Can I cut and crown a fluted barrel?

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elrotundamundo

New member
I have a Mossberg 4X4 in .270 Win. with a 24" barrel. For some reason Mossberg saw fit to equip it with a muzzle brake which adds another 2 1/2 inches. The screw on cap that replaces the muzzle brake opens the groups up from 3/4" to 2" so I put the brake back on. Besides being loud, and unnecessary on a .270, the brake makes the rifle a pain in the thick woods I hunt in here in North Idaho.

I would like to have the barrel cut to 22" but it is fluted right up to within 3/4" of the threads on the end. Can a barrel be cut and crowned in the fluted area?
 
Yes. Though the ends of the flutes will need the sharp edges broken, but the bore can be crowned easy enough. It can be done in a lathe easily. The pressure is not a great amount at the muzzle, like it is at the chamber, when fired.

Edit: I forgot to add, that I can't guarantee what this might do to barrel whip and resonance. You run that risk any time a barrel is shortened. Sometimes, it can even cure resonance, and the groups get better, but they could get worse, or stay the same.
 
Maybe all it needs is a new/better 'screw cap' thread protector. It seems that's what's opening up your groups. The stock one, could be damaged or faulty.
 
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I cant tell you as a scientist or engineer.Seat of the pants mechanic opinion,aside from aesthetics,the flutes make no difference vs a non fluted barrel as far as shortening it.



If I was doing it in a lathe,I'd just chamfer it to clean to the bottom of the flutes,so the chamfer would be full diameter,and scallop back at the flutes.

Bores can have tight and loose spots.A tight spot at the muzzle is better than a loose spot at the muzzle.

If you want 22,cut it at 23,or so,see how it shoots.I would not go too short on a 270.It needs a little powder burning room.
 
I'd see if a Browning "Boss" is compatible with the threads.

They make a "brake" that isn't really a brake in that is has no holes, but with the addition of a thin lock nut it can be adjusted in or out to find the "sweet spot" of accuracy for different loads

It sounds like what you have is changing the harmonics in a bad way, and a screw on muzzle weight can fix that sometimes cheaper than cutting and crowning, which still might not help at all
 
As far as the cap goes, I rather doubt that just screwing on the cap will affect accuracy. I suspect the hole in the cap is not on center and is affecting the exit of the bullet.

Jim
 
I rather doubt that just screwing on the cap will affect accuracy
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It's probably not so much putting on the cap as it is taking off the weight of the brake, and changing the overall harmonics

I suspect the hole in the cap is not on center and is affecting the exit of the bullet.
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It's a threaded knurled cylinder with inside dimensions equal to the OD of the threads

There is nothing in front of the bore

Another solution would be to cut the brake itself just behind the first holes
 
Thanks, all

I appreciate all the thoughts. I think I will have it cut to 22" and then work up a load for best accuracy. When I bought the rifle four years ago, I lived in Southeast Idaho and mostly hunted mule deer and pronghorn and needed a good long range rifle. Since moving up to the Panhandle, I have killed a cow elk at 50 yards and a whitetail at 70, so maybe I am needlessly concerned with sub MOA groups. Shorter rifles are easier to carry through the brush.
 
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