What free bore for 7.5 T Dasher?

[DanSavage]

Looking to shoot 107s or 110smk.

 

[22DASHER]

.135-.155

 

[swd]

.135-.155

This^^^

 

[DanSavage]

.120 is what the smith's reamer is, maybe he can throat it a little more for me.

 

[Geronimo Jim]

I got .135....wished I had gone with .155.

 

[jamesdmock]

.120 is what the smith's reamer is, maybe he can throat it a little more for me.

I believe that you should go with the .120. My 8.25 to 7.75 gain twist Bartlein was used last Saturday to win a 600 yard match. When this barrel was new it had a .095 free bore and I shot 105 Berger Hybrids in it. It was new in 2009 and after ~2500 rounds it still shoots well. The FB is no longer .095, but the wear has not kept it from shooting well. I am not recommending a .095 FB, but I would be very hesitant to use a throating reamer to change a .120 to a .130-.135. The throat on a Dasher wears fairly quickly and if I were you I would stay with the .120. James Mock

 

[KenOath]

I went .120 for the 107s, next time will go .135 to allow for more jump.. haven't used 110s.
Cheers Rushty

 

[RussellJ]

Looking to shoot 107s or 110smk.

Chambering the 6BR and 6 Dasher
The Right Reamer Makes All the Difference -- Dave Kiff
We normally go with a 1.5 degree lead angle, unless the customer wants something different. For 60-68gr bullets we recommend a .060" freebore. For the 80gr bullets, .080" is a good setting. For the 100-107gr VLDs, a .115" -.120" freebore will allow you to get the base of the bullet up out of the doughnut area. This will save you lots of aggravation over the life of the barrel

 

[dkhunt14]

According to all the match shooters i know and talk with, .120 isnt enough. Most use .135 to .155. I use a .155. It allows the pressure to stay down so i can reach the velocity without poundimg the cases. Matt

 

[johara1]

Chambering the 6BR and 6 Dasher
The Right Reamer Makes All the Difference -- Dave Kiff
We normally go with a 1.5 degree lead angle, unless the customer wants something different. For 60-68gr bullets we recommend a .060" freebore. For the 80gr bullets, .080" is a good setting. For the 100-107gr VLDs, a .115" -.120" freebore will allow you to get the base of the bullet up out of the doughnut area. This will save you lots of aggravation over the life of the barrel

You can't lump the two together, one with a long neck and one a very short neck. With a Dasher and 105's you had better be in the .135 to .155 area plus it can change if you jump or seat them in, but those numbers will cover it. A 6BR or 6BR IMP. and a 105 .125 seems to be where you want to be........ Jim

 

[DanSavage]

Just found out that the actual reamer is a .270 neck and a .130 free bore. Should be pretty good, it is going to be a Kreiger Savage small shank bull pre fit.

I've have really good accuracy with a 6br Bartlien pre fit with x count at 30+ out of 40 at 300 yards.

 

[DanSavage]

I usually end up jammed or just off the rifles.

 

[Bkluke]

I use a.155 in my Dasher.

 

[bblackwell]

I've used the 107 Matchking in a Dasher and speaking from experience you need at least .155 , personally i'd probably go more than that. And 7.5 is the perfect twist for it.

 

[bobinpa]

Help me understand..... I thought a Dasher was just like a 6mm BR-AI (except the Dasher is .080 longer), and if so, in other threads on the 6mm BR-AI, some well known smiths are using reamers with .100 - .110 freebore with 105 class bullets. If all of this is true, why does it seem common or popular to run .125 - .155 in a Dasher?

 

[Sheldon N]

Help me understand..... I thought a Dasher was just like a 6mm BR-AI (except the Dasher is .080 longer), and if so, in other threads on the 6mm BR-AI, some well known smiths are using reamers with .100 - .110 freebore with 105 class bullets. If all of this is true, why does it seem common or popular to run .125 - .155 in a Dasher?

Reference off the neck/shoulder junction. 6BRA has a longer neck, so needs less freebore to keep the bullet clear of the neck shoulder junction and any potential donuts there.

 

[bobinpa]

Reference off the neck/shoulder junction. 6BRA has a longer neck, so needs less freebore to keep the bullet clear of the neck shoulder junction and any potential donuts there.

Ok, I'm confused..... I understand that freebore is referenced off the neck shoulder junction (to keep the bullet out of the donut), but doesn't that make the neck length irrelevant to a degree???? Aside from that, I picked the BR-AI vs the Dasher because I thought from the body/shoulder junction to the mouth of the case they were the same.

 

[johara1]

free bore is from the end of the chamber, look at a print the throat area... Jim

 

[savagedasher]

.135 works great . Depending on the barrel some wear fb faster then others .
Larry

 

[bobinpa]

Thanks guys.... I had my blinders on and couldn't see it..... I appreciate the responses/help.
Bob