Looks nice, Give the brass a hard look and make sure you don't see any leakage around the primers or if they are pushed back any.
There's a good chance you are about ready to see a pressure spike.
What Length did you end up at?
Why 300 BLK? This is why.
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Re: Why 300 BLK? This is why.
300 Blackout, not just for sub-sonics.
Re: Why 300 BLK? This is why.
I'll measure what's left this weekend.
I was intrigued to see the brass loaded with SST's looked great and the 125 SMK brass pierced primers at a full half grain LESS powder. Obviously more bullet in the case causing higher pressure.
Just for wear and tear caution, I'm guessing somewhere inbetween those two loads will be the load to go with. That is if I can duplicate the accuracy above 2330!
I also shot my Mk12 Mod 1 clone with it's 18" barrel for the first time last week. So awesome. I was just doing barrel break in and the piece of crap DPMS low profile gas block snapped in half, pooped the set screws out the quad rail. It's being fixed at ADCO right now. I got my new 1-6 scope for the AAC 16" upper so the 2.5-10 Viper PST FFP will go on the 18" upper.
When I get done with load development, I'll continue this post with comparisons, velocities, etc. Then it's time to do some real world leg stretching with them. JBM is great and all but real world hits at where they are supposed to at the actual distance desired is fact.
I was intrigued to see the brass loaded with SST's looked great and the 125 SMK brass pierced primers at a full half grain LESS powder. Obviously more bullet in the case causing higher pressure.
Just for wear and tear caution, I'm guessing somewhere inbetween those two loads will be the load to go with. That is if I can duplicate the accuracy above 2330!
I also shot my Mk12 Mod 1 clone with it's 18" barrel for the first time last week. So awesome. I was just doing barrel break in and the piece of crap DPMS low profile gas block snapped in half, pooped the set screws out the quad rail. It's being fixed at ADCO right now. I got my new 1-6 scope for the AAC 16" upper so the 2.5-10 Viper PST FFP will go on the 18" upper.
When I get done with load development, I'll continue this post with comparisons, velocities, etc. Then it's time to do some real world leg stretching with them. JBM is great and all but real world hits at where they are supposed to at the actual distance desired is fact.
Re: Why 300 BLK? This is why.
Not to be a dick about it, but you should know both measurements and the seating depth of both. I am not surprised you pierced a primer.nolwark76 wrote:I'll measure what's left this weekend.
I was intrigued to see the brass loaded with SST's looked great and the 125 SMK brass pierced primers at a full half grain LESS powder. Obviously more bullet in the case causing higher pressure.
You need a comparator, because just using overall length will get you hurt.
125 smk is 1.125 long and has a base to ogive of .425
125 SST is 1.035 long and has a base to ogive of .405
So your 125 smk was a minimum of .020 deeper in the case if you matched cartridge base to ogive length with the 125 SST.
If you matched overall length, then the SMK was more like .090 deeper.
The SMK also has .020 more bearing surface in the bore which will also increase chamber pressure, more resistance.
This is why I chose the 125 SST for the AR. If you are going to run that hot you will want to know all of those numbers and what they potentially do to pressure.
The other thing you need to be careful of, is since there will be less bullet in the case with the SST, is that the bullet does not move forward and hit the lands when it chambers. Fire a couple and pull one from the chamber and check that the length is the same as when you seated it.
Sorry for the rant,(not really, maybe I should have pm'ed it) but I kind of got you going on this. If you had worked up slowly, you would not have pierced a primer. Make sure you check your firing pin and bolt for damage.
There is a lot of potential in handloading 300 Blackout that is not realized. The idea is to keep that potential on the target and not blowing up in your face.
Please be careful.
300 Blackout, not just for sub-sonics.
Re: Why 300 BLK? This is why.
Yep, this should have been a PM. You aren't being a dick dellet, you and I don't know each other so a word of caution is fine. You didn't push me to do this though. I've wanted to push the 300 BLK before we talked.
Sorry I misspoke, misstyped. I know the measurement, off the top of my head, at that moment, I don't remember because I wrote it down.
I DID work up VERY SLOWLY. I looked at my brass as I went. The page before this is showing some signs of pressure with the primers but they aren't flattened or pushed out. I went up in .1 grains from there. On round 2 (due to the shade, I didn't realize that I pierced a primer on the first one) I stopped due to an obviously pierced primer.
I didn't give out how many grains of what I am using. I said GO SLOW but that the 300 BLK can do more than factory. This is true of basically all calibers. The manufacturer HAS to go a little slower due to variations in any companies chambers. They can't hot rod mass produced ammo because some idiot will make a slightly undersized chamber and it will blow up. Then all they will hear is that their ammo is too hot and blows up ALL guns.
My friend has a GAP .308 rifle that he is pushing 190 SMK to 2800+fps with RL17. Too bad it's so temp sensitive. Brass looks great. A mutual friend of ours with a custom rifle liked that idea so he wanted to develop the same load. They started very, very slow and only got to 2500 fps+ before seeing signs. Not all rifles are the same and can't do what others can do.
If you work slowly and think about what you are doing, you can be safe. I didn't say "gee whiz, is the smk longer and causing a problem?" I know why it pierced a primer at much slower than the SST.
I'm glad the SST looks good because that's what I wanted anyway. I'd like to develop a load with the SMK just because I've got a lot of them but obviously less fps than is safely achievable IN MY RIFLE than the SST.
Sorry I misspoke, misstyped. I know the measurement, off the top of my head, at that moment, I don't remember because I wrote it down.
I DID work up VERY SLOWLY. I looked at my brass as I went. The page before this is showing some signs of pressure with the primers but they aren't flattened or pushed out. I went up in .1 grains from there. On round 2 (due to the shade, I didn't realize that I pierced a primer on the first one) I stopped due to an obviously pierced primer.
I didn't give out how many grains of what I am using. I said GO SLOW but that the 300 BLK can do more than factory. This is true of basically all calibers. The manufacturer HAS to go a little slower due to variations in any companies chambers. They can't hot rod mass produced ammo because some idiot will make a slightly undersized chamber and it will blow up. Then all they will hear is that their ammo is too hot and blows up ALL guns.
My friend has a GAP .308 rifle that he is pushing 190 SMK to 2800+fps with RL17. Too bad it's so temp sensitive. Brass looks great. A mutual friend of ours with a custom rifle liked that idea so he wanted to develop the same load. They started very, very slow and only got to 2500 fps+ before seeing signs. Not all rifles are the same and can't do what others can do.
If you work slowly and think about what you are doing, you can be safe. I didn't say "gee whiz, is the smk longer and causing a problem?" I know why it pierced a primer at much slower than the SST.
I'm glad the SST looks good because that's what I wanted anyway. I'd like to develop a load with the SMK just because I've got a lot of them but obviously less fps than is safely achievable IN MY RIFLE than the SST.
Re: Why 300 BLK? This is why.
A 9" 300 Blackout and a Mk12 SPR formatted 5.56 can cover all applications that I can think useful in the AR platform for my needs.
Just received 1,000 rounds of the Black Hills 77gr TMK yesterday. I have high expectations of this round - higher bc than the smk and ability to expand. Just need to know the expansion results better. I am content for now not having any other AR variant but who knows.
Just received 1,000 rounds of the Black Hills 77gr TMK yesterday. I have high expectations of this round - higher bc than the smk and ability to expand. Just need to know the expansion results better. I am content for now not having any other AR variant but who knows.
Re: Why 300 BLK? This is why.
Those TMK should be awesome. However, for pure energy, on paper, the 300 BLK wins.
5.56/.223 is not irrelevant or going away. It shouldn't. But if you are going to pick two guns and one of them is a 300 BLK SBR, why not also have a 16-18" 300 BLK? Yes the drop and drift will be more but not by a gigantic margin. If you can't make a hit or need more energy than a 5.56 or 300 BLK can deliver at a given distance, you need a .308 anyway.
5.56/.223 is not irrelevant or going away. It shouldn't. But if you are going to pick two guns and one of them is a 300 BLK SBR, why not also have a 16-18" 300 BLK? Yes the drop and drift will be more but not by a gigantic margin. If you can't make a hit or need more energy than a 5.56 or 300 BLK can deliver at a given distance, you need a .308 anyway.
Re: Why 300 BLK? This is why.
nolwark76 wrote:Those TMK should be awesome. However, for pure energy, on paper, the 300 BLK wins.
5.56/.223 is not irrelevant or going away. It shouldn't. But if you are going to pick two guns and one of them is a 300 BLK SBR, why not also have a 16-18" 300 BLK? Yes the drop and drift will be more but not by a gigantic margin. If you can't make a hit or need more energy than a 5.56 or 300 BLK can deliver at a given distance, you need a .308 anyway.
I mostly agree with that. Having two ARs of the same caliber is missing the opportunity of, 1) variety, and, 2) shooting an affordable round. The 223/5.56 can be a great, affordable plinker. The 300 BO, not so much. And really, a 16" BO is not sufficiently better than the 9" for which the platform was designed.
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