Deep Recessed Muzzle Crown

[Edd]

Is there a reason a barrel couldn't have the crown recessed an inch?

 

[J E Custom]

Is there a reason a barrel couldn't have the crown recessed an inch?

That's a good question Edd. and this is what I think, and my experiences have shone.

After trying many different barrel crowns My experience has been that you don't any of the gasses
to impinge on the barrel that may/might reflect back and strike the bullet once it leaves the barrel.

I have observed many crowns that leave a carbon trace radiating out from the rifling groves and
found that the 11 degree crown has the least trace on it. It has also been my most consistent and accurate crown.

With that said, I would think any recessed crown of that magnitude of set back could possibly
effect accuracy.

This is also the reason that muzzle brake seem to work best with .020 to .025 thousandths clearance
over bullet size.

It is mostly theory. But it seems to be consistent if applied.

So once the bullet leaves the control of the barrel you don't want anything acting on the bullet
that could cause it to yaw or pitch.

Just an opinion

J E CUSTOM

 

[FearNoWind]

... So once the bullet leaves the control of the barrel you don't want anything acting on the bullet
that could cause it to yaw or pitch.

J E CUSTOM

^^^^^^^^^^^^^^^^^

If you want to recess the crown, do in at the starting end of a good muzzle brake.

 

[Hired Gun]

I don't think the gasses will hit the bullet. The bullet is gone before much gas escapes at all. It will redirect the supersonic pressure wave inward and down range for the depth of the recess. It should make a little less pressure/noise for the shooter just as if the barrel was longer.

 

[Bart B]

In spite of gasses leaving 3 to 5 times faster than bullets, foot long tubes with 3/4"inside diameters past the muzzles of rimfire and centerfire match rifles cause no accuracy problems.

Google 'bloop tube' and see the different types.

Gas will bounce off bloop tubes, flash hiders, muzzle brakes and supressors onto bullets. As long as it is repeatable from shot to shot, good accuracy happens.

 

[J E Custom]

Is there a reason a barrel couldn't have the crown recessed an inch?

One question.
Why would you want to recess the crown that much? Just curious.

I have seen the "Bloop Tubes on match rifles, and they are primarily use for lengthening the sight radius also they are normally 11/4" to 11/2" in inside diameter and Most barrels are 1'' or less at the muzzle so in order to recess the crown to maximum diameter it would be much smaller that existing "Bloop Tubes".

The other thing that worries me about using something like a Bloop tube on a Long range rifle, Is the difference in the powder charge and the amount of gasses produced. I will be the first to admit
that I don't know what the effect would be and would not be comfortable using one until I had proff that they improved accuracy. The use of sight extensions is not new and in fact they are quite common on small bore rifles and pistols to increase the site radius with iron sites but before the Bloop Tube they were normally just a rail that extended the front sight.

The other thing is, we (Long Shooters) don't normally use iron and already have longer barrels for big caliber bullets to Get High velocity.

Again: this is just a discussion and hopefully I can learn from some of the other guys that can explain the benefits, if any.

Thanks again for your post Edd.

J E CUSTOM

 

[Edd]

One question.
Why would you want to recess the crown that much? Just curious.
J E CUSTOM

This is a question I've been meaning to ask ever since I read the article about threading the muzzle causing the barrel bore to change sizes.

My thought was, why cut off an inch of the barrel and throw it away then thread and deform the bore. Why not counterbore and thread that inch or whatever length you needed.

 

[Bart B]

All the bloop tubes I've seen on smallbore and centerfire rifles have 3/4" to 1" inside diameters. Up to a foot long at times. They're used so the shooter can focus his aiming eye precisely on the front sight and still see the bullseye reasonably well to center it in the front aperture, not to improve how precise the rifle can be aimed. Centering the front sight in the view seen through the rear aperture puts in the middle regardless of how far away it is. The hand-held aimed rifle's line of sight has random angular wiggling the same amount regardless of the sight radius

The most popular long range matches in the world require iron/metallic sights; Palma ones. NRA Any Rifle Metallic Sight match rifles don't have scopes. Hunting rifles for longer ranges rarely have anything but a scope.

I doubt threading a muzzle will deform the bore enough to matter. High power match rifles typically have their muzzles turned down to 3/4" or 7/8" and a band clamped on with a front sight base on it. That clamp squeezes the metal down and reduces the bore/groove diameters a few to several millionths of an inch. Garands cleaned from their muzzles with bare steel rods rubbing the lands and grooves wear the bore/groove dimensions .001" to .002" over new diameters after cleaning every 50 or so rounds. No accuracy degradation from that wear for the first 3000 rounds which is their normal best accuracy life. There's no copper wash from bullet jackets the last 3/4" of the bore on lands or in grooves.

 

[westcliffe01]

Don't use a die set for threading the barrel. Use a single point cutter the way any good thread is cut.

I am willing to believe that the multiple cutting faces of a die which makes a single pass could distort the bore, especially on larger caliber barrels where the wall thickness is not that great in the thread location.

My rem 700 Classic in 8x57 was a good example. An 8mm bore (0.323") and the OD of the brake was 5/8". The thread diameter was less than 0.5"

 

[J E Custom]

This is a question I've been meaning to ask ever since I read the article about threading the muzzle causing the barrel bore to change sizes.

My thought was, why cut off an inch of the barrel and throw it away then thread and deform the bore. Why not counterbore and thread that inch or whatever length you needed.

If a barrel is properly stress relieved and the thread size of the brake is as large as it can be based on barrel size, there should be no barrel diameter change if threaded correctly (Single pointed on a Lathe)

It is also important that the thread fit be very, very good and not over tightened.

A poorly installed brake can cause all kinds of problems, But one properly installed will not effect accuracy and in many cases, it can improve accuracy.

If the barrel is already threaded for a brake and you want to change brakes, it is not uncommon
for the smith to remove the old threads (To assure it is threaded correctly) and cut new threads
to get the best fit and also cut a new crown to insure a good job.

Sometimes I cant believe the horrible brake installations I see and there effects on accuracy.
This is one of those things that seems easy for anyone to do and is often done by people that are not qualified or have the right equipment and skills and the outcome is normally not good.

So in My opinion, A properly installed brake does not distort the muzzle of a barrel, so the need for counter boring the muzzle is not necessary. After reading all the talk about altering the bore size by installing a brake I started checking the bore with reamer bushings (They are normally In .00001 increments)and found no sign of this problem occurring when a brake is properly sized and installed.

A clamp on brake has a higher probability of altering bore diameter if tightened excessively than a screwed on brake that is installed properly.

Now I under your question Edd, and the reason, but it should not be necessary if all things are done right.

Just My Opinion

J E CUSTOM

 

[EddieHarren]

".00001" Really?

 

[J E Custom]

".00001" Really?

Sorry, Typo. One to many zeros.

.0001

J E CUSTOM

 

[EddieHarren]

J.E. you are forgiven. Had me worried there for a second. Eddie

 

[KEB0]

Could you try this in various amounts and get back to us?? Now I'm curious...