6 Dasher Build Help

[MvHTjy]

Hello, new guy here. Looking at getting back into PRS-style competition (ran 6mm creedmoor a few years back) and trying to build a new 6 dasher rig. Thinking about ordering a preferred barrel blanks barrel for Lapua Dasher with .104fb and .274 neck (w/alpha reamer?) Also planning on running Alpha OCD brass and thinking about a SAC modular sizing die but I'm not sure if I need the Alpha Dasher or the regular dasher die...why is this so damn confusing? Norma vs Lapua vs Alpha legacy reamer vs wtf...

 

[MvHTjy]

or if anyone can point me to a solid reference explaining all of the 6 dasher chambering nuances (if it even exists), I'd appreciate it. So far I've concluded that Norma brass has different specs than Lapua brass...and Alpha Munitions brass has the same as Lapua. However, the Alpha legacy reamer has different specs and therefore needs it's own special sizing die?

• Modular Sizing die Alpha Dasher is intended for chambers reamed with the Alpha Legacy reamer specs with utilizes a .0750 Neck / Shoulder radius and a .0300 Body Shoulder Radius

anyone know what the "standard" reamer specs are?

 

[Mordamer]

If you have it reamed with the Alpha reamer (which is a great reamer and spec'd near perfection) you can use either the Alpha bushings from SAC or the regular bushings and either should work fine. The normal neck/shoulder junction on most non-alpha chambers is .060". If you use the regular bushings in combination with an Alpha reamer it will only slightly size more right at the radius of the neck shoulder.

A guy could get into some interference and sizing problems if he used the alpha bushings in the SAC die and didn't have an Alpha chamber reamer, but not the other way around.

 

[MvHTjy]

@Mordamer thanks for the info! Makes perfect sense now. I was getting tripped up on what the neck-shoulder radius actually meant. Alright now that that's settled, the only other thing I'm concerned about is the neck size for the barrel. PBB only offers .274 but my alpha brass (and SAC bushing) is .266. Is an eight thousanths difference too much? I'm not sure what the acceptable range is.

 

[Krob95]

that’s pretty standard on neck diameter for loaded rounds and the chamber. You’re good to go man.

 

[MvHTjy]

Awesome, thanks guys. Now comes the waiting game for the barrel

 

[45-90]

Hello, new guy here. Looking at getting back into PRS-style competition (ran 6mm creedmoor a few years back) and trying to build a new 6 dasher rig. Thinking about ordering a preferred barrel blanks barrel for Lapua Dasher with .104fb and .274 neck (w/alpha reamer?) Also planning on running Alpha OCD brass and thinking about a SAC modular sizing die but I'm not sure if I need the Alpha Dasher or the regular dasher die...why is this so damn confusing? Norma vs Lapua vs Alpha legacy reamer vs wtf...

I built a 6mm Dasher with finish reamer 104" FB and .272" neck, standard Wilson bushing dies ...works terrific with Alpha brass, very accurate, and takes my high pressure loads as well as target loads very well. Bartlein 7.5 Twist 28" M 24. Works with bullets from 55 to 115 gr.
58 gr vmax 4100 fps for varmints. 107 SMK 3134 fps 110 gr SMK 3085 fps, 115 Dtac 3020 fps, for speed...or RL 15 and Varget for 105, 107, 108 gr Berger or Sierra for tiny groups in 2950 to 3020 fps area. Also recommend Remington 7 1/2 primers for Alpha brass as they are slightly beveled on the front and seat normally, whereas CCI are square and quite snug, with new Alpha brass...just load and shoot... no fireforming, expect small groups.
I "chambered" my own barrels, (no, I did not, "spun it up", morons, that statement tells me all I need to know about you!)... and set it up with Alpha brass as the go gauge and the go gauge with slight resistance. Super accurate, no recoil.
With 110 gr SMK at 3085 it's good for way past 1000 yds, if you're interested in that.

 

[Cornerstonearmory]

For reference you can always call SAC. Mark and his team are extremely versed and informative. Those people are awesome. They will answer any questions you have. Also, they know their products better than dudes online.