Help with load analysis (6BR, 80GR Berger FB, N135)

[urbanrifleman]

My straight 6br never did group great with the 80 berger, but it shoots barts 80gr dominator very well. 12 twist ABC barrel, 30.5 gr of h4895.

Must be broken. I've never had a barrel not shoot the Berger varmint 80.

I am planning to order some Dominators to try too. I wish they made a 80 grain Varmegeddon fb for pdogs

 

[Fyrchief]

My 6BR 8-twist Bartlein really loves 80 gr. Bergers with 30.0 gr. N-135 at 2.230" COAL.

 

[urbanrifleman]

Just got home from the range. Ar comp workup fireforming 6bra with 80 Bergers jumping 20. BRUX 7.5

 

[urbanrifleman]

Y’all shootin hundred yards,huh ?

That is 600 yards.

 

[urbanrifleman]

Not really

 

[urbanrifleman]

Humm
Looks like a new World Record

I was just kidding those are 100-yard groups I was actually working on loads getting ready to go on a prairie dog hunt and these are very preliminary but I am pretty happy so far

 

[Brians356]

I live in Henderson (next to Vegas)... so i am basically already shooting in an oven

Hooterville, huh?

PS

Since that went over like a lead zeppelin, words of explanation: In the '70s I went to college with many kids from Boulder City and Las Vegas, some still my friends. I learned that Henderson was referred to somewhat derisively as "Hooterville" in honor of the mythical village in the popular TV sitcom Green Acres. Later one of those friends became a prominent pediatrician in Henderson, so what goes around comes around.
-

 

[Poor Shot 65]

Hi

I just rebarreled my 6mmBR and I am looking for help in determining the load to use.

Barrel is a Krieger LV 8 twist chambered with a .60 free bore.

Shooting 80GR Berger FB bullets. Bullets have been seated .015 jammed.

Powder is N135

Targets are at 100 yards. Each square of the target (I believe) is 1”.

At the start of this session, the barrel had 20 rounds shot through it.

Please see all the attachments for target info and raw numbers (speed, SD, ES etc). As my handle says, I am not a great shot, but im looking for a little direction here (stick with N135 ? which charges look good ? direction to go with seating etc ? or just give up :> ?) .

Looks to me that there are two possible nodes:

29 to 29.3 or 31 to 31.4 .. nothing looked really good though.

at 32 I saw signs of pressure - so im not comfortable going above 31.7 at this point in time.

Thanks

Adam

Results of seating tests using N135 and 80GR FB Berger bullets.

All groups consisted of 3 shots with all bullets loaded with 29.3 GR N135. All targets were 100 yards from the bench.

1 - .030 JAM
2 - .020 JAM
3 - .010 JAM (please note that I might have pulled one of the shots)
4 - .005 JAM


5 - .005 JUMP
6 - .010 JUMP
7 - .015 JUMP
8 - .020 JUMP
9 - .030 JUMP

Seems to me that I might want to retest #3 (.010 JAM ) and #6 (.010 JUMP) and #7 (.015 JUMP) look really good.

Thanks

Adam

 

[Poor Shot 65]

Hooterville, huh?

PS

Since that went over like a lead zeppelin, words of explanation: In the '70s I went to college with many kids from Boulder City and Las Vegas, some still my friends. I learned that Henderson was referred to somewhat derisively as "Hooterville" in honor of the mythical village in the popular TV sitcom Green Acres. Later one of those friends became a prominent pediatrician in Henderson, so what goes around comes around.
-

Henderson isn't in the sticks anymore It is huge now (second largest city in Nevada) and has (unfortunately) one of the highest growth rates of any city in the US.

 

[urbanrifleman]

Results of seating tests using N135 and 80GR FB Berger bullets.

All groups consisted of 3 shots with all bullets loaded with 29.3 GR N135. All targets were 100 yards from the bench.

1 - .030 JAM
2 - .020 JAM
3 - .010 JAM (please note that I might have pulled one of the shots)
4 - .005 JAM


5 - .005 JUMP
6 - .010 JUMP
7 - .015 JUMP
8 - .020 JUMP
9 - .030 JUMP

Seems to me that I might want to retest #3 (.010 JAM ) and #6 (.010 JUMP) and #7 (.015 JUMP) look really good.

Thanks

Adam

Annnnnnd... there you go. I shoot 20 jump to start with that bullet and rarely am I wrong. It always seems to shoot best at 20 jump. I consider 15 jump to be in the noise because I always figure the "touch" is an estimate to the best of my ability anyway.

 

[Poor Shot 65]

So what would happen with the seating depth if I changed powders ? Is it assumed that the seating depth would remain the same ?

Thanks

Adam

 

[urbanrifleman]

So what would happen with the seating depth if I changed powders ? Is it assumed that the seating depth would remain the same ?

Thanks

Adam

Correct.

 

[gunsandgunsmithing]

Annnnnnd... there you go. I shoot 20 jump to start with that bullet and rarely am I wrong. It always seems to shoot best at 20 jump. I consider 15 jump to be in the noise because I always figure the "touch" is an estimate to the best of my ability anyway.

Lol..because that's just funny! .005 is NOT within the noise of a good rifle and load.
I'm not saying that his best seating depth won't be found at either..every barrel is different.. just that .005 can be big increment if you're working with a very accurate rifle. I don't care who's right or wrong, as long as he finds what he's looking for.
Just from my own experience, and some might call that substantial, I would refine the increments to .003 at a time and work from .010 in to .010 out. The op has a .010 incremental leap right in the middle of that range that hasn't been touched upon. Just let the gun tell ya what it wants...and try some 8208. I prefer not to be there when possible, but right at touch is where it's at quite often....Smack in the middle of the untested range.
I will say that you are right about differing methods of finding touch will yield different results, though.

 

[urbanrifleman]

Lol..because that's just funny! .005 is NOT within the noise of a good rifle and load.
I'm not saying that his best seating depth won't be found at either..every barrel is different.. just that .005 can be big increment if you're working with a very accurate rifle. I don't care who's right or wrong, as long as he finds what he's looking for.
Just from my own experience, and some might call that substantial, I would refine the increments to .003 at a time and work from .010 in to .010 out. The op has a .010 incremental leap right in the middle of that range that hasn't been touched upon. Just let the gun tell ya what it wants...and try some 8208. I prefer not to be there when possible, but right at touch is where it's at quite often....Smack in the middle of the untested range.
I will say that you are right about differing methods of finding touch will yield different results, though.

That's what I said... I didn't say 5 thou was in the noise for a load i said finding the lands is...

Well, now he knows how to do a seating depth test, and he doesn't have to listen to anyone.

 

[gunsandgunsmithing]

That's what I said... I didn't say 5 thou was in the noise for a load i said finding the lands is...

Well, now he knows how to do a seating depth test, and he doesn't have to listen to anyone.

Oh, ok. Thanks.

 

[Brians356]

The important thing to identify (and replicate) is which cartridge length-to-ogive shoots best, not necessarily exactly where that puts the bullet in relation to "the lands". So different methods of finding the lands can all lead to a known good load length, since they really just suggest a reasonable but arbitrary starting seating depth.
-

 

[urbanrifleman]

The important thing to identify (and replicate) is which cartridge length-to-ogive shoots best, not necessarily exactly where that puts the bullet in relation to "the lands". So different methods of finding the lands can all lead to a known good load length, since they really just suggest a reasonable but arbitrary starting seating depth.
-

You really might be onto something here because there does seem to be a type of sweet spot to be found regardless of the location of the lands. Not that it would be the most ideal but I have found that certain magazine length loads will shoot in any ar15 no matter the chamber.

 

[BCP1980]

My straight 6br never did group great with the 80 berger, but it shoots barts 80gr dominator very well. 12 twist ABC barrel, 30.5 gr of h4895.

I know this is an older post but I am looking at chambering a 12 twist 6BR barrel and am looking for recommendations on reamer freebore length for shooting 80g bullets. Any guidance you’d be willing to share would be appreciated.

 

[boltfluter]

I know this is an older post but I am looking at chambering a 12 twist 6BR barrel and am looking for recommendations on reamer freebore length for shooting 80g bullets. Any guidance you’d be willing to share would be appreciated.

.080 fb was amazing in my 6BR. From 80gr up to a 105 VLD, everything shot little groups. Hard not to love the little 6BR. An amazing cartridge.
Paul

 

[BCP1980]

.080 fb was amazing in my 6BR. From 80gr up to a 105 VLD, everything shot little groups. Hard not to love the little 6BR. An amazing cartridge.
Paul

Thank you…..I’m still looking at reamers hoping to find one available without special order but shortest free ore I’ve found on a no turn is .094, do you think that would still work with the 80g class bullets?