Long subsonic 300AAC projectiles

[marek313]

I have been shooting my 300 blackout for a while now but so far I havent played with any subsonic loads. I got these solid copper 308 projectiles from a friend but I'm not sure if these can be used in 300AAC since these are so long at 1.5". I made couple dummy rounds loaded to max 2.26" and they cycle but since these have to be seated so deep I'm starting to worry that I'm going to spike pressure too much. Does anyone know if these could be safely used in 300 blackout?

[sureYnot]

If you give the weight, seating depth, and powder, you might convince someone to run it through Quickload for you. Quickload doesn't replace published data. It would be merely a place to begin your own guessing from. Nobody is going to tell you to go ahead and declare it safe. Your safety is your responsibility. But someone might share the output with you.

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[cwlongshot]

I arrive at my subs opposite from all other loadings... I start high and work DOWN until I'm below SoS. (Of coarse the loads are KNOWN safe pressure wise.)

I have refused to buy the 300BLK powder as its not enough different from 1680 and up to a 25% more in cost. I find 1680 and 4227 does everything I need from this caliber for subs. Add 296/H110 for light supers and that's my trifecta of powders I ever need in this caliber. If I had to pic one powder, It would be 4227.

I haven't had good accuracy luck with cast. But 208 & 194 subs have shot pretty well for me. I now shoot mostly 147 & 150G. the Speer 150 GD made for the 300 is a dandy bullet on game! THe 147 FMJ is my plinking bought as pulls. Its pretty cheap.

CW

[marek313]

I guess I should rephrase my question since I realize that nobody is going to guarantee anything and load development is on me. The question should have been has anyone used projectiles as long as 1.5" in 300AAC? Quickload data is what I'm looking for sorry I couldnt remember the name of that program when posting. With brass within specs at around 1.36" and 1.5" projectile that would end up with around 0.9" inside the case so it would def limit case capacity. So far I've been using H110 as my go to powder but I also have some Lil'Gun and #9 that would probably work.

[Conditor22]

My cast 230 gr+ boolits are 1 5/16, my favorite subsonic load is 4 grns of pistol powder (that doesn't take up a lot of room)

Actually, 3 of my 4 favorite BO loads are fast pistol powder, the 4th is TB

measure how far the bullets go into the case then measure how high the powder is in the case and find out if you are actually compressing the load

[marek313]

My cast 230 gr+ boolits are 1 5/16, my favorite subsonic load is 4 grns of pistol powder (that doesn't take up a lot of room)

Actually, 3 of my 4 favorite BO loads are fast pistol powder, the 4th is TB

measure how far the bullets go into the case then measure how high the powder is in the case and find out if you are actually compressing the load

I have Power Pistol, LongShot, TB and couple other pistol powders. I tried couple TB loads before but those wouldnt cycle my AR which has pistol gas system. Granted I only had 160gr pills at the time but those were def subs, nice and quiet. I would imagine all those would be great in bolt action but I'm not sure if these would produce enough gas to cycle AR though.

I did cast some of those Lee 230s as i just got that mold too but I havent loaded any as I still have to PC those.

[sureYnot]

According to Quickload, a 230 grain bullet, seated to a depth of 0.9, over 7 grains of H110 will produce 27,288 psi and 1018 fps out of a 16 inch barrel.
8 grains will produce 40,265 psi and 1153 fps.
I do not recommend or endorse these loads. This information is for entertainment only.

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[sureYnot]

Case capacity is 86.8 & 99%, respectively.

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[marek313]

According to Quickload, a 230 grain bullet, seated to a depth of 0.9, over 7 grains of H110 will produce 27,288 psi and 1018 fps out of a 16 inch barrel.
8 grains will produce 40,265 psi and 1153 fps.
I do not recommend or endorse these loads. This information is for entertainment only.

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Great. Thank you

[chuckbuster]

Only thing I might add would be that you might want to get a cannelure on your bullets so that you can develop a positive crimp so that your loaded length does not change under recoil. I am sure opinions vary greatly on this, just sharing a thought.
I am not familiar with the bullet you have but know of many guys using 220 Sierra Matchkings and 230 Berger Hybrids for same application, .300 Blackout Subsonic, and due to the Boattails they are at least 1.5 long.
Kevin

[McFred]

I don't have a 300AAC BO and am generally ignorant about 'factory' guns for that cartridge but at 230gr and 1.5" length I'd double check your twist rate for subsonic use, especially if you intend to put it through a suppressor. New Jersey sounds like one of those miserable states that hates you as a firearm owner/operator so maybe the suppressor's a moot issue. But I digress.

For subs at sealevel using that projectile it appears that to get reasonable stability you should have about a 1:9 twist. 1:10 might work but is 'marginal.'

http://bergerbullets.com/twist-rate-calculator/

[marek313]

No suppressors allowed in my lovely state on New Jersey so thats out of the question. My barrel is 1:8 so it should stabilize just fine. I do like that calculator though I'm def going to bookmark that website.
Thank you

[Sig556r]

I'd go low on powder to start as the copper bullet occupy way more space that lead or Js of the same weight. Most BLK powders are fast-burning & with less confined space, may cause pressure spikes. They may not cycle your AR at lowest charge (watch out for squibs using minimal loads) then can gradually increase charge until your AR cycles or notice extractor swipes/flattened primers whichever comes first. It may also help if you have adjustable GB.

[Tackleberry41]

Solid copper like that will be alot longer than a cast bullet of the same weight. They also have a habit of getting stuck vs cast.