Gunsmithing Question on 11 degree target crown (amateur)...

[Wannashootit]

Just did this 11 degree target crown.
My question: is there an "optimal" surface area which should remain flat crowned? I left just a small ring for protection, should the 11 degree section be smaller with a larger flat crown?

 

[x ring accuracy]

Re: Question on 11 degree target crown (amateur)...

The most important spot is where the projectile exists the bore. To make the 11 degree smaller or larger is a point of contention with many benchrest guys.

 

[former naval person]

Re: Question on 11 degree target crown (amateur)...

As X-Ring says. The 11 degree is supposed to be the angle at which the gases exit from the bore, thereby causing less interference with the bullet base...the professionals I have spoken with, say that the exit point is important...not the angles nor curves. JMHO

 

[Wannashootit]

Re: Question on 11 degree target crown (amateur)...

Thanks, guys.
I'll see how it shoots this weekend...

 

[wnroscoe]

Re: Question on 11 degree target crown (amateur)...

Your fine as is. The most important point is what the bullet touchs last upon exit. I'm using a 15 degree more and more as of late, if for no other reason, I seem to like it better

 

[LRI]

Re: Question on 11 degree target crown (amateur)...

Off topic yet related.

Often overlooked is how sharp/crisp the crown is. I personally believe it should be a razor sharp transition. Crisp/sharp angles on a valve/seat flow better. Seems to me it'd help here too.

Maybe/maybe not.

C.

 

[JJones75]

Re: Question on 11 degree target crown (amateur)...

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: C. Dixon</div><div class="ubbcode-body">Off topic yet related.

Often overlooked is how sharp/crisp the crown is. I personally believe it should be a razor sharp transition. Crisp/sharp angles on a valve/seat flow better. Seems to me it'd help here too.

Maybe/maybe not.

C. </div></div>

So touching up the crown with a countersink and a hand drill isint a good idea??

couldent help it i actualy saw a guy do that at the range once

 

[CS223]

Re: Question on 11 degree target crown (amateur)...

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: C. Dixon</div><div class="ubbcode-body">Off topic yet related.

Often overlooked is how sharp/crisp the crown is. I personally believe it should be a razor sharp transition. Crisp/sharp angles on a valve/seat flow better. Seems to me it'd help here too.

Maybe/maybe not.

C. </div></div>

Clay Spencer is of the same school of thought, transition is so sharp on his barrels you'd swear there was a burr.

 

[SONIC SAAMI]

Re: Question on 11 degree target crown (amateur)...

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: C. Dixon</div><div class="ubbcode-body">Off topic yet related.

Often overlooked is how sharp/crisp the crown is. I personally believe it should be a razor sharp transition. Crisp/sharp angles on a valve/seat flow better. Seems to me it'd help here too.

Maybe/maybe not.

C. </div></div>

Chads crowns are as sharp, razor sharp. I have a cut on my finger that will prove this.

 

[JFComfort]

Re: Question on 11 degree target crown (amateur)...

Once we cut a crown you can cut yourself on it like DaveD did, after test firing the rifle we also look for that nice symmetrical star pattern.

 

[Wannashootit]

Re: Question on 11 degree target crown (amateur)...

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: C. Dixon</div><div class="ubbcode-body">Off topic yet related.

Often overlooked is how sharp/crisp the crown is. I personally believe it should be a razor sharp transition. Crisp/sharp angles on a valve/seat flow better. Seems to me it'd help here too.

Maybe/maybe not.

C. </div></div>

Thanks...
I was about to take a brass pilot and 600 grit lapping compound to break the edge of the rifling. It passes the "q-tip" test, so I'll leave it as-is and see how she shoots...

 

[LRI]

Re: Question on 11 degree target crown (amateur)...

If you decide to leave it this way, be sure to pay close attention when running a jag.

Brushes are pretty harmless to crowns, but going bezerk with a jag can result in hammering an edge on the crown. We used to remove the jag completely, but anymore I just walk to the front of the gun and push it back till its inside the bore. Just don't go yanking on it and ding an edge.

Good luck! Cut well the crown should leave a nice, symmetrical "star burst" pattern on the face.

 

[Wannashootit]

Re: Question on 11 degree target crown (amateur)...

That's crazy looking...looks like rams horns to me...like cloud gazing...wow, man...

Seriously, those patterns are the residue from the powder? Never seen anything like that.

 

[LRI]

Re: Question on 11 degree target crown (amateur)...

Here's one with a true 11* tgt:

This is off my 6mm BR 300M Free Rifle.