Struggle with slow twist 6BR

[urbanrifleman]

Larry i have worked with your loads and they shot good, but again inconsistent

I suspect you really have never found the seating depth sweet spot. Seating depth is really the key to consistently small groups.

 

[LarryDScott]

All along I was thinking the inconsistency was
because I was a faulty operator. LDS

 

[gunsandgunsmithing]

Larry i have worked with your loads and they shot good, but again inconsistent

I scanned back over the posts here and didn't see it mentioned yet, so here goes...Are you using wind flags?
The biggest key to consistently shooting small is not pulling the trigger at the wrong time, especially with the lighter bullets. Getting a 6BR to shoot is the easy part.

 

[swadiver]

I scanned back over the posts here and didn't see it mentioned yet, so here goes...Are you using wind flags?
The biggest key to consistently shooting small is not pulling the trigger at the wrong time, especially with the lighter bullets. Getting a 6BR to shoot is the easy part.

i am not using flags at the moment. but as i mentioned above, i am shooting early am here in florida in virtually calm conditions. mirage at theses hours are usually not an issue as well.

the problem is the groups are radically different, sometimes vertical, sometimes horizontal. we are talking from the mid/low .2's to .4's+. sometimes it is 4+1 with a flyer vertical or horizontal or just an opened up group.

 

[swadiver]

I would set up a chronograph to see what the velocity's were doing.....how many rounds fired so far ?....new fireing pin spring ?

around 500 rd down the pipe, i have chronode but don't recall the results. i was looking at just group performance. as for firing pin spring, it was replaced with a Gre-Tan spring when i had the bolt bushed

 

[swadiver]

I suspect you really have never found the seating depth sweet spot. Seating depth is really the key to consistently small groups.

i am going to concentrate on that. brass was just annealed

 

[gunsandgunsmithing]

i am not using flags at the moment. but as i mentioned above, i am shooting early am here in florida in virtually calm conditions. mirage at theses hours are usually not an issue as well.

the problem is the groups are radically different, sometimes vertical, sometimes horizontal. we are talking from the mid/low .2's to .4's+. sometimes it is 4+1 with a flyer vertical or horizontal or just an opened up group.

Put out flags or at least some surveyor ribbon. It's still the most likely thing causing your problem and is the cheapest, if you use surveyor tape.
There are very few truly calm times. A 1 mph wind reversal can turn a .250 group into a .5 group. You can hardly even feel a 1 mph wind at all.

It's easy to see from this why I feel like shooting without flags is a waste of components and barrel life. Much less trying to tune a rifle to it's potential without them. The need for flags during load work up simply can not be over stated IMHO. And anything is better than nothing...Just put some surveyor tape on about 4 pieces of wire that you can stick in the ground, just high enough to be below the path of the bullet.

 

[Steve Ladino]

Try the Bart's with around 32gr of XBR8208 or Varget just touching. Fed Match primers might also help.

I was up to 34.3 of Varget ( about all I could get in ) with Barts 68 ULTA and 68 Boatail's & 450's seated soft …….have builder recheck everything > okay > bad tube.

 

[swadiver]

I was up to 34.3 of Varget ( about all I could get in ) with Barts 68 ULTA and 68 Boatail's & 450's seated soft …….have builder recheck everything > okay > bad tube.

i shot a couple of good groups with the Berger 64.2 Columns with 34.2 grs of Varget. went out the next time with the same load in virtually the same conditions and went to crap

 

[gunsandgunsmithing]

i shot a couple of good groups with the Berger 64.2 Columns with 34.2 grs of Varget. went out the next time with the same load in virtually the same conditions and went to crap

I've bought several 6br's that the owner said wouldn't shoot light bullets well. When I asked what powder they were using and they said Varget....I bought it then and there.

Varget is not the best choice with light bullets in a 6BR(not often anyway).

I'd get the gun, feed it some H322 or n135 and the groups would instantly be like half of what the seller said they were getting..even with no load work up.

Varget is great in a 6BR with heavy bullets but only a few times, have I seen it work well with light bullets.

YMMV but, stop wasting money...Put out some flags, re test H322 and N135...and report back.

I've been down this road more times than I can come close to remembering. If it won't shoot a stiff charge of one of those two powders with the bullets lightly jammed, something else is wrong. Granted, some barrels just won't shoot teens, ever, but the majority these days will, at least sometimes.

 

[swadiver]

I've bought several 6br's that the owner said wouldn't shoot light bullets well. When I asked what powder they were using and they said Varget....I bought it then and there.

Varget is not the best choice with light bullets in a 6BR(not often anyway).

I'd get the gun, feed it some H322 or n135 and the groups would instantly be like half of what the seller said they were getting..even with no load work up.

Varget is great in a 6BR with heavy bullets but only a few times, have I seen it work well with light bullets.

YMMV but, stop wasting money...Put out some flags, re test H322 and N135...and report back.

I've been down this road more times than I can come close to remembering. If it won't shoot a stiff charge of one of those two powders with the bullets lightly jammed, something else is wrong. Granted, some barrels just won't shoot teens, ever, but the majority these days will, at least sometimes.

thanks for the advise. i had already decided not to pursue Varget.

 

[AndyTaber]

Never and always, two words to careful of.

I load my 14 twist 6br Varmint for Score rifle with 33gr of Varget, cci 450’s and Berger Column bullets. I am on my second barrel with this combination and it just plain shoots for me.
It’s the wind that gives me grief.

 

[SmokinJoe]

Another thing that a lot of people fall into is what you are trying to do, and that is shooting in "calm" morning conditions, especially without flags. Those are the absolute worst, most deceiving conditions I ever tried to shoot in. Listen to what Mike is telling you, get some good windflags & learn to use them, then do your shooting in the best "honest wind" conditions when the humidity has stabilized a bit during the day. If you work at it, you will see those groups come down and be more consistent. FWIW, I started out shooting a 14 twist 6BR in short range group shooting and my best combo involved a warm load of N-135, BR4 and a 66 gr bullet jammed about .006 - .008". Good luck with your shooting development.

 

[lpreddick]

N133 has been good to me with my 14 twist Kreiger and 66-68 gr bullets. Did I miss your neck tension? .002 works best for me as I seat .020 into the lands if my groups are small...occ bullet powder combo likes .015 into the lands. My barrel has 1100 firings and the lands have not receded evenly, so a bullet .005 into the lands will not have 4 land's engravings.

 

[AlNyhus]

I'll echo the comments on wind flags. Nothing will make groups more consistent than a decent set of flags. Without them, you're just shooting blind.

There's always something out there moving either the bullet or the target image. Light conditions can be very, very tricky and are not to be trusted. -Al

 

[swadiver]

an update on my 14 twist project:

went out today with the rifle. typical early am Florida conditions. little or no wind. i did use a wind flag today, but about 90% of the time it never moved. that's when i shot.

I went back to the Berger 64.2 Column bullets, those having been my best shooter overall. i had done seating depth testing with these prior to today, but wanted to nail that done if i could. most significantly, i used N135, having received numerous recommendations for this powder in this application.

loads were all 31.5grs of N135, either +.010" into the lands or -.012" off.

overall, this was the most consistent the rifle has shot. the -.012" seating depth MAY have been slightly better than the jam. not a gigantic difference either way. i am going to use the -.012" depth in the future. the 5 shot groups were respectable, but the real issue was the 4 plus 1 grouping. five of the six groups shot exhibited this to one degree or another. all the "misses" were vertical. the 4 shot groups were all in the low to high .1"s" see pic below.

so, i am going to stick with the N135, the Berger Columns -.012" off, and work up the load to around 32.5 grs were i believe there is another node. also, it recently dawned on me that my stock is quite butt heavy with this 23" HV contour barrel. having read this butt heavy balance may contribute to unexplained vertical shots, i am going to try and add some weight up on the forearm of the rifle.

overall, i am encouraged by today's outing with the rifle. it still remains a "work in progress", however.

thanks to all for their inputs on this project.

 

[gunsandgunsmithing]

an update on my 14 twist project:

went out today with the rifle. typical early am Florida conditions. little or no wind. i did use a wind flag today, but about 90% of the time it never moved. that's when i shot.

I went back to the Berger 64.2 Column bullets, those having been my best shooter overall. i had done seating depth testing with these prior to today, but wanted to nail that done if i could. most significantly, i used N135, having received numerous recommendations for this powder in this application.

loads were all 31.5grs of N135, either +.010" into the lands or -.012" off.

overall, this was the most consistent the rifle has shot. the -.012" seating depth MAY have been slightly better than the jam. not a gigantic difference either way. i am going to use the -.012" depth in the future. the 5 shot groups were respectable, but the real issue was the 4 plus 1 grouping. five of the six groups shot exhibited this to one degree or another. all the "misses" were vertical. the 4 shot groups were all in the low to high .1"s" see pic below.

so, i am going to stick with the N135, the Berger Columns -.012" off, and work up the load to around 32.5 grs were i believe there is another node. also, it recently dawned on me that my stock is quite butt heavy with this 23" HV contour barrel. having read this butt heavy balance may contribute to unexplained vertical shots, i am going to try and add some weight up on the forearm of the rifle.

overall, i am encouraged by today's outing with the rifle. it still remains a "work in progress", however.

thanks to all for their inputs on this project.


View attachment 1066922

Sounds like you're on the right track. Ime, 32.5 and a little north of there is where n135 starts coming around. I'd still work with some amount of jam around that powder charge. Just my 2 cents worth.

 

[AlNyhus]

It's really double grouping (vertically). More powder and/or more neck tension should take the vertical out. You're close.

 

[swadiver]

Another update on my slow twist 6BR. i hope i am not boring everybody.

as previously posted, i have been struggling with getting consistent good groups from this rifle. the key word is CONSISTENT.

i figured out fairly quickly that the Berger 64.2 Column bullets were liked by this barrel. the problem was finding a powder that would give consistent results. outside air temp has not been an issue as it is has been warm consistently (75 to 85 deg) here in south FLA. all the powders i tried with various loads shot some good groups but were pretty erratic. i did start using a wind flag, but also was able to shoot early AM, usually with almost dead calm conditions.

my research led me to prioritize the following powders and this is the order i tried various loads/seating depths with each.

1) Western LT-32 ( a few very small groups but very erratic)
2) Hodgdon H322 ( some good groups but struggled with vertical flyers)
3) Hodgdon Varget ( very erratic)
4) Vhitavuori N-135 ( fair groups, inconsistent)

Finally, Hodgdon Benchmark. I started at 30 grs and worked up to 32.4 grs in .2 gr increments. 31.0, 31.6, and 32.2 look very promising. i have repeated the 31.0 and 31.6 loads a couple of time and both have shot well each time. 32.2 is showing some mild pressure signs. i need to repeat that load again.

it was very interesting that all the Benchmark loads i shot from 30.0 and up shot very good. some better than others as noted, but i did not see some of the wild grouping swings that i saw with the other powders. I ended up using .012" off the lands for all the testing, but am going to experiment some more with seating depths. i think i am pretty close though.

As i noted in my initial post, i have a fair amount of experience loading for fast twist 6BR's shooting 105/108 gr bullets. these setups are usually pretty easy to get shooting well from the git go. this has been my first foray into to slow twist/light bullet 6BRs.

Lessons learned:

1) i think i spent too long testing powders that were erratic right off the bat, in comparison to the Benchmark that shot very good to excellent right away. i used up more components than necessary and more importantly used up more barrel life than i would have liked to

2) listen to your gunsmith. i had asked my smith who chambered the barrel and had personally used this reamer, what powder did he recommend. his answer was a bit vague on details but he did say he thought he remembered Benchmark. i did not fully take that to heart because he didn't seem totally sure and all my research lend me to believe it was powder further down the list to be tried for this application.

3) it's not the destination it's the journey!! Ha!!

 

[hogpatrol]

I may have missed it but have you tried 8208? Also, I would go with a custom bullet. I had good results with Precision Ballistics 66s and 68s, .005 off. My best was with 135 and Fed match primers, .002 neck tension, .005 off. Chamber is a .271