Quickload For 450 Bushmaster

Joec7651

Handloader
Apr 7, 2019
936
1,256
I’m actually finding accuracy and velocity with H4198 in my new 450 Bushmaster. I have Lil Gun and it works great with all but the heaviest bullets. Would one of you be kind enough to run a couple Quickload projections for H4198 and IMR4198?

450 Bushmaster
Barrel length of 18.63” with a 5r 1:16” rate of twist
Hornady once fired brass
Bullet is Hornady 300 grain XTP Mag
Remington 7 1/2 Benchrest primer
The OAL is 2.165” at .035” off the lands
Powders are H4198 and IMR 4198, and any help would be greatly appreciated.

The load it likes so far is 43 grains H4198 giving 1948 fps with a SD of 1 for three shots. It gives 1 1/4“ish groups at 100 yards. It is a compressed load but very little. So little that it’s not really compressed, just touching the bullet base. Nicely rounded primers and cycles the action without any hiccups. Ejects cases at a perfect 2:30 x 3:00 position. As a side note, the nitrided barrel doesn’t seem to copper foul at all after 29 rounds fired.

I can fit 45 grains of the H4198 in the case at this OAL, but that’s the very most I’d be willing to compress. I haven’t fired a 45 grain load because I wanted some general idea of potential pressure. I am also wondering if the IMR version would work better due to it being a smidge faster burning.

It’ll never be a match rifle but I want to safely get as much as I can from it with regards to accuracy and velocity with 300 grain bullets. I’ll use Lil Gun for 225-260 grain bullets. I may end up going with Accurate #11FS for the 300’s as it’s a flash suppressed W296/H110. Although the H4198 is giving me within 100 fps of my 45-70 deer load without any headaches so far.

I got long winded but thanks in advance to anyone that would be kind enough to run the Quickloads.
 
looks like your 43.0 grains is over max . 40.9 grain looks to be a max load

Cartridge : .450 Bushmaster
Bullet : .452, 300, Hornady XTP MAG 45235
Useable Case Capaci: 45.727 grain H2O = 2.969 cm³
Cartridge O.A.L. L6: 2.165 inch = 54.99 mm
Barrel Length : 18.6 inch = 473.2 mm
Powder : Hodgdon H4198

Predicted data by increasing and decreasing the given charge,
incremented in steps of 2.0% of nominal charge.
CAUTION: Figures exceed maximum and minimum recommended loads !

Step Fill. Charge Vel. Energy Pmax Pmuz Prop.Burnt B_Time
% % Grains fps ft.lbs psi psi % ms

-20.0 83 32.72 1541 1582 21079 2731 75.0 1.520
-18.0 85 33.54 1578 1659 22433 2830 76.2 1.479
-16.0 87 34.36 1615 1738 23871 2929 77.5 1.438
-14.0 89 35.17 1653 1820 25397 3027 78.7 1.399
-12.0 91 35.99 1690 1904 27019 3124 79.9 1.361
-10.0 93 36.81 1728 1989 28744 3221 81.1 1.324
-08.0 95 37.63 1766 2077 30576 3316 82.3 1.289
-06.0 97 38.45 1804 2167 32529 3409 83.4 1.255
-04.0 99 39.26 1842 2259 34607 3501 84.5 1.222 ! Near Maximum !
-02.0 101 40.08 1880 2353 36821 3592 85.6 1.191 ! Near Maximum !
+00.0 103 40.90 1918 2450 39186 3680 86.6 1.160 !DANGEROUS LOAD-DO NOT USE!
+02.0 105 41.72 1956 2548 41710 3766 87.6 1.130 !DANGEROUS LOAD-DO NOT USE!
+04.0 107 42.54 1994 2649 44408 3849 88.6 1.102 !DANGEROUS LOAD-DO NOT USE!
+06.0 110 43.35 2032 2752 47295 3930 89.5 1.074 !DANGEROUS LOAD-DO NOT USE!
+08.0 112 44.17 2071 2857 50389 4008 90.4 1.047 !DANGEROUS LOAD-DO NOT USE!
+10.0 114 44.99 2109 2964 53708 4083 91.3 1.021 !DANGEROUS LOAD-DO NOT USE!

Results caused by ± 10% powder lot-to-lot burning rate variation using nominal charge
Data for burning rate increased by 10% relative to nominal value:
+Ba 103 40.90 2027 2736 46362 3855 93.2 1.081 !DANGEROUS LOAD-DO NOT USE!
Data for burning rate decreased by 10% relative to nominal value:
-Ba 103 40.90 1789 2132 32535 3386 77.9 1.260



Cartridge : .450 Bushmaster
Bullet : .452, 300, Hornady XTP MAG 45235
Useable Case Capaci: 45.727 grain H2O = 2.969 cm³
Cartridge O.A.L. L6: 2.165 inch = 54.99 mm
Barrel Length : 18.6 inch = 473.2 mm
Powder : IMR 4198

Predicted data by increasing and decreasing the given charge,
incremented in steps of 2.0% of nominal charge.
CAUTION: Figures exceed maximum and minimum recommended loads !

Step Fill. Charge Vel. Energy Pmax Pmuz Prop.Burnt B_Time
% % Grains fps ft.lbs psi psi % ms

-20.0 87 32.80 1591 1686 21179 2980 81.6 1.492
-18.0 89 33.62 1629 1768 22523 3087 82.9 1.453
-16.0 91 34.44 1667 1852 23950 3192 84.2 1.412
-14.0 93 35.26 1706 1938 25462 3295 85.5 1.374
-12.0 95 36.08 1744 2026 27065 3397 86.7 1.337
-10.0 98 36.90 1783 2117 28769 3496 87.9 1.301
-08.0 100 37.72 1821 2209 30576 3593 89.0 1.266
-06.0 102 38.54 1860 2304 32499 3687 90.1 1.233
-04.0 104 39.36 1898 2401 34541 3778 91.1 1.201 ! Near Maximum !
-02.0 106 40.18 1937 2499 36714 3866 92.1 1.170 ! Near Maximum !
+00.0 108 41.00 1976 2600 39028 3950 93.0 1.140 !DANGEROUS LOAD-DO NOT USE!
+02.0 111 41.82 2014 2702 41493 4030 93.8 1.112 !DANGEROUS LOAD-DO NOT USE!
+04.0 113 42.64 2053 2807 44125 4107 94.7 1.084 !DANGEROUS LOAD-DO NOT USE!
+06.0 115 43.46 2091 2913 46934 4179 95.4 1.057 !DANGEROUS LOAD-DO NOT USE!
+08.0 117 44.28 2130 3021 49937 4246 96.1 1.031 !DANGEROUS LOAD-DO NOT USE!
+10.0 119 45.10 2168 3131 53151 4309 96.8 1.005 !DANGEROUS LOAD-DO NOT USE!

Results caused by ± 10% powder lot-to-lot burning rate variation using nominal charge
Data for burning rate increased by 10% relative to nominal value:
+Ba 108 41.00 2082 2889 46138 4019 98.1 1.062 !DANGEROUS LOAD-DO NOT USE!
Data for burning rate decreased by 10% relative to nominal value:
-Ba 108 41.00 1843 2262 32468 3696 84.5 1.240
 
Jim, in a situation like that, do you go off the speed or the load charge? I tend to go off the speed a charge is making when comparing, which even at that is showing over pressure, but would come out around 41.25 grains on the pressure that would produce that speed.
 
Thank you Jim. It looks like it’s back to the drawing board. I worked up using Hodgdons data which shows 42.8 grains as max I think, and didn’t think there would be such a disparity in pressure with the lack of indicators. Regardless, a few fps isn’t worth the risky possibilities. Again, thanks for the information. This is exactly why I asked. Have a great day guys.
 
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Also I just measured fired case water capacity. Case Is fired, unsized, with primer intact. It will hold 84.5 grains of water. The water is filled until it is domed at the case mouth but does not overflow. OAL of the loaded round is 2.165”, 43 grains H4198, and produces 1948 fps. Just thought this may assist in giving actual performance and pressure for my specific load and chamber. The above results somewhat surprised me I must admit. The factory Hornady Custom 250gr ammo had much more flattened primers than my loads. I’m not questioning your information, it just surprised me when Comparing my load with the factory round. Thanks Again.
 
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Jim, in a situation like that, do you go off the speed or the load charge? I tend to go off the speed a charge is making when comparing, which even at that is showing over pressure, but would come out around 41.25 grains on the pressure that would produce that speed.


speed is a good indicator of pressure . there are a few things that can be tweaked in quickload to try and bring the numbers closer together , but without knowing all Joes details this should be good in the ballpark info .
 
Also I just measured fired case water capacity. Case Is fired, unsized, with primer intact. It will hold 84.5 grains of water. The water is filled until it is domed at the case mouth but does not overflow. OAL of the loaded round is 2.165”, 43 grains H4198, and produces 1948 fps. Just thought this may assist in giving actual performance and pressure for my specific load and chamber. The above results somewhat surprised me I must admit. The factory Hornady Custom 250gr ammo had much more flattened primers than my loads. I’m not questioning your information, it just surprised me when Comparing my load with the factory round. Thanks Again.


Joe , please double check your case capacity , there is a discrepancy there . quickload default is 60.0 gr , you say you are measuring 84.5 gr . use a unsized fired case . fill with water to a flat top .if you get a slight bubble on top , or a dripper down the side , touch it with a twisted corner of a paper towel , it'll absorb it right off . be sure you didn't drip water on the scale .
 
This is a factory Hornady Custom load. I have no idea where I came up with 84.5 grains. It holds 59.1 grains of water So Quickloads number of 60 is dead on. Maybe I saw one number and a completely different one registered in my mind. My sincere apologies. Here are the photos of the operation from start to finish. Scale on and calibrated, the case weight, zeroed with case on the scale, and case full of water with weight. Bottom line is that the load would be over pressure regardless of what the primer looks like. This factory load was more flattened than mine which is where my line of thought started. The numbers do not lie though. Mathematics don’t change or waver. Also, with such a low SAAMI max pressure I could be overloaded and not see traditional pressure indications. This one is turning into a unique little project.
IMG_0167.jpegIMG_0168.jpegIMG_0169.jpegIMG_0170.jpegIMG_0171.jpeg
 
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I think I’ll just use my Lil Gun to load for it and quit being stubborn. Lol. I think I’ve been determined to prove a 3/4” wrench will work on a 5/8” nut, so to speak. “Use the right tool for the job Joe.“ 🤣
 
Joe , no apology needed . I saw about a 50% difference and thought holly cow I wonder if quickload has some bad info . I'm glad it's just a mistake .
 
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