KAC 300BLK Upper

**cosmo223** · 09-23-15, 12:30

With the price of 300 BLK ammo coming down, I'm considering taking the plunge and buying a 300BLK upper. I have a lower I've already put together myself (Spikes Tactical receiver and lower parts kit, RRA National Match trigger). I'd plan on paying my $200 to make this a registered SBR lower and then put a 9.5-11.5 inch 300 BLK upper on it.

In doing research, I see that KAC has decided to stop making 300 BLK uppers and I have found a place that looks like they are trying to get rid of their existing inventory, so I could pick one up for about 60% of MRSP. Of course, because its KAC, the upper would still cost north of $1,000. I have a number of AR's, but have never owned a KAC and am kind of curious to see what all the fuss is about.

Anyone have a KAC upper (or rifle) in 300 BLK? If so, are you happy with the performance, reliability, accuracy of the gun? The bargain hunter in me is finding this discount pretty tempting, but I don't want to spend a over a grand when I could just go out and buy a Radical Arms upper for a couple of hundred bucks, unless the performance, reliability, fit and finish, etc justify the additional costs.

**MichaelVain** · 09-23-15, 16:26

Originally Posted by cosmo223

With the price of 300 BLK ammo coming down, I'm considering taking the plunge and buying a 300BLK upper. I have a lower I've already put together myself (Spikes Tactical receiver and lower parts kit, RRA National Match trigger). I'd plan on paying my $200 to make this a registered SBR lower and then put a 9.5-11.5 inch 300 BLK upper on it.

In doing research, I see that KAC has decided to stop making 300 BLK uppers and I have found a place that looks like they are trying to get rid of their existing inventory, so I could pick one up for about 60% of MRSP. Of course, because its KAC, the upper would still cost north of $1,000. I have a number of AR's, but have never owned a KAC and am kind of curious to see what all the fuss is about.

Anyone have a KAC upper (or rifle) in 300 BLK? If so, are you happy with the performance, reliability, accuracy of the gun? The bargain hunter in me is finding this discount pretty tempting, but I don't want to spend a over a grand when I could just go out and buy a Radical Arms upper for a couple of hundred bucks, unless the performance, reliability, fit and finish, etc justify the additional costs.

I have both the 11.5 and 9.5 KAC uppers and they are worth it compared to my AAC. They come with slick sided urx and qdc compatible FH for KAC suppressors. The barrels are Noveske stainless barrels and you get the E3 bolt which is KAC's strength. It also comes with KAC sights.

It's a quality upper using quality parts.

My AAC is ok, I use it to shoot Freedom Munitions bimetal ammo that I won't want to shoot through my KAC.

So yah, if you can get it for 60% of retail, I would recommend buying it.

**tom12.7** · 09-23-15, 17:52

What is the intended end use for the OP?
There are some pro's and con's with either the AAC or KAC uppers. As far as the market goes now, those two venders seem to be the leaders from what I've seen, and I've seen more than a few. For possible serious use, those are the only ones I would recommend over the others.
Both are good, the AAC has .30 caliber ramps that feeds some ammo better, the radiused E3 BE runs close, a conventional 5.56 BE may run into issues. Opening up the ramps in the KAC uppers to .30 caliber may have not been logistical in business on the KAC guns on their BE's and upper's with a reduced need compared to normal 5.56 components.
I will say that that KAC uppers have had the capacity to shoot smaller groups than the AAC in general, but not always, sometimes ammo depending. I know the AAC barrel is harder, and should be longer lasting for most. I don't think the intention of AAC was to make match grade barrels, just good ones, most seem to be.
KAC uses conventional carriers in theirs, AAC has their own. The caming and the coating has changed for the AAC. I've seen the flaking from the AAC coating, but It didn't impede function. The 9" AAC runs very well with their carrier, but I do not think personally that is best for other options. Personally, I'm kind've stuck on this since I know of better carriers that could come to market when consumers finally demand it, my "personal bitch" in this.
A great inclusion into this system would be an A5ish or rifle like action system that delays the carrier caming and timing events in time in general, there seems to be only a few drawbacks, but many potential gains.

**cosmo223** · 09-24-15, 08:10

Thanks for your responses - although I'm not sure I'm smart enough to understand tom12.7's response in its entirety.

What is BE an abbreviation for? I assume something different than BCG (Bolt Carrier Group). I think your basic points are that the AAC may be more reliable with some types of ammo, that the KAC has the capacity for greater accuracy because of its stainless steel match barrel, but will also not have the same barrel life as the AAC.

As for my intended use: it will primarily be used like most of my guns - I go to the range and shoot them. So no hunting. Also, due to the caliber and the fact that it will be an SBR intended range will be 50-200 yards and I will probably pop an Aimpoint (or a Primary Arms micro dot if I decide to save some $). Having said that, I do like an accurate gun and I would certainly prefer a gun that holds nice tight groups if I bench it, or shoot prone or sitting. Barrel life isn't an issue, since I own a number of guns and even with weekly trips to the range I'm not going to be shooting out the barrel anytime soon. (And if and when I do, I have no problem replacing it).

Finally, I suppose all of my guns do double duty as a SHTF/home defense guns and the size, weight and ballistics of a 300BLK SBR make it a top candidate for this role.

**MtCarbine** · 09-24-15, 17:30

BE =barrel extension

**cosmo223** · 09-24-15, 18:05

Thanks, MtCarbine, I was thinking it was something to do with the bolt extractor spring or the function of the bolt extracting rounds from the chamber - i.e. FTE problems, so clearly I was confused.

**Failure2Stop** · 09-24-15, 18:44

KAC didn't stop making .300 BLK uppers/guns, just bringing them into the new generation, and 16" 5.56 guns were in line first.

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**cosmo223** · 09-24-15, 19:55

Very interesting. I was wondering why KAC got in and then out of the 300 BLK market so quickly. I think this caliber holds a lot of promise, particularly if you want to go the SBR route or run your gun suppressed. So eventually KAC is going to release Mod 2 SR30's? Will these keep the stainless barrels or switch to chrome lined like the SR15's?

Also, although it's nice to get the latest and greatest iteration of anything, I've decided to go forward with getting the original SR30 since I can pick one up at such a substantial discount. Very excited since this will be my first SBR AR. Now I just need to move out of Massachusetts so I can also do the paperwork for a suppressor.

**Failure2Stop** · 09-24-15, 20:12

I still have a soft spot for mod 1 guns. Sounds like you found a good buy.

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Jack Leuba
Knight's Armament Company: Military/Govt Product Liaison
F2S Consulting: Director of Shooting Stuff