** UPDATE II** My New Project: 7mm-08 Ackley for F-Open

Discussion in 'Big Stuff -- 6.5mm, 7mm, 30 Cal' started by ShootDots, Sep 8, 2017.

  1. ShootDots

    ShootDots Gold $$ Contributor

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    I have had such great success with my .260 Ackleys that I thought I would see if the benefits would translate over to 7mm. I have had enough 7mms, such as "Straight" .284's, Shehanes and SAUMs to know that more often than not, getting the level of accuracy I want (not larger than 1.125" @ 300 yards) can be a frustrating proposition. I have found the "7's" to be a bit on the finicky side. I have never found that to emanate from the 6.5's.. I have often wondered if it was inherent in the 7's or case design or what..
    I also know that the .284 and it's variants, suffer from weak primer pockets and many, if not most times, you do not get the life from them as one would expect. Not so with "non-rebated rim" cartridges, especially the cartridges formed from the .308 Palma brass. So I decided to see if I can get the strength and accuracy out of the 7mm by going to a 7mm-08 and making it into an Ackley, using the Palma brass.
    Rifle Specs: Pierce Short Action "coned bolt" action as the basis.
    Jewell trigger set at 2oz.
    Krieger 1.250 "straight" w/ conventional 4 groove rifling, utilizing a 1-9 twist set at 30".
    Ray Bowman "Electric Blue" wood laminate "LowBoy" stock
    PT&G Reamer with a .313 neck and .270 freebore
    180 gr. Berger Hybrids / RL-16 Powder and Remington 7 1/2 BR Primers.
    GOAL OF PROJECT: To have a 180gr Hybrid (or a 180 VLD) running somewhere north of 2750F.P.S. with the level of accuracy noted above..

    FIRST ITEM was to fireform 130 pieces of brass formed into 7mm-08 Rem from the .308 Palma brass. This would get the brass ready AND get over 100 rounds down the barrel in the hopes of going past the "speed-up" associated with new barrels. This was done over a period of 3 days. They came out nicely fireformed. About the only thing "lacking" was the nice "sharp / crisp" shoulder you get with 2-3 firings.

    SECOND ITEM was to go and run some 180 Hybrids using the RL-16 powder. Since there is really NO load info for what I was doing, I was "flying by the seat of my pants" and did not want to run into problems. I know that RL-16 has a near identical burn rate as H4350, so I looked at several manuals and their loads for a "straight" 7mm-08. Since these manuals appeared to be using the 175 Nosler Partition (which by the way has a long bearing surface) and they were stating "about" 42.4 grs of H4350, I thought that with RL-16 I could use that as a starting place and work up from there.

    RESULTS OF FIRST DAY OF LOAD DEVELOPMENT: I went from 43.2 to 44.2 in 0.20 increments. This would give me a base-line to then use QuickLoad to see where I could or needed to go from there.
    43.2 gave me about 2560f.p.s. "average" with fairly HIGH e.s.'s.. I believe this was from the powder not burning efficiently due to lower than anticipated pressures.
    43.5 right at 2600 f.p.s. STILL with high e.s.'s
    43.7 right at 2620 with much tighter e.s.'s..
    44.0 right at 2640 with good e.s.'s.. and
    44.2 right at 2655 with 4ft. e.s.'s!!
    ALL loads shot either at 1" or under, except 1, the last one opened up to just about 1.250". THIS RIFLE WILL SHOOT! ALL LOAD DEVELOPMENT IS DONE AT 300 YARDS..
    This is still at least 100 f.p.s. slower than I want. However, this did set up a base-line for QL to tell me where I need to go..
    Johnny Ingram and Joe Regina (Johnnyi and JoeR on this forum) are both QL "guru's" and were helping me out. They are both VERY helpful in the QL arena for me since I am about as computer savvy as I am about brain surgery!
    Their input told me that I could EASILY go to 48.0 grains and still be under 65K PSI. Now I am not one to go near "max" loads and am a firm believer that a grain or so less is where good accuracy usually is. So, the next time out (next week sometime) I will load up from 46.0 to 47.3. This SHOULD put me right in the velocity range I want to be with no more (according to QL) than 61K pressure. This is easily handled by the Palma brass.

    NEXT UPDATE>>> NEXT WEEK..
     
    Last edited: Sep 8, 2017
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  2. sdean

    sdean

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    Benjamin just when I ordered my 6.5-08AI reamer,as JGS likes to call it, now I need to get another one? Good luck.
     
  3. Alex Wheeler

    Alex Wheeler Gold $$ Contributor

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    I just ordered a reamer for this yesterday :) Palma brass will take about 70k it seems;)
     
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  4. ShootDots

    ShootDots Gold $$ Contributor

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    Oh you don't need another! The .260A.I. is a very formidable F-Open cartridge. I doubt very seriously I will ever be without one! I am always embarking on some "brain-storm / project", this simply being my latest foray! LOL!! But this one does appear to be very promising! I did a 30-06A.I. that appeared promising too, only to find out it created inconsistent accuracy... However, this one not only looks promising, it is on a tried and true case! I think this one will prove to be a winner..
     
  5. ShootDots

    ShootDots Gold $$ Contributor

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    I know some of the F-T/R shooters I shot with at Bayou Rifles were up in the 67-68p.s.i. range without problems.
     
  6. johnnyi

    johnnyi Gold $$ Contributor

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    he wont go 70k ;)
     
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  7. Alex Wheeler

    Alex Wheeler Gold $$ Contributor

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    I was asked by a top Br shooter about picking a round to buck the wind, that wont kick like a 300 wsm. This is the one I decided to go with. I remember reading about some Australians shooting this in open a couple years ago and using the palma cases. I always wanted to give it a try. Quickloads shows 2840 fps with 30" and rl16. I bet it will do all of that. So long as the chamber is finished right.
    Found the thread, good info in here,
    http://forum.accurateshooter.com/threads/7-08-ai-the-little-round-that-could.3908576/
    edit, I just read though it again and see you already found it lol. Either way I like it!
     
    Last edited: Sep 8, 2017
  8. ShootDots

    ShootDots Gold $$ Contributor

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    Yes Sir! If you look at the 6 Dasher, you see it can come "fairly close" to .243 velocities, using 105 class projectiles. The .260A.I. is in reality a 6.5 "Long" Dasher. And it captures many of the qualities of the Dasher. 1.) Extreme accuracy; 2.) H-I-G-H velocity for a "smallish" case! (Very efficient case design); 3.) a VERY strong case from Palma brass.. If I can get anywhere near the velocity range I am hoping for WITH the level of accuracy that case can deliver, I will consider it to be a GREAT success for my project. I never thought of it as a Benchrest round, however, if it achieves the same level of accuracy I get with my .260A.I.'s, it most certainly could and would be VERY competitive!
     
  9. Alex Wheeler

    Alex Wheeler Gold $$ Contributor

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    My thoughts exactly. It seems like the smaller cases that are efficient, handle pressure, and shoot with the larger case are extremely accurate. I would bet this case will run with a 284 and agg better. We are gonna find out!
     
  10. johnnyi

    johnnyi Gold $$ Contributor

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    I'm pretty sure this post needs more photos...?!?
     
  11. MattPeetz

    MattPeetz Silver $$ Contributor

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    So you think 12-15 reloads on 284 brass is bad? I have some with that many still going strong. I am pushing the 180's 2820-2850. It's easy on brass
     
  12. ShootDots

    ShootDots Gold $$ Contributor

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    You are exactly right! That is good brass life. I have a .284 using 54.0grs of RL-23. No primer pocket issues. However, compare the 'strength" (if it can even be done) of the S/R Palma brass and T-Rust me, P.S.I. wise, it aint even in the same ballpark! I am fortunate to still have Lapua "Gold Box" 6.5 x 284 brass which DOES appear to have good primer pockets. But even those, running up against the Palma brass can not match the sheer strength. I have a "straight" .284 and so far so good with primer pockets. Having said that, I have had some miserable experience with them too!
     
  13. DocDoc

    DocDoc

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    Check out the experience of a good Australian shooter on Ozfclass. He went back to a bigger case.
     
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  14. MattPeetz

    MattPeetz Silver $$ Contributor

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    70,000 psi isn't going to be good no matter how you slice it in regular or palma brass. Palma brass will handle it better but it won't last.
    It will be a good project though.
     
    Last edited: Sep 8, 2017
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  15. ShootDots

    ShootDots Gold $$ Contributor

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    I have a .284 and a 7 SAUM. I am not concerned with "speed" per se. I want e-x-t-r-e-m-e accuracy coupled with "enough" speed and "worry-free" brass life. I spend A LOT of time prepping my brass and then having to fireform it. This is time consuming and not at all "pleasurable". Keeping those chores to a minimum is one of the benefits derived from Palma brass..
     
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  16. Steveb

    Steveb

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    If you look on the Australian F-Class website site there is a posting on this exact cartridge and what you are building in great detail. You might want to read the multiple pages. I think it is a very interesting cartridge and one I have also been interested in.
     
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  17. holstil

    holstil Silver $$ Contributor

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  18. Mulligan

    Mulligan Silver $$ Contributor

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    Alex, do you have the reamer specs or print?
    I'm in.
    CW
     
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  19. Ringostar

    Ringostar

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    Maybe @spclark will update on his go with the 7 Inch. I would be interested to here how it worked. It is a lengthened 7-08 with shortened neck.
     
  20. spclark

    spclark Gold $$ Contributor

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    Works great. Earned me a tie for Senior Open Sight 1,000 yard LR National Record late June last year, 200-15x.

    2800 fps with 180 Hybrids out to 1,000 yards, 1:9 30" Bartlein.

    Began finding telltale case head separation lines late last year, never an actual failure. Opinions from several involved think fire-forming may have been when cases stretched.

    Once fire-formed I'd been careful to size w/no shoulder bump yet sized cases still allowed bolt to lock.

    Starting this project with multi-times fired 308 Palma brass maybe wasn't such a good idea?

    Have to wait 'till I swear off Palma Alliance membership to find out, sticking with 308/155's/irons for this year at least.

    Only drawback I can tell of is suitable powder: only one I found that works consistently well is H4350. Believe it when I say I tried everything out there (excepting IMR4350, which was next when I lucked into finding 8's last September; I bought two) that I thought might work.
     
    Last edited: Sep 9, 2017

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