6mm Dasher vs 6mm Creedmoor

[NickB1075]

Sure would be nice if guys would state what length barrel they're running when spouting off velocities...

My Dasher is a 28"
Creedmoor is a 27"

Nick

 

[Kracken McGraw]

Talking of the 6mm Creedmoor as a Varmint cartridge, is it versatile enough to shoot 75 grainers or bullets like the Sierra #1530? I really like the accuracy of the 6.5 Creedmoor and this necked down version has my interest if it’s a allarounder like the .243. I didn’t know if it was specifically built justfor the 107 grain type bullets.

 

[NickB1075]

Talking of the 6mm Creedmoor as a Varmint cartridge, is it versatile enough to shoot 75 grainers or bullets like the Sierra #1530? I really like the accuracy of the 6.5 Creedmoor and this necked down version has my interest if it’s a allarounder like the .243. I didn’t know if it was specifically built justfor the 107 grain type bullets.

I can't speak for the 75 grain class bullets but my rifle with a 1and 8 twist shot extremely well with the 88 grain flat base Bergers.

I don't think the light bullets will give a problem. The only issues I would see is the long freebore often found on the reamers designed for the the 105 class bullets.

Nick

 

[RampedRaptor]

Try the 6 creed out. I’m ordering my 3rd Barrel now. Easy to load for. Great brass/performance. Barrels don’t last long but nothings free in life so that should be a known. 26” Barrel, 1:8, 3140-3160 fps with a 105gr bullet. Mag length. Can go faster but some comps require less than 3150fps.

 

[Kurz]

Sure would be nice if guys would state what length barrel they're running when spouting off velocities...

'Spouting off', you mean as if the velocities are exaggerated?

The high node I quoted is from a broken in 30" barrel on a single shot action. The velocities were monitored and recorded by both a LabRadar and a Magnetospeed V3.

I have also recorded velocities from 26" and 28" barrels. I might even be able to find some 19" barrel information along with some from 22" to 24".

Talking of the 6mm Creedmoor as a Varmint cartridge, is it versatile enough to shoot 75 grainers or bullets like the Sierra #1530? I really like the accuracy of the 6.5 Creedmoor and this necked down version has my interest if it’s a allarounder like the .243. I didn’t know if it was specifically built justfor the 107 grain type bullets.

This will depend upon the reamer specification used to cut your chamber. Before getting involved with longer range accuracy, I used to shoot a wide variety of bullet lengths (weights) in some rifles with other more generic chambers. Now though when many of my Creedmoor chambers are cut to accommodate the longer VLD bullets, I make another barrel using a reamer and a twist rate more specific to varmint style bullet. Much of the discussion here is oriented around the longer range bullets with chamber cut to accommodate them. It's nice to see that there are some folks who think the Creedmoor will make a good varmint cartridge, which is does!

 

[Rob01]

Yup the chamber reamer and freebore will come into play with those lighter bullets but actually those shorter freebore chambers for the longer VLD style bullets would probably work better for the 75grn bullets than the longer .183 freebore that was the spec chamberin most factory rifles and even the customs. That .183 works great with the 108 ELDs though as it's the chamber I have in my rifle. Those longer VLDs have the ogive back farther so they shorten up the freebore to keep the OAL down as you know.

 

[reubenski]

Comparing a Dasher and a 6 Creed are a bit apples and oranges. I have shot a Dasher for the last 6 months over two barrels. I shoot Hybrids and DTACs at 2950 and 2900 respectively using Varget. 27" and 26" barrels. It treated me well in PRS and I was pretty happy with it but Varget has turned out to be a throat torcher and your options for a Dasher are H4895 and 8208 which are both faster powders and I'm doubtful would help barrel life. Bottom line those loads I shoot are probably over 55K PSI chamber pressure. They are also reasonable if you compare what other Dasher and BRX shooters are running. Another annoyance is running it from a mag. It ran great for a while but as soon as you get a fair amount of dust and grit in a mag the stubby little case starts to nose dive or hang up, even in a TL-3.

I am considering switching to a 6 CM or 6SLR and downloading them with a slow burning powder to 2950 or so; keep the chamber pressure under 55K. I don't feel at a disadvantage running 6mm at that speed compared to guys shooting 6 Creeds at 3150. My theory, so far, is that by using a "grown-up" cartridge it will feed more reliable in the less than ideal conditions of Colorado, Utah, and other windy, dusty areas. And obviously that I will get longer barrel life. 6SLR has more capacity so chamber pressure will be lower at 2950 - 3000, but 6CM has a shorter OAL for chasing with 110's and of course no-nonsense Lapua brass.

 

[Rob01]

Reubenski that would be a good option. Always easy to download and run at a lower node. I did that with the .243 and the 115s back in 2004 when running them in what is now called PRS matches. I ran them at 2990fps and everyone else was running them at 3100fps. I was at 1880 rounds when I sold the rifle and it was still a solid half MOA rifle and that was after hard match shooting. Some stages of 20 shots in a minute and the like. Downloading the ^ Creed to 2900-2950 would be a good option to save barrel and still get performance.

 

[Kurz]

Another annoyance is running it from a mag. It ran great for a while but as soon as you get a fair amount of dust and grit in a mag the stubby little case starts to nose dive or hang up, even in a TL-3.

My theory, so far, is that by using a "grown-up" cartridge it will feed more reliable in the less than ideal conditions of Colorado, Utah, and other windy, dusty areas.

While I can't disagree with your choice of the 6mm Creedmoor, I can also recommend the use of a much older design from Mike Walker. This is the 250 Savage with the neck pushed back slightly and necked down to take the 6mm bullets. This was very popular on some of the benchrest circuits. From personal experience, this cartridge feeds fluidly from magazines even in dirty conditions, has a short case length like the Creedmoor and is just about the right balance for your 55K pressure and 2900 - 2950 fps. I've use the cooler burning, temperature stable Re16 with great results. Here you have access to the Lapua 22-250 brass to use and pushing the neck back cures any small variations in the resulting cases.

The improved version of this is the 6XC from David Tubb. Since it's improved the case capacity is higher but you can use a cooler powder such as Hybrid 100V to keep both the temp and pressure down while enjoying your lower velocity node. David's newest release of brass is actually really good.

Personally, I would run the 6x47 Lapua and call it a day. The near ideal case capacity, modern brass from Lapua loaded over Hybrid 100V is just what you asked for.

6mm INTERNATIONAL (WALKER VERSION)
American wildcatters began fiddling with the 6mm's after WW2. This is one of several versions that exist of these experiments and were popular with Bench Rest shooters. Based on the 250 Savage necked down, but differs from the Donaldson version as it retains the original length but with a longer neck and the body taper the same as the original 250 Savage.

 

[reubenski]

Interesting suggestion Kurz. I've already ruled out the XC and x47 bc as the two smaller of the "usual 6mm suspects" downloading them 150 - 200fps is probably going to look more like 2850 - 2900fps. At that point I could probably just load the Dasher at 6BR speeds and the wind call at 800 is probably the same.