Question on 6BRAI Necks

[FTRinTexas]

Changing one of F-Class .284 to the 6BRAI. After fire forming the 6mmbr brass, do you need to turn the necks? Using a reamer with .270 neck. Thanks

 

[Ackman]

Changing one of F-Class .284 to the 6BRAI. After fire forming the 6mmbr brass, do you need to turn the necks? Using a reamer with .270 neck. Thanks

Gold box 6BR is .269 loaded. Don't know about blue box..

 

[tmwinds]

Measure a loaded round and turn for the clearance you want if necessary. I have a .271 neck and unturned blue box gives me a .269 loaded round. I lightly skimmed the necks just to clean them up and now have about .0025 clearance.

 

[Falfan2017]

You will probably need to turn some if you’re using a .270 reamer. .272 should be a no turn.

 

[Tim-o-thy]

You will probably need to turn some if you’re using a .270 reamer. .272 should be a no turn.

Mine is a 272 neck and if you’re using blue box I’d recommend skimming them. You could try the new alpha brass. I can’t speak about longevity (they have this new ocd case head or something) but I’ve never had more consistent brass out of the box as I did with my 6gt. I’m pleased as punch with those cases. My first 300 break in loads on virgin brass had single digit sd’s

 

[R.Morehouse]

I suggest turning the necks......

Regards
Rick

 

[JFrank]

I turned necks prior to FF with a 30 degree cutter

 

[johara1]

Measure your bullet you plan to use plus the case necks and add it up then load a dummy round and mic. it.... If you are around a .001 clearance I would skim them to get .002 -3 clearance. ... jim

 

[dgeesaman]

Mine is a 272 neck and if you’re using blue box I’d recommend skimming them. You could try the new alpha brass. I can’t speak about longevity (they have this new ocd case head or something) but I’ve never had more consistent brass out of the box as I did with my 6gt. I’m pleased as punch with those cases. My first 300 break in loads on virgin brass had single digit sd’s

I just got my first box of Alpha 6BRA. Neck thickness ranges from .0118 to .0124 for the pieces I checked.

The good news is the Alpha should clean up fully with a light skim to .0115.

David

 

[Tim-o-thy]

I just got my first box of Alpha 6BRA. Neck thickness ranges from .0118 to .0124 for the pieces I checked.

The good news is the Alpha should clean up fully with a light skim to .0115.

David

I think I can get one more barrel out this brass I have, then I might switch to alpha for the next one after. I don’t have my book in front of me but that seems much thinner than Lapua. Am I right about that?

 

[dgeesaman]

I think I can get one more barrel out this brass I have, then I might switch to alpha for the next one after. I don’t have my book in front of me but that seems much thinner than Lapua. Am I right about that?

Measuring the same way (ball end tubing mic, touching about 3/16 deep in the neck), my blue box Lapua 6BR brass is .012 to .013 thick. My Peterson 6BR brass is .0125 to .0135.

That said, the thickness will also vary from case mouth to shoulder. The Peterson is definitely thinner at the mouth. I vaguely recall the cleanup on Lapua to be more uniform but still some variance. Point being, your final loaded diameter must still be checked since the bullet and seating depth play a role in final chamber neck clearance.

Really these appear to be three very good options for 6BRA. I’m going to run the Alpha only in a sporter rifle that’s getting rebarreled in 6BRA since the markings will help ensure I dont mix up my loads.

David

 

[Tim-o-thy]

Measuring the same way (ball end tubing mic, touching about 3/16 deep in the neck), my blue box Lapua 6BR brass is .012 to .013 thick. My Peterson 6BR brass is .0125 to .0135.

That said, the thickness will also vary from case mouth to shoulder. The Peterson is definitely thinner at the mouth. I vaguely recall the cleanup on Lapua to be more uniform but still some variance. Point being, your final loaded diameter must still be checked since the bullet and seating depth play a role in final chamber neck clearance.

Really these appear to be three very good options for 6BRA. I’m going to run the Alpha only in a sporter rifle that’s getting rebarreled in 6BRA since the markings will help ensure I dont mix up my loads.

David

Yeah that head stamp is smart. My wife shoots straight br and I have a bra, it adds to sorting time for sure. I usually just shoot the gt on husband/wife range days to simplify things. She only goes every third trip or so, so that’s good. I switched her from a 6 creed after she ate a barrel in less than 1000 rounds. She doesn’t care to understand cooling or loading ammo. She just likes to lay prone and walk rounds out as far she can. I just now got to stop drawing her a reticle picture to explain wind lol. I do love that she goes with me though.

 

[dgeesaman]

Yeah that head stamp is smart. My wife shoots straight br and I have a bra, it adds to sorting time for sure. I usually just shoot the gt on husband/wife range days to simplify things. She only goes every third trip or so, so that’s good. I switched her from a 6 creed after she ate a barrel in less than 1000 rounds. She doesn’t care to understand cooling or loading ammo. She just likes to lay prone and walk rounds out as far she can. I just now got to stop drawing her a reticle picture to explain wind lol. I do love that she goes with me though.

Sounds like you should carry a small whiteboard with the reticle drawn in permanent marker. Could be handy for other reasons.

 

[Tim-o-thy]

Sounds like you should carry a small whiteboard with the reticle drawn in permanent marker. Could be handy for other reasons.

I bought her a coletac little white board on a bungee that hooks around her scope I’ should have printed an actual picture of her reticle and tape it to her stock. But I think she’s got it now

 

[johara1]

The first thing is to measure the bullet you plan to use, If you use Berger 6mm bullet you can find they vary a lot from what found was .2429 to .244, measure to the .0001 and turn for it to give you .002-3 clearance on a loaded round. Do one first and check it if you need to adjust do it once...... jim

 

[DJSBRS]

Most reloaders do not have the correct equipment and methodology to consistently measure brass to .0001. That is one tenth of one thousand. If they had the correct tooling, they still must be able to hold each piece of brass exactly the same way on every measurement taken. That in its self is challenging for the experienced machinist.

Trying to find and measure the pressure ring, then measure the neck wall variance consistency for variances lower than a half thousand can be very cumbersome.

To keep it simple, measure a loaded round and then subtract from your chamber maximum diameter. I recommend .003 neck clearance and the bullet should drop inside a fired round.

DJ
DJ's Brass Service
205-461-4680

 

[johara1]

Almost every mic. has tenths as well as a tubing mic...... jim