3B with an 8 1/2" spindle bore. Not only can I leave the barrel in the action I can fit the complete rifle, stock and scope included , down the headstock with room to spare (; ............:D
 
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Well.... I took the rifle ( A brand new remington 700 SPS V ) And put the 4 jaw on and indicated the OD of the barrel and the action assembled the moved the in ID of the Barrel had it running out just under .001"

So I decided to go ahead and part the barrel I cut it off at 21"

so then I crowned it at 11 degrees and took a 60 degree counter sink about .004" deep just to break the edge it looks great and the rifle sheaded what feels like a full pound....

I just wanted to have a shorter rifle and I hope it turns out being a good choice if not here comes a new Shilen and a Blueprinting....

I am going to shoot it in a couple of days.
I will get back to ya'll
 
Dave Manson makes an incredible crowning kit. It ain't cheap but it does an amazing job. Better than lots of inexperienced lathe operators could do. Maybe get together with a few friends and purchase it. Allows you to recrown barrels in the field........$360-$529

http://www.brownells.com/aspx/NS/st...e=PRECISION REAMERS MUZZLE CROWN REFACING KIT

513000092.jpg


Mfr: MANSON PRECISION

No Lathe Way To Cut A Perfect Crown In Minutes & Improve Accuracy


Modified power driver with spring-loaded adapter provides a fast, no lathe way to cut a smooth, concentric muzzle crown on both rifle and handgun barrels for an immediate improvement in accuracy. Expandable pilots provide precise alignment of the facing cutter with the bore. Spring-loaded adapter with neoprene damper absorbs vibration providing a consistent, chatter-free cut. Includes two facing cutters for 0° or 11° crowns, each with precision ground three-blade inserts that quickly and easily remove the toughest material and provide a perfectly square barrel crown. Outside chamfer cutter deburrs the sharp edges for a clean, even finish. Kits include 0° facing cutter, 11° facing cutter, outside chamfer cutter, and two or five pilots depending on kit, plus a 1/8" pilot wrench, 5/64" allen wrench, setup gauge, power driver or manual handle, adapter, instructions, and storage case. Manual version includes a manual handle and adapter for slow even cuts and precise indexing of muzzle brakes. Power version includes a modified power driver for a professional looking crown in less time. Spring-loaded adapter with neoprene damper absorbs vibration, providing a consistent, chatter-free cut. Uses four AA batteries, included. 2-Pilot Kit contains .22 and .30 caliber pilots. 5-Pilot Kit contains .22, .30, 6mm, 7mm, and .338 caliber pilots. Power driver with adapter and neoprene damper also available separately.

SPECS: Facing Cutters - Steel, carbide inserts. Chamfer Cutter – Steel. 1.25” (32mm) diameter. Pilots - Steel, 8¾” (22.2cm) overall length. Kits include power driver or manual handle, 0° facing cutter,11° facing cutter, outside chamfer cutter, (2 or 5) pilots, 1⁄8" pilot wrench, 5⁄64" allen wrench, setup gauge, power driver, adapter, instructions, and storage case. 2-Pilot Kit - .22 and .30 caliber pilots. 5-Pilot Kit - .22, .30, 6mm, 7mm, and .338 caliber pilots.
 
I shot it today I was pretty happy with the results
I lost 90 fps I took nearly 6" off of it and my groups avg 1/2 to 3/4
so I am now going to develop the load the base line I used was 26.5 gr n135 with the sierria 1410 52 gr smk bt lapua brass with fed gmm 205 primer
avg vel was 3390 with a 10 fps spread
 
A comment about powder burning. No matter the powder you use in a .223 it will be long since burned before you get to the minimum legal length (16"). There will still be residual gas pressure at lengths far beyond what is practical to pack around in the field. Long barrels are usually relegated to long range target shooters.

Most AR-15s have 16" barrels. I think 14.5" is better but that will get you in trouble with ATF unless you are LE. The only problem with short barrels is that the muzzle blast is increased significantly. All other factors being equal, a shorter barrel is more accurate than a longer one.

Enjoy your now more portable rifle.
 
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