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6mm BRA
- Thread starter cjherrman
- Start date
Yep, with better actions, rifles, & brass you can’t always read overpressure by typical brass markings or bolt lift. You can probably go over SAAMI specified max without seeing physicals signs. What constitutes safe May not be the same for all. I personally would rather not go over SAAMI max as I have found with good wind calls 100 fps doesn’t really matter that much.
Accurateshooter has a big thread with load data on the 6BRA. So if no one chimes in here, I would have a gander at the thread going over there.
Just keep in mind that BR shooters like to run on the high side of pressure, and their rifles don't get exposed to adverse conditions and gets dirty and wet like ours. So I would recommend working up a load that's more conservative then what you will find over there.
Has anyone played with 90grain ELDX with Varget? I am running 103's right now at @ 2900 with 30.6 of Varget. I would like to push the pretty hard this is out of a 20'' coyote rig. I will do load devlopment, just seeing what others have had before I order 90S
I'm betting you could get 2800 easy with the 112s and ~30gr varget. MBs have shot really well for me out of an XC and x47 in the past. I have about 1200 on the shelf. I wouldn't mind seeing anyone's data on them either.
112 Match Burner, MHSA 6BRA barrel, 24"
Lapua brass, 2.456" COAL
RL-16: 28gn, 2398 fps - 30.1gn, 2562fps
8208XBR: 25.5gn, 2449fps - 28.2gn, 2717fps
I had room to add a little more RL-16 in the case, but figured it was too slow to make it worthwhile even with an extra 2gn.
8208 pressured out and I didn't want to go higher - I actually shot it around 26.6gn and it groups fantastic, just unacceptably slow.
ca. Aug '21, so no extreme cold temps to skew velocity.
I think the 112 is a better bullet than the 105, but it's just too heavy for the little BRA case. It might get there in a dasher, but IME it's best suited to the CM/XC sized cases.
Lapua brass, 2.456" COAL
RL-16: 28gn, 2398 fps - 30.1gn, 2562fps
8208XBR: 25.5gn, 2449fps - 28.2gn, 2717fps
I had room to add a little more RL-16 in the case, but figured it was too slow to make it worthwhile even with an extra 2gn.
8208 pressured out and I didn't want to go higher - I actually shot it around 26.6gn and it groups fantastic, just unacceptably slow.
ca. Aug '21, so no extreme cold temps to skew velocity.
I think the 112 is a better bullet than the 105, but it's just too heavy for the little BRA case. It might get there in a dasher, but IME it's best suited to the CM/XC sized cases.
Well that sucks... they've been awesome in my 6 creed, was hoping to go BRA when the barrel is toast but I may have to look at the 6GT
I can’t help with any matchburner data, but I think you will be happy with a 6 bra or 6 GT. I’m shooting both & they are both awesome. On my 6 bra I gave up on Alpha brass and am fireforming Lapua in a barrel that Alex Wheeler chambered for me. It’s the most precise rifle I ever shot except a 6 GT I put together from Impact Precision with Wade Stuteville chambering. Bought everything through them using advice from Tate Streater & Khianna. Though, on the 6 GT I wasn’t fireforming. I don’t know how my 6 bra is going to be more accurate after fireforming. It’s just one solid hole on a 10 shot string. I’ll post a pic if I can find it. Doesn’t look that great, but it’s off just a bipod without a rear bag.
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BRA, it’s just a fireforming load for a BRA Alex Wheeler chambered for me. No load development. I had given up on another bra barrel reamed with an alpha reamer & using alpha bra brass. I still have 100 more pieces of Lapua BR to fireform before starting load development. I had heard people shot matches while fire forming, but it was hard to believe. This is my 1st time to fire form. I do have a 6 GT that shoots as well.
No, I’ve stayed with 450s because of the thicker cup. I don’t have a small firing pin. I have REM 7-1/2s & BR4s which also have the stronger cup, but I’m shooting 1 hole groups so leaving it alone.
I’m getting a 6bra 7.5 twist barrel spun up from PVA as we speak. From what I’m reading 30 grains of varget should be a good fire forming load with 105 class bullets? I’ll be using Peterson brass.
I bought a few jugs to try in my 6 GT, but looks like it should do good with the 6 BRA. I’ll be testing soon & will post results afterward.
Good point, though a friend of mine is getting a BRA done and is thinking about buying Lapua 6 BR ammo. At a little over $2.60 per round vs $1 per case + $.25ish per primer + $.60ish per projectile + $.20ish for powder, you're at more than $2.00 and you're spending the time to do up forming rounds.
The good news with fireforming BRA is that it's stupid simple to FF, and accurate as heck.
First firing is really accurate 6BR, second firing is slightly faster BRA.
Nothing to lose.
I plaid the bra game with alpha brass and it was frustrating trying to find a reamer(used lapua and alpha spec) with alpha brass. I tried 3 different sizing dies, and I had bolt thrust, lift, ejector marks all with 105-108gr bullets at 2850-2830 from two a 28" 237 bore 7.5tw HH barrels. I sold all my bra shit away, recut them to 170fb 6gt, shooting 115 dtacs at 2850. I think my issues would disappeared running lapua brass, but I'd already invested 1k pcs alpha. Running these short walled cases with low taper and sharp angles def requies chamber/brass relationship to be correct for it all to jive well, especially with the hard ass alpha ocd case head.
Seems like a lot of people on accurateshooter report issues with Alpha brass and 6BRA.
It's an easy and forgiving cartridge with Lapua brass.
I've never had any issues with my Alpha brass. I guess my smith just got it right with his reamer choice. He's been shooting the same reamer specs with Peterson and 105s and it's been great for him too. Sucks to hear it didn't work out well for some here. New components for a different cartridge aren't cheap, especially if you're doing 1k brass pieces at once. Yikes.
I’m on my 10th reload, two barrels, Alpha brass, Whidden dies and JGS BRA #1 .272 reamer- still shooting in the low 2s.
I don’t understand the problem.
(The attachment is from load development, from 29.5 - 31.5 gr Varget in .03 steps - so every 5th shot. Second barrel just stayed with 31, shoots just as well. About a grain less for 4895)
I don’t understand the problem.
(The attachment is from load development, from 29.5 - 31.5 gr Varget in .03 steps - so every 5th shot. Second barrel just stayed with 31, shoots just as well. About a grain less for 4895)
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Here's a thread on accurate shooter in regards to early pressure issues with Alpha brass:
Out of curiosity, who chambered your barrel? That sounds similar to a situation a friend of mine had with a bad 7 SAUM chamber from proof. He was getting all kinds of pressure signs at 2700 fps and 180 hybrids. After taking it to a Smith, the chamber ended up being off centered/tilted it something.
It's not my chamber(s) my smith send me indicating videos of all my barrels and they're always perfect. 3 different barrels, same results. It's the alpha ocd brass I believe. I've left the bra game, but if I had to do it all over again, I'd run a Forster bushing bump die that doesnt size the case walls for the first 3-4 firings then prob run a Harrels D1 die. I tried a Wilson 6bra and Harrels D3 die as this is what all the lapua guys recommend. I feel the problem was, my fired brass was only 469 and sized was 4675, the Chamber is 471, so the brass wasn't expanding enough to grip the chamber walls.
I honestly prefer the GT anyways as I can easily run 115s at 2850+, and be a long ways away from pressure, and I've not had any feeding problems like I did with the bra. The tiny bit of recoil added by 2-3gr of powder isn't tangible in my observations.
Does your Smith not take into consideration what brass you'll be using? Mine always asks so he can get the chamber right, especially with regards to neck thickness. He's got several reamers for each of the 6mms just to account for brass choices.
He cut my last two 6bra barrels with Alphas reamers. His other two 6bra reamers are for Lapua brass, being larger at 0.200 line.
Want to avoid all this bs? Start with lapua brass lol.
I also use the aforementioned gunsmith. He’s top notch, experienced, educated, & most important of all takes pride in his work.
if you're just going to 6gt and still warm loads don't expect any significant barrel life increase.
I made the switch to GT a few months ago and love it, I'm not chasing speed just consistency.
112 match burners will go well beyond 2900 but I've settled in at 2850
Put my new 6bra barrel on and I’m having some issues. First I loaded up some Hornady 108’s just to throw down the barrel and clean per the gunsmiths direction. After that was done I loaded up 5 Berger 105 hybrids. All of those rounds with 30 grains of varget, Peterson brass, rem 7 1/2 primers. They all had heavy bolt lift with ejector marks. Hornady shot like dog shit, bergers showed promise. So I went home and loaded up 10 with 29 grains of varget, 5 with 29.5 grains. All show ejector marks still, groups not great. 1 group had potential but opened up on last shot. 30gr varget with Hornady 108’s were 2780fps, 30 grains varget with 105 bergers were 2800 fps, 29.5 grains Berger 105was 2730 and 29 grains varget Berger 105 was 2690. Why am I getting pressure signs? Chamber is clean, primers look ok, speed isn’t through the roof. So my questions are:
Should I put more rounds down the barrel before I hope for better accuracy?
Ejector mark im seeing normal during fire forming?
Should I be doing something different?
I was just hoping for something to shoot under a half minute while fire forming and go shoot a few matches but results arent great thus far.
There is a total of 40 rounds down the barrel
Should I put more rounds down the barrel before I hope for better accuracy?
Ejector mark im seeing normal during fire forming?
Should I be doing something different?
I was just hoping for something to shoot under a half minute while fire forming and go shoot a few matches but results arent great thus far.
There is a total of 40 rounds down the barrel
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Im assuming this is virgin Peterson BR brass? Speeds and primers lead me to believe this isn't true pressure signs. Im thinking there is too much headspace and brass is coming back and slamming your bolt face. I had this with one of my BRA barrels and come to find out that HS was too long and it wasn't supporting the brass when fire forming. I ended up jamming bullets and it went away until all my brass was fire formed. Easy way to check would be to strip the bolt and try to chamber a piece of brass. The BRA chamber should actually crush fit BR brass to hold it when fire forming. If your bolt drops free on a virgin piece of brass this is most likely your issue.
Are the projectiles seated into the lands, or are you jumping them?
Is there resistance when you close the bolt on your ammo prior to firing?
Who chambered your barrel? Is it a tight neck chamber? Did the gunsmith chamber it up to have 4 thou of crush on the first firing?
Yes virgin Peterson 6br brass. I’ll strip the bolt and report back.
Edit: I stripped the bolt and the bolt doesn’t fall when chambering a virgin piece of brass, it’s a crush fit.
Sorry I ment to mention that, jumping .020”. I stripped the bolt and the brass is a crush fit for virgin brass. Not sure on specs other than freebore is .104” I believe.
Yep, it slides all the way in with little to no resistance.
