300AAC 90-125gr Subsonic question , need help .

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300AAC 90-125gr Subsonic question , need help .

Post by Cannonsville69 » Wed Jan 29, 2020 1:43 pm

Looking for some load info confirmation for subsonics with 90gr to 125 gr projectiles .

I found alot of Trail Boss info, and loaded up a few TB loads at the numbers below, (and a few at 0.2 -0.3gr gr below and above)
Just an't find any organized, homogenized info on 300aac light loads (90-125gr)

What I did find was scattered across multiple pages, threads from many long inactive users posts several years ago.

90gr Xtp i've read anything from 4.2gr TB/925Fps to 4.5 and 4.8gr TB/1095 Fps
110gr Sierra i've read anywhere from 5gr TB/1030fps to 5.6gr TB/1050fps
125gr 5.6 to 5.8 TB for 1030-1060 Fps

Anyone been running these 90-125gr subs a while and can confirm or share their thoughts.
I also have Unique , 1680 and 4227 which i did find brief mentions of people using for subs, most of these
references said Unique is quieter for subs... unfortunately they gave no specific loads (except for 90gr which SteveUrquell was kind enough to share)

I have a 16" barrel bolt gun, I don't use a supressor. Yes i'm aware and alert for a stuck bullet.
Aware of low case vol, position sensitivity, detonation, hence the TB. Aware short C.O.A.L ammo doesn't feed well even in bolt guns.
Yes i have a chrono. Yes I'm aware of the shortcomings of slow sub rounds, larger group, more drop.
I have a 223 , a 22/250 , a 30-06 and a 243 that cover distance/precision needs . All bolt guns except my 10/22
I got this 300aac just as a cheap rifle for light load subs, plinking and possibly small/medium pests.

Mostly i'm looking for any organized, homogenized info on 90-125gr sub loads with TB or Unique from people been running subs a while.
Like to hear peoples thoughts on such a short C.O.A.L with 90-125gr projectiles ...bullet jump concerns ?
Since I don't use a suppressor, i'd really like to stay in the 900-1030 range. Like to plink and not make a racket for my very kind neighbors.

Thanks in advance, I appreciate it !

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Re: 300AAC 90-125gr Subsonic question , need help .

Post by msurveyor » Thu Sep 09, 2021 9:17 pm

I played with loads for old M1 carbine 115 gr cast in the 300 blk, I can't find my load notes but i found some loaded rounds still in marked boxes. 4.6-4.8 Trailboss was marked subsonic and as i recall i was getting under 1000 fps.
I also recall i also tried Bullseye and lilgun

I was using a single shot. I recall the Bullseye loads got very smoky and dirty before i got slow enough to be a concern.
Remember to check your barrel and never use jacketed at below book loads.

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