First 450, and First AR. Looking for help on Loads

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First 450, and First AR. Looking for help on Loads

Postby michtech » Sun May 12, 2019 6:13 am

For years I have been a bolt collector and reloader, and have enjoyed it very much. A few months ago I decided to get two things that I did not have, a 450 Bushmaster because I wanted to have something other that a muzzleloader to hunt with my brother in southern MI, and an AR version rather than bolt action. Figured it was about time to start learning something new, so my purchase was the Ruger AR-556 MPR Model 8522 and added one of my favorite scopes, a Vortex Crossfire 4-12X44. Needless to say I was pretty excited, like a kid with his first Daisey BB gun. The specs for the AR is as follows -

Barrel Length - 18.63"
Twist Rate - 1:16" RH
Grooves - 5

I bought Hornady Black 250 FTX factory rounds to start things of with, and was impressed with the groups at 100 & 200 yards. The other thing that was different from the specs on the box was the drop from 100 to 200 was 6" not 4.1. Which made me wonder if I was really getting 2200 fps out of them as stated, and as a reloader figured it should not be hard to improve on that.

The 2 bullets I have purchased to use is the Hornady 250gr FTX, as I would like to try and improve on the factory rounds. The other bullet is the Barnes 200gr XPB. I have all kinds of reloading manuals, but have always looked at them from a bolt action perspective. And I never assume I know it all, so a little help please. Loading for an AR is different than a bolt action, correct? The main difference I am reading is in pressures? I know from my limited time on this site, there are some very seasoned AR & bolt users of the 450BM and would like to hear your thoughts.

The reason I decided to inquire about some references rather than just load and try, is the expense of these. Quite different than buying a box of .243 to send down range. If you own this AR or another AR with similar specs and have found a load for these 2 bullets, I would appreciate hearing from you.

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Re: First 450, and First AR. Looking for help on Loads

Postby Hoot » Sun May 12, 2019 8:02 pm

My experience with the 250 FTX has been that loading it over 37gr of Lil Gun, using Rem 7 1/2 primers and seating the bullet to yield a COL of 2.26 inches, yields a muzzle velocity as measured with two different chronographs, of 2200-2220fps from my 20" 1:24 AR based platform. That will be different than what you experience using an 18" 1:16 barrel. If that was what I had to load for, I would start at 35gr Lil Gun and see what your chronograph tells you, as well as how the brass looks when you shoot them. Not talking about primers. The real "tea leaves" will be how much the case expands at its fattest diameter down where the web transitions to the case wall. With that indicator in mind, I walk my charge weight up in half grain increments. A chronograph is not optional if you reload. Otherwise, its like building up a race car without a tachometer/speedometer.

Again, my experience with reloading the Barnes 200gr XPB will be different from yours due to the difference between our barrels. My advice would be to start again at 36gr and work up in the same half grain increment. I'm betting someone else here has already worked up a load using a barrel like yours and will chime in with their experience. Lately, it seems like more barrels are coming to market with 1:16 twist barrels. They cater better to heavy projectiles at 300gr and beyond.

I realize working loads up is not a cheap endeavor but that's the only way your gun will be able to tell you what it safely likes.

In Theory, there is no difference between theory and practice. In Practice, there is.
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Re: First 450, and First AR. Looking for help on Loads

Postby Bmt85 » Sun May 12, 2019 8:58 pm

Hoot had a lot of good points. Especially when saying watch case head growth. Get a good blade micrometer for this.

When reloading 450B, I try to get a load to the point of no hang fires and a complete seal of the case to the chamber. Then I will work up from there, checking all measurements, especially case head growth. If you have an oily chamber or a case that has carbon marks down the side after firing, that means your not getting a complete seal. The way I see it, those will give you more bolt thrust, which isn’t good for an AR bolt opened up to the size of the 450’s. Not getting a complete seal is the main reason I don’t run factory ammo anymore.

As to your bullet choice, the 200 XPB is a great bullet, but I would keep hunting distances up to 100yds. Maybe a little more depending on muzzle velocity. The 250 FTX, in my opinion is not a great bullet. For hunting, it has been shown to separate or lose too much weight, even at normal pressures. As a plinking bullet, it’s pretty good, but there are cheaper alternatives. The 225 FTX is a better plinking bullet in my opinion. Great results and cheaper. For a great hunting bullet, the 275 TSX is going to be hard to beat. It can be pushed hard and still hold up at close distances, yet can still expand at distances most people won’t shoot a 450B. I think the 250gr Makers would be a good alternative, too. I think they have a 275gr version now, also. I know black butterfly sells a 275gr version of Maker’s bullet, don’t know if it’s the same though.

Where abouts do you live? There might be someone here to help you out.
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Re: First 450, and First AR. Looking for help on Loads

Postby michtech » Wed May 15, 2019 7:37 pm

Thank you Hoot & Bmt85. I have been unable to get back here till now.

I live in the Houghton Lake area, appreciate any help people in this group can provide. I managed to load up several rounds with the 250FTX this last weekend, I found that the rounds around 35gr to 36.5gr had a lot of carbon marks. They seem to disappear around 37gr. The groups were not the greatest at 100, or 200 yards. I will go up from there slowly, and pull some chronograph readings along the way.

I also will attempt to get some of the 200XPB's loaded up, the reason I picked those up was because I thought a 200gr bullet should be heavy enough to stabilize for accuracy as well as good enough for whitetail hunting.

Thank you again, and will keep you up dated.
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