6 BRX loads after fire forming?

[DHuffman]

Fireformed some 6 BRX cases to start testing with. After researching the threads here I settled on putting a .257 false shoulder on the neck then sizing to where they chambered a little tight. Loaded up 30.5g Varget and seated a Nosler CC 107 jammed .025

Cases blew out very well IMO and had 1 FTF that went the second time.

Getting ready to start testing with them and my question is should I jump up to 32 - 34 or should I shoot them another time at an intermediate weight like 31-32

15 shot string fireforming @ 30.5 was 2746 fps sd 5.7 es 18

 

[bozo699]

I would start load testing
Wayne

 

[NV_Dmax]

When I had my BRX built I wasn’t concerned with speed at all. I started at 32 gn Varget. I shot groups at 600 before I shot these groups at 100. I was done load with development after 65 rounds (including 15 for barrel break in). There’s my scorecard from the Berger SW Nationals with the 32.2 load. I still haven’t chrony’d the load yet.
my final load.: Lapua brass (no prep, only fireform in a fireform chamber from the same reamer) 108 Berger, Federal Gold Medal primer, 32.2 gn Varget, jump .025.

 

[DHuffman]

Very nice shooting! I'm not concerned with speed either, I was curious where the ff load was running.

Everything I've read says the 6brx "will" run up to 3100 but a lot of people seem to agree 2950 - 2975 is where it's at.

I'm jumping the gun a little, weather still sucks up here.

 

[comagutsa]

mine in a 30 inch 1:7.5 twist kreiger with 32.4gr and 105gr hybrids and varget was doing 3000fps . was accurate as
I tested loads from 32gr to 33.7gr , was just starting to get pressure signs up top

 

[lee1982]

Everything I've read says the 6brx "will" run up to 3100 but a lot of people seem to agree 2950 - 2975 is where it's at.

2950 or so was the sweet spot for me depending on the powder in 26 and 28 in barrels. Anything much over 3000 gave me ejector swipes with varget and 8208. I moved to the 6x47 this year and I'm getting an extra 150 fps, but inside 1000 I can't tell much difference other than needing a little less elevation.

 

[swd]

Start at 31.5. Not every lot of Varget or every barrel will end up above 33gr without pressure. I've had several BRX's that won't get there, but they are still hammers! Varget, RL15, RL16 , 4895 and 8208 are all worth a try.

 

[DHuffman]

Start at 31.5. Not every lot of Varget or every barrel will end up above 33gr without pressure. I've had several BRX's that won't get there, but they are still hammers! Varget, RL15, RL16 , 4895 and 8208 are all worth a try.

Thanks, this is what I was thinking 31.5 - 33 g Varget to find the mid 2900 node. If I were to try 4895 where would you start and up to what range would you look for the same node?

 

[swd]

Thanks, this is what I was thinking 31.5 - 33 g Varget to find the mid 2900 node. If I were to try 4895 where would you start and up to what range would you look for the same node?

I'd start around 30.5. Look for nodes in the same places but it may or may not get to the upper nodes.

 

[DHuffman]

I'd start around 30.5. Look for nodes in the same places but it may or may not get to the upper nodes.

30.5 is what I fire formed with and was getting 2750

 

[swd]

30.5 is what I fire formed with and was getting 2750

With 4895 or Varget? I've made the mistake of starting too high and been bitten so I start very conservative and work up.

 

[JEFFPPC]

Fireformed some 6 BRX cases to start testing with. After researching the threads here I settled on putting a .257 false shoulder on the neck then sizing to where they chambered a little tight. Loaded up 30.5g Varget and seated a Nosler CC 107 jammed .025

Cases blew out very well IMO and had 1 FTF that went the second time.

Getting ready to start testing with them and my question is should I jump up to 32 - 34 or should I shoot them another time at an intermediate weight like 31-32

15 shot string fireforming @ 30.5 was 2746 fps sd 5.7 es 18

I have been thru 9 barrels in 2 rifles over the last 6 yrs with the BRX shooting 106 gr bullets. Load for 8 barrels has been from 33.4 to 34.0 gr Varget. They were all cut rifle barrels. One button barrel which I shot all last yr,1400 rounds,and will start this yr with, likes 32.6 Varget. BRX has served me well from 100 to 1000yds. Use only CCI BR4 primers. All but the button barrel have been loaded into the rifling, the button barrel is jumped .005.

 

[BAT M 284]

Start at 31.5. Not every lot of Varget or every barrel will end up above 33gr without pressure. I've had several BRX's that won't get there, but they are still hammers! Varget, RL15, RL16 , 4895 and 8208 are all worth a try.

I would be interested in your PET loads for 4895,RL15.for BRX

 

[gme]

Fireformed some 6 BRX cases to start testing with. After researching the threads here I settled on putting a .257 false shoulder on the neck then sizing to where they chambered a little tight. Loaded up 30.5g Varget and seated a Nosler CC 107 jammed .025

Cases blew out very well IMO and had 1 FTF that went the second time.

Getting ready to start testing with them and my question is should I jump up to 32 - 34 or should I shoot them another time at an intermediate weight like 31-32

15 shot string fireforming @ 30.5 was 2746 fps sd 5.7 es 18

All my BRX's seem to like something between 32.5-33.5 of Varget, 108 Berger .008-.020 jump, velocities around 2950-3020

 

[Judd]

Be careful with some of these loads guys...especially if you have a shorter freebore and run the 105/108's. I run a .104 freebore and I can't run the amount of powder most of the guys above me run. My last 3 barrels have all liked 32.6 of Varget...when I've tested with RL15 the new slower stuff prefers 33.1...I've tried to get it to work and it shoots well. It just walks up to much during the day.

 

[swd]

I would be interested in your PET loads for 4895,RL15.for BRX

Both my BRX's are cut with same reamer, .140" free bore. I shoot 107SMK's seated in the lands with 450's. I don't have my 4895 notes any more. I settled on 32.6 of RL15 in that rifle. My main rifle likes 35.4 RL16. Next week my #1 rifle will have a new 1-7.3" twist going on it to try 110's. I'll start with RL16 and go from there.

 

[JEFFPPC]

Be careful with some of these loads guys...especially if you have a shorter freebore and run the 105/108's. I run a .104 freebore and I can't run the amount of powder most of the guys above me run. My last 3 barrels have all liked 32.6 of Varget...when I've tested with RL15 the new slower stuff prefers 33.1...I've tried to get it to work and it shoots well. It just walks up to much during the day.

Judd, I feel your free bore is way too short for 105 class bullets. I suggest having it throated so the base of the bullet you like to use is about half way up the neck to start, then adjust seating depth to what the barrel likes.

 

[urbanrifleman]

Judd, I feel your free bore is way too short for 105 class bullets. I suggest having it throated so the base of the bullet you like to use is about half way up the neck to start, then adjust seating depth to what the barrel likes.

I am curious. What is "way too short"? A long freebore on a Dasher is .125". Are you saying 20 thou is a deal breaker?

 

[DHuffman]

Here

With 4895 or Varget? I've made the mistake of starting too high and been bitten so I start very conservative and work up.

Varget

 

[Judd]

Judd, I feel your free bore is way too short for 105 class bullets. I suggest having it throated so the base of the bullet you like to use is about half way up the neck to start, then adjust seating depth to what the barrel likes.

People have said that but it keeps shooting so I keep using it. It’s competitive with my dashers...I still use the .104 freebore on those too. I’ve not been given a real good reason to change based upon I can and know what the load work up is right out of the gate. The advantage to the shorter freebore is I build speed (and consequently pressure) with less powder than the longer freebore. The pressure ring on the bullets are real close to the bottom of the neck but are not lower than it.

Jeff’s right...it’s short and I probably need to explore a longer freebore, laziness and the fact they are still competitive has kept me from doing so. Also, a long freebore for the dashers is north of .150, there are some running more than that.