Can I punch out my 6br to Dahser without a lathe???
- Thread starter queen_stick
- Start date
Kelbro:
I don't think it's on the gunsmiths. I think that people are simply afraid to do something like this, and there seems to be some sort of idea that an accurate chamber can only be cut in a lathe. A lot of smiths turn the last 10 (or so) thousandths by hand... using the EXACT same process I just did. I just went about 10x that distance
D-mon:
Good question!
First, I did not polish the chamber, nor do I feel I need to. This is based solely on how my brass comes out f the chamber. I see no marks in the brass that would indicate a need to polish. (A while back, there was a crazy thread on this forum about polishing a chamber... A debated topic). However, It's a simple thing to do with a drill and some emery cloth.
I did polish the throat. As mentioned early, I cut the throat forward .035" (with a separate throating reamer). That process is much more sensitive than cutting the chamber. It cut's SO easy, that you could take a .100" chunk out of there without even realizing it. You MUST have a stop or an indicator in place to get it right. Anyway, fresh-cut lands will have nice little razor sharp edges, which I don't feel is ideal, so I lapped the throat after I cut it. I used a cleaning rod with a jag, tight fitting patch, JB bore paste, and threw some 'media' on the paste. (the 'media' is about 600grit). I only did about 10 passes (5in, and 5 out), and figured that would knock the edge down without doing any damage. I'm going to have enough fire and bullets passing over the throat during load development, any remaining 'edge' in there should be gone in short order.
The only thing I wash I had when doing this... a bore scope!
I don't think it's on the gunsmiths. I think that people are simply afraid to do something like this, and there seems to be some sort of idea that an accurate chamber can only be cut in a lathe. A lot of smiths turn the last 10 (or so) thousandths by hand... using the EXACT same process I just did. I just went about 10x that distance
D-mon:
Good question!
First, I did not polish the chamber, nor do I feel I need to. This is based solely on how my brass comes out f the chamber. I see no marks in the brass that would indicate a need to polish. (A while back, there was a crazy thread on this forum about polishing a chamber... A debated topic). However, It's a simple thing to do with a drill and some emery cloth.
I did polish the throat. As mentioned early, I cut the throat forward .035" (with a separate throating reamer). That process is much more sensitive than cutting the chamber. It cut's SO easy, that you could take a .100" chunk out of there without even realizing it. You MUST have a stop or an indicator in place to get it right. Anyway, fresh-cut lands will have nice little razor sharp edges, which I don't feel is ideal, so I lapped the throat after I cut it. I used a cleaning rod with a jag, tight fitting patch, JB bore paste, and threw some 'media' on the paste. (the 'media' is about 600grit). I only did about 10 passes (5in, and 5 out), and figured that would knock the edge down without doing any damage. I'm going to have enough fire and bullets passing over the throat during load development, any remaining 'edge' in there should be gone in short order.
The only thing I wash I had when doing this... a bore scope!
just got back from the range.
I tested Varget and RL-15 with 3 different primers (Tulla SRM, CCI-450, and 205M). The purpose of such a test was to see which combo of powder and primer I would start with. This also allowed me to get some trigger time behind the new Dasher
Problem number 1 - horrible conditions for load development. The wind was gusting, but even worse, the mirage was absolutely terrible. There were some very respectable shooters at the range, and even they were struggling with the mirage.
All shooting was at 300 yards. Powder/primer ::: group size (vertical and horizontal)
32.5gr of powder, and 105gr Amax seated with a .010" jam.
Varget/Tulla SRM ::: 2.638verticle, 1.776wide
Varget/205M ::: 1.360vertical, 2.133wide <---------------
Varget/CCI-450 ::: 2.250vertical, 4.006wide
RL-15/CCI-450 ::: 0.816vertical, 2.513wide <---------------
RL-15/Tulla SRM ::: 1.853vertical, 1.002wide
RL-15/205M ::: 1.457vertical, 0.356wide <---------------
As you can see, there's nothing to write home about. However, the three targets (with arrows next to them) had 3 shots touching, and two shots out. I'm convinced the 'flyers' were due to conditions and the driver... nothing else.
I'm not to skilled in reading the mirage (I'll be the first to admit it), and I did not have my wind flags out (range was too busy). I know that one of the 3 loads above will shoot very well.
What's interesting, is that the "RL15/CCI450/AMAX" combo was the most accurate out of the 6BR chamber. Looks like that may be the case with the Dasher as well, so that's the load I'm going to start with. Now that I have the components selected, I'll start tweaking bullet seating depth, charge weight, and maybe neck tension.
I can't wait for a "good day" to do some more development. I'm 100% convinced this thing will shoot as small or smaller than the 6BR chamber, and that's all I was looking for
I tested Varget and RL-15 with 3 different primers (Tulla SRM, CCI-450, and 205M). The purpose of such a test was to see which combo of powder and primer I would start with. This also allowed me to get some trigger time behind the new Dasher
Problem number 1 - horrible conditions for load development. The wind was gusting, but even worse, the mirage was absolutely terrible. There were some very respectable shooters at the range, and even they were struggling with the mirage.
All shooting was at 300 yards. Powder/primer ::: group size (vertical and horizontal)
32.5gr of powder, and 105gr Amax seated with a .010" jam.
Varget/Tulla SRM ::: 2.638verticle, 1.776wide
Varget/205M ::: 1.360vertical, 2.133wide <---------------
Varget/CCI-450 ::: 2.250vertical, 4.006wide
RL-15/CCI-450 ::: 0.816vertical, 2.513wide <---------------
RL-15/Tulla SRM ::: 1.853vertical, 1.002wide
RL-15/205M ::: 1.457vertical, 0.356wide <---------------
As you can see, there's nothing to write home about. However, the three targets (with arrows next to them) had 3 shots touching, and two shots out. I'm convinced the 'flyers' were due to conditions and the driver... nothing else.
I'm not to skilled in reading the mirage (I'll be the first to admit it), and I did not have my wind flags out (range was too busy). I know that one of the 3 loads above will shoot very well.
What's interesting, is that the "RL15/CCI450/AMAX" combo was the most accurate out of the 6BR chamber. Looks like that may be the case with the Dasher as well, so that's the load I'm going to start with. Now that I have the components selected, I'll start tweaking bullet seating depth, charge weight, and maybe neck tension.
I can't wait for a "good day" to do some more development. I'm 100% convinced this thing will shoot as small or smaller than the 6BR chamber, and that's all I was looking for
Looking forward to more results. Nice job on the chamber. 8)
Regards,
Paul
www.boltfluting.com
Regards,
Paul
www.boltfluting.com
holstil said:
got it boxed up last night. I wanted to make sure it shot ok before sending it back. If it didn't, I'd be sending everything down (including my action and barrel) to have it set back.
Boltfluter - Thank you sir!
I forgot to mention, my friend Jim (holstil) loaned me the tools and reamers to do this... no cost except for shipping (PA - NC). That's a heck of a deal for me, and I can't thank him enough!
Walt
small update.
Conditions have been pretty bad for load development lately. I got a nice calm morning on Friday, and I was lucky enough to have off work that day
I picked the load that showed the best sign in my first outing (32.5gr RL15, CCI 450, 105 Amax) and simply played with bullet seating depth.
At about .020 jump (I haven't actually measured it yet, just set it on my micrometer Wislon seater), I shot 3 groups that have 1/4" of vertical or less. The only thing I have to work out is horizontal in the groups. The best group was 1/2" wide, 1/4" tall. The other two groups were .9 inch and 1.21 inch. Both with 1/4" of vertical.
I have some room to go up in the powder charge, so I might try that next.
I think this thing will shoot better than I can drive it! I'm glad I tried this!
Side Note - I did the" tough mudder" yesterday... holy shit I'm sore today! (If you don't know what that is, google it...)
Conditions have been pretty bad for load development lately. I got a nice calm morning on Friday, and I was lucky enough to have off work that day
I picked the load that showed the best sign in my first outing (32.5gr RL15, CCI 450, 105 Amax) and simply played with bullet seating depth.
At about .020 jump (I haven't actually measured it yet, just set it on my micrometer Wislon seater), I shot 3 groups that have 1/4" of vertical or less. The only thing I have to work out is horizontal in the groups. The best group was 1/2" wide, 1/4" tall. The other two groups were .9 inch and 1.21 inch. Both with 1/4" of vertical.
I have some room to go up in the powder charge, so I might try that next.
I think this thing will shoot better than I can drive it! I'm glad I tried this!
Side Note - I did the" tough mudder" yesterday... holy shit I'm sore today! (If you don't know what that is, google it...)
Update!
Got up to Williamsport for the first time this year, which was also the first trip to the 1K range with my new Dasher chamber.
Did about 30 mins of load development on Friday evening, and found this:
WHOA! Best group I've ever shot at 1K! 3.6"
A single 5-shot group is far from ideal, in terms of 'proper 1k load development.' However, that's all the time I had, so I went with it...
Shot the World open on Sat and Sun with that load... Didn't do too well :-(
All my groups were forming at about 7" ~ 8", but I was missing the conditions, or over-compensating for the conditions. Smallest group of the weekend was 9," which won't even get you close to a top 25 spot. lol!
long story short, the rifle is more accurate than I am... that's all I need!
I think this thing has great potential if I do some proper 1k load development
Got up to Williamsport for the first time this year, which was also the first trip to the 1K range with my new Dasher chamber.
Did about 30 mins of load development on Friday evening, and found this:
WHOA! Best group I've ever shot at 1K! 3.6"
A single 5-shot group is far from ideal, in terms of 'proper 1k load development.' However, that's all the time I had, so I went with it...
Shot the World open on Sat and Sun with that load... Didn't do too well :-(
All my groups were forming at about 7" ~ 8", but I was missing the conditions, or over-compensating for the conditions. Smallest group of the weekend was 9," which won't even get you close to a top 25 spot. lol!
long story short, the rifle is more accurate than I am... that's all I need!
I think this thing has great potential if I do some proper 1k load development
old_heli_logger
Gold $$ Contributor
Excellent write-up! Thank you!!!
Erik Cortina
Team Lapua Brux Borden Captain
Keep in mind that re-chambering a 6BR to a Dasher is different that re-chambering to an Ackley cartridge. The Dasher shoulder is moved forward on the 6BR, on the Ackley version it only changes the shoulder angle and blows out the walls some, but I believe the headspace stays the same. So, I would advice like others have to set barrel back at least two threads and then ream it out to Ackley to insure proper chamber clean up and proper shoulder geometry.
old_heli_logger
Gold $$ Contributor
Got it, thank you very much!! I'll leave this stuff to the professionals...
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