What 600 yard cartridge to rebarrel a 6ppc boltface to?

Discussion in '6PPC, 6-6.5x47, 6XC, 6 Rem, 243' started by slm9s, Dec 19, 2017.

  1. Ledd Slinger

    Ledd Slinger Gold $$ Contributor

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    I agree the PPC bolt face does limit selection to cartridges with smaller capacities, but the 243 LBC Turbo 40 or 6mm AR T40 (both are identical and basically just "Dasher PPC's") will push the 105gr bullets up to 2900 fps from a 26" barrel. Not a speed to brag about by any means, but enough to get the job done at 1K and far more than enough poop for 600 yards.
     
    Last edited: Jan 11, 2018
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  2. steve_podleski

    steve_podleski

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    What load gives this cartridges 2900fps?
     
  3. Ledd Slinger

    Ledd Slinger Gold $$ Contributor

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    Working up with RL15 and BLC-2 will get you there with the 105s. I'm running a 27" barrel on my 243 LBC T40
     
  4. steve_podleski

    steve_podleski

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    How much powder?
     
  5. Dan Hall

    Dan Hall Silver $$ Contributor

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    I also just had a Grinch barrel cut for a Borden short range gun I’ve got and it’s showing lots of potential.
     
  6. Dan Hall

    Dan Hall Silver $$ Contributor

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    Today I was forming brass with my Grinch at 100 yards and shot 10 groups Of 5. The ag was .210” which doesn’t suck for forming loads. With a 6PPC as parent case I see the Grinch as one very accurate cartridge. Next step...600 yards. I would look at the 6 Grinch very closely.

    Dan
     
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  7. gunsandgunsmithing

    gunsandgunsmithing The best tuners and wind flags on the market Gold $$ Contributor

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    For those that are on the fence about the 6 Grendel or Grinch...don't be. It's an impressive case and has a lot of flexibility. Enough that I think it can win at short and long range. That's impressive , all by itself if true.

    I run a straight 6 Grendel rather than the Grinch. I think both are excellent but I prefer the simplicity of not having to fire from and being able to just drop a bushing in a Redding Grendel die.

    Mine is currently a 12 twist and shoots 68-80 grain bullets well enough that I think it's as good as a PPC but with better bc.

    You can rebate rims and have more case options but I highly recommend trying a Grendel or Grinch before getting tied to rebating rims or the expense of opening the bolt. Imho, it's just not necessary.--Mike Ezell
     
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  8. Alex Wheeler

    Alex Wheeler Gold $$ Contributor

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    Straight 6br is still probably the most used in 600, I would do a grinch and not feel like I am missing out. But if you can have the bolt face opened up then you can run anything you like.
     
  9. Dan Hall

    Dan Hall Silver $$ Contributor

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    I agree that the Grendel would be a simple turn key tack driving machine. The parent case is a proven winner, the brass is top notch and the bullet selection is getting close to perfection. Both these cartridges have the potential to set records. My next barrel is going to be a Grendel. This level of accuracy is addictive.
     
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  10. Ledd Slinger

    Ledd Slinger Gold $$ Contributor

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    The improved version of the Grendel. "243 LBC T40" aka: "6mm AR T40". Basically a 6mm Grendel "Dasher" (shoulder blown forward and out to 40 deg)
    Produces velocities with 105gr bullets adequate for shooting 1K. Easily enough gas in the tank for 600.

    Pic of my 'improved 6 Grendel' next to a standard 6mm PPC case. You can see the line in the shoulder where the original 6.5 Grendel shoulder was located prior to fireforming.

    2018-01-05 09.16.43.jpg
     
    Last edited: Jan 11, 2018
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  11. Al Elliott

    Al Elliott Silver $$ Contributor

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    You might want to look back at a "6 Rampage" or 6.5 Jap. If I remember correctly the 6.5 Jap case has the ppc head size. The Rampage was made by running in a ppc reamer long to match the 6.5 Jap case. It was used in Hunter Benchrest competition and was not hard to make but it wasn't used much because we didn't have the custom full length size dies we can get today and got tight after a few hot firings without a full length size die.
     
  12. mr.big

    mr.big

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    my Farley right eject port is too short for the x47 Lapua case but it wouldn`t take much if somebody wanted to open it a little,,but if I wanted a Dasher that would work,,
     
  13. searcher

    searcher

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    I have a Sako 6ppc that I have long waffled on what to do with it. I have other custom-built ppc's and such that I would use for matches - and the light weight of the Sako sucks for seeing your hits when varminting. I don't want to put a brake on a barrel that is 3/4 shot - especially now that I have to shoot lead-free ammo where I live and it takes a faster twist than what I have (1-14) to stabilize them. That led to what others have suggested to you - open the bolt face, put a heavier barrel chambered in , say, 6br. I fear doing that with my dainty little Sako as the bolt is so slim as to provide almost nothing to shroud the case as it is. Just not enough there to safely do it - or at least I don't think so. Most guns, I think, do have the material where you want it to get the job done - as not much is coming off the bolt face. Then you are in serious business if you do a 6br, Dasher, etc. for 600. I'd definitely do that before going the route of the Grendel. The Grendel is a very high-pressure cartridge - and is one that is not to be pushed - or much, anyway. I have blown three bolts in my A/R. Done with that. Factory or less loads are the rule now. You will also get less velocity than others have indicated probable. I like the Grendel - but it will get smoked by a 6BR or Dasher.
     
  14. gunsandgunsmithing

    gunsandgunsmithing The best tuners and wind flags on the market Gold $$ Contributor

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    The weak link in your post is not the cartridge, but the AR15 platform.

    I've built dozens and have shot several custom bolt guns chambered in variations of a Grendel. They all like pressure and the Lapua brass is fantastic.

    I've also built more than a few AR based rifles on it. That's where you are correct. The bolt is the weak link in that platform but there are better bolts that are an improvement over stock bolts.
     
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  15. searcher

    searcher

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    I agree with you completely gunsandgunsmithing. The Grendel DOES love pressure and of course, bolt guns can handle more pressure than the "weak-link" A/R bolt will allow. The Lapua brass is VERY stout in that caliber. The Grendel shoots absolutely the best when fully throttled. Take the 6.5 Grendel. It can shoot a 107 grain bullet about as fast as a 6BR per most manuals. But that is where the manuals and reality end. Almost ALL 6.5 Grendel full-power factory-velocity loads are highly compressed loads. So much so that the bullets will back out if not heavily crimped. I won't split hairs and say one can't find a faster-burning powder that you can't get more of it into the case. I DO know that I CAN get far more 'extra' powder into a Dasher, for example, to bring my velocities up to where you just can't get a Grendel safely with a similar bullet. And I can do that without being paranoid about reaching for my "extra wide" safety glasses. Interestingly, I bought the best touted "upgraded" bolts after each bolt blowout, thinking I had a 'cheap' or defective bolt. I won't mention the high-status names that also failed- as I WAS overloading. Again, I'm not knocking the Grendel variants. But if i had a choice, I still stick by what I said, even in a nice bolt gun. That, of course, if bolt-face allowing. My reasoning is you can obtain higher "safe" performance from the Br and the Dasher. Guess I felt the urge to include the bolt blow-ups, though I got off the point.
     
  16. gunsandgunsmithing

    gunsandgunsmithing The best tuners and wind flags on the market Gold $$ Contributor

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    I won't disagree with you but I'm getting 3,400fps with 80's and around 3,700fps with 68 gr bullets from a straight 6 Grendel case in a Borden BR bench rifle. I'm getting 3,000 with 118 gr 30 cal bullets from the same rifle and same Grendel case and can push it harder. The gun shoots great there and brass life is approximately 50 firings on Lapua 6.5 Grendel brass.

    If all else is equal, bolt thrust is in part based on cartridge head diameter. Larger head=more bolt thrust. So, strictly speaking to bolt lug stress, the smaller head of the Grendel will result in less bolt thrust at equal pressures. This is just physics though. I'm not arguing.

    It does stand to reason that a bigger case will out perform a smaller one. Smaller cases of the same bore diameter tend to work better with slightly faster powders. This does account for a small part of it's excellent efficiency.

    The other side of the coin is when pushing heavy for caliber bullets, there isn't a full replacement for displacement...meaning the larger case shines most, then, wheras the smaller case can keep up with lighter bullets.

    Another example is a 7 Mag vs a 280 AI. The velocity numbers are very close but the capacities are quite different. When you go to the heavier projectiles, the 7 Mag walks away from it, but not by much. This is an example of cartridge efficiency.
     
  17. searcher

    searcher

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    You fail to win me over, if that is your intent. The 7 Mag vs 280 comes down to a few hundred fps. Not much - but that IS why we have Dashers, Ackleys, the new Nosler line of cartridges, etc.. That all said, I am less than enamored with your velocities as you had to go almost 20% over max book recommended loads to get there. And that was my point - which caliber has the best 600-yard performance potential with the safest pressure. Safe does not just describe a load which doesn't blow a primer or stick a bolt (or blow up A/R bolts as I did). I doubt you know what the pressure is you are running - only that it seems safe in your rifle with the load you are using. And that is O.K. for you. The poster was looking at informal targets at 600 and varmints. I guess it would be up to him to decide how hot he is willing to load to have the "better" Grendel. Frankly, I'm AMAZED you have 50 loadings on your brass running those velocities, even assuming you are using a custom "slight full-length" die or neck sizing only. What powder are you using?
     
  18. gunsandgunsmithing

    gunsandgunsmithing The best tuners and wind flags on the market Gold $$ Contributor

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    I'm using n120 in the 30 and n135, Benchmark and lt 32 in the 6. I am curious where you found data for either the 6mm or 30 cal Grendel cases, though. Both are wildcats and there is no min or max book data for either. FWIW, I have a Pressure Trace system. They are far from the end all, be all tool, but they do give you a good idea of relative pressures.

    I was trying to be helpful to the op. Our conversation should probably stop so that the op can get his needed info relative to a ppc bolt face cartridge, rather than our pissing match, which is what it is becoming.
     
  19. johnfred1965

    johnfred1965 Silver $$ Contributor

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    To the OP, I also like the grendel case and it would be a piece o' cake for you. One thing I would be wary of though is to take reloading advice from someone who has blown 3 bolts out of an AR system. They may not be a bolt action, but those bolts are damn hard!
     
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  20. nockhunter

    nockhunter

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    How about a 8 twist 6ppc, or 6grendel????

    Mike
     
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