Issues with “finding the lands” / 6 BR / possible throat issue

[AlNyhus]

That's how I have done it for 30 years. I can't hardly convince anyone to do it... I have no idea why. works better than anything I have tried. Fast too.

I used to do it that way. The problem with a slit neck is that the neck tension decrease (from slitting) can give you a false reading as the bullet can stay 'in' the lands a bit before moving out when the case is extracted. Throat angle, number of lands and how concentric the chamber is relative to the lands can all influence this.

With the 'sized case/stripped bolt/steel wool' method, none of those factors will effect your measurement. You can check it and check it and the numbers will always be the same. It's also a great method to see just how concentric the chambering is to the rifling. If the bullet marks aren't even and identical on the bullet....it doesn't take too long to connect those dots.

The Stoney Point (Hornady) tool also works good if you've got a case that fits the chamber well. For falling block style actions it's what I use along with a modified case.

My 2 cents worth on it on a snowy morning.....

Good shootin' -Al

 

[urbanrifleman]

I used to do it that way. The problem with a slit neck is that the neck tension decrease (from slitting) can give you a false reading as the bullet can stay 'in' the lands a bit before moving out when the case is extracted. Throat angle, number of lands and how concentric the chamber is relative to the lands can all influence this.

With the 'sized case/stripped bolt/steel wool' method, none of those factors will effect your measurement. You can check it and check it and the numbers will always be the same. It's also a great method to see just how concentric the chambering is to the rifling. If the bullet marks aren't even and identical on the bullet....it doesn't take too long to connect those dots.

The Stoney Point (Hornady) tool also works good if you've got a case that fits the chamber well. For falling block style actions it's what I use along with a modified case.

My 2 cents worth on it on a snowy morning.....

Good shootin' -Al

If I do it three times and hit the same number I'm done.

Use a bit of sizing wax on the ogive and pinch the neck tighter.

 

[AlNyhus]

If I do it three times and hit the same number I'm done.

Use a bit of sizing wax on the ogive and pinch the neck tighter.

I might have tried that years ago....

Good shootin' -Al

 

[markT]

Barrel has been shipped back to Shilen for inspection. Looking forward to their findings.

 

[foxguy]

Curious minds ...

Do you recall what the twist rate is of this barrel?
Did you purchase this barrel already chambered by Shilen.

 

[markT]

1:8 twist
Shilen chambered it in 6 Norma / large shank Savage

 

[foxguy]

Thanks-
I would suspect that it should have .100 free bore being a 1:8 twist.

 

[JFrank]

1:8 twist
Shilen chambered it in 6 Norma / large shank Savage

I’ve seen this play out previously with Shilen, guys could not get any speed and the free bore was a mistory and no reamer print available. Not sure what’s up with that but hopefully you can get some answers.

 

[Dave M.]

It is a new barrel never fired. Set with Go gauge. Scotch tape on head and bolt will not close. I worked with a dummy round and it seems like the throat is really tight. I'm new at doing this.. But compared to my other 6 BR's the bullet is now is very deep in the neck.... I ran a brush down the bore and ran some Boretech cleaner thru.. It seems like the machining is maybe too tight. Maybe call Shilen and see what they say. I just dont know..

What is the chamber neck? Measure the neck diameter of a loaded round. Let us know what you find.

Dave

 

[moajoe]

I have a Savage 12F that I rebarreled from a 6.5/284 to a 6 Dasher. I pulled the firing pin assembly from the bolt and removed the ejector pin/spring and ejector plunger. Now there is very little resistance in closing the bolt. As others said before... Seat a bullet long in a uncharged/unprimed case. Slowly bring the bolt handle down until you feel resistance. Seat and .005 deeper and try again. Eventually the bolt handle will close without any resistance or maybe a bit as the bolt handle bottoms out.

 

[markT]

Shilen technician called me today.. He did a chamber cast and the throat measured .2432". He said .2435" was the "norm." He said "they no longer use that reamer."
He is going to work on this and ship the barrel back.
They have very prompt, professional and nice... Very good experience so far.. In fact excellent..

 

[Dave Zander]

If the barrel is off look up finding the lands by Mark Gordon.
By far the most accurate way I've ever used. Barrel has to be removed from receiver .

 

[markT]

Title edited: might be a little more explanatory

 

[FNSafari]

If you were into the lands there would be a mark for each land, being as that is all the way around is there a carbon ring in the throat?

Who made your reamer? I once had a new reamer that was out of spec and would not cut a .3085 diameter throat it was less and put a nice bright ring around the bullet when it hit the constriction. The reamer was replaced. I sold it without opening the box.

 

[JEFFPPC]

Well here is a novel approach....using the Search Function.......you can read on this topic until your eyes cross.

 

[Will Henry]

Looked like a burr at the front of the chamber neck to me. Either that or the throat is not compatible with the bullet diameter. I have run into this with some Sierra bullets which were .0007" over nominal diameter. WH

 

[markT]

Shilen called late yesterday afternoon. Barrel is being shipped back to me. I believe they opened up the throat to .2435”. It Was .2432”.
This is a Savage BBL. I have no idea who makes the reamer(s) for Shilen...

 

[markT]

Barrel came back from Shilen.. I got it put on my Savage PTA... Shot it late today with my old load and not sure what is going on. I am ordering a Rifle Basix SAV 2 tomorrow.. Load is 30.5 gr Varget / 87 gr Vmax/ CCI 450's.. Much more work to do.

 

[Shooter13]

Lookes like the bullet is stuck in the lands and you are pulling it out of the case before you are pushing it all back with the rod. Just an uneducated guess.

 

[markT]

New Rifle Basix trigger installed. 31.8 gr Varget and barrel throws the 87’s fairly well.