I read a post a few weeks back about using a brass screw in a drill to smooth up the crown. How do you pick the screw size and what shape head? What cutting/lubricating fluid should you use? Any help would be appreciated.

If you just want to smooth it up a little, use a spitzer bullet that is a caliber larger and chuck it in a drill. Coat the contact area of the bullet with a very fine valve grinding compound and proceed slowly.

I used a small round dremmel grinding ball in a variable speed drill with a drop or two of light oil on the crown. I wanted to use something round figuring I had the least chance of making it lopsided. I used a low speed and just touched it up - a few seconds at most. The improvement in group size was immediate.

To touch up a crown I use a method like Kenjs.

Link

Thanks for the info. Sounds like the bullet method would be less 'intrusive' for a beginner. Although, I do have a dremel with plenty 'o tips... I think I feel an 'OH Schitt' coming on! Gotta love power tools.

Since your removing a little blueing, should you touch it up or will the gun oil, carbon, etc take care of it?

I would not use the Dremel motor at all. Its way too fast.

Use a battery powered variable speed drill with that Dremel stone in it or another tool or a bullet.

Do it like I wrote in the link. Your only breaking the corner on the crown. Do a little and shoot it. Then do it again deeper if it needs it.

I've done it on a couple of rifles and it worked fine improving groups sizes. I used a slotted brass screw about 1/2 again larger than the bore with extra fine grinding compound. I plugged the bore about 1" back with tissue to keep the stuff from dribbling down the bore. The brass screw was chucked in a drill.

The only tip to remember is to rotate the drill in a circular motion over the bore instead of holding it still kinda like stirring a spoon motion. This will help keep the work centered.

.

Brownells sell a cool little kit with different sized brass tools for a power drill..

Here are two crowns I broke the corners on and now they shoot very well. I am pretty sure the one on the left is a .277".

The Dremel tool I showed does not cut smaller bores well as it goes in too deep for a good looking cut. Otherwise it works.

I used the brass screw in a drill with some 600grit compound and touched up the crown on my Kimber, huge difference and now all is good.

You guys all sound confident using hand held drills and dremels turning screw heads and backward bullets into a rifle crown, but it makes me cringe. I cannot see how anyone can place an even crown on a barrel, regardless the degree, w/out using precision equipment.

GVA

It does not seem to matter. The rifles group. Then just sight them in.

Well...I see this as a last ditch effort at trying to turn a avg shooting rifle into a better shooting rifle, not match grade, as someone posted elsewhere, I have no misconceptions about possible improvements. If it doesn't work and or does damage...SO WHAT! It's a turd anyway and will hold up a tomato plant come next spring! Thanks for the input guys.

All you are doing is removing a very small amount off the edge of the rifling at the end of the bbl, giving it a new crown.

I was scepical, but have ahd good results a couple of times doing it.

.

The cool thing about using a sphere shaped cutter/stone is that you cannot cut the crown crooked.

I use a carbide cutter called a burr. Most of the time I use it in a brace. A few turns with light pressure and oil will do it. A small pc of oil coated 600 Wet and dry sandpaper shaped to conform to the sphere polishes up the finish. It has brought accuracy in many rifles.

There are actual mandrels out there for this, and are not expensive at all.

I bought all 3 sizes from Brownells, and have helped many a factory rifle shoot to its ability.

I even got a carbon buildup in a Hart barrel, that took many passes with JB to get it out.

I washed out the crown in the process but was able to bring it back with the mandrel, and it shot better than before.

http://www.midwayusa.com/eproductpage.exe/showproduct?saleitemid=718110&t=11082005

Azshooter - that seconds what I was saying. Round at any angle seemed like insurance for, well, staying round. No knock on the other methods as I'm sure they work. I was sceptical but mine was already jacked up anyway by someone I paid to do it! It was a mess soooo PLAN A - find a REAL smith, Plan B -If I tried and botched it - refer to Plan A. I was all smiles when I saw that hack job turn into a nice perfect ring on the crown. I remember thinking after just a few quick touches "Hey that 'looooks' better right????? Thought so - so what the heck. So I stopped. I have to admit that I was dang pretty bow-chested next time at the range. It shot so much better. I was grinning thinking.."yeah, I did that!" Stupid little thing like that really gave me a boost.

If it were me,I'd never mess with my rifle crown,I'd have my gunsmith do it.If you mess it up,barrel won't shoot worth a crap,if you go to far might have to cut off barrel.

Critter, you should not be going that deep at all using any of the above methods. When I did mine the crown just looked bad, no major angle problems, just a bunch of chatter marks. I could not measure the amount of material removed but it was pretty small.

As far as I know, there's isn't a 'good' gunsmith within many many hours of my house. If there are, I haven't heard about them. (So no offense if your good and live close, if so..pm me.)There are plenty of jack leg wanna be's around, so I'm pretty leary. One guy was claiming all sort of stuff, 20 yrs here, 10 yrs there, yada yada...I went to his shop and looked at a few of his 'customs'. Well...I'll just that a retarded monkey with a screwdriver and a ballpeen couldn't have done any worse, hell...I couldn't have done any worse. Surplus mauser actions with A&B barrels in the ugliest stocks on the planet. Imagine a Savage crossed with a Mosin Nagant...pretty close. And they were a steal at $700.00 ea.

I touched up a dinged 30 caliber crown with a bullet and a fine emory paper, it worked OK and gave a better group. If you dinged your crown pretty bad any relief with any tool as long as you don't make it worse will work from my experience.

I can't see anything wrong with trying one of the home "bubba" methods for touching up a crown of poor shooter. Me I would start with a bullet/compound and then maybe the brass screw/compund...if that didn't work I might even try the stone. With a little care, the worse that can happen is you have to have gunsmith recrown in a lathe.

I would try the home method, not because I can't pay the $30 for a smith.. but because to drive 90 minutes.. then drive back 1-3 weeks later for a 10 minutes fix is a PITA

So, if you have a rifle shooting 1" groups at 100 yds, would any of you touch up the crown on it?
Selmer

Consistant 1" groups? Id leave it be..put it in the safe and move on to the next project.

What about non-consistent 1" groups?

Any problems with a crown will be consistent. My rifle cited above was 4" down to sub 1" at 100.

I would love to see an update from 7mmManiac

So yous guys are recommending this for rifle that are shooting patterns, not groups, right? I mean really, if a hunting rifle will honestly put 5 shots into 1 1/2" at 100 yds or 4" at 300 yds consistently, there's no need to mess with it. I've never experienced a rifle with a bad crown, maybe I need to buy more rifles.
Selmer

Interesting how this old thread popped up. I was going to comment as I read along and discovered I had ALREADY posted!!

Selmer, There is no need to guess if the crown needs dressing. I have a rear eye piece from an old rifle scope. When inverted it is one heck of a magnifier. If you do not have such a piece get a jeweler's loop or a strong magnifying glass. Inspect the crown in bright light and look for a tiny imperfection, nick or an area that is shaped differently. If it isn't uniform around the entire circumference it needs attention.

When a known rifle goes sour I always look at the crown. Many times it is the cause of the larger groups.

The gunsmith that showed me how to do this used a lead sphere of about .5" diameter with a brass screw run through it. He called it "ball cutting". The procedure was to chuck the ball's screw in a drill press, then swing the press table out of the way and bring the muzzle up to the slowly spinning ball (charged with lapping compound). Then move the rifle in a cone shaped pattern while letting the ball do its thing.

I tried it on an uncles Savage M99 that one of my cousins had been cleaning from the muzzle and egged out the crown. Recutting brought groups from 4" to 5" to about 1".

jim

Midway USA has a how-to video clip of executing the ol' brass screw procedure on YouTube. It turns up pretty quickly when you search with the likely key words.

Crown video

All I can say is that touching up a crown isn't brain surgery, especially if you use a soft enough cutting tool such as brass or lead. With these you are just taking the little nicks off a crown, not recutting it.

I have recrowned dozens of barrels with a Brownells hand tool, and generally in the end use a leather washer (homemade) faced with a piece of fine emery cloth, both on the face of the Brownells tool. This does the same thing as the various brass/lead techniques described here. It doesn't affect the angle of the crown at all. Instead it just does the final polishing.

Well, this is the first I've ever heard of doing something like this. So, I just used the "bullet in the drill backwards" technique, using the appropriate caliber, boat-tail bullet for each of my rifles. I have a variable speed drill, and went nice and slow. I did the 7Mag, 25-06, the .308, and the .22-250. I didn't use, or have for that matter, any lapping compound. Just the backwards bullet. We'll see if that helped at all.

After using this technique on my 4 rifles, as stated above, I went out and shot them all today. The 25-06 was shooting <1" 3-shot groups with every load I fed it (including some necked down, non-neck turned, 30-06 brass loads that were shooting patterns, not groups before this) The 100gr TSX load was shooting 3-shot groups of 0.8"
The 7mmRM has a featherweight barrel on it, and the 140gr TTSX load shot the first 2 shots into 0.4", and the 3rd with a hot barrel opened the group up to 1.2". Oh yeah, I also pulled that 3rd shot a little

The .308 and .22-250 showed improvements as well, but the improvements were minor, maybe 0.1-0.2" tighter with a 3-shot group.

All groups were fired at 100 yards.

Good to hear you got that Tikka squared away. I did not want to demoralize you with my .270 groups, they went from 1.5" to 1" at 200 with the runout cleared up.

That's awesome shooting!

Thanks for the support and all the advise that helped me get the Tikka sorted out! I'm going to shoot it some more this evening, I'll let you know how it turns out

Here's a picture or two of a target I shot this evening with the Tikka. I used Federal fusion factory ammo. The first 2 shots went into literally the same hole, and the 3rd was about 0.75" from the center of the first hole. The second pic is of the same gun shooting my 100gr Sierra PH load. It measures 0.7"
The 3rd pic is of my Win 88 .308 that I couldn't get to shoot into better than 2" at 100 yards. Today I free floated the barrel after touching up the crown yesterday. This is the target showing the results after two sighter shots, and then a 5 shot group.

Oh BTW, before I get flamed for it, I'm a broke student who's getting married in a couple days, so I have to re-tape and re-use my targets as much as possible.

Or you can go hi tech like this, chunk of red duct tape on a target backer

Very nice video, concise and to the point.

http://targetz.com/targets01.htm

Glad you got your Tikka figured out Jordan! Congrats on the marriage and I feel you pain as a broke student, taping and reusing targets, especially when trying to figure out what's wrong with a rifle, is just fine.
Selmer

Thanks Selmer,
I appreciate the support. Really, I do. I'm kind of nervous these days. I'm broke, getting married, and a full-time student, but luckily I have stock piled enough ammo for hunting season.

BTW, I think that the Tikka really just needed about 75 rounds through it before it decided to settle down and shoot. I'm sure switching the scope and polishing the crown helped, but in the end, I believe it just needed some break-in in order to show what it can really do!