6mm BR Rem using 6mm BR Lapua brass

[Harnic]

When I built my 6mm BR last winter I used my 20+ year old Clymer 6mm BR Remington reamer. I was unable to find any Reminton brass here in Canada, but Lapua brass was easily obtained. I bought the deluxe set of 6mm BR dies by Redding & started shooting. My action is a Ruger #1 so with no bolt to cam the cartridges into the chamber, shoving them in with my thumb takes considerable force, even when the full length size die is used. Will Redding's small base die solve my problem, or am I back to square one looking for Remington brass again?

 

[FryeGuy]

if it is the old remington 6br, you will need to trim the cases to the correct length. there is a description of your problem in the sierra loading manual. it states that remington "standardized" the cartridge in 1989, and the new case has a neck length 0.040" [1.106mm] longer than the original case. the new standardized length is 1.560" [39.624mm]. I had the same problem a couple of years ago when i bought a custom 6br, i just trimmed and fired away.

 

[Harnic]

Wow! Quick response! Ty Fryeguy. I checked the length issue after chambering with a cast, no clearance problems there. My cases are binding because they're too fat! When I chamber a loaded case then extract it without firing, you can see the scuff marks from the shoulder all the way to the base.

 

[FryeGuy]

then the body die, or a small base die is your answer. i think the body die will size down all the way to the min. specs, so that should do it. i had a 6brx, that after a few firings it was tight, a full length die wouldn't get the job done, but the body die would. if you have a lathe, you can also take your full length die and trim some off the bottom of die so that you can bump shoulder a little bit. ,i will get some reactions on that one) i did that once for a 243ackley, and bumped shoulder just a touch and it chamber much easier that way.

 

[Harnic]

Good tip on the die Fryeguy. I did the same by taking a spare shell holder & trimming .015" off the top of it with a carbide tool bit on my lathe. All I got was lots of lube dimples in the shoulders on most of the brass... It made no difference to the diameter of the cartridge. I ordered Redding's small base die this morning, I was just looking for confirmation I'm heading in the right direction! Thanks.

 

[Harnic]

Everyone seemed to be out of stock on Redding's 6mmBR small base die so I butchered my 6mm CHeetah sizer die by cutting about 1/3 inch off the bottom in my lathe. I chamfered & polished the new opening to eliminate shaving brass & ran a well-lubed, fired case into the die. It works perfectly! Now the brass chambers very nicely. I will anneal all the necks after I size the brass in my new body die & carry on with my load development. Now that the cases fit the chamber gauge I made from a piece of old 6mm barrel using the same reamer I used on my new rifle, I can get an exact measurement for seating depth which has been near impossible with the tight case fit up until now. Thanks for all the great info this site has provided!

 

[mwood]

Yes,
You can bump the sholders by modifying the bottom of a full lenght die,as I did). but it may be cheaper to simply have someone kiss the top of a shell holder a few thousanths.
The risk of doing it that way is that, if you take too much off the shell holder, it may break when backing out the brass.
That is why I shaved my body die by about 10 thou, then you can adjust sholder bump using shim stock and the press lock nut, or buy a set of Redding shell holders that have varying thickness in increments of two,2) thou.

 

[Harnic]

Michael, headspace is not the issue with my chamber, it's diameter. The reamer I used is at least 20 years old & was made by Clymer to Remington specs. Sizing the body of my Lapua brass to Remington specs has solved the chambering problem & the loaded rounds now fit the chamber well. I doubt I will need to do it again with this batch of brass, but will save the altered CHeetah sizer die for any new batches I purchase in the future.

Thanks for your input.

Harry