450Bushmaster.net

I have a 20" BM upper coming tomorrow. Have 40 rds. of Horn. Black ammo. and 2 boxes of 225 FTX and new Lee dies. I'll try refilling with the 38 gr. LG/R7.5 load. Any other advice, warnings, suggestions?

Welcome Aboard and you should find that the 20" Bushmaster Upper loves the 225 FTX. About all I'd recommend is seating them so that most of the cannelure is just below the mouth and taper crimp down into that cannelure to yield a mouth diameter of .474-.475 inch, The Bushy upper may take a while to break in run the BCG wet and wipe the resultant slurry off from time to time. Its mostly displaced sulfate from the parkerizing. IE Its gritty. Action may likewise feel gritty when hand cycling it.That's normal until it polishes out over time. That's a chromed bore. IIRC, mine took around 200 rounds to settle in. Not that you'll notice much difference. Groups will tighten up a little, velocity SD will drop (good thing) a little and it's get easier to scrub the copper out. Wet patch until the loose chunks are gone, then wet brush the heck out of it and patch again. You'll be mazed at how much additional crud the bronzr brush knocks loose. Put it away with the bore wet with whatever solvent you use (I prefer Kroil) and dry patch is before shooting the next time out. Plan on 1 or 2 fouling shots each time out. Do not use copper dissolving solvent in a Chromed Bore ever.

Enjoy!

Hoot

Thank you so much for the tips. Do you have a recommendation for plinking ammo for breaking in?

As noted before, I have the latest Lee dies. I've been looking through the site and have seen a lot of info on crimping. I'm still confused about the stab crimp. Will just using the Lee die as you instructed above be sufficient? A trick I've used in other cartridges is to not use the expander/flare die, but use the Lee universal flare die so that the neck is not expanded, but it makes seating the bullet possible without damage.

It is a chromed chamber and barrel. As you said, the action is very stiff and gritty. Hornady only rates the 225 FTX up to 1600 fps. Do you download it, or will it work at higher velocities or blow up? I'm planning to use the cartridge for whitetail.

After the first time out shooting and cleaning repeatedly, I broke mine in just shooting it with reloading experiments. Wait a while before worrying about stab crimping. I didn't use any special ammo, I just shot it. The evidence of the bore being broke in is not a night and day observation, it just gets a little better over time. I have probably tossed around 500) 225 FTX bullets over time, mainly because they made me feel good about my shooting capabilities. This was my first sincere effort to shoot an AR well and since they need more effort than a bolt action, the trigger time was a double payoff. The 225 FTX holds up to the 450b velocity just fine, at least from my experience. If you watch your sales and Midway special deals on blems, you can get them from time to time, cheaper than non-discounted 230 FMJ bullets. First impressions have a lasting impact. Shoot bullets that will boast your confidence. I've never used light loads for anything other than fire forming bottleneck calibers.

Hoot

What do you use for an COAL for the 225 FTX?

Hubcap500 wrote:What do you use for an COAL for the 225 FTX?

Without going down to the shop to measure, somewhere in the vicinity of 2.12. More importantly, whatever it takes to almost bury the cannelure beneath the case mouth, with just a a little of it still peeking out. Hangs onto the bullet better that way.

Hoot

Why is it bad to use something like barnes copper cleaner in a chrome lined bore.
Just curious to know.

45r wrote:Why is it bad to use something like barnes copper cleaner in a chrome lined bore.
Just curious to know.

You cant chrome directly to steel. The process requires to first plate the steel with copper and then plate the chrome to the copper. Even the best laid layer of plating has micro pores. Copper solvent can penetrate through those pores, down to the copper layer and slowly dissolve it. The result can be the chrome plating flaking off in spots. I put over 2k rounds through my original 20" 450b barrel and all I ever used to clean the bore was a regimen of Kroil and alternating between bronze brush and patches, while it was still warm at the range, when I was done for the day. After about every 5 range visits, I gave it a good scrubbing with JB compound but then I do that with all my centerfire barrels. It served me well. The caution about copper solvent in a chromed barrel is not just a "Hootism". Its widely accepted in gun care documentation.

Hoot