Hi All,

I have a couple of KAC SBRs (15/30) and associated QDC suppressors (one in 556 / the other in 762 - 300 BLK) that should be getting out of jail in the next couple of months (I'm counting the days).  Anyway, in anticipation, I would like to start stocking up on ammo - high quality ammo for HD, SHTF etc.  Something that will really work well with the configuration of the rifles / suppressors.

So, a couple of ammo specific questions:

1)  For the 556, from what I have gathered from my search, it looks like the 62 gr Gold Dot might be the way to go.  My search seemed to indicate that these would be better than 75 gr due to higher muzzle velocity from a short barreled rifle.  Question:  Is there anything better for an 11.5" / suppressed rifle from a defense standpoint?  By better I mean effect on target, not necessarily sub-MOA accuracy.

2)  As for 300, I am at a total loss on what to do.  I have never shot 300 but know there are two classes: lighter (super) rounds and heavier (sub-sonic) rounds.  I think I am interested in the sub-sonic rounds for CQB / lower decibel reasons.  I had looked at 190 Grain Sub-X Hornady but they seemed to get mixed reviews  in terms of performance.  Anyway, if there is a "go-to" sub-sonic round for 300 BLK CQB / HD I would love to hear your recommendations.

Thanks for reading, thanks for your time, and thanks for your input.

Radio_Silence

With regard to door #2, subsonic is always going to be categorically inferior in terminal performance compared to supersonic rounds, but good subsonic rounds will be somewhere in the realm of "high-end PCC territory". Barnes 110-grain TTSX/TAC-TX (same round, different branding, confirmed by Barnes to be the case) is the gold standard for effect on target in supers, and for subs LeHigh makes one that expands reliably (I can't remember the weight/name, I've never used it) and the el cheapo S&B 200gr FMJ rounds will reliably penetrate IIIa soft panels and most ballistic helmets at home defense distances but do NOT expand or do anything fancy on impact (just poke holes).

Generally speaking, .300 BLK subs do not expand well and should only be used when noise is the primary (or ONLY) concern, and not when you're looking for terminal performance. I use them for pest control because rattlesnakes and coyotes don't really care what they're hit with, and keep a couple of mags buried somewhere around here loaded with the above 200gr FMJ rounds just in case the world turns into a Tom Clancy novel and I need to quietly dispose of some sentries in soft armor.

Hornady 75 gr. TAP SBR

We do #1 pretty frequently. Pick a winner from any of those threads and you’ll be fine. For #2, you do you, but for HD I want the best round possible. Anything indoors is loud, to definitely include suppressed subs. Leave chasing dB at the range. 110 TAC-TX and be done with it.

On the 300BO subsonics, one school of thought is you don't HAVE TO run the gun in semi-auto mode.
Install a gas block that allows you to completely turn the gas off.
Install a large charging handle to give you lots of leverage on the charging handle to jack each spent case out of the chamber after firing.
This will reduce ALL of the bolt noise if you are only firing one shot, and it will eliminate any gas coming out of the ejection port into your eyes if you are running a suppressor.
And rendering it a manual-operated weapon will almost surely eliminate any cycling/feed issues.

Another option if the non-semi-auto mode is appealing to you: Consider the straight-pull KALI-Key charging handle/bolt conversion. The seriously extra-large KALI charging handle gives you a LOT of leverage on the charging handle, while allowing you to not have to futz with an adjustable gas block between loads. You get to leave your gas block set up for full-power ammo. When shooting subs, just swap to the the KALI bolt/carrier assembly and the KALI charging handle. The KALI-Key swap takes less time than futzing with gas adjustment.

If you handload, Lapua makes an EXCELLENT 200-grain .30 caliber bullet designed for good accuracy at subsonic velocity. If there is an easy-button for .30 caliber subsonic bullet selection, the Lapua bullet is probably it. Very stable - so your suppressor is not at risk of baffle strikes from a crappy bullet. Cost is 50 cents per bullet. No expansion. But no expansion needed if your shot lands inside the 8-ring. Expect full penetration of deer-sized targets inside 100 yards with the Lapua 200-graing bullets at subsonic velocity. Deer shot in the lungs, liver or heart. Die fast - expansion or no expansion. I've seen them succumb quickly lung-shots from 10 pumps from a BB gun (not that I recommend that method though). I gotta believe a 200 grain .30 caliber bullet is at least as effective with a lung shot.

Otherwise, run a supersonic load with a premium bullet designed to expand at 300 BO velocities for "operational" activities - however you define "operational." Suppress it if you have the money, and you don't mind the extra weight out front.

For shooting tin cans at 10 yards, just shoot the cheap supersonic factory ammo.

I issue Hornady TAP SBR for work in 5.56 and the TAP versions in 300blk as well.

I like Fusion MSR for .223/5.56, just based on threads here that included gel shots at distance, and reports from hunters. Bonded Soft Point that expands down to ~1700fps.

Will be building a .300 soon and will go with TAC-TX. Cheapest Subs for Night Shooting to keep the neighbors happy. I admit that Silenced Lehigh Maximum Expansion Subs seem sexy AF to me, for some reason... but at the end of the day, actual rifle ammunition is what should be used.

RELATED LINK

Fusion 62g, Gold Dot - Pretty much any decent soft point will work with the 5.56. MK262 clones at short range will get the job done too.

I prefer Mk318, but over penetration does not concern me.

For subsonic 300, the Lehigh 194g Max Expansion is the way to go, imo. Expands very consistently and very large.

That said, I'd still suggest going with a supersonic round when your life depends on it.
110g Vmax or Varmageddon will jack shit up, and no over penetration concerns. 110g Tac-Tx, 115g Lehigh CC, Fiochi 125g SST or even the cheap Remington 120g OTM works very well, if you're not concerned with over penetration.