Window of tune - 6BRA vs the others?

[Curious]

I’ve been able to monitor speed a little easier since buying a Labradar with its ease of set up .. what I did notice recently was after around 900+ rnds on the barrel I put some rounds past the lab before a comp which gave an averaged 2960, previously it averaged 2991. I shot it at 2960 and it shot worse than ever.
I’m yet to get down to the range and run the speed back up to see if accuracy returns but I intend to as soon as possible.

It would be very interesting to see if a given/long standing MV for that barrel was your LR tune point.

It could make keeping barrels in tune so much easier for the sake of a good chrono and it would save the need for LR ladders after you had established the first results. I guess you would have to make sure the barrel had finished speeding up before you established your first load/datum.

That could also be useful if changing powder batches if it worked.

 

[KenOath]

It would be very interesting to see if a given/long standing MV for that barrel was your LR tune point.

It could make keeping barrels in tune so much easier for the sake of a good chrono and it would save the need for LR ladders after you had established the first results. I guess you would have to endure the barrel had finished speeding up before you established your first load/datum.

That could also be useful if changing powder batches if it worked.

Yes I knew the barrel had stopped speeding up and 2991 was my average..
I will soon see, I plan on running a powder test to see..I agree it could be useful..

 

[KenOath]

I alluded to this on a different thread bit think its probably best discussed separately.

Have any of you guys felt the 6BRA took more tuning or was harder to find the very best tune than your other 6BR derivatives?

Could the 6BRA tune window be smaller than the others for some reason?

I didn’t find it harder to tune than say a straight br or Dasher, but for me so far the tune window isn’t as broad as my previous straight BRs... I find the window about the same size as my previous Dasher but the BRA has stayed in tune for a longer period of time than th3 Dasher and I believe it’s because of the very little throat wear with the BRA. I know some who have struggled with finding a tune with the BRA but I don’t know if it’s there Barrel or there methods or the conditions they chose to test in and/or possibly there ability to read and compare ones load testing..

 

[Badbob]

Heres a 1k ladder. Each group is .1 gn. apart. Thats the widest node I have ever seen at 1k. It is NOT normal. This ones a solid +/- .1gn. They normally are not that wide. Thats for anything at 1k I have seen. Even my magnum hunting rifles get down to +/- .2 and they are burning over 80 grains of powder.
I shot 2 agg records in 2014 (Willamsport 1k) with my dasher. That barrel had a node +/- .05gn.

View attachment 1052300

Sorry to be "Johnny come lately" to this thread but it caught my attention while looking at BRA loads. I'm working on my first BRA. Shooting Bart 105s with H4895. So my mind is fresh on looking for a node and tuning.

So Alex, when you say the window is .1grains wide do you mean that .1 grain + or - will toss you out of tune. For example, my window of tune might only exist between 30.40g and 30.50g of H4895. Am I understanding you correctly?

Would you then explore 30.42, 30.44, 30.46, 30.48, 30.50?

Many thanks,

Rob

 

[Alex Wheeler]

Im saying if you go .1 either way the groups will get bigger in my experience. Not by a huge amount, but if you want to shoot 1"s you have got to be right on it. If your looking for 5" then the window is pretty wide. That goes for anything really. I have yet to shoot anything that gave you a wide window of peak accuracy at 1k. Percentage wise they are all pretty close. Some stay in tune better though.

 

[urbanrifleman]

I think a lot of folks have missed the real secret suace for the 6bra over the 6br.

It shoots better at the very hot 6br node "fireforming node" than the 6br, which at the same speed is hammering the crap out of the brass. 2880 FPS is just stupid consistent with 6bra. There is a massive flat spot nearly half a grain wide where the velocity stays the same. Shoots tiny. Happy happy.

 

[Badbob]

Im saying if you go .1 either way the groups will get bigger in my experience. Not by a huge amount, but if you want to shoot 1"s you have got to be right on it. If your looking for 5" then the window is pretty wide. That goes for anything really. I have yet to shoot anything that gave you a wide window of peak accuracy at 1k. Percentage wise they are all pretty close. Some stay in tune better though.

Ok, that makes sense . .. thanks for clarifying.

So if you are doing an initial load test, looking for a node and spacing charges .3 apart, you will find evidence of a node but it will require finer charge tuning to hone into 1" 1000yard gun. For example, I shoot 30.0, 30.3, 30.6, 30.9, 31.1 h4895 and I notice 30.3 and 30.6 have tight vertical and identical POIs. Would you go back and then shoot: 30.42, 30.44, 30.46, 30.48, 30.50, 30.52 and so on (assuming your scale can weigh no closer than .02grs)?

Ok, one more question--in terms of process will you hone the charge weight prior to tinkering with seating depth, neck tension, primers, etc? That seems logical but being a newb I thought I would ask.

Cheers!

 

[Alex Wheeler]

I dont go that fine, .1 is enough for me once you isolate an area that looks good. I personally do find a good powder charge first, then seat, nt and primers. I have tried to go after seating before finding a decent powder charge and chased my tail, but I know some do that with success.

 

[normmatzen]

Ya! Terrible to tune!
What ever you do, don't chamber your BR gun for a 6BRA!!!

Heh! Heh!

 

[Northridge]

my findings are that the window is similar not really smaller or larger, but like the other variants if you are on the wrong bushing it can and will be very narrow, not even a sniff of good coming in to tune or leaving tune.
As I have said many times if you are on the preferred bushing everything else will come easier I promise.

Shawn Williams

 

[Dave Way]

To answer your question I think it would depend on the level of accuracy you are looking for. If you are striving for 2” or less of vertical in your load at 1K, the window can be rather tight. Im talking say splitting the difference between like 30.5 and 30.6. If you are looking for a more forgiving tune, and it can be found, you should be able to find a larger window and shoot consistent 3” groups. I lean that way when I have to travel to matches and need to pre-load. I can have that kind of accuracy with a plus or minus a tenth or maybe even a tenth and a half.

I have some experience with a dasher and for me it was more difficult to dial in but that was on a different platform so the comparison isn’t fair.

Dave.

 

[Badbob]

Hey there . . . I got a few more followups.

I'm exploring Barts 105s and VT 103s. The Barts seems more more forgiving. Agg'ing about less than 2" @600yds with few wallet groups less than 1.5" I have a nice tuning window between 30.4 and 30.6 H4895. So I did a seating depth test at 30.5g. Jammed at .009 and .012 looks good
and jumping .003, .006 and .009 also looks tight. Mirage was heavy in shifty conditions but these 4 shot groups are just around 2"

The VT are erractic. Its been very challenging just to discern a tuning window. Basically vertical is just steadily going up. I've tested 29.0 to 31.0 H4895. I was gunna drop these and focus on the Barts. But two targets showed sub 1" groups at 30.0g. 29.8g and 30.2g are more like 3" at 600yds--not impressive These are loaded touching the lands, 7 1/2 primers.

Anybody else finding the VT challenging to tune?
Should I stick with it, is 30.0g worth exploring or are these just one off wallet groups?
Should I just drop the VT and focus on the Barts?
Or go back and shoot 29.9 and 30.1 and perhaps explore seating?

obviously not sure what to do here.

Many thanks in advance for your suggestions. BB

 

[SHall]

Hey there . . . I got a few more followups.

I'm exploring Barts 105s and VT 103s. The Barts seems more more forgiving. Agg'ing about less than 2" @600yds with few wallet groups less than 1.5" I have a nice tuning window between 30.4 and 30.6 H4895. So I did a seating depth test at 30.5g. Jammed at .009 and .012 looks good
and jumping .003, .006 and .009 also looks tight. Mirage was heavy in shifty conditions but these 4 shot groups are just around 2"

The VT are erractic. Its been very challenging just to discern a tuning window. Basically vertical is just steadily going up. I've tested 29.0 to 31.0 H4895. I was gunna drop these and focus on the Barts. But two targets showed sub 1" groups at 30.0g. 29.8g and 30.2g are more like 3" at 600yds--not impressive These are loaded touching the lands, 7 1/2 primers.

Anybody else finding the VT challenging to tune?
Should I stick with it, is 30.0g worth exploring or are these just one off wallet groups?
Should I just drop the VT and focus on the Barts?
Or go back and shoot 29.9 and 30.1 and perhaps explore seating?

obviously not sure what to do here.

Many thanks in advance for your suggestions. BB

Nothing wrong with VT 103’s! But it sounds like your particular barrel has an affinity for your BARTS bullets. Stick with what it is shooting the most consistently small groups with. When tuning you can always get a very small “fluke” group that gets you excited that you have found an awesome tune. Make sure the barrel will repeat it ( or close) a couple times before you settle on it. Rarely will a barrel shoot all bullets good, no matter how great the bullets are. You must find the bullet that particular barrel likes.

 

[dbduff]

24hrs and very little activity on this thread, usually a 6BRA thread stimulates a whole load of discussion - why not this one I wonder?

It may be folks are being conservative with their remaining components as replacements are few and very dear.

 

[Badbob]

Nothing wrong with VT 103’s! But it sounds like your particular barrel has an affinity for your BARTS bullets. Stick with what it is shooting the most consistently small groups with. When tuning you can always get a very small “fluke” group that gets you excited that you have found an awesome tune. Make sure the barrel will repeat it ( or close) a couple times before you settle on it. Rarely will a barrel shoot all bullets good, no matter how great the bullets are. You must find the bullet that particular barrel likes.

Ok, thanks . .. Ya I defiantly feel the "OMG" factor when I see the small group(s) but my head says this is not going to agg well.

But what you are saying is the VTs are NOT particular hard to tune, in general. So I'll assume my barrel does not like them and move on. Cheers!

 

[dat]

my findings are that the window is similar not really smaller or larger, but like the other variants if you are on the wrong bushing it can and will be very narrow, not even a sniff of good coming in to tune or leaving tune.
As I have said many times if you are on the preferred bushing everything else will come easier I promise.

Shawn Williams

Please explain "if you are on the preferred bushing"

 

[Northridge]

Please explain "if you are on the preferred bushing"

to just pick a bushing on projected result based off static grip or loaded tension is really not enough. some will "argue" you can tune around the bushing alone, not that I disagree completely but it can be short sided at times. at shorter ranges this can be harder to nail down by the less trained eye & often for me the bushing that wins out at short range will flip choosing a heavier one at distance. what I look for and deem the "correct" bushing is the one that develops the laziest tune window. what im attempting to develop when im doing this is when coming in to tune it will start to calm down say a tenth before the spot then you nail the middle, then as you push your rifle out of tune say the next tenth up it will just start to diminish with out large spit shots before a dramatic quadrant move ensues. developing a tendency like this is very forgiving and on the occasions we slightly miss the good the edge in and edge out will still competitive may not first but a 2nd or 3rd place verses middle pack or even last. solid approach for agg shooters for sure. for me the bushing that is not "correct" or premium will be aggressive coming in to tune will be messy and freaky "BAM" you hit the middle and it ladders sub small then as you push the rifle out of tune it freaks out kicking shots as it pushes out the top. day to day your rifle will be far more finicky "hero to Zero" tune as we call it Deep Creek.


Shawn Williams

 

[dat]

to just pick a bushing on projected result based off static grip or loaded tension is really not enough. some will "argue" you can tune around the bushing alone, not that I disagree completely but it can be short sided at times. at shorter ranges this can be harder to nail down by the less trained eye & often for me the bushing that wins out at short range will flip choosing a heavier one at distance. what I look for and deem the "correct" bushing is the one that develops the laziest tune window. what im attempting to develop when im doing this is when coming in to tune it will start to calm down say a tenth before the spot then you nail the middle, then as you push your rifle out of tune say the next tenth up it will just start to diminish with out large spit shots before a dramatic quadrant move ensues. developing a tendency like this is very forgiving and on the occasions we slightly miss the good the edge in and edge out will still competitive may not first but a 2nd or 3rd place verses middle pack or even last. solid approach for agg shooters for sure. for me the bushing that is not "correct" or premium will be aggressive coming in to tune will be messy and freaky "BAM" you hit the middle and it ladders sub small then as you push the rifle out of tune it freaks out kicking shots as it pushes out the top. day to day your rifle will be far more finicky "hero to Zero" tune as we call it Deep Creek.


Shawn Williams

Thanks for you very good explanation!

 

[dbduff]

to just pick a bushing on projected result based off static grip or loaded tension is really not enough. some will "argue" you can tune around the bushing alone, not that I disagree completely but it can be short sided at times. at shorter ranges this can be harder to nail down by the less trained eye & often for me the bushing that wins out at short range will flip choosing a heavier one at distance. what I look for and deem the "correct" bushing is the one that develops the laziest tune window. what im attempting to develop when im doing this is when coming in to tune it will start to calm down say a tenth before the spot then you nail the middle, then as you push your rifle out of tune say the next tenth up it will just start to diminish with out large spit shots before a dramatic quadrant move ensues. developing a tendency like this is very forgiving and on the occasions we slightly miss the good the edge in and edge out will still competitive may not first but a 2nd or 3rd place verses middle pack or even last. solid approach for agg shooters for sure. for me the bushing that is not "correct" or premium will be aggressive coming in to tune will be messy and freaky "BAM" you hit the middle and it ladders sub small then as you push the rifle out of tune it freaks out kicking shots as it pushes out the top. day to day your rifle will be far more finicky "hero to Zero" tune as we call it Deep Creek.


Shawn Williams

Would appreciate a tutorial on the sequence in tuning as to when attention is paid to the bushing and how to know when it is in need of tweaking and how to know if more or less neck tension is needed. There must be a sequence regarding velocity, grouping, seating depth, neck tension. Any rudimentary advice?