300BLK case separation - need help

[ExFlyinguy]

Okay, I had an uhh ohh today.

I was testing out some of my new subsonics. Just trying to fine tune the recipe and I had noticed that others using the same PC 215gn bullet had actually seated them deeper than I started off with so I used a depth of 2.080 Actually working down the charge. I was at 8.8 gn of IMR 4227 and I fired 3 shots averaging 1035 fps before I had a failure to feed. Could not get any more to feed so figured I needed to investigate.

Once I found the spent case on the ground I no longer had to guess why I couldn't feed. It had separated right at the shoulder. That neck is still in the chamber.
Just some details in case they are helpful. This occurred on a Barnes case that was already 300AAC from factory. I had previously tried to re-anneal it as it has about 6-7 reloads on it. This could be where I screwed up. Primer looked fine, the charge was very mid-range for subsonic.

So, everybody has a free opportunity to tell me what a dumb ass I am, but you have to educate me too, but more importantly I can't get the neck out of my chamber, and that's where I really need help.




*UPDATE: Well just when I thought I the world was coming to an end, and was all set for a good cry, I decided to run ram the biggest fucking patch I could down the barrel. The first attempt met with me punching a hole through the cleaning cloths. The second attempt well see for yourselves .


So IDK, I'm guessing maybe I should throw away my old stock of empties, get new ones and/or stop annealing. It's tough annealing these short 300's anyway without burning the piss out of your fingers.

[wanneroo]

I find 300 BO cases a bit fragile compared to something like a 308. I think the weak case necks contribute to it and so far I have found case life is not great. Lake City converted 223 brass seems to work good, the worst I had was Jamison brass. All of that had constant splits at the neck and mouth. Also I transitioned to the Forster sizing die. I found the RCBS die did not form the case neck as well as the Forster.

As I recall the same thing happened to me once with 300 BO and I think it was with that crappy Jamison stuff, not a reload either.

[ExFlyinguy]

I find 300 BO cases a bit fragile compared to something like a 308. I think the weak case necks contribute to it and so far I have found case life is not great. Lake City converted 223 brass seems to work good, the worst I had was Jamison brass. All of that had constant splits at the neck and mouth. Also I transitioned to the Forster sizing die. I found the RCBS die did not form the case neck as well as the Forster.

As I recall the same thing happened to me once with 300 BO and I think it was with that crappy Jamison stuff, not a reload either.

Man, thanks for sharing. I was really disheartened today. This is certainly a learning experience for me. I want to be able to say that I have every bit of confidence in my re-loads as I do in factory ammo, but this was a critical failure that was not easily or quickly fixed.

[aubie515]

Just curious did you use a Sheridan case gauge for your reloads? I know when I load 300BO with Lehigh Defense 174gr CF that the case does not fit inside of the case gauge. I have the standard Sheridan, but now they offer an open case gauge, so you can see where the round is stuck in the case.

I've seen guys loading 300BO with 10+ loadings from the same case. I haven't gotten that many as I use my 300BO for hunting as it's a bolt action. I haven't fired my AR15 in 300BO.

Glad you weren't injured.

[ExFlyinguy]

Just curious did you use a Sheridan case gauge for your reloads? I know when I load 300BO with Lehigh Defense 174gr CF that the case does not fit inside of the case gauge. I have the standard Sheridan, but now they offer an open case gauge, so you can see where the round is stuck in the case.

I've seen guys loading 300BO with 10+ loadings from the same case. I haven't gotten that many as I use my 300BO for hunting as it's a bolt action. I haven't fired my AR15 in 300BO.

Glad you weren't injured.

Thanks Aubie.

Interestingly enough I do have a cut away Sheridan. I checked the empty brass with it and they were within tolerance. Then I made my first 5 cartridges and seated them at 2.160 I think, and you know for some reason I never thought to check them again once loaded with the Sheridan.

They all worked flawlessly, but not knowing where exactly my sub/super sonic barrier is I thought I could probably reduce velocity a tad more just to make sure they were all subs.
So I re-read the Kings Shooter's PC thread again and that's when I noticed Yellowfin's post about COAL:

Some preliminary testing so far yielded the following:

1. OAL of 2.095 works very well.

~snip~

So I checked them in the Sheridan while seated at 2.160 and just like you said, they wouldn't seat. I had to reduce them to 2.080 I think before they would fit in the Sheridan. Ironically it was a cartridge seated at 2.080 that separated.

I've read and viewed many examples of how folks anneal. I think it's a bit of an art & science to do it right. I initially concluded when chopping .223/5.56 brass it probably prudent to anneal the new neck that is created. I also had another Barnes factory original that would not maintain any neck tension. I'd seat the bullet and it would fall all the way into the case so I started annealing all of them.

IDK, maybe I under or overheated the neck on this case? Maybe I just used it 1 too many times? It's siblings are getting tossed. Not placing any fault on the bullets. They seem great.

Unfortunately with my new load I'm not getting last round hold open.

[wanneroo]

Annealing 300 BO cases by hand I think would be hard to do right due to their size and thin case necks. One of the companies like Giraud I think makes a automated machine for $400-$500. I might get that one day. Personally I have decided due to the volume I do annealing by hand just isn't going to happen. I'm already months/year behind on many reloading projects and if it means shortened case life so be it.

In previous years I have bought 1000 case bulk lots of converted brass on sale from Palmetto State. Primer crimps have to be removed but so far most of it has worked well. So if a case gives me issues I just toss it.

I think for a lot of reloaders they try to stretch out case life as much as possible. But for me I'm not reloading any rare calibers so it's not a concern for me. Any cases that go through my system, any problems or issues at all they get tossed without a thought.

[ExFlyinguy]

Annealing 300 BO cases by hand I think would be hard to do right due to their size and thin case necks. One of the companies like Giraud I think makes a automated machine for $400-$500. I might get that one day. Personally I have decided due to the volume I do annealing by hand just isn't going to happen. I'm already months/year behind on many reloading projects and if it means shortened case life so be it.

In previous years I have bought 1000 case bulk lots of converted brass on sale from Palmetto State. Primer crimps have to be removed but so far most of it has worked well. So if a case gives me issues I just toss it.

I think for a lot of reloaders they try to stretch out case life as much as possible. But for me I'm not reloading any rare calibers so it's not a concern for me. Any cases that go through my system, any problems or issues at all they get tossed without a thought.

Amen! Sounds like the way to go for me.

[243winxb]

Separation is caused by brass stretching on firing. When full length sizing, try to push the shoulder back as little as possible, while still allowing the round to chamber. Place fired brass from full power factory ammo into the gage. I used Wilson. Note where* the case head is. Size the fired brass so the positions match. Fired brass will spring back some, so its not the full lenght of the rifles chamber. Plus, reduced loads after firing, may have a shorter head to datum measurement, then they were, before firing. http://www.brownells.com/.aspx/lid=1...nd_Maximum_COL

[aubie515]

I never thought about annealing 300BO brass because because it's cheap and can be made easily.

For me, the Sheridan case gauge should be used to check your OAL once the brass has been loaded.

I don't have my info as I'm at work, but I used to use 208gr Amax for my subsonic load, but I've switched to 174gr Lehigh CF for my hunting needs.

[ExFlyinguy]

I never thought about annealing 300BO brass because because it's cheap and can be made easily.

For me, the Sheridan case gauge should be used to check your OAL once the brass has been loaded.

I don't have my info as I'm at work, but I used to use 208gr Amax for my subsonic load, but I've switched to 174gr Lehigh CF for my hunting needs.

Yeah, not sure I made a wise decision to go that route. I agree it's too much of a pain in the ass to try and anneal it when it's so easy just convert newer stuff from 5.56. I live & I learn.