Why is the 6mm Dasher so popular?

[SDC]

So, I've been happily shooting my "old-school" 6.5 Creedmoor PRS style rifle but I'm starting to think about jumping on the lower-recoiling 6mm bandwagon. The question is, which one?

My usual crowd-sourcing method for making these decisions is to look at what other people are using for the same task. According to the latest "What the Pro's Use", the 6mm Dasher makes up 41% of the top shooters in PRS.

What confuses me though is the average velocity numbers:

• 105 gr. = 2,847 fps (based on 21 shooters)
• 109-110 gr. = 2,825 fps (based on 18 shooters)

Just looking at the velocities, it appears that a straight 6mm BR (the smallest case capacity of the common 6mm cartridges) with a modest charge of Varget would accomplish the same speeds.

Is there something I'm missing as to why so many are running the Dasher if its case capacity isn't really needed?

 

[TheOfficeT-Rex]

2850 with a 105 is pretty quick from a straight BR. Dasher gets you a little more powder room to run the speed and you get the 40* shoulder.

 

[7mmMato]

Split it in the middle and go with a BRA. Can get 2850 easily and leaves room for no pressure problems in the heat or rain. Dasher will do the same but you have a shorter neck. Realistically any of the three will work just fine.

 

[morning would]

The thing about it is, how hard are you pushing it. With my 6 ARC I am shooting 105 VLD’s at 2815fps with a top end load of LeverEvo. In a bolt gun, of course. But the brass lasts 5-6 firings with Starline converted from Grendel brass or 2-3 with Hornady brass. With my Dasher I run the 108BTT from Berger at 2940 and the Alpha brass lasts forever. I think it’s probably the same with the BR. But I don’t own one yet. It’s next on the build list. I think. Just not sure where it would fit between the ARC and the dasher.

 

[Mordamer]

With Alpha 6 Dasher brass being plug and play there is no advantage to a straight 6 BR like there used to be when you had to make Dasher brass. You are way better off running a low pressure load than a high pressure load.

 

[RegionRat]

Is there something I'm missing as to why so many are running the Dasher if its case capacity isn't really needed?

Well look at it this way... this trend of the pack leaders running Dasher predates the availability of factory Dasher brass.

What that is telling you is that if we could have shot straight BR at those speeds we would have.

There is just enough advantage to Dasher when going out past 800 that it was worth the trouble back when fire forming was required. Now that you can just buy factory brass in Dasher (or BRA), there is no forming required, so why would you fight it?

If you really want to try and push straight 6 BR that hard, then nobody will stop you but the advice is to run one of the improved versions just to have the case volume margin and pressure in your favor. YMMV

 

[45-90]

So, I've been happily shooting my "old-school" 6.5 Creedmoor PRS style rifle but I'm starting to think about jumping on the lower-recoiling 6mm bandwagon. The question is, which one?

My usual crowd-sourcing method for making these decisions is to look at what other people are using for the same task. According to the latest "What the Pro's Use", the 6mm Dasher makes up 41% of the top shooters in PRS.

What confuses me though is the average velocity numbers:

• 105 gr. = 2,847 fps (based on 21 shooters)
• 109-110 gr. = 2,825 fps (based on 18 shooters)

Just looking at the velocities, it appears that a straight 6mm BR (the smallest case capacity of the common 6mm cartridges) with a modest charge of Varget would accomplish the same speeds.

Is there something I'm missing as to why so many are running the Dasher if its case capacity isn't really needed?

Because its almost perfect for accuracy and velocity needed to accomplish the task.
If ya don't have one, it should be your next rifle.

The 6 Dasher has several modes of operation, Varmints 58 gr Vmax 4100 fps.

Total accuracy very tiny groups, Varget, RL 15, running 105 to 109 gr bullets 2950 to 3020 fps for low S/D excellent accuracy little recoil.

High velocity steel loads or LR, I run 110 gr SMK at 3085 fps and 115 DTAC coated to 3020 fps.
But mostly the 110 SMK on steel high BC 3085 fps is flat trajectory, good accuracy, for way out there, so easy a child can shoot it.

 

[Lightning8]

To me, Dasher opens up more powder options with its more case capacity than straight BR.

 

[Niles Coyote]

The guys I play PRS with and use the 6mmBR seem to like the 2750-2800fps range for 105-110 weight bullets, most of these shooters have used dashers prior to moving to BR's. The BR will go faster but that seems to be a great area for consistency in all weather conditions and doesn't tax the brass much. The folks I know running a dasher tend to run them in the mid 2800's for the same consistency reasons and that is where I run my GT as well.

If your wanting to be in the mid 2800's I'd go with the Dasher or GT.

That said you are going to see some movement in this year's "what the pro's use", as 25cal's (both GT and 47L) are becoming more popular. Alpha's 25 GT brass in 500 packs sold out in a day and the 100 packs didn't last more than a week. Whether the 25's catch on long term is any one's guess... I opted to try the 25x47L but I am not sure there is a there yet outside of matches known for high winds or longer target engagements.

 

[kthomas]

With Alpha 6 Dasher brass being plug and play there is no advantage to a straight 6 BR like there used to be when you had to make Dasher brass. You are way better off running a low pressure load than a high pressure load.

Longer necks in BR/BRA.

But yeah, having straight up dasher brass ready to go certainly helps.

 

[kthomas]

I think it's a coin flip between Dasher/BRA.

I happen to have a BRA, but I'm sure I would be just as happy with a Dasher.

They more or less do the same thing, with subtle nuances between them.

I don't really see a reason to pick BR over a BRA (or Dasher). Fireforming is incredibly easy with a BRA - just load BR rounds for the first firing and away you go. If you go Dasher, start off with Dasher brass, as it's more fickle to fireform.

BRA's have longer necks, which those in the BR world will tell you is an advantage. How much is an entirely different conversation, and probably much more academic then practical, especially for PRS.

No matter which way you go, make sure your gunsmith uses an appropriate reamer for your uses. There's a lot of tight neck reamers for these cartridges (due to the BR crowds), which is a hindrance for our type of shooting.

 

[RegionRat]

No matter which way you go, make sure your gunsmith uses an appropriate reamer for your uses. There's a lot of tight neck reamers for these cartridges (due to the BR crowds), which is a hindrance for our type of shooting.

Yes. It is important to let them know the type of shooting, the bullet and seating depth too. Sometimes, they even name the reamer for the type of brass e.g. Alpha Dasher.

The reamers are not a problem and haven't been for a long time. The reason is that the same folks who shot Mid Range Highpower in sling and F-Class have been doing this a long time and many want to run Dasher in LR matches when/if the wind allows. When the eTargets became popular for avoiding pit duty, it became necessary to stay supersonic for the transducers to pick up the shot. Thus, the Dasher over the 6 BR for the margin against sonic at 1200 yards.

 

[SDC]

All great replies, thanks for the info.

My assumption regarding 6BR velocities was based on some quick forum searching, not first-hand experience. From this feedback, I'm guessing the reports of 105's at 2,850 fps were from some stressful loads.

I think the availability of Alpha brass and prefit barrels for my 737r makes the decision easy.

 

[Rio Precision Gunworks]

All great replies, thanks for the info.

My assumption regarding 6BR velocities was based on some quick forum searching, not first-hand experience. From this feedback, I'm guessing the reports of 105's at 2,850 fps were from some stressful loads.

I think the availability of Alpha brass and prefit barrels for my 737r makes the decision easy.

If people could actually see the pressure they are running, most would be pretty surprised. 6br running 2850 and 6 dashers running over 2950 are mainly going to be over the 65k psi mark pretty easily a decent amount of the time. Not always, but much more than people realize.

As @Mordamer previously stated, staying in lower pressures makes ammo "happier." You'll have much more consistent ammo and never run into any mechanical issues when temp/humidity changes.

 

[kthomas]

If people could actually see the pressure they are running, most would be pretty surprised. 6br running 2850 and 6 dashers running over 2950 are mainly going to be over the 65k psi mark pretty easily a decent amount of the time. Not always, but much more than people realize.

As @Mordamer previously stated, staying in lower pressures makes ammo "happier." You'll have much more consistent ammo and never run into any mechanical issues when temp/humidity changes.

Some barrels are definitely faster than others. My 6BRA barrel is surprisingly fast, given the powder charges it consumes.

However, most people are definitely running close, if not into pressure with their loads. And BR based cartridges hide pressure signs well.

 

[anisbet75]

I run 105 hybrids in a strait BR at 2816. Pretty hot load. I shoot next to a dasher a lot and he is consistently a couple tenths inside or flatter than I am running 108s at almost 2900. Doesn’t matter at all inside 600 but beyond that little bit of velocity and a couple tenths of wind advantage can really help a bad wind call. With the dasher your not as hot as a 6cm so van still see your shots and have less recoil. I shoot straight BR mainly because it is easy on me.

 

[louu]

It's to late to setup a 6mil now everything is out of stock. You gotta do that shit in November-December

 

[BoilerUP]

I run a 20" Dasher "do everything" rifle...get 2800 with a 107 and 32.4gr Varget.