New upper range report

Talk about the AR15 style rifles chambered in 450 Bushmaster.

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New upper range report

Postby Hubcap500 » Tue Aug 07, 2018 7:56 pm

Got a Bushmaster 20" upper and finally got to take it to the range last Sunday. Took some Hornady Black ammo and handloads of 225FTX/38.0 LG/R7.5.

I used the BM mag (7 rd.), a modified (front "rib" removed) Pmag, and an aluminum GI-type 30 rd. Pmag wouldn't feed. GI worked OK, though I didn't put more than 5 rounds in. BM worked OK, but not great. Overall, disappointed with function, but I realize it's new and will probably work better with a higher round count. One of the Hdy. rounds refused to light off after multiple attempts.

Hndy averaged 2209 for 10 shots. 225's avg'd 2261. Extreme spreads were 194 and 187 respectively. :o :( Groups (5 rounds for Hdy, 10 rds. for mine) were about 5" and 3" at 100 yds using a 4X scope. :( (I'm capable of better, so my "excuses" are very gusty winds, no sandbags, and some recent short-term eye issues. Also the bullseye I was using was small enough that the reticle covered it.)

So, all in all, I'm disappointed with the accuracy. and not impressed with function. I may try upping the 225 load to see how that affects accuracy and internal ballistics.

Any suggestions or perspective will be given due process.
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Re: New upper range report

Postby Al in Mi » Wed Aug 08, 2018 3:51 am

New uppers I oil the snot out of them to the point of dripping for 50-100rds, has worked wonders for breaking on.

It's been said that chrome lined bores take a little time to settle in, so I wouldn't give up on anything just yet. Maybe your next outing get on some bags, try some 50yd shooting to see what groups look like.
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Re: New upper range report

Postby Hoot » Wed Aug 08, 2018 4:47 am

AR's are tricky to master in lighter calibers, let alone biggun's like the 450b, that buck and snort. The more trigger time you can put in, the better. Those 225 FTX are accurate from a stable platform at just about any speed. I wouldn't hustle them up more in hopes of increasing their accuracy. Your idea of a bigger aiming spot with that 4X is sound advice.

In Theory, there is no difference between theory and practice. In Practice, there is.
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Re: New upper range report

Postby plant_one » Wed Aug 08, 2018 9:49 am

take your upper apart, and clean *ALL* the lube off the BCG and track in the upper receiver that it rides in. you want bone dry. use something like Gun scruber or brakeclean.

without any ammo or magazine in place, hand cycle it 200 times or so. just pull the charging handle and let it drop.

this will essentially lap the surfaces into each other and remove any burrs that may be causing hiccups, or at least get most of them gone.

then as mentioned, lube the hell out of things - your BCG should be dripping, and you should wear a shirt you dont like to the range as the first couple shots are gonna be messy. wear eye protection.

you should see a remarkable difference in reliability.

i'd also suggest getting your hands on a BARTZ mag for your 450.

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