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[ziconceo]

I'm loading some 300 blk for my 16.5 ar. Imr 4227 has me a little sketchy since the last load I used with it blew up in my face.

Here's the load:

300blk brass
Oal: 2.060
16.8gr imr 4227
125 grain Sierra bullets
Cci small rifle primer

Am I good?

[liber]

You can verify that on the Hodgdon site yourself.

http://www.hodgdonreloading.com/data/rifle

This is what they show for a 125 gr. NOS BT

Manufacturer - IMR
Powder - IMR 4227
Bullet Diam. - .308"
C.O.L. - 2.060"

Start
Grains - 16.5
Velocity - 1,818
Pressure - 38,000 CUP

Max
Grains - 17.7C
Velocity - 1,965
Pressure - 49,800 CUP

[ziconceo]

You can verify that on the Hodgdon site yourself.

http://www.hodgdonreloading.com/data/rifle

This is what they show for a 125 gr. NOS BT

Manufacturer - IMR
Powder - IMR 4227
Bullet Diam. - .308"
C.O.L. - 2.060"

Start
Grains - 16.5
Velocity - 1,818
Pressure - 38,000 CUP

Max
Grains - 17.7C
Velocity - 1,965
Pressure - 49,800 CUP

Right, that's exactly the site I got it from, just double checking is all.

I guess I just can't understand why 4227 blew up in a 95% case full of 223 yet is fine in a 95% full 300 blk.

[Kmai24]

Not saying you aren't but if you didn't, knock off 10% of the min and do work ups just to be safe

[NewbieLoader]

Right, that's exactly the site I got it from, just double checking is all.

I guess I just can't understand why 4227 blew up in a 95% case full of 223 yet is fine in a 95% full 300 blk.

I don't see a load listed for .223 with IMR 4227 on the hodgdon web site. The same powder will act totally different from one caliber to another. So comparing the amount of powder in a .223 case VS a 300 blk case does not really tell you anything.

[ziconceo]

I don't see a load listed for .223 with IMR 4227 on the hodgdon web site. The same powder will act totally different from one caliber to another. So comparing the amount of powder in a .223 case VS a 300 blk case does not really tell you anything.

That's because you aren't supposed to use it at all in 223 haha

[NewbieLoader]

That's because you aren't supposed to use it at all in 223 haha

That is my point exactly!

[liber]

That's because you aren't supposed to use it at all in 223 haha

So how do you know what 95% full is for 4227 then?

There's a lot that is not told here, what type of cases you're using...could be military or match or even just plain 223. Same goes for your 300 BLK, you haven't given too much information about the cases. Thick wall cases will have less volume.

As with any load, you should start at the bottom and work yourself up. Your 300 BLK load is closer to the bottom, so it's *probably* safe.

[glassparman]

You should NOT look at anything having to do with reloading smokeless powders as 95% or any other percent. As others have said, one caliber to another acts totally different with a given powder. Research load data ALWAYS.

Load data for "smokeless" powder is measured in grains as in weight, not volume. Using anything else than properly published loads for a given caliber, powder and such, can kill you.

If you REALLY want to work up your own loads, get a Chrony and a powder scale and start lower than the published load data as Kmai24 said. Work your way up in half grain increments until you get to the desired or proper velocity.

We really want you to be around for next holiday season so be safe and research!

As a side note, black powder in the old guns can be loaded by volume as long as there is no air gap between the powder and bullet but black powder is a whole different ball game.

[SinisterBud]

[ziconceo]

Uh oh, hold on guys, your missinterpretating what I said. I don't measure by volume, I use a beam scale and load data

I said 95% full because when I eyeballed the case it was about 95% full of powder. 22.5 grains of 4227 almost fills up a case of 223. 16.8 grains of 4227 almost fills up a case of 300blk.

I'm using cases stamped "rp" on the bottom.

For the 223, I'm just using hornady cases.

[Metal God]

Since your talking volume . Think of it this way . A 30 cal bore is much bigger then a 223 bore . There is significantly more space/volume in the bore behind a 30cal bullet then a 22 cal bullet as they travel down the bore . That extra space will reduce pressure or make it harder for the powder gases to expand fast enough and keep up the pressure as the bullet goes down the bore creating even more space in the bore to pressurize behind the bullet .

4227 is a magnum pistol powder and to fast for the little .223 bore diameter . It's generally used in much larger diameter bores with shorter barrels . The .224 bullet was not able to get out of the way of the quickly expanding gases fast enough do to the small diameter/volume of the bore compared to the 30cal bore . This caused a huge pressure spike .

It's not to unlike seating a pistol round deeper reducing case volume resulting in higher peak pressure . The reduced space of the 223 bore compared to the 30cal bore allowed the pressure to spike quicker then the bullet could move down the bore resulting in a even larger pressure spike .

Although the above is not something every reloader understands . Reading a reloading manual from start to finish minus all the data would have helped you understand pistol powder is a no no in rifle cartridges . Yes the 300blk is a rifle cartridge but it is a specialty round that often has very specific requirements . There is a good reason why it uses a very slow pistol powder or UBER fast rifle powder . Just because the 223/5.56 uses the same case does not mean in any way they can be loaded the same way with the same powders .

That's my general understanding of what likely happened . I'm sure there is a better rocket science explanation as to why you blew up your gun .

[opos]

You should NOT look at anything having to do with reloading smokeless powders as 95% or any other percent. As others have said, one caliber to another acts totally different with a given powder. Research load data ALWAYS.

Load data for "smokeless" powder is measured in grains as in weight, not volume. Using anything else than properly published loads for a given caliber, powder and such, can kill you.

If you REALLY want to work up your own loads, get a Chrony and a powder scale and start lower than the published load data as Kmai24 said. Work your way up in half grain increments until you get to the desired or proper velocity.

We really want you to be around for next holiday season so be safe and research!

As a side note, black powder in the old guns can be loaded by volume as long as there is no air gap between the powder and bullet but black powder is a whole different ball game.

Fully agree and I think some of the "% of volume" ideas that some folks get is when they look at something like the Trail Boss "loading formula" which deals with % of case space...I've had to talk a couple of new loaders out of trying to apply % information to other powders...the book and proven manufacturers recipes and careful testing might just keep all the fingers and face parts in place..playing with smokeless powder is like giving a 2 year old a rattle snake instead of a baby rattle...it's going to bite.

[ziconceo]

Not using volume, not using volume, not using volume.


I shot the loads, they functioned perfectly, not one single jam

I noticed as I was loading the mag that I should've seated the bullets to 2.206 NOT 2.026 or whatever I posted haha they were inaccurate.

2" at ~80 yards

Sent from my 0PJA2 using Tapatalk

[Metal God]

I understand you are not using volume to load .

I guess I just can't understand why 4227 blew up in a 95% case full of 223 yet is fine in a 95% full 300 blk.

My post went directly to the above quote and believe so did the others . Volume has nothing to do with , if a load will be safe . For example check out some 45-70 loads . some only fill the case about 1/4 . It can at times help with accuracy though but again that does not mean fill the case if you want accurate loads .

If you don't understand why 4227 is to fast a burn rate for a 223/5.56 you need to read more about smokeless powders . This is not to be snarky . It's to make sure you keep all your fingers .