6MM GRINCH Defeats entire Field of 6PPCs

[Terry Altom]

I'd love one of these for short range, but the local club shoots for score, so of course 30BRs rule that.

 

[moondog]

Hi Tom
I get 2970-3005 with 31.5-31.8 of RE15, I can get similar velocity with Varget (2208) but it's a little hard the cases.
I agree with Jim the best part or the Brackley is how easy it is to make GOOD cases, this was my big reason to move away from the Dasher, it was just to hard to make GOOD cases, easy to blow cases out to right shape but I struggled to control where the case got blown out from, the shoulder (where we want it to come from) or a combination of shoulder and the web area (BAD !!).
Matt P

Hey Guys, as far as making good Dasher cases, Do you think hydro-forming would minimize the
issue?

 

[1911mag]

What freebore is for the 103's?

 

[Brett S]

With the Grinch the 135 freebore works best

 

[Ghansen]

Just some Grinch load feedback FYI,

I ran up some loads to the point primer pockets got loosened which is not a great thing to realize but in the absence of any other pressure signs to 31grains I got the following data.

25" 8.5 twist Krieger (re-birthed) .270 neck standard #3 print free bore to .130

105 Berger VLD naked, Fed205m primers- very warm low humidity

Powder H4895
@ 30.8 grains (actual 31.1) @ 30c/86f punctured a primer. No velocity data.
@ 30.3grains 2960fps (shot this load at 550yds with minimal vertical. Consensus - Load too hot for this barrel, I like to re-use my brass a few times)
@ 30.0 grains about 2900fps and shot well within expectation (shot this load at 1000 and was very predictable in windy conditions)

Powder RL15
@ 30.5 grains avg. 2860fps with 30fps ES.
Grouped well for 105's at 100 @ 30.3, waiting on some powder to arrive, so will test more soon and maybe try CCI 450's as well.

Powder Benchmark, 80g Berger Varmint Naked Fed 205M no real results yet but I am suspecting a lower charge with my barrel might be ok.
@30.3 gave 3118fps
@30.5 gave 3129fps

I will test more loads in depth and update for your info.

 

[Rtheurer]

You guys should give 31.3gr or there abouts of CFE223 with 87gr Berger VLD or any bullet under that grain wait actually. Seems to be good in a lot of Barrels and bullet combo's.

 

[Tim Singleton]

I've been thinking of trying one of these in short range 100-200 yd
Just wasn't sure the 80gr at 3150 has that much more to offer over the 68gr at 3400

No way to know but try it
Good project for the winter

 

[tbeasley]

Jim,

I knew my Dasher comment would step on a few toes. There are guys that absolutely have the Dasher humming. It is an extremely accurate cartridge. But it's finicky compared to the 6BRs and others.
That's not just my opinion but that of several top shooters in the 600 yard competition. At 600 yards there a disproportionate amount of 6BRs and 6BR variants shooting and winning compared to the amount of dashers on the line.

Never had a flyer with your Dasher. That's a pretty bold statement. Bring your Dasher to my house and let's shoot it. If you can shoot an agg at 100 and 200 yards without a flyer I'll send you home with all the bullets you have on order for free. Besides I'd enjoy the visit!

Bart

Bart

I'm finding the accuracy node to be between 2920-2960 fps just depending on the barrel. You start pushing it up there at Dasher velocities and you'll see the extractor groove grow to the point it'll no longer go into your shell holders.

I agree James...nearly any 8 twist barrel with said 105-107gr bullets fly freaking accurate in the 2910-2950fps.
I feel if folks would just run their dasher at these lower speeds, there mouths would drop...the vertical alone I have seen from 3 different 6mm cartridges at these speeds are stupid crazy. Done with 6brx, 6xc, 6 comp.match

 

[BartsBullets]

Just some Grinch load feedback FYI,

I ran up some loads to the point primer pockets got loosened which is not a great thing to realize but in the absence of any other pressure signs to 31grains I got the following data.

25" 8.5 twist Krieger (re-birthed) .270 neck standard #3 print free bore to .130

105 Berger VLD naked, Fed205m primers- very warm low humidity

Powder H4895
@ 30.8 grains (actual 31.1) @ 30c/86f punctured a primer. No velocity data.
@ 30.3grains 2960fps (shot this load at 550yds with minimal vertical. Consensus - Load too hot for this barrel, I like to re-use my brass a few times)
@ 30.0 grains about 2900fps and shot well within expectation (shot this load at 1000 and was very predictable in windy conditions)

Powder RL15
@ 30.5 grains avg. 2860fps with 30fps ES.
Grouped well for 105's at 100 @ 30.3, waiting on some powder to arrive, so will test more soon and maybe try CCI 450's as well.

Powder Benchmark, 80g Berger Varmint Naked Fed 205M no real results yet but I am suspecting a lower charge with my barrel might be ok.
@30.3 gave 3118fps
@30.5 gave 3129fps

I will test more loads in depth and update for your info.

Best accuracy I've seen with the Grinch With 103/105 gr bullets is around 2920. If you run it much hotter than that you better get use to making new brass!

3180 seemed to be a sweet spot with 12 twist barrels and my 80 gr boattails.

Bart

 

[RickB]

I'd say winning a short range match is new and it won't be long until it's winning 600 yards matches. What I like about it, is it just doesn't throw shots like a Dasher.

Bart

The Grinch seems to be achieving velocities very much like those achieved by the 6 BR Ackley (BRA). How does it compare case capacity wise?

 

[Brett S]

I've been thinking of trying one of these in short range 100-200 yd
Just wasn't sure the 80gr at 3150 has that much more to offer over the 68gr at 3400

No way to know but try it
Good project for the winter

I decided to try and see how hard I could push Barts 80 gr bullets in my Grinch last weekend. I started getting pressure at 3420 fps with benchmark powder. It shot really well around 3350. Another shooter called me and he was getting the same results. All testing was done with a labradar.

 

[Brett S]

Dave Dorris shot a Grinch at the last match in Memphis and had a great weekend. His agg was 1.9XX for 16 targets. Now I don't have a clue what git down powder is or what fireform bullets he was using.

 

[Tim Singleton]

I decided to try and see how hard I could push Barts 80 gr bullets in my Grinch last weekend. I started getting pressure at 3420 fps with benchmark powder. It shot really well around 3350. Another shooter called me and he was getting the same results. All testing was done with a labradar.

Now that'll get your attention 3350 with the 80s

 

[Frankr]

Congratulations .

Are you saying old T.J. Jackson was right. All indications were you should have made a right but everyone went left or something to that sort.. Was some of my favorite articles from Precision shooting was T.J. Jackson and how he made 6BR's shoot in the zero's.

 

[Rtheurer]

Dave Dorris shot a Grinch at the last match in Memphis and had a great weekend. His agg was 1.9XX for 16 targets. Now I don't have a clue what git down powder is or what fireform bullets he was using.

Makes his own bullets..

 

[IdahoSharpshooter]

Bart is my hero...

 

[BartsBullets]

The Grinch seems to be achieving velocities very much like those achieved by the 6 BR Ackley (BRA). How does it compare case capacity wise?

The BRA with the shoulder blown out has a bit more capacity then the Grinch. I believe Brett tested the straight 6BR and Grinch case and found them to be nearly identical. Accuracy wise I run my Grinch at 2910 to 2920. The Bra I shoot at 2920 to 2930. Both will shoot faster, but the accuracy just wasn't there for me. Some are having success at 2960 to 2970 with the BRA. But that's not where mine shoots.

Bart

 

[tclaunch]

Dave Dorris shot a Grinch at the last match in Memphis and had a great weekend. His agg was 1.9XX for 16 targets. Now I don't have a clue what git down powder is or what fireform bullets he was using.

That powder is pulldown RL15 sold by HighTech out of St Louis, some of the best RL15 I ever shot. Its what I used in the 2012 600 yd Nats, and came in 2nd Lt Gun group. Great powder. Its called Long Range Match on their site.

 

[GSPV]

With the 13.5 lb weight limit, the unlimited class, and the caliber neutral target, it will be interesting to watch the 6 Grendel-ish and 6 BR variants in UBR.

Around here, we have various “flavors” of “varmint” matches. One of them is 300 yards on varmint outlines with a 1.5” X ring. There are no sighters. We shoot it through the winter. So far, 1:10 6 BRs with 80-90 grain bullets with H4895-ish powders are the most consistent winners. Of course, the real deal is learning to play the wind without wind flags or sighters.

 

[gunsandgunsmithing]

Powder Benchmark, 80g Berger Varmint Naked Fed 205M no real results yet but I am suspecting a lower charge with my barrel might be ok.
@30.3 gave 3118fps
@30.5 gave 3129fps

I will test more loads in depth and update for your info.

I've run 30.8gr of BM in my 26" barrel some. It shoots well there, which is right at 3,200 fps in my barrel. It actually likes a hotter load better but I haven't revisited it since it got hot outside. It was borderline too hot then and I backed it down to keep from wrecking my brass right outta the gate. The hotter load is running right at 3,400fps though, and is a hammer! I'm gonna screw that barrel back on the gun as soon as I can. I was fireforming before..now it's all formed and a bit cooler out. I'll do a bunch of testing with it very soon. Looking forward to spending some time with it as it shows real good potential. Also have some new 80's to try in it made by Larry Moore(Hillbilly Bullets). He just won a UBR match with them at 100-200 yards this weekend in a 6 BRA .The winds were 15-25mph and switchy though, so he earned it and the 80's probably were a good choice on a day like that. Mine is in a straight 6 Grendel with 80gr EPS bullets and .070 freebore, specifically for the 80's but that freebore works well with 65-80 grainers. The 68's that I shot in it over 33.0 gr of n133 were drilling a hole and had to be screaming along, but I did not shoot them over a chrono. I bet they're running 3,700-3,750fps range!