A1680 and 230gn HPBT SMK issue!

[luigi]

New Guy here and joined up to get some advice from the 'knowledgeable' folks here about a reloading issue I had.

My son got a WC AR15 ( suppressed ) in 300 AAC and I wanted to reload some 'subsonic' rounds for him. I purchased some Sierra 230 gn HPBT SMK bullets and due to my research bought a 1 lb. bottle of A1680 powder. I attempted to load 10.9 gn to a COAL of 2.245".

I was using the SIerra Load Data:

https://sierrabulletsblog.com/2017/12/2 ... load-data/


When I tried to set the bullet the load was obviously 'compressed' and the bullet tip was deformed! The Sierra data shows from 11.2gn up to 14.5gn.

Has anyone had experience with this bullet using this powder? If I can't get 10.9 gn to load...how could you load 14.5 gn??

Since January 2020 I have sent several emails to SIerra Bullets with NO RESPONSE.

I finally posted a message on their FB page just trying to get someone to talk to about this load data.

Any advice and help would be appreciated.

PS I ended up using some H110 powder ( I use for M1 carbine ) and it worked great in his AR for subsonic!

[bangbangping]

Nothing wrong with compressing A1680. You could load that bullet to mag length to compress a little less, and you need a new seater stem if you're messing up the bullet. Personally, I would (and have) run with the 200-220 gr. HPBT rather than the 230.

[luigi]

Bangbangping,

Thanks for the response.

The max COAL I have seen is 2.260". ....I could not get to this without deformation of bullet tip. I am using Lee dies and had no problem loading H110 to 2.245" without deforming the bullet.

Have you loaded this particular bullet w/ A1680? It may be the bullet is too long ( 1.75") ?

My point is it may be their load data may be off? I have been reloading for many years and never had a issue like this.

I am getting frustrated with Sierra Bullets for not responding ( I started emailing in January ).

[wildfowler]

I would use what the manufacturer told us way back when this first came out.

He said to use 11.2 grains and adjust down as needed. This was with a 220 grain SMK.

https://web.archive.org/web/20161002074 ... ckout.com/

Be sure and save a copy of this in case it ever disappears because I don’t believe it’s active online anymore?

If I remember correctly from my original 10 inch barrel 11 grains put me just a hair under 1100 ft./s and I wound up using 10.8 or nine grains.

Edit: Most importantly, how did the load shoot for you? Because the dinging up of the tip is probably not as big of a deal as you think?

Also, if that bullet tip bothers you too much, you might try to contact the die manufacturer and ask if they could either make or supply you with a different seating stem that matches your bullet?

[luigi]

Thanks WIldflower.

Next time I will go with smaller bullet ( 220 gn ) but unless I hear from Sierra it won't be theirs!

[wildfowler]

How did they shoot?

I was mainly suggesting that you reduce powder charge below the minimum to see if that helps with your bullet issue you’re trying to use now.

Also, try calling this number and ask to speak to a technician. (660) 827-6300

Email is much too slow for my taste and I always pick up the phone and call someone, because I want my answer right now.

I think after speaking to someone in person about this you will be happy you did. Sierra is good people.

[dellet]

Sadly, this will be a bullet issue. I am having the same problem with the Hornady ATip bullets. This new Sierra bullet will be about the same.

There are multiple issues.

First the data is hopeful at best, garbage at worst. With 11 grains 1680 in the case you have to push the bullet into the powder about .110”. That’s a a big displacement of powder.

The bullet design does not lend itself to rough handling. The best jackets for accuracy are the thinnest. They are more consistent but also the most fragile. Even too tight of a neck while seating will leave a mark and compromise the jacket.

These are best seated with a dedicated seating stem. I have tried 4 different stems for the Hornady. If I continue to use them I will buy the stem Hornady designed specifically for this bullet.

Unfortunately I think Sierra pulled this data off the computer. With the right seater, you might get 11.5-12 grains. I call bullshit on 14 at 2.2anything

Sorry Luigi, I think a powder change is the best option.

For what it’s worth the 250 A Tip is 1.875”. Trying to get enough powder under that has proven almost impossible to stay under 2.260”.

[luigi]

Wildflower & Dellet,

Thanks for the great responses! I can try slightly lower than min.( < 10.8 gn ) on the A1680 and see show this works! As longs as his AR cycles OK and accuracy is decent then I can still use the A1680! I will give SIerra a 'call' next week. Would like to see if they actually reloaded this bullet with A1680 at those weights!

The H110 worked great at about 8.5 gn. My son sent a short video and his rifle sounded like a BB gun.....delay....then ping! I think it was an 8" gong at about 100yds ( off hand )?

I also think next time going with a 220gn bullet will save me from going crazy again..LOL

Your help is exactly why I joined this forum. I appreciate your help!

[certifiable]

the 250 A Tip is 1.875”

Is that the bullet oal?

[dellet]

the 250 A Tip is 1.875”

Is that the bullet oal?

Yes, here’s the bullet sitting on the bottom of the case next to a loaded 110 Nosler. Measures 2.050”. Not much left for powder at magazine length.



I started fooling with it a couple months ago. So far no AR functioning load.

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