Benchrest

[Nick 53]

Hi all,

following a  recent purchase of a 6br Savage action with Louther 1-8 28” barrel in a Bell and Carson stock. This rifle is to be used for Benchrest and Fclass shooting.

using a micrometer myself and Steve measured a loaded 6br case neck and was 270 thou. Now we measured a fired case around the neck it was 270 thou. The louther barrel says Non Standard Barrel!

giving how the bullet will chamber and once fired the brass isn’t flowing back . 

What is the clearance of the loaded round into the rifling ?

what reamer was used ?

i want to use T66 Bushing with a Match Grade Die, but if we have a little clearance I need to know before ordering a T66 bushing.

is there anyway I can find the relevant information?

Thanks Nick 

 

[Ronin]

Non standard marked on barrels after going to proof means the chamber does not conform to CIP (European) Spec - likely the rifle smith who produced the gun used a SAAMI (US) spec reamer 

If the barrel does not have a neck size marked near "Non standard spec" such as .268" NK 04 .270" NK (for example) it is likley your chamber is standard and  not tight neck.

Im sorry I do not know what a T66 bushing is, but if your chamber produces fired brass with a .270" Neck diameter it is likley to be that diameter - (what do loaded non turned neck rounds measure at the neck?)

E.G. - A base line measurement would be .243 (bullet diameter) + .014 + .014 (standard brass neck wall thickness) = .271"

Measure your loaded round diameter

If there are no markings to suggest a fitted neck (ie a number stamped with NK beside it) then its likley to be standard

However if standard the fired brass against loaded brass diemeters are very close and little allowance for expansion / bullet release.

Perhaps try neck turning the brass - .001" of the current neck wall thickness wich would give a little more room - you should really have .0015" to give .003" all round clearance (Max) 

 

Without measuring the chamber with a low temp casting metal / plug guage its hard to accurately say what the neck diameter is.

 

Hope this helps

 

 

[The Gun Pimp]

Nick - just trust Steve.  He has plenty of experience in this area.  As Ronin says the neck will be standard - otherwise the neck diameter would be engraved on by the Goof House. 

It's just a 6BR - don't over-complicate it.  Trouble with forums - everyone has an opinion.

 

[Nick 53]

Yes.

I am in good hands with Steve.

Brian has solved part of the question.

Thanks Vince