Muzzle Crown

[goodconcretecolor]

I am thinking of recrowning the muzzle on my 30-06. I cannot get boattail bullets to shoot well and I have been told that the muzzle crown is often responsible for this. It has been suggested by another member of my rifle club that for less than the cost of a gunsmith's services  I could buy the tools to do it myself. Any thoughts onthis? Ease or difficulty. Risk vs. benefit, Pointers

[wncchester]

You don't mention the accuracy you are getting with flat based bullets.  If they shoot ok the boattails should too and you just need further load development.  Is it the crown?

Before playing with the crown, hold it under sunlight and take a good look at it with a magnifying glass.  Push a small wad of cotton ball or balled toilet paper inside the muzzle and push it down about a quarter inch so it will reflect the light back toward the muzzle for easy viewing.  Then carefully observe the full circumfrence of the bore, looking for any "ding" AND rifling wear.

If you find a ding, recutting the crown will likely help.  If the ding is very small you can do it yourself IF you a careful worker and understand things mechanical.

If the rifling is worn unevenly at any point you will need to have that portion of the barrel cut off and then recrowned by a 'smith. 

Muzzle dings come from accidental bumps.  Worn rifling comes from cleaning through the muzzle, from cleaning rod wear, so clean rifle bores from the breech and even then use a rod guide in the chamber.

[gwindrider1]

Excellent advise wncchester!

[goodconcretecolor]

I get 0.5-0.75 inch at 100 yards(3 shots) very consistantly with Hornady 150 gr spt(flat base) and 56 gr IMR 4350. with a Lee factory crimp( the crimp cut the group size in half). With Hornady SST, 2 inch groups, similar results with Nosler Balistic tips. I am trying IMR 4064 and H414. Any further suggestions. I only cripm ed the SST since it has a cannelure. Seating out further with no crimp was even worse.

[flintlock]

Not trying to be smart...But, if you are getting those kind of groups....Leave it alone!!!

[beemanbeme]

Some rifles just don't like certain bullets.  I accept that as truth without getting too excited about it.  I have two target rifles, both .223.  One likes 52gr Sierra HPBT's and the other prefers the 53gr Sierra HP (flat based).  Go figure.  I just feed each one it's preferred diet and don't worry about it. 
The comment about more load development is a good one.  The fact that a charge of xxx will drive xxx bullet into a little-bitty group doesn't mean the same charge will drive all bullets into the same tiny group.  Changing bullet brands can sometimes cause as dramatic a change in point of impact and group size as changing powders.
What I'm trying to say is, if you're getting .5 groups with a flat based bullet, I'd buy a whole bunch of them in case they stop making 'em for some reason. 

[Redhawk1]

If your getting that kind of accuracy with your current bullets, why change?

[kyote]

It was not mentioned,so I thought I might add something to this post.How clean is your barrel?some times a good cleaning will help a whole bunch.If you understand good cleaning.If you are shooting 1/2 and 3/4 in groups consistently.I believe you can tighten em up a little more.the powders you are using work for me and my o6.If not allready there,I would work my way up to max.that is where the accuracy comes in for me.and try a box of sierras 168gr bt match hollow points.no crimp on them.and seat em about 30k off the lands.
and for the question can I recrown my barrel.if you have a good understanding of mechanical skills and a very smooth hand yea,might happen.all a good gun smith has to do is take yer barrel off chuck her up in his lathe cut a 11 degree inverted crown polish well make sure he has left no bur/burr's.does not even have to reblue the cut.and you will have helped in the accuracy depart pretty good.
taken her to a gun smith might even be cheaper then buying the hand tools to recrown it your self.good luck.

[Zachary]

If your getting that kind of accuracy with your current bullets, why change?

I totally agree.

Zachary

[Slamfire]

Boat tails don't demonstrate a great deal of superiority, over flat bases, until the velocity drops below the speed of sound. Stickin' with the good load won't cost you a thing. 

[wncchester]

Yeah, I have a suggestion: don't touch a thing!   Shoot those good flat based bullets and forget boat tails!   

Man, I wish my -06 shot as well as yours.  Of course. it might if I tried enough bullets to find something better but I'm getting 1.25" with Remington bulk 150 SPCL pills and that's good enough for me in the deer woods.  They impact within .75 inch from point of aim and they do work good when they hit.  You're getting half that!

As Beeman says, some rifles just don't like some bullets and there is no way to change that.

Jim <><

[goodconcretecolor]

I just got back from the range with the SST's over 51.5 gr 4064. 1.0-1 1/8" groups 2970 fps.This is 200fps faster than the flat base load. Guess I'll leave the crown alone. One other thing, my rifle shots better with a dirty barrel. A half dozen shots brings the accuracy back after a thorough cleaning. I would surmise that the bore is a little rough and the fouling smooths it out. Would i benefit from fire lapping?

[R.W.Dale]

I just got back from the range with the SST's over 51.5 gr 4064. 1.0-1 1/8" groups 2970 fps.This is 200fps faster than the flat base load. Guess I'll leave the crown alone. One other thing, my rifle shots better with a dirty barrel. A half dozen shots brings the accuracy back after a thorough cleaning. I would surmise that the bore is a little rough and the fouling smooths it out. Would i benefit from fire lapping?

 I have yet to see a rifle that shoots better through a clean barrel than a somewhat fouled one.


 Firelapping?  I'm gonna be frank, You seem bound and determined to ruin the otherwize fine accuracy your rifle exibits.

[jvs]

It is my understanding that the 30-06 was designed to shoot 165 gr bullets.  If you shoot 165 gr boattails, you should be doing what the designers hoped for.

Having said that, you did not state what the twist is in your barrel.  Knowing the twist can tell you approximately what weight bullet you shoud be firing.  Oddly enough, my 06 doesnt really like 165 gr boattails, it likes 150 gr hunting loads alot better.  Most boattails do not have a good performance  after the hit.

Even the component parts of the ball will affect accuracy.  Not all bullets are created equal, and accuracy pays.  What you have so far is just about all anyone can hope for out of a modern mass produced rifle.  You can tinker if you want, but I doubt it will get tighter.

[dave375hh]

As Beemanbeme stated some rifles just don't like boatail bullets. I had a .222 that shot flat bases into .5 to .6 all day. Every boatial I thied with it went 1.25 to 1.5.

From the sounds of it your rifle is shooting fine as is, leave it alone!

As to the question about recrowning it can be done by hand easily. I use a 12 flute 45 deg piloted cutter from Brownells. then smooth it up with a 45 deg. brass lap with 550 grit compund in a slow drill.  I've found factory barrels with lopsided crowns and poorly finished ones. Again I don't feel this is your problem(I recrowned that .222 and it still wouldn't shoot BTs).

[goodconcretecolor]

Muzzle crowning and lapping were only last resorts. I know each risks a ruined barrel. I was simply wanting a load with better long range potential. I was after a high BC bullet. The highest BC flat base bullet I found was the Remington Bronze Point. My rifle did not like them at all. I wote to hornady to ask if they could produce a plastic tipped bullet with a flat base as the bulk of the high bc of balistic tips and sst's comes from the ogive and tip(or meplat) of the bullet. The boattail only adds about 5% or less to the BC.

[beemanbeme]

Geeez, do you have some sort of death wish for your rifle? 

[goodconcretecolor]

Hey Guys,
Thanks for warning me off of recrowning or lapping. Some further load development has produced the results i was after. A fellow on the reloading board suggested recrowning.

[jro45]

Its not the crown that causes B.T.s not to fly streight. It how deep your chamber is. I can't shoot them in some of my rifles either. No loss flat base are just as good and they have high BCs also.