Chambers

[daltoncasady]

First off I just wanted say as a new member here, PRS/NRL shooter, and this being only the third threaded started in the PRS/NRL/LR section, I think it's awesome that Jerry and the others have made space for the PRS/NRL community here on Rimfire Accuracy! Personally I think it's awesome to have a forum of the benchrest community where they squeeze every bit of precision out of a rimfire rifle and have several years of experience/knowledge doing it, can hopefully teach and share some that information with the newer PRS/NRL rimfire community.

So with that said, I wanted to start a topic where hopefully BR builders like Mr. Stiller himself and PRS/NRL builders like David of DI Precision can chime in together for guys that want a better understanding of chambering/setup of rimfire rifles. It seems (to me personally as least anyway) most manufacturers and gunsmiths that are rebarreling/cutting prefits and are catering to the PRS/NRL community got their start in the market building those products for the centerfire side of the sport. With that said it seems most of them simply carry over the same care and methods they've used for chambering centerfire barrels to their rimfire counterparts. That maybe ok (not meaning to drag anyone through the mud), but when I have visited with rimfire shooters and gunsmiths or read topics on rimfire benchrest centered forums such as this one, there seems to be more variables or details that need to be considered. Often when I bring this up to my fellow competitors it seems they just want to sweep those rimfire specific variables/details under the rug with "do you really think that matters" or "thats the black magic of rimfire" not really taking the time to understand how those variables/details work. Personally for myself and a few of the other shooters in my circle we have started reaching out to gunsmiths with a good reputation for building rimfire benchrest rifles to have our rifles rebarreled, and for the most part have a better understanding of the mechanics of a rimfire rifle, as well as better performance from them in doing so.

So finally the nutshell of my long winded post, what variables or details should go into chambering a precision rimfire rifle, and how do they interact with the ammo and rifle components so the shooter can better plan their build, maintain, and troubleshoot for their rifle?

Does barrel length matter in relation to the bore after slugging or other method of gauging it?

What's the ideal headspace for the given ammo they may plan to use?

What's the effects of a shorter .030 bullet engagement or something deeper that goes well into the drive bands?

Does leade angle matter in relation to which brand of ammo is used?

What's the effects of cleaning only the chamber/carbon ring versus the whole bore?

Is there any difference chambering a single shot versus a repeater?

What is considered "broken in or seasoned" and roughly number of rounds to do so?

Any other details that may not pertain to centerfire, but make a difference in rimfire, or do they really?

Thanks again!

 

[MS Guy]

I’m not a gunsmith so most of the questions you’re asking I’ll leave to those that are much more knowledgeable.

As far as breaking in a new barrel my personal experience has been between 500-1K rounds. A good barrel will shoot good from the get go, but will improve after break-in, a bad barrel may or may not improve.

A big difference between. CF and RF is ammo. With CF the reloader can adjust the load to the rifle, of course RF shooters can’t do that so we’re forced to test different brands and lots in search of the ammo that shoots best in your gun.

 

[tim simbari]

You ‘re essentially asking for the complete history of building a great RF match rifle,
I’d guess, few if any are typing pages upon pages of replies.
Primarily here, take liberal advantage of extensive search function and you will get hours of reading.

 

[Rick Clark]

I pretty much asked this same question on this site a few weeks ago.
Got the same response from the same person. Good luck with your enquiry.

 

[Hozzie]

Not specific to chambers, but if you haven’t read this, it’s a good place to start.

What does it take to really get to the top??

I have had more than a few guys ask me "What does it take to get to the top??". I'm not sure why they are asking me, but I decided to put up my opinion on what it takes and what I have done to TRY and get there. Someday maybe I can get a little better and pull of a big win on a consistent...

www.rimfireaccuracy.com

 

[VLNBYR]

Read this book "The Art of Rimfire Accuracy"

 

[David Lott]

I pretty much asked this same question on this site a few weeks ago.
Got the same response from the same person. Good luck with your enquiry.

First off I just wanted say as a new member here, PRS/NRL shooter, and this being only the third threaded started in the PRS/NRL/LR section, I think it's awesome that Jerry and the others have made space for the PRS/NRL community here on Rimfire Accuracy! Personally I think it's awesome to have a forum of the benchrest community where they squeeze every bit of precision out of a rimfire rifle and have several years of experience/knowledge doing it, can hopefully teach and share some that information with the newer PRS/NRL rimfire community.

So with that said, I wanted to start a topic where hopefully BR builders like Mr. Stiller himself and PRS/NRL builders like David of DI Precision can chime in together for guys that want a better understanding of chambering/setup of rimfire rifles. It seems (to me personally as least anyway) most manufacturers and gunsmiths that are rebarreling/cutting prefits and are catering to the PRS/NRL community got their start in the market building those products for the centerfire side of the sport. With that said it seems most of them simply carry over the same care and methods they've used for chambering centerfire barrels to their rimfire counterparts. That maybe ok (not meaning to drag anyone through the mud), but when I have visited with rimfire shooters and gunsmiths or read topics on rimfire benchrest centered forums such as this one, there seems to be more variables or details that need to be considered. Often when I bring this up to my fellow competitors it seems they just want to sweep those rimfire specific variables/details under the rug with "do you really think that matters" or "thats the black magic of rimfire" not really taking the time to understand how those variables/details work. Personally for myself and a few of the other shooters in my circle we have started reaching out to gunsmiths with a good reputation for building rimfire benchrest rifles to have our rifles rebarreled, and for the most part have a better understanding of the mechanics of a rimfire rifle, as well as better performance from them in doing so.

So finally the nutshell of my long winded post, what variables or details should go into chambering a precision rimfire rifle, and how do they interact with the ammo and rifle components so the shooter can better plan their build, maintain, and troubleshoot for their rifle?

Does barrel length matter in relation to the bore after slugging or other method of gauging it?

What's the ideal headspace for the given ammo they may plan to use?

What's the effects of a shorter .030 bullet engagement or something deeper that goes well into the drive bands?

Does leade angle matter in relation to which brand of ammo is used?

What's the effects of cleaning only the chamber/carbon ring versus the whole bore?

Is there any difference chambering a single shot versus a repeater?

What is considered "broken in or seasoned" and roughly number of rounds to do so?

Any other details that may not pertain to centerfire, but make a difference in rimfire, or do they really?

Thanks again!

Thanks for the mention but let me preface, I am NOT a gunsmith or a machinist( my hope is to one day have half of the knowledge of Jerry Stiller), I am a shooter that knows what I want out of a rimfire. In my limited experience (4 years) of actually trying and learning to chamber a rimfire we have tried all sorts of things, some work some don't . IF you want to get good at this, my suggestion is to do the same thing, TRY different methods and attempts. If you simply do what everyone else does YOU will never know "why" it worked. Words to live by "Experience is what you get when you don't get what you want!!!".


Also a very valuable lesson that I learned along the way is that, how do you know you did something right if you are not capable of shooting what the rifle does?

Again experience is your friend not an opinion no matter who it comes from...


We chamber very differently than most, using a Doosan CNC turning center with live tooling(the reamer turns clock wise while the barrel turns counter clockwise then finish up with some other tools and methods. I was told my many gunsmiths that this method would not produce good results but the rifles shoot pretty well.