case lenth

[RonDye]

Need help.
Building 6 mm br.All diagrams show case lenth of 1.520".Lapua brass comes 1.560".What is correct lenth.
Ron

 

[fdshuster]

RonDye: Suggest you consider the "Sinclair Chamber Length Gauge", page 47 of their 2007-B catalog. Cost is $6.50. Use the gauge to find the actual true length on your chamber, not "one-size-fits-all", as shown in the various loading manuals. Actual chamber lengths are easily .020" to .025" longer than max. case length, so if you trim back without knowing the length of your,emphasize the word "your"), you may be creating an overly short case, like a 22 short in a long rifle chamber. This "gap" in front of the case mouth is also where a ring of carbon will build-up. Works for me, for 15 years now.

 

[FClasser]

Ron:
It depends on which reamer was used to chamber the barrel. If it was the Rem 6BR chamber, the trim length would be 1.520. If, it was the newer 6BR Lapua chamber, the max length would be 1.560 with a trim length of 1.555. All of this info is on this website under 6BR. Much 6BR info is located there.
Tom Nichols

 

[RonDye]

gentlemen,
I needed to give you more info.I'm building a 6 br on XR 100 action.I'm also building a 22 br on 700 Rem. action, using 22- 250 barrel from XR)Will pick up 22 br this Wednesday so forming some cases from 6 br,redding dies).I'm a little confused by diagrams.I measured neck lenth on 22 br reamer,clymer)and came up with .321".Can't measure case lenth on reamer.I'm trying to prep cases for loading and having problems with info from diagrams.One showed 1.560"and another 1.520"as case lenths.These are my first br's.My question--- are both 6 br and 22 br case lenths the same and if so,what lenth.
Thank you for your help. Ron

 

[fdshuster]

RonDye: As a continuation of the previous posting: Get the Sinclair chamber length gauge and stop guessing. Actual chamber lengths will vary, even when cut with the same reamer. Reamers wear and a new/first time reamer will cut a longer chamber length than one that is ready for the scrap barrel. I also re-chambered a 22-250,Shilen 1-12) to 22BR, very happy with the results. Chamber neck dia. is .251", loaded round neck dia., Lapua 6BR brass), is .249"/.2495". I have my 6BR brass,3 rifles) length to within .005" of chamber length. Was able to arrive at that exact length w/ the Sinclair gauge. No, I don't work for Sinclair, just think they are great people to deal with.

 

[RonDye]

Thanks everone,will order gages.This is my first post so please excuse my manners.
I'm 63,old f---)been shooting for over 50yrs,rimfire and centerfire.Live in S.W. Va. My first venture into b. r. calibers.Varmint hunter and informal target shooter. I really appriciate all the help.I love all old guns and accurate new ones. Thanks again. Ron Dye

 

[fdshuster]

RonDye: No apology necessary. Asking questions, with an open mind is the way we all learn. I've been at this "game" since 1960, and am still learning,, born 1938)that's what makes it all so interesting. If I can be of any help, feel free to e-mail: fdshuster@hotmail.com,sw pa)

 

[Preacher]

When you get those gauges, you'll be surprised at how long some of the cases can be
and still not touch.
I use my Hawkeye borescope to find out the same thing, by enlarging the primer hole to take the end of the borescope.

 

[fdshuster]

Preacher: it's interesting to find someone else doing the same thing you are. I've also used my borescope as you described. Really frustrating when you have a really "long" chamber, and the brass you're using does not stretch, ever, so the "gap" of .030" to as much as .040" remains. Guess the "long" chambers are lawyer mandated, as a precaution for those who never measure case's that do stretch. I have several factory chambers that measure .035" longer than max. case length. Before that brass stretches enough to fill the "gap", the neck splits. I'll keep this in mind the next time I order a reamer, and will specify chamber length, just as we do neck dia.