6 Dasher reamer

[Alex Wheeler]

So long as the shank of the bullet will fit in the freebore your fine. The pressure ring will be larger than the freebore diameter, that is ok. .2435 works well, if you ever get a bullet that big send it back. Reamer grinders will error on the large side, so that .2435 is -0+.0002. So unless you can measure your reamer that precisely you dont really know if it is .2435 or .2437. If you ask for a .2438 you may get a .244. The JGS reamers I own have been as close to the print that I can measure, but its very hard to measure a reamer to the ten thousandth.

 

[stansrifles]

The question I have is why are leaning towards such a long freebore on these dashers like .135 an .155.
Stan

 

[stansrifles]

The question I have is why are leaning towards such a long freebore on these dashers like .135 an .155.
Stan

I thought I ask a legitimate question obviously not I don't know all I ask was what reason for the longer freebore .
Stan

 

[dkhunt14]

To get the pressure ring out of the junction and it seems to help reduce pressure to get 3050 without pounding the brass. Matt

 

[stansrifles]

What bullets do we have this trouble with an why are shooters trying to run them so fast.
Stan

 

[Dan Hall]

I have the same question as Stansrifles. Why are the free bores so long? The reamer for my 6BR is a PTG with no turn new Lapua brass, .2704 neck and .104 freebore. 105 Berger hybrids seated 10-20K into rifling have the bullets pressure ring well out from the neck/shoulder junction of the brass. Is the Dasher that different to cause the need for more freebore or is there just a lot of room in regard to the freebore with this class of bullet? I'm about to get a barrel chambered in 6 Dasher so I'm trying to figure out what's best. Thanks in advance.

 

[dkhunt14]

I believe because the Dasher neck is shorter the freebore amount doesn't work the same as a BR. Stan Most guys are running the 105 class bullets around 3000 or so. With the VLD the bearing is farther front then the others. It just works good. Most of the guys I know either run .135 or .155. I am not sure about the Montana guys though. I believe they are probably in that neighborhood also. Matt

 

[DJ111]

Stan and Dan,
Just to add what Matt said with the dasher you loose .070+" of neck from the 6br so you need to push the bullet out farther. Also you need to look at the overall case legnth. Your 6br may be at 1.570 and some guys are running shorter 1.555 lengths due to the cases getting shorter when formed so there again it can be another .015 loss.

I run a 1.560 case length and .135 fb, it works fine for hybrids, alright with vlds...too short for 108s. Matt is probably closer with his 1.55 fb.

Good luck.

 

[stansrifles]

Thanks for the response to these questions but I don't think there is enough evidence here to make me change from my existing .104 leade I don't have any problem with getting into a donut with the freebore that I have an don't run any faster than 2970fps thanks again for the positive responses.
Stan

 

[DJ111]

There are many ways to skin a cat! The short free bores work, I can shove a 108 way past the donut area and they still shoot good!

 

[ridgeway]

Stan...it's not so much of a donut issue...its where the sizer stops sizing on the neck. Most run a bushing die and sizing all the way to the neck shoulder junction is probably not happening. If your heel of the bullet is just shy of this area, I'm sure you are good to go. If you like what you see on paper, by all means run it, lol.

On a side note, I have two reamers pretty much spec'ed out the same with a .136" FB. Difference between them is, one has a larger freebore DIAMETER. Turns out, the one reamer is way short in freebore. I am talking .030"+ shorter, but both are supposed to be a .136". Quick work with a Throater in a separate operation takes care of it. Point being, that .104" marked reamer may be much longer?

 

[stansrifles]

I will measure how much bearing surface is in my neck I do use harrels bushing dies I think I have about .140 or so in the neck I will check to how much for sure.
Thanks Stan

 

[jrm850]

You also asked why try to get 3000+fps... Many believe there is a node around 3030fps+- where Dashers like to run.

 

[stansrifles]

I totally understand why the speed but predictable accuracy is more important to me you still have to shoot the conditions given you when going to record in competition.
Stan

 

[johara1]

I think the simple explanation is if you plan to shoot a bullet that the pressure ring is .0005 larger than the shank you need to adjust your free bore so the heel of the bullet is in the sized portion of the neck. If not and goes through zero neck tension, not enough spring back to hold the bullet. If you use a pressure gauge bullet seater like 21st century or K&M. you can see the pressure drop soon as it goes through. Just use the the throater to move the bullet ahead enough to keep it in the sized part of the neck……… Free bore diameter .0005 larger than the pressure ring doesn't hurt a thing, i found the fat bullets shoot better that way………. jim

 

[6mmcldasher]

I think the simple explanation is if you plan to shoot a bullet that the pressure ring is .0005 larger than the shank you need to adjust your free bore so the heel of the bullet is in the sized portion of the neck. If not and goes through zero neck tension, not enough spring back to hold the bullet. If you use a pressure gage bullet seater like 21st century or K&M. you can see the pressure drop soon as it goes through. Just use the the throater to move the bullet ahead enough to keep it in the sized part of the neck……… Free bore diameter .0005 larger than the pressure ring doesn't hurt a thing, i found the fat bullets shoot better that way………. jim

Jim, how much of the neck should we be sizing ? I just did a quick measure , my Wilson only sizes about .180 of the top of the neck , that leaves about .080 unsized . is this normal or should I be sizing more.

 

[johara1]

I think the simple explanation is if you plan to shoot a bullet that the pressure ring is .0005 larger than the shank you need to adjust your free bore so the heel of the bullet is in the sized portion of the neck. If not and goes through zero neck tension, not enough spring back to hold the bullet. If you use a pressure gage bullet seater like 21st century or K&M. you can see the pressure drop soon as it goes through. Just use the the throater to move the bullet ahead enough to keep it in the sized part of the neck……… Free bore diameter .0005 larger than the pressure ring doesn't hurt a thing, i found the fat bullets shoot better that way………. jim

Jim, how much of the neck should we be sizing ? I just did a quick measure , my Wilson only sizes about .180 of the top of the neck , that leaves about .080 unsized . is this normal or should I be sizing more.
[/quote



Never used a Wilson die, I FL. size on a Harrell's. How long are your cases? Are you just neck sizing?……… jim

 

[6mmcldasher]

I think the simple explanation is if you plan to shoot a bullet that the pressure ring is .0005 larger than the shank you need to adjust your free bore so the heel of the bullet is in the sized portion of the neck. If not and goes through zero neck tension, not enough spring back to hold the bullet. If you use a pressure gage bullet seater like 21st century or K&M. you can see the pressure drop soon as it goes through. Just use the the throater to move the bullet ahead enough to keep it in the sized part of the neck……… Free bore diameter .0005 larger than the pressure ring doesn't hurt a thing, i found the fat bullets shoot better that way………. jim

Jim, how much of the neck should we be sizing ? I just did a quick measure , my Wilson only sizes about .180 of the top of the neck , that leaves about .080 unsized . is this normal or should I be sizing more.
[/quote



Never used a Wilson die, I FL. size on a Harrell's. How long are your cases? Are you just neck sizing?……… jim

I use a redding body die then size the neck with the Wilson , I have a Forster FL but it sizes down to .257. cases are 1.55" to 1553" , I trim to 1.55 . I measured again and it looks closer to .160" sized of .230" length neck.

 

[noload]

I have just started to do load development with a Dasher. i have definitely found less neck tension with the Dasher short necks, as opposed to the longer BR necks. This causes me to use a smaller neck bushing than I normally would.
My normal neck tension will not allow for a .010 jam on a Dasher, the bullet will push into the case and create a jam of .008". when I close the bolt. So at that neck tension, my max jam is.008".
I'm only saying this because I see a lot of Dasher guys using a .010" jam....

 

[johara1]

I prefer to jump them if i can, you don't have to worry about neck tension. The lower the neck tension the more uniform and the lower the ES. and SD. This lowers the vertical ……….. When i shot Spencer bullets the pressure ring was .0005 larger than the shank and they liked to be in but after a long time fighting them, i tried jumping them and it worked ……. jim