First 450 Bushmaster Loads

Joec7651

Handloader
Apr 7, 2019
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Well I loaded some test loads with 300gr XTP Mag bullets. I started at 40 grains of H4198 going up to 43 grains in .5 grain increments. According to Hodgdon information it gets a little better velocity with 300 grain loads than the others. Hopefully it will cycle the action.
I’m running Hornady brass, REM 7 1/2 primers, H4198 powder, and Hornady 300gr XTP Mag bullets. OAL is taper crimped at 2.115” and feeds properly from the magazine. The powder may be too slow for the AR action but it’s what I had on hand for the first test. I’m going to try and get to the range tomorrow with the Magnetospeed to check velocities and function.
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I forgot to mention that I had to use my 45-70 seating die to seat the bullets. The seating stem in the Redding die is too short. It applied a proper taper crimp but I’ll contact Redding on Monday to have them send the correct seating stem.
 
At the top end of 43 grains it’s a compressed charge, though not overly so. Depending on what the rifle tells me, I wouldn’t want to go much over 44 grains. At that point the case would be stuffed pretty full. I’d like to get 1900ish but that may be pushing it for an 18.6” barrel. May be closer to 1800.
 
My brother has a CVA in 450B. I have the same bullet here to try , just waiting on him to get me some fired brass.
 
My brother has a CVA in 450B. I have the same bullet here to try , just waiting on him to get me some fired brass.
The Scout V2’s shoot exceptionally well. I had one in 45-70 that would shoot a ragged hole. I wish I hadn’t sold it.
From the information I’ve found, the 300gr XTP Mag looks like it’s a really tough bullet. Much tougher than the 300gr Interlock HP I load for my 45-70. I just want it to be accurate. At minimum it makes a half inch hole, and if it’s as tough as what I’ve read you could use it for just about anything.
 
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Lil’gun was the powder if choice in my 450 BM. I really like the Barnes 275gr TSX. It is the load you need for bear protection salmon chaser.
 

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Lil’gun was the powder if choice in my 450 BM. I really like the Barnes 275gr TSX. It is the load you need for bear protection salmon chaser.
I always thought that was the ticket. We had a supply of Buffaloe Bore ammo for Duty use, so to speak, saved the Hornady ammo for porcupines and practice.
 
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Lil’gun was the powder if choice in my 450 BM. I really like the Barnes 275gr TSX. It is the load you need for bear protection salmon chaser.
I would have tried them, just can’t find them. I really wanted to give the 200gr XPB a go, but again I can’t find them. I think it would be great for deer and black bear.
 
Well, the 43 grain load of H4198 is the most consistent load. Extremely consistent actually. I didn’t shoot long shot strings because I don’t like my Magnetospeed to get beat up from the muzzle brake. It probably doesn’t hurt it but I only use it with a brake when necessary.
They all shot well and cycled without a hiccup, so no worries there. Recoil isn’t bad. It’s a push rather than a slap. Below is a 3 shot group of the 43 grain load without the chrono on the barrel. Here are the numbers, its A very consistent load. It looks like a shade over 1” at 100 yards. I have a Hornady modified case for OAL on the way, and may try different seating depths to see if I can walk them in but to be honest I’m ok with where it’s at. After all I’ll be using it as a woods rifle and as it stands it would be fine inside 250 yards. Today wasn’t my best day at the bench as well, it probably has better potential on another day.

450 Bushmaster
Hornady brass
Rem 7 1/2 primer
300gr XTP-Mag
43 grains H4198
OAL 2.115”
Vel. 1948 fps
ES 1, SD 0
1- 1948 fps
2- 1948 fps
3- 1949 fps
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It’s a factory stock Ruger MPR 450 Bushmaster. It has a nitrided 1:16 5r rifled barrel that’s 18.6” in length. It’s new and only has 30 rounds fired but seems to want to shoot.
 
As for The seating stem, Redding is sending the correct one. It ended up with a 45-70 stem (#5) instead of the one for 450 BM (#36).
 
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