6BR Rem, how to get it correct?

[Dave King]

I recently picked up my latest rifle, a switch barrel rig with two 6BR Rem barrels and one 308 Win barrel. The 6BR Rem chambers are .262 neck and the barrels are one each slow and fast twist (14 and 8).

I haven't messed with any BR stuff so these two 6BR Rem things are new to me.

I have been told by the smith to use 7BR Rem brass, turn necks and them make the 6BR Rem brass that I need. I can see that by turning the necks on the 7BR Rem brass and then running them into the 6BR Rem die I push the neck turning edge up onto the shoulder and then have no donut. I turn the necks (I've been playing) so that I end up with a .260 and .262 diameter with a loaded bullet...I believe I should be about .261 but its a little difficult to control the process to that level for me).

I'm using a 68gr bullet at this time in the 14 twist and plan to use a 107 in the 8 twist.

Questions are:

What should be the neck diameter with a loaded bullet?

What is a good powder to start with for the 68gr bullets (I've tried 3031 and it seems okay, not great but okay)?

What powder for the 107s?

I've noticed that the cases are shorter than the stated "trim to length" (I guess because of the 7BR Rem to 6BR Rem resize) is there anything to consider with this?

Any by-the-way tips for a novice 6BR guy? I'm going to use this as a plinker, F-Class, groundhog, deer and whatever gun.

The rifle is a single shot Rem 40X with the factory wood stock and I'll be shooting it from a bipod in all cases. (I did stick a Badger base and rings on it and a spare Leupold 6.5 x 20 30mm Mark4 Gen2 mildot so I'd feel normal.)

 

[BLASERMAN]

You know there is a web site 6BR .com there you should find all the answers.

 

[Dave King]

Thanks

I've already been there and read a pile of stuff, I'm now looking for additional somewhat specific info.

 

[jb1000br]

Dave -- You ARE allowed to post over there BTW /ubbthreads/images/graemlins/wink.gif

the link is actually http://www.6mmbr.com

First Tip...scrap the rem chamber and punch it out to a 6BR Norma...then use lapua 6BR brass.


.260" loaded round is plenty tight IMO...i like 0.003 total clearance in 1KBR

powder for the 68s = n135, benchmark

107's = varget, RL15, h4895/IMR4895, h4350 will make a nice compressed load too.

THe 6BR Rem chambers are shorter...so dont go by 6BR norma trim-to length.

HTH,
JB

 

[jb1000br]

BTW -- a good neckturning job will hold to +-0.0001"

 

[Dave King]

JB

Thanks

I know I can post there but I have about a zillion places I post and am trying to cut back a bit.

It's good to know about the 3 thousanths clearance, I thought I might be getting the necks too thin for no good reason, I believe I'll stick with the .260.

The fella I spoke with at at Sinclair suggested N140 but I'd seen N135 in several places too, I'll try the N135 first.

I want this as a play and learn gun so I'll probably leave it at the 6BR Rem chambering... plenty of little things to do to make it work and I have a lot of "easy" to use rifles.

I'd seem Varget for the 107's and have plenty of it around and I have some of the others you list too (left over from the pre-Varget days).

I wasn't sure of the trim-to-length for the 6BR Rem. If I recall correctly the Sierra book shows 1.550 (sounds like Norma 1.560 length) but my brass is at 1.520 and the brass I have from the smith's test rounds is 1.520.

On the turning and resize.. I turn the 7BR Rem brass necks to about .008 or so and it thickens on the resize/form to 6mm but the amount seems to vary a bit and I'm trying to eliminate the return once the brass is 6mm.

 

[jb1000br]

FYI -- you can probably find 6BR Rem brass if you post a WTB over there. It has come up several times.

Your varying thickening doesnt sound good to my ears, cause im pondering the same setup but going from 6.5-284->284...might have to move the nk first, then turn it ..in fact I will have to with the above arrangement...

Sorry, i kind of "assumed" varget...was just giving other options...varget is the most popular with heavies.

Jackie Schmidt on BR central has played extensively with 135 and the light bullets in a BR.

1.520 is the rem. number...stick with that.

JB

 

[BountyHunter]

Dave

Jason is correct IF you really have the Rem chamber. Redo them to a .271/.272 no neck turn for Lapua brass.

Look at the Jackie Schmidt testing going on at 6mmbr and think you will find many questions answered. Such as he thinks RL15 is better powder for the BR than say Varget for extreme accuracy.

BH

 

[Dan B]

DAve...I don't have any answers for your 6BR questions...just wanted to piggyback on your neck turning question. I just got a XP-100 .222 Rem Mag (45 degree shoulder) and .248" neck.

From what I'm reading...my turned necks with a loaded bullet should be .245"??

 

[Ballistic64]

Dan B, .245 loaded neck dia. with .248 neck chamber will give you .0015 clearance per side,which is considered a match grade neck clearance.
Just out of curiousity,whats the thickness of your brass.Or what im asking is how much your turning off to get to .245?

 

[milanuk]

107gr SMK's seated 20 thou off the lands over 29.5gr Varget in a Lapua case lit off by a CCI450 works pretty slick in my Savage 10FP w/ a 27" SSS/Douglass barrel w/ a 1-8" twist @ 2700fps. The barrel came as a .272" neck no-turn chamber, but I did turn anyways, just a light cleanup (50-80%) to about 0.0131"... loaded rounds measure just a RCH over .270" at the neck and shoot very, very well out to 500yds (furthest I've shot it so far).

I haven't tried RE-15 yet, though I think I also read some interesting results in one of the gun-of-the-week articles (36? or so) using IMR4895.

Neat little case, any way you slice it.

Monte

 

[Dan B]

I've not turned any yet. The brass is Herter's and I've heard the necks are thin to start. I bought the gun as built and the seller can not find the dies...so he's buying me a new set...so I'm waiting on the dies to size all the parent .222 RM brass then turn, load and ff.

 

[Mysticplayer]

Did some digging in my notes when I was playing with a 6BR. I used Rem brass (7BR brass to be exact) and had no problems at all for LR plinking and such. Clays at 750yds were a no brainer.

I started with some 70gr TNT but these proved irratic in QC from lot to lot. Just fine for PD popping but certainly not a LR match quality bullet.

I used CCI BR4 primers, H322, Rem brass with 2 thou chamber clearance and a 12 thou neck thickness. Was getting 3300fps with these TNT's molied.

I then started LR shooting and found one of the best kept secrets, the 87gr Vmax. These things are accurate and fly superbly. Just adjusted the load amounts and was shooting 1's and clays at said 750yds. Velocity was 3150fps.

Things to watch out for: Do turn again once necked down and fireformed to 6mm. You want to keep those necks as consistent as possible. I just do a light cut and remove up to 75% of circumferance. Don't like under 12thou or over 14thou neck wall thickness.

Anneal your brass. Because of the tight tolerance, you don't need to size the necks. The spring back is enough to hold your bullets again. I just popped out the primers and seated a bullet. This worked great for a while then loads went very irratic. The cause was work hardening of the necks.

Remember that in a BR chamber, that brass is going to be reloaded over 20 times. I would suggest annealing at least every 6 times, more often if you compete.

A bushing or collet neck die is the way to go. I found that 2 thou of neck tension was min with up to 4thou being ok.

As I work through the cannon phase, I am looking back at such nice cartridges as the 6BR. No muss, great accuracy, no recoil/noise, low cost, etc. Maybe a barrel will be cut in the not too distant future.

I hope that you will enjoy the 6BR as much as I did. Just keep an eye on your groups. If you get a flyer, mark that brass and if it throws the shot the next time, get rid of it.

I have done this sorting on all my target rifles. This way I get components that are as close to identical as possible. I find this much more productive then any other type of brass sorting.

Anytime I can shoot in the 1's and 2's at moderate ranges with a LR rig, I am happy.

Jerry

 

[Dave King]

Jerry

Thanks for the excellent info. I noticed that the resized necks (7mm to 6mm) had "ripples" and figured I should turn them again but was reluctant to mess with things too much in the learning phase... I'll trim them again as you suggest/state.