This topic contains 3 replies, has 2 voices, and was last updated by  Glenn 3 months ago.

  • Author
    Posts
  • #69269
     Glenn 
    Participant
    • Silver
    • ★★
    • Posts: 41
    • Comments: 210
    • Overall: 251


    The .458 Speer 350 in the 450 Bushmaster.
    I have gone through three boxes of these Speer 350s, and several powders in search of the magic load for my Ruger AR 450 Bushmaster. First off the bullets were lubed with Imperial Sizing Die Wax and stuffed through a Lee .451” cast bullet sizing die. After sizing, the Speer 350s measured .452” and lengthened to .990”. I checked the distance to the lands and it was at 2.322”, but they wouldn’t fit the magazine. When seated to 2.300” the round would fit in the magazines, feed and cycle the action just fine. I couldn’t find any published load data for a 350gn bullet in the 450 Bushmaster, so I used Quickload and compared that to starting loads for the 460 S&W from the Hodgdon.com site that listed pressure data also.
    With looking at Quickload, I was hoping to get to 1800fps and set that as my target velocity. I loaded all of the ammo with Starline brass and Hornady dies. I taper crimped to .475” and then used a LEE FCD.
    I first tried CFE BLK with a charge that was way too light and the action got fouled with piles of unburnt powder. After scrubbing everything out, I switched to Lil-Gun. I tried a couple of loads and accidentally got to 1911fps and pressure signs on the case heads.
    IMR 4227 topped out at 1640fps with35gns.
    A1680 never would burn consistently. I tried standard and magnum primers, but got wide velocity ranges. At 41gns of A1680 I got an average velocity of 1746fps, but in the five shot string got a low of 1622 and a high of 1834.
    IMR4198 gave 1739fps with 38gns and burned clean. 39Gns was too hot.
    RL7 burned real clean and gave some acceptible groups. 42 gns gave 1765fps.


    Lastly I went back to CFE BLK and tried some heavier charges. I used CCI 450 primers. 43Gns gave an average of 1792fps, but the cases were covered in soot.


    So I think that I will go with 42gns of RL7. The cases came out clean, it gave good accuracy and the action cycled fine. For accuracy testing, I put on a Vortex 3.5x10X scope, but will be switching it out for a 1-4X Vortex with lighted reticle to take it Hog hunting in a couple of weeks.

  • #69272
     Jniedbalski 
    Participant
    • Silver
    • ★★
    • Posts: 20
    • Comments: 167
    • Overall: 187

    Nice rifle and write up

  • #69273
     Jniedbalski 
    Participant
    • Silver
    • ★★
    • Posts: 20
    • Comments: 167
    • Overall: 187

    Forgot to ask how much does your top end loads kick ? Like a 12 gauge  turkey load I have heard

  • #69274
     Glenn 
    Participant
    • Silver
    • ★★
    • Posts: 41
    • Comments: 210
    • Overall: 251

    Recoil is not bad at all.  About like a 6.5 Mauser.  I don’t know if it’s the semi-auto action or the muzzle brake, or both.

You must be logged in to reply to this topic.

© 2017 Goodsteel Forum. Designed by Covalent Designs, LLC.