300 AAC

Here is a shorty sub sonic 300 AAC, with its temporary stock.

http://i1004.photobucket.com/albums/...ps6f584f9e.jpg

It is 780mm long, weights 2.945 kgs, 6.5 lbs as pictured with the VXR 3-9x40 scope

http://i1004.photobucket.com/albums/...ps23bfc45b.jpg

Shoots the 240 SMK really well at 1010 fps, sub moa with slightly oval holes.

http://i1004.photobucket.com/albums/...psc94c82d9.jpg

Zeroed at 50m it needs 3.25 moa for 75m & 7.75 moa for 100m, 25moa for 200m :o, didn't try 200m, sorry pic is a bit messy....

http://i1004.photobucket.com/albums/...ps18f9a45c.jpg

It will be interesting to compare its terminal performance with the 450 Bushmaster.

Nice.
8 twist?

Boy that is short!

Would a 75y zero not be a bit more practical on a subsonic ?

Awesome

Don't mean to be picky, but the correct designations for this chambering, as ratified by SAAMI, are "300 AAC Blackout" or "300BLK". Not "300 AAC" or any other combinations... :D

Nice wee build, but if the holes are slightly oval, are the pills not quite stabilising?

Quote:

---

Originally Posted by veitnamcam

Boy that is short!

Would a 75y zero not be a bit more practical on a subsonic ?

---

If it didn't have a dial scope yep.

Easy enough to wind 3-5 moa on dial & be GTG :)

Quote:

---

Originally Posted by ishoot10s

Don't mean to be picky, but the correct designations for this chambering, as ratified by SAAMI, are "300 AAC Blackout" or "300BLK". Not "300 AAC" or any other combinations... :D

Nice wee build, but if the holes are slightly oval, are the pills not quite stabilising?

---

Yep the approx 7" long 8 twist looks like they aren't quite stable, very accurate & staying in line all the same though.

Quote:

---

Originally Posted by madjon_

Nice.
8 twist?

---

Thanks Jon, yep 8 twist TF approx. 7" long

Quote:

---

Originally Posted by Kiwi Greg

Yep the approx 7" long 8 twist looks like they aren't quite stable, very accurate & staying in line all the same though.

---

That's interesting, so with that twist and length combination they're not gettng driven a full rotation before clearing the rifling. I wonder if there's an established formula that applies in respect to that. Mine is a 16" 1/8 so my 240SMKs get almost two full driven turns. You're still getting good accuracy though, can't be too much of an issue.

My 300 whisper JDJ is 8 twist 16"
Fcuk I miss my rifles,Albany shooters club had a range day today an I had to do the craft market thing in Denmark:pissed off:

The 240 grn smk were the worst grouping load in my rifle the best I could get would be 3 inches at 50m with the load mentioned above. Lehighs group really well just a bit expensive for hole punching paper.This is out of a 12.5" barrel.

Quote:

---

Originally Posted by Markgibsonr25

The 240 grn smk were the worst grouping load in my rifle the best I could get would be 3 inches at 50m with the load mentioned above. Lehighs group really well just a bit expensive for hole punching paper.This is out of a 12.5" barrel.

---

What is your twist rate ?

1:8. It will near enough same hole group supersonic stuff at 100m and subsonic with the Lehigh is a inch at 50 m. I couldn't get anything decent with the 240 grn smk

out of this

Subs are all about balance of the projectile rather than twist.. Or you can add twist to make up for longitudinal balance.
You will be able to launch a crayon shaped projectile at sub speeds in almost any twist and have it stabilize, but you have to spin a heavy VLD a lot faster

I need some crayons

I would have thought a slightly longer barrel with the same twist rate would give similar or better results not worse?

Quote:

---

Originally Posted by veitnamcam

I need some crayons

---

Red ones will chrony faster :)