300 H&H Improved

Discussion in 'Reloading Forum (All Calibers)' started by Viperplt, Apr 10, 2019.

  1. Viperplt

    Viperplt

    Joined:
    Mar 22, 2019
    Messages:
    12
    I bought two custom rifles based on the Remington Model 30S Express, one in 358 Norma and one in 300 H&H Improved. I bought a set of dies from BIGMAC to start loading up cartridges for the 300 H&H imp. In my reading I found that 300 Weatherby would fit the chamber (I tried one I had on hand and it did chamber). Midway had a good price on Norma 300 Weatherby cases and I obtained 50 from them. I ran the cases through the improved die set and loaded up ten rounds. They shot fine but my question is on loading data. I have a large collection of loading manuals and researched on the internet loading data but couldn't find any. The Ackley manual says just use the Weatherby data but my research shows the difference in the freebore makes that problematic. Using the Nosler number 8 manual it shows a load of 67.0 grains of IMR 4350 as max for the 300 H&H with a Nosler 165 grain solid base bullet with an OAL of 3.600. It shows 76.0/74.0/72.0 grains for the 300 Weatherby with an OAL of 3.560. I loaded with the 72.0 grain load to an OAL of 3.600.
    My question is does anyone have loading data for the 300 H&H Improved for different bullet weights? With the increased case capacity am I on the correct track for load data?
     
  2. wboggs

    wboggs Gold $$ Contributor

    Joined:
    Nov 29, 2007
    Messages:
    1,406
    You need to measure the throat on your custom chamber. Do not just use Weatherby data. The freebore (throat) is almost sure to be different.
    Start with standard .300H&H data and work up from there. The throat length will allow you to seat bullets to a length that will give you the best accuracy.
     
    MrMajestic likes this.
  3. butchlambert

    butchlambert Site $$ Sponsor

    Joined:
    Jan 18, 2005
    Messages:
    6,507


    Any photos?
     
  4. riflewoman

    riflewoman Gold $$ Contributor

    Joined:
    Feb 24, 2015
    Messages:
    918
    You could get a copy of this and get data from the man hisself...

    https://www.amazon.com/dp/1626541019/?tag=accuratescom-20

    But the reality is that your rifle will dictate the loads it can tolerate as even Ackley would admit. So start with the starting load data for the Weatherby round and work up in half grain increments. Back off a full grain or (better) a grain and a half when you get high pressure signs.
     
    MrMajestic likes this.
  5. 10XSHOOTER

    10XSHOOTER Gold $$ Contributor

    Joined:
    Mar 20, 2013
    Messages:
    101
    I have shot a .300 Ackley in the past. I started with the max H&H load and worked up in 1/2 grain iincrements until I hit pressure. Then backed off 1.5 grs and worked in that area.
    I was shooting 190 gr molyed bullets. This was a great 100yd prone rifle. Was using RL-19 think I ended up around 75 grs.
     
  6. centershot

    centershot Silver $$ Contributor

    Joined:
    Jun 1, 2013
    Messages:
    657
    I am shooting a regular .300 H & H. With 185 Bergers, I shoot 68 grains of H4831 and R-19. Get fairly decent groups with my Classic Remington.
     
  7. Viperplt

    Viperplt

    Joined:
    Mar 22, 2019
    Messages:
    12
    I have the original copy of that and it just says "use the 300 Weatherby data".
     
  8. Viperplt

    Viperplt

    Joined:
    Mar 22, 2019
    Messages:
    12
    I see you are a "Former USAF F-4 INS Tech". I flew the F-4 from 1983 until 1986 and the F-16 from 1986 until I retired in 2017 with the Vermont ANG.
     
    LukeTitan and Dusty Stevens like this.
  9. Viperplt

    Viperplt

    Joined:
    Mar 22, 2019
    Messages:
    12
    I will take a couple and attempt to post them.
     
  10. Viperplt

    Viperplt

    Joined:
    Mar 22, 2019
    Messages:
    12
    I can do a chamber cast because I bought a drilling and didn't know what the rifle barrel was chambered in. Turns out it was 9.3X72R! I found some cases and bought a set of used dies for a reasonable price and got her shooting again!
     
  11. Viperplt

    Viperplt

    Joined:
    Mar 22, 2019
    Messages:
    12
    300 H&H.jpg 358 Norma.jpg
     
    mikeinct and Zero333 like this.
  12. wboggs

    wboggs Gold $$ Contributor

    Joined:
    Nov 29, 2007
    Messages:
    1,406
    The chamber cast will be very informative and answer all the questions.
     
  13. centershot

    centershot Silver $$ Contributor

    Joined:
    Jun 1, 2013
    Messages:
    657
    I assume you flew "e" models. I worked on "c" models. We could talk for hours!! Too bad we live so far appart.BTW, I love my H & H.
     
  14. Viperplt

    Viperplt

    Joined:
    Mar 22, 2019
    Messages:
    12
    We had D models that had flown in Vietnam and were pretty beat by the time we got them. I also have an unmodified 300 H&H Winchester model 70 XTR that I picked up. They get shot occasionally but are a little over powered for whitetail hunting so they have never gone out hunting. Although I hunt with a 30-06 so should probably bring it along for a hike some day.
     
  15. MrMajestic

    MrMajestic Gold $$ Contributor

    Joined:
    Oct 24, 2010
    Messages:
    3,017
    I crewed 68-429 F4-E with the 33rd TFW at Eglin in 1977. Shark teeth were visible after it was flown in the rain...Alerted for Panama Canal and threw my dufflebag on the pile but Carter chickened out...
     
    mikeinct likes this.
  16. Ggmac

    Ggmac Gold $$ Contributor

    Joined:
    Aug 11, 2012
    Messages:
    3,073
    Curious as to your 9.3x72r . I've got a drilling and it's the same , I've been looking for a few cases , any suggestions?
    Thanks .
     
  17. Viperplt

    Viperplt

    Joined:
    Mar 22, 2019
    Messages:
    12
  18. Viperplt

    Viperplt

    Joined:
    Mar 22, 2019
    Messages:
    12
    F4 9-84 7.jpg
     
  19. Dusty Stevens

    Dusty Stevens COVFEFE- Thread Derail Crew

    Joined:
    May 8, 2014
    Messages:
    10,837
    Im an f4 fan.
     
    MrMajestic likes this.
  20. Zero333

    Zero333 Silver $$ Contributor

    Joined:
    Dec 24, 2015
    Messages:
    1,840
    300 Weatherby has more internal volume than the 300hhAI... I would not use Weatherby data.

    Like others stated, there is no way of telling what kind of Improved version you have. Some are shortened and blown out and don't gain any capacity, while others gain plenty more boiler room.

    Chamber cast is the safest thing.

    However, you did state that 300 Weatherby chambers. Therefore you could start at the top end of the standard 300H&H data.

    72 gr of H-4831 (or H-4831sc) pushing a 180 gr bullet is a popular fireforming load.
    Once the shoulders been formed you can add more powder. 76-77 gr H-4831

    Making a false shoulder on the neck by sizing it up and then down till you get a crush fit is a good idea.
     

Share This Page