Question for Dasher or 6BRA shooters: What is your preferred loaded round neck to chamber neck clearance?

[BoydAllen]

I am primarily looking for input from those who compete at long range, in benchrest matches, but anyone is welcome to chime in.

 

[avidflyer]

I am primarily looking for input from those who compete at long range, in benchrest matches, but anyone is welcome to chime in.

I had accuracy issues with 2k….

 

[BoydAllen]

I had accuracy issues with 2k

So what is your preferred loaded round to chamber neck clearance?

 

[avidflyer]

So what is your preferred loaded round to chamber neck clearance?

4k fixed it, but I think 3 would do the trick.

 

[JLT]

I shoot F Open, not BR, but I run .003" in my Dasher. Works pretty well.

 

[LRPV]

3-4

 

[17VLD]

.0025” for me but I’m still learning.Lots of 4 shot groups under or at an inch at 600 yards that 5th shot gets me.Finally got a screamer at an IBS match which I feel proves the load and that it’s enough clearance.I just need to be smoother and faster and see better

 

[Northridge]

.003-.004 does a lot of work

Shawn Williams

 

[wasskeet]

I'm probably the oddball here at .007" in a no-turn neck Dasher (.275"). It is capable of better than I am at 1000 yd IBS.

 

[DJSBRS]

I recommend .003 for 6mm or less. Also recommend .004 for .257 and up. Really helps with long bullets with flyers.

DJ
DJ's Brass Service

 

[Pres100]

Is the chamber neck dimension from the reamer print or actually measured?

If measured, is that from a fired case? cerosafe cast of the chamber or other method? I would assume an actual measurement, but I rarely ever hear anyone discuss the process.

Mostly hear people talk about the "neck tension" when resizing and/or seating.

 

[LRPV]

I have a set of minus pin gauges in .001”. On each new barrel, I pin them to see which one fits until they don’t anymore and consider that the size of the chamber neck. I check the pin with a mic to make sure it is in fact what it says. I measure a loaded round with the bullets I intend to shoot with a mic and subtract the numbers. I like to have .003” on 6mm stuff and more on 7mm/30. I err on the side of too big.

On another note, has anyone realized that all 6mm bullets don’t actually measure .243”? I see a lot of times people assume that’s just a standard as well as using calipers for these types of measurements which calipers are not adequate in my opinion.

 

[Alex Wheeler]

Most of the time, chamber necks will be bigger than the print and tapered even if not speced like that. Unless the reamer is very worn. I recommend .003" which in reality is more than that. I have run tighter but all you get with tighter is problems. Tested up to .005" in a dasher with no change in accuracy. Clearance is clearance, in my opinion the rifle has no idea if theres .003" or .005", but it does know when its not enough. A lot of records, most Id say are right around .003" ish.

 

[Bugs]

Ok folks, when you say .003, that means .0015 on a side, correct ?

 

[JLT]

Ok folks, when you say .003, that means .0015 on a side, correct ?

That's what I meant . . .

 

[JEFFPPC]

6 brx .262 neck. .002 total clearance for lots of barrels, for a long time. Never had a reason to change.

 

[wildcatter]

I believe in the theory cut thin to win. I ran .002 to .0025 for a long time, I now cut .003 to .004 and seem to see fewer WTF's. Yes that's total.

Just for referance my beard hair is .003" so that is like half a hair on each side, still quite tight.

 

[Chaotik]

6 Dasher- 0.002-0.0025"

 

[Bill Norris]

I believe in the theory cut thin to win. I ran .002 to .0025 for a long time, I now cut .003 to .004 and seem to see fewer WTF's. Yes that's total.

Just for referance my beard hair is .003" so that is like half a hair on each side, still quite tight.

I like at least .003 total clearance with my turned brass.

 

[J.D.Erwin]

I have .003 in my dasher and .004 in my 6bra