Blue dot

[riggeek]

I've never seen it done or even heard of it. i was wondering if any of you guys had heard of using blue dot for loading 223? Most of what I seen looked to be with lighter bullets. It was discussed a fair bit with Dogtown bullets.


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[The_Shadow]

Likely The Blue Dot loads are reduced velocity.  Not the best option for a gas driven AR

[sqlbullet]

Consulting the Lyman Cast Bullet Handbook 4th Edition I find data for a number of pistol powders in bullet weights from 44 grains to 60 grains.

None of these loads are going to approach 223 max velocity or pressure and non will cycle an AR platform rifle.  They might have a chance at cycling a modified AR pistol with a pistol length gas system and a "longer" pistol barrel of 12.5", but you would likely have to drill out the gas port to a larger size, run a low-mass bolt carrier and a reduced power action spring just strong enough to strip/chamber a round.

In a bolt gun, these would provide low recoil fun and make for a very hot 22 magnum replacement.

Blue Dot is likely unsuitable for such loads as it is well known to not burn well until it gets some pressure.  Reduced loads probably result in inconsistent ignition and burn of Blue Dot.

One of the other pistol powders for which there is data (700X, Unique, True Blue, N105, AA#9, 2400, Red Dot, Green Dot) would be a much better choice as these powders do burn uniformly with reduced pressure charges.

[riggeek]

Here's where some of the info seems to be coming from

http://www.jamescalhoon.com/tobee2.php


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[The_Shadow]

Thanks for the link!

[DDRiller]

I ran it on QL and those numbers are believable.  Would have never thought to use Blue Dot in a .223.

[sqlbullet]

Yeah.. I buy those numbers.

What pressure is quickload calculating?  I am gonna guess 35K-40K PSI which is right in the sweet spot for Blue Dot burn.

[DDRiller]

Yeah.. I buy those numbers.

What pressure is quickload calculating?  I am gonna guess 35K-40K PSI which is right in the sweet spot for Blue Dot burn.

42k for the 14 gr. load

[The_Shadow]

DDRiller, could you run the numbers in QuickLoads for Blue Dot for 64 grain & 77 grain bullets to see what those loads look like and pressure generated?
Thanks in advance!

[DDRiller]

DDRiller, could you run the numbers in QuickLoads for Blue Dot for 64 grain & 77 grain bullets to see what those loads look like and pressure generated?
Thanks in advance!

Used Nosler bullets 20" barrel and 2.25 COL
64 gr. 78% fill 15.0 grains BD 61,800 psi 2735 fps
64 gr. 73% fill 14.0 grains BD 53,500 psi 2625 fps
77 gr. 77% fill 13.8 grains BD 62,000 psi 2460 fps
77 gr.  67% fill 12.0 grains BD 47,000 psi 2265 fps

[The_Shadow]

DDRiller, could you run the numbers in QuickLoads for Blue Dot for 64 grain & 77 grain bullets to see what those loads look like and pressure generated?
Thanks in advance!

Used Nosler bullets 20" barrel and 2.25 COL
64 gr. 78% fill 15.0 grains BD 61,800 psi 2735 fps
64 gr. 73% fill 14.0 grains BD 53,500 psi 2625 fps
77 gr. 77% fill 13.8 grains BD 62,000 psi 2460 fps
77 gr.  67% fill 12.0 grains BD 47,000 psi 2265 fps

Thanks!  Just an interesting study!

[DDRiller]

I don't have enough blue dot to experiment with.  I use it for most of my 12 gauge buckshot loads.

[sqlbullet]

Very interesting.

I was thinking about this last night mulling over the question of why this data isn't in the cast bullets manuals.  Then it dawned on me that the speeds you hit once you reach pressure for Blue Dot to burn put cast bullets over the RPM threshold, even in a slow twist barrel.

I wonder how that 12 grain load would work with a 77 grain cast bullet.

[DDRiller]

67% fill 47500 psi 2240 fps

[sqlbullet]

Thanks DDRiller.

Lest you think I am dense, I did see that in the original post.

I am actually getting senile because I was sure that I had typed "I wonder how that 12 grain/77 grain cast bullet load would work in my 7.5" AR pistol."  But obviously I didn't.

:-)