** 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. holstil

    holstil Silver $$ Contributor

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    My 7-08AIs love h4350
     
  2. ShootDots

    ShootDots Gold $$ Contributor

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    Yes they do! That's why I chose RL-16. It is the same burn rate AND will produce substantial increases in velocity. However, if I can not get the accuracy level I desire, I will head straight back to H4350. So far, RL-16 looks like it will produce equivalent accuracy>>>>>but I am still in the early stages of this project. Once I get a load down at 300, I will try it out at 500 and hopefully 1000 too. We are coming into the "fall shooting season" here in Arizona and we have a 600yard State Championship in October>>>>I would love to have this rifle ready for that. BUT if I don't, I have 2 / .260A.I.s that ARE ready and they DO produce phenomenal accuracy at 600, T-Rust me!
     
  3. AR Shooter

    AR Shooter

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    Very interesting thread. Have not yet chambered my new 24" long 7mm hunting rifle and wonder if this might be a good alternative to the the 7mm SAUM or 280AI? Do you think one could get 2750fps out of a 175gr hunting bullet in the 24" barrel with the 7-08AI?
     
  4. ShootDots

    ShootDots Gold $$ Contributor

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    **UPDATE** As promised, I have an update. I went out today, once again to 300 yards, with the intent to see just how fast I can go without signs of pressure and hopefully find some good accuracy! Well I got a pleasant and not so pleasant surprise! Getting past 2800f.p.s. was no problem whatsoever. Cases went in and out like butter. I started from 46.0 and crept up to 47.3. Alex, when you said earlier in a post here that this round can make 2840, I have no doubt it can go well past that! However, the accuracy will not be there! :( The velocity figures are as follows:
    1.) 46.0 grs netted an average of right at 2730f.p.s.
    2.) 46.3 grs " " " " right at 2742
    3.) 46.7 grs " " " " right at 2465
    4.) 47.0 grs " " " " right at 2793
    5.) 47.3 grs " " " " right at 2808
    These figures were the "pleasant" surprise>>>> However, the "not so pleasant" surprise was that the groups averaged right at 2 inches! All these were in a complete scatter-node! According to QL, I have to go up to just shy of 49.0grs to get to the next accuracy node! I have NO DOUBT that it can not be done without ruining brass. The next node down is about 44.8grs which will get me about 2690f.p.s. I will go out next time and run from 44.4 to 45.2 to see if I can find that accuracy node. Additionally, according to QL, I can get to a "mid-node" using RL-26 with "about" 50.0grs and net somewhere around 2770.. I may have to see about going there. However, for me accuracy IS the TRUMP card, not velocity. Since this is primarily going to be a "Mid-Range" gun, the 2690f.p.s. node should be just fine, especially if it gets the level of accuracy I believe it can!

    Next UPDATE, >>>next time out!
     
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  5. gstaylorg

    gstaylorg Silver $$ Contributor

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    Ben - if you're using QL to predict "accuracy nodes" using barrel times (OBT) as the output, just be aware that there are more nodes than can be accounted for solely by OBT. If you cannot realistically hit a given OBT node due to pressure limitations, try a ladder in the region below that node, going as high up in charge weight as you can safely go. Chances are very good you'll find another node that you can safely hit that will be much closer (faster) than the next slower OBT node from the table, which is likely WAY slower. Because you're only looking at vertical in the ladder, having the exact seating depth/grouping isn't critical. You can tune the group in afterwards using seating depth. As an example, it is almost impossible to hit Node 4 in an F-TR .308 load with 200+ gr bullets, regardless of barrel length. Most are running an in-between node that shows up in the 2650-2700 fps range. That node shoots very well but you probably wouldn't find it using barrel time and QL.
     
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  6. ShootDots

    ShootDots Gold $$ Contributor

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    Oh believe me I know.. That was one of the ideas for today.. I was hoping to find one of those "in between" nodes. I know I could safely go up to 48.0grs. However, that would be MAX.. That would only leave me a very narrow window. I would rather find an extremely accurate load at the 2690 "window" OR after that testing is complete, go try RL-26 where the possibility exists I might be able to get an accurate node close to 2770.. T-Rust me, I do understand what you are saying.. In this particular case, from where I was going, I got the velocity I was after>>>but no accuracy.
     
  7. ShootDots

    ShootDots Gold $$ Contributor

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    I don't know>>>>BUT it would be right at the top of the pressure ladder if you could...
     
  8. JLT

    JLT Gold $$ Contributor

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    Don't forget about RL-23. Could be a better match for the bore/capacity ratio. I've tinkering with RL-23 in my .260 AIs and it's looking good with the 140s. RL-26 is very dense and you can get a bunch in the case but it still might prove to be a little on the slow side for the case. One man's opinion, anyway . . . .
     
  9. ShootDots

    ShootDots Gold $$ Contributor

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    Because of the "Bulk Density" of RL-23, I doubt I could get enough in the case to gain any velocity. It is just about like RL-16 in kernel size and getting 47.3 in was accomplished with a 6" drop tube. I believe I could get 48+/- with RL-23 and that would be too slow velocity wise. Now, because of the higher density of RL-26, I believe I could get at least 50.0 grs in. This MAY (and I mean only may) be able to get me to my goal..
    In one of my .260A.I.'s I am using 45.7grs of RL-23 with excellent results. I have found in my .260A.I. that RL-23 is considerably faster than H4831SC, or at least it is acting that way. Alliant states that RL-23 is slower than RL-22, which IS slower than H4831. However, my experience with RL-23 tells me it is FASTER than H4831SC in every application I have tried it in..
     
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  10. Alex Wheeler

    Alex Wheeler Gold $$ Contributor

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    Keep putting powder in there. I have never seen where you had to run over 100 fps under max to get accuracy. She'll come back in.
     
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  11. mac86951

    mac86951 I prefer my targets level and unmoving

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    Tag, out of curiosity, what length is the 180 when seated? I'm guessing you're over the short action lengths?

    -Mac
     
  12. ShootDots

    ShootDots Gold $$ Contributor

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    My base of the case to the tip of the bullet is 3.155"..W-A-Y, W-A-Y over "standard case length"..
     
  13. ShootDots

    ShootDots Gold $$ Contributor

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    I am a bit reluctant to keep going up.. There were no real pressure signs and I believe I could get to 48.0grs safely. However, being safe and getting some bolt opening resistance are two different things. I am quite certain I would at least start to experience resistance opening the bolt at 48.0grs, I don't like being that close to REAL pressure..
     
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  14. Alex Wheeler

    Alex Wheeler Gold $$ Contributor

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    Many shoot right there. You will need to go much higher than a little bolt lift to risk serious problems, but do what your comfortable with. All the little 6 br imp cases like to run on the edge, often only a few tenths from heavy bolt lift. So I may just be used to it. Thats the whole point of using palma brass right ? ;)
     
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  15. FJIM

    FJIM

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    If it were me I would go right to RL17 and a CCI 450 Primer. I would also seat the bullet as far off the rifling just to see what happened. I have had a few times here recently trying to get a certain bullet to shoot well I jumped it .040 and it was much better and the speed went up 30 FPS which I did not expect. I have a buddy shoots a 22" 7/08 hunting rifle using a 162 and RL17 at 2,850 FPS. I personally like the RL17 in a few cartridges decent accuracy and good speed. I fooled with RL26 in a 6XC with a 115 and found it shot incredible and Great speed but it was way too temp sensitive to use the load unless you shot in the same temp. Now a few guys use it in 7Mag and 7WSM have said it does not seem too sensitive to them but RL17 in everything I have shot it in has been very good temp stability until around 90 deg then it picks up but from 30 deg to 80 deg it works for me. Just a thought unless you dislike the RL17 it is what you are needing.
    Look up the article 7mmx47L I think it's a good read.
     
    Last edited: Sep 11, 2017
  16. JBT

    JBT Gold $$ Contributor

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    Have you considered using Viht N550 or 560? I get much higher speeds using both of these powders in various cartridges. I've gotten so used to speeds (along with great accuracy) that N550 yields in my 6.5x47 that use of any other powder is disappointing.

    Some say it eats up the throat but I am not at all concerned with that. I'll rebarrel when I need to.
     
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  17. ShootDots

    ShootDots Gold $$ Contributor

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    I used N550 one time in a 6.5 x 47 using 130 VLDs. They were very accurate and gave me 2970 with a 28" barrel. I got a whopping 1500 rounds out of it.. I used N560 one time in my first 6.5 x 284. THEE most accurate powder in that case and with 2grs UNDER max, I was getting 3120 with 140 Hybrids! It killed my barrel in short order... I don't use those powders anymore. GREAT for hunting>>>not for 20+ shot strings in F-Open!
     
  18. JBT

    JBT Gold $$ Contributor

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    I completely understand your point.

    I'm using both of these powders exclusively in 2 of my rifles at present. We'll see how long these barrels last. So far I am very pleased with accuracy and velocity.
     
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  19. ShootDots

    ShootDots Gold $$ Contributor

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    I bought some RL-17 when it first came out. I could not get it to shoot very well in anything I tried. AND in Arizona here, temps always hit triple digits. I need the most stable powders I can find. So far I have been able to switch to RL-16 and RL-23 in 3 rifles. If I get this one going with RL-16 it will be 4! I just can't seem to make my SAUM work with it. H4831SC is still the king in that cartridge with 180's!
     
  20. Ringostar

    Ringostar

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    Ben, Have you ever tried Hybrid 100V? Hodgdon shows higher velocity with less pressure than 4831sc in a 7-08.
     

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