New Remington 300 BLK UMC Subsonic ammunition.

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300Blk
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Re: New Remington 300 BLK UMC Subsonic ammunition.

Post by 300Blk »

The non-UMC are Sierra bullets. Everyone knows this, right?
rimshaker
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Re: New Remington 300 BLK UMC Subsonic ammunition.

Post by rimshaker »

I've actually had a few L300AAC4 UMC rounds go supersonic in my suppressed AAC Handi Rifle. Weather was 70-80deg here in FL so it's not the temps. UMC feels and sounds like slightly hotter loads than the R300AAC8 ammo.

Got the same lot numbers mentioned: S27 KB1

What's the rated velocity on the 220gr UMC?
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m4a1sof
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Re: New Remington 300 BLK UMC Subsonic ammunition.

Post by m4a1sof »

rimshaker wrote:UMC feels and sounds like slightly hotter loads than the R300AAC8 ammo.
I finally got a chance to shoot some and my experience was the same. I like this alot better than the R300AAC8. With that I had some failures to pick up the next round, failures to lock back on the last round, and the ejected cases just sort of dribbled out of the ejection port. It's not as nice and shiny as the old stuff, but this new round has a nice positive ejection and much better operation.
1018
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Re: New Remington 300 BLK UMC Subsonic ammunition.

Post by 1018 »

So to make sure I have this...

The L300AAC4 is the flat base projectile- UMC? And this is the newer product ?

and the R300AAC8 is the Sierra Boat Tail projectile? What's the difference in the "L" designation and the "R"?

Everything else is equal? Brass, powder, primer?

velocity is the same? or is that what's in dispute?

Sorry, a lot of questions.
1018
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Re: New Remington 300 BLK UMC Subsonic ammunition.

Post by 1018 »

Anyone? Anyone? Bueller?
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m4a1sof
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Re: New Remington 300 BLK UMC Subsonic ammunition.

Post by m4a1sof »

1018 wrote:Anyone? Anyone? Bueller?
Since I don't have a scale or a chronograph I can only answer the first two questions, yes it has the flat base and is the newer product.
1018
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Re: New Remington 300 BLK UMC Subsonic ammunition.

Post by 1018 »

Thanks.
I have the opportunity to pick up several boxes of the R300AAC8, but just wanted to make sure of what I was getting.
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Re: New Remington 300 BLK UMC Subsonic ammunition.

Post by Elmojo »

Ok guys, my brain officially hurts.
I bought a box of this UMC 220gr AAC Blackout ammo to test my brand new AR pistol with an 8.5" barrel and pistol gas system.
The first round fired through my chrono measured 1152fps. The second was 1157. Both were OBVIOUSLY supersonic, sound-wise.

So I called Remington Consumer Services and spoke with Jim.
He proceeds to tell me that he cannot find the order number for this round (21422), that it doesn't appear anywhere in his 2014 master list, and that Remington does not manufacture ANY subsonic rifle ammo.
Further, he was adamant that if the ammo was subsonic, it would be labeled as such on the box.
I directed him to various web sites, including Midway, JoeBob, and Primary Arms, all of which clearly state that this is subsonic ammo, designed to travel at ~1050fps.
He said that all those sites (and by extension the hundreds of others selling online) are posting incorrect information.
Other than calling Jim (who was very nice, BTW) a liar to his face, what's my possible recourse?
I have a $30 box (I know, ouch) of useless ammo, since my whole goal with this rifle is to build a subsonic platform so I can get a can for it in the near-ish future.
I'm at a loss as to where to go from here. Any advice appreciated.
-Mike
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Re: New Remington 300 BLK UMC Subsonic ammunition.

Post by 300Blk »

I would call again and maybe you will get someone else.

BTW, there is no way to know if the problem is the rifle or the ammunition. That ammunition may be subsonic in most barrels and in Remington's test barrels. Or maybe it is the ammo. It depends if your rifle fires other brands of subsonic fast too.
Elmojo
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Re: New Remington 300 BLK UMC Subsonic ammunition.

Post by Elmojo »

I would call again, but from my conversation with Jim, it sounded like they are all in the same room and they all agree that they don't know anything about that round.
Is there another number I could call to get someone more knowledgeable?
I called the Ammunition Product Services division in AR, and they rerouted the call to the customer service section at headquarters in NC.

I would have thought that with an 8.5" barrel, pretty much anything that's supposed to be even close to subsonic would be well under.
I guess not! I don't have access to any other factory ammo, so I have nothing to compare against. I'm not about to spend another $30-40 for a box of ammo that may or may not work for me.
I'm working up a handload for it, and so far I'm down to 7.5grs of IMR4895 on top of a 147gr bullet. I'm not certain of the velocity on that one, as the sun went down just enough for my chrony not to work before I could test them. I'm hoping to try that load tomorrow.
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