Can the overall length for 300Blk vary?

[Lead Head]

Hi all:
So I've gotten all the reloading components to start on 300Blk.
I just want to get clear on one thing and that is the overall length. I've researched this and out of the 4 sources I came across, they all say 2.260.
I'm only going to be shooting these rounds out of an AR and would like to know if the 2.260 dimension is set in stone.
Of course I know that feeding is the first concern with an auto gun, but would like to know if any of you diverge from 2.260 with an AR.
I'm shooting 125 gr. bullets with no canelure.

Thanks for replies

[Smurky]

Hi all:
So I've gotten all the reloading components to start on 300Blk.
I just want to get clear on one thing and that is the overall length. I've researched this and out of the 4 sources I came across, they all say 2.260.
I'm only going to be shooting these rounds out of an AR and would like to know if the 2.260 dimension is set in stone.
Of course I know that feeding is the first concern with an auto gun, but would like to know if any of you diverge from 2.260 with an AR.
I'm shooting 125 gr. bullets with no canelure.

Thanks for replies

2.260 is max length using a magazine in the AR15. COAL can vary quite a bit, bullet manufacturers ususally recommend a COAL for each bullet. The published COALs along with published load data should result in safe pressures and published velocities in similarly configured rifle, but there is always a disclaimer for load data. Deviating can have devastating results if you’re not very careful and fully understand what you’re doing, even then problems can occur. For example a bullet seated deeper (shorter COAL) than recommended will usually result in higher pressure and potentially excessive pressure (KABOOM) can occur.

I would suggest reviewing more of the posts on 300blk regarding changing bullet seating depths and what occurs before deviating from published load data.

[plant.one]

what sources are you referring to?

that might help us level the conversation a bit

[Lead Head]

what sources are you referring to?

that might help us level the conversation a bit

The sources I got it from are:
A chart in Brownell's
Wikipedia
The Hogedon site
And I forgot the other one

ANYWAY, you guys have scared me enough; I'll be sticking to the stated OAL. LOL

[dellet]

viewtopic.php?f=141&t=101983

[plant.one]

my post wasnt about scaring you - it was about furthering the converstaion.



so i should have added - what 125gr bullet are you using, specifically which mfg and which 125gr bullet of theirs are you using?


not all 125gr bullets are equal, especailly when it comes to speciality bullets.


details are important when it comes to reloading.

[Lead Head]

Hey, I was only kidding about you scaring me. I've been reloading since the 70s and am still here.
The bullets I'm starting out with are Speer 125gr TNT. They're just flat base spire points.
My only concern when it comes to the 300Blk ( or any other caliber for that mater ) is that I don't want to use a load where the bullet compresses the powder in the case.

[20X11]

I usually load my speer 125gr TNTs to an COAL of 2.075

[r.tenorio671]

....most of the powder manufacturers web sites that offer load data will publish the COAL figures for the bullets they have tested. The AAC manual contains some recommendations for handloading both sub and supersonic ammo here ---> http://www.advanced-armament.com/assets ... iniBro.pdf

[rebel]

Hey, I was only kidding about you scaring me. I've been reloading since the 70s and am still here.
The bullets I'm starting out with are Speer 125gr TNT. They're just flat base spire points.
My only concern when it comes to the 300Blk ( or any other caliber for that mater ) is that I don't want to use a load where the bullet compresses the powder in the case.

Sometimes compression is desirable, sometimes it is not. Depends on the powder, and the bullet. You should be a bit scared, it's new and you can get into trouble quick if you haven't messed with these type cartridges before. Magnum pistol powder doesn't suffer fools. Not that you are one, just preaching a bit of caution.