Gettin' antsy for spring and warmer weather.... load experimentation

[BrianK]

There was a time that I played around with .308s and sabots and .22 bullets and got 3500 or was it 3600(?) fps out of a 15" handgun. Mediocre accuracy at 100 yards had me call a halt to the experiment when the mfgr told me that was about the best I could expect. Fast forward 20+ years to today.

I'm getting the bug to try the sabots in the 300BLK with a homogenous copper solid .22. Will it feed reliably? What will I get for velocity and accuracy? The sabots won't get stuck in my can due to the nature of the way it's built but that should be interesting also. It'd be nice if the sabot would get shed outside the can and not inside. 

FWIW, my original .308 testing found me not using the load data that came with the sabots. It was just ridiculous data. The powder was too slow and what came out of the barrel looked like a candle flame. I wound up moving up the burn rate chart to powder more in line with a .22 centerfire, and lots of it. Blast was a sharp smack to the chest sorta like the hit from the blast from a .50BMG, just not as much. I would expect reliable function (enough gas) in the 300BLK AR as long as the sabotted bullet feeds reliably. I feel the need to try this.

[shooterrex]

Sounds like fun.

[98Z5V]

1 hour ago, BrianK said:

I'm getting the bug to try the sabots in the 300BLK with a homogenous copper solid .22.

The .300BLK case, with a .224 projectile...   That's called .223 Rem or 5.56 NATO.  That's exactly what it is. 

WTF are you doing here?

[sketch]

You could just buy some Remington hollow point crap 300BLK,  but I would not use this ammo with a can. I have a post somewhere about this ammo.  What is going on here? 

[JMJ]

6 hours ago, 98Z5V said:

The .300BLK case, with a .224 projectile...   That's called .223 Rem or 5.56 NATO.  That's exactly what it is. 

WTF are you doing here?

[BrianK]

11 hours ago, 98Z5V said:

The .300BLK case, with a .224 projectile...   That's called .223 Rem or 5.56 NATO.  That's exactly what it is. 

WTF are you doing here?

No not really. The difference is the size of the piston that the pressure pushes on and the lightweight bullet as payload. It's totally different than 5.56. Load data gets thrown out the window*. I might need to use scary fast powder and as I get older I get less adventurous. FWIW, I never blew up anything because I always made small moves and I will this time too.

Maybe .220Swift or .22/250 would be more like what I was getting from the .308 handgun, but That would require another rifle. I'm also not going to look and see what the load data is for those cartridges. Maybe they use similar powder charges, but I doubt it. They don't need it because they don't use an oversize piston.

It's probably not going to give me what I want though due to the low volume of the 300BLK case. It's certainly not going to be as dramatic as what I got with .308 Win. I would expect it to give me higher velocity than I would get from the same short barrel if it was chambered for 5.56. But there's only one way to find out.

As for as the can... Not all cans are built the same. Should the sabot get caught in my can it's just a matter of unscrewing the can from the barrel (or just use long rod through the upper) and push it out. Think of the innards as a sort of smoothbore barrel extension. It's less about quiet and more about being short and containing the blast which it does very well (Amtac CQB).

*I'm not going to check my actual load data, so no one should think that what follows is something to be copied. With .308 I remember a full charge (40+ grains) of 1680. The load data that came with the sabots used powder that would have been used with, for example, a 150 grain .30 bullet. I tried their load but knew before busting a primer that it was all wrong; safe, but wrong. If I hadn't run out of room for powder in the case I could have gotten even higher velocity. Or I could have gone to an even faster powder, but my next fastest powder was IMO too big a jump so I stopped where I was. Maybe today I could make that jump, but that experiment was shelved. I didn't expect better accuracy if I got higher velocity. 

But I want to see what a 10" barrel in 300BLK will give me. That's the reason for doing it. Not to duplicate what a 5.56 will do. Right now my fast load is a Maker 85 @2300 fps. I know I can do better than that with a bigger piston, lighter bullet, and MUCH faster powder. If it feeds, and that's a big if, will it even cycle the action? Will there be enough gas at the pistol length gas port for function? I suspect yes, but I don't know that due to the greatly reduced powder volume.

[98Z5V]

Help me understand this.  You're taking 300BLK cases (shortened 5.56 case, from start, technically a 7.62x35 case), and then necking those 300BLK cases down to .224?  Basically a barrel chambered for 300BLK, but bored for .224? 

[98Z5V]

14 hours ago, JMJ said:

[shooterrex]

Sabots. Not necking  down. Unless I read it wrong.

[98Z5V]

 

This? 

If that's the answer, and it's yes, then what barrel are you shooting this through?  When does this shiit separate?  In flight?

Edited January 26, 2023 by 98Z5V

[BrianK]

2 hours ago, 98Z5V said:

Help me understand this.  You're taking 300BLK cases (shortened 5.56 case, from start, technically a 7.62x35 case), and then necking those 300BLK cases down to .224?  Basically a barrel chambered for 300BLK, but bored for .224? 

(You posted again)You'd be wrong in that understanding. It remains a .30, no change to the case. I'm not going to explain a sabot. Look it up (I see that you did). They're in common use esp' in tanks for the same reason I want to play with them. 

What I have are nylon sabots that hold a .223 bullet, what you pictured is at least similar if not exact. I just never played with them in a semi auto, or the 300BLK. 

Not a put down, but if you don't know reloading that might be the issue you're having. I can't promise results worth repeating, but I intend to pursue this. First they need to feed. Then the action needs to function. After that I need to get something worthy that the 300BLK can't do all by itself. But I think it's worth the experimenting. 

[98Z5V]

2 minutes ago, BrianK said:

Not a put down, but if you don't know reloading that might be the issue you're having.

I've been reloading for a very long time, Brian.  I've never seen anything like this in a 300BLK with a .224 inserted projectile, ever.  So, in light of that, and your definite lack of an explanation, or a picture of what you're doing - understand that. 

 

[BrianK]

I already stated it was out of a 10" barrel. When does it separate? I also already indicated that I didn't know and that was part of the experiment. It could be in the can which wouldn't be desirable as it would screw accuracy up but not be a disaster for the can due to the way it's made. Best if it separates outside the can. How will I know? Work up a load or loads and test. First w/o the can then with.

[98Z5V]

9 minutes ago, 98Z5V said:

When does this shiit separate?  In flight?

Now, @BrianK - get to this one...  When does this shiit separate? 

 

[98Z5V]

Posted at the same time.

[98Z5V]

3 minutes ago, BrianK said:

When does it separate? I also already indicated that I didn't know and that was part of the experiment. It could be in the can which wouldn't be desirable as it would screw accuracy up but not be a disaster for the can due to the way it's made. Best if it separates outside the can. How will I know? Work up a load or loads and test. First w/o the can then with.

Good luck.    This shiit legal?

[BrianK]

I'm not a reloader, I'm a handloader. There's a huge difference. I wasn't fishing for attaboys, but just making "conversation". I expect nothing major as a result due to the limited powder space (I HATE repeating myself!) but stay tuned. I'll post even if it fails. It won't surprise me if it does fail. 

[BrianK]

Absolutely legal as far as I know. Tomorrow? Who can tell, fjb and the BARF. The Sabots were still being advertised for sale in the last Firearms News.

[98Z5V]

1 minute ago, BrianK said:

I'm not a reloader, I'm a handloader.

As I am, as well.  If you're fishing for an argument, you'll get it from me.  If you want to fling insults - I'll play. 

If you want to calm your ass down, and chill out a little - that will help.  If not, let's get it on.  You can play Dickhead as much as you want, and it's not gonna end pretty here on the board.  You decide where this goes.

[BrianK]

I'll do as I stated and post my results + or -, my interest is in helping the forum. 

[98Z5V]

4 minutes ago, BrianK said:

I'll do as I stated and post my results + or -, my interest is in helping the forum. 

Helping how?  You're not even answering basic questions that were asked of you. You're evading and deflecting. 

[jtallen83]

Thank you for the work Brian, I find this experiment very interesting, used to shoot those sabot rounds Remington put out but never saw any accuracy worth a crap. When you've gotten further along I'll try to pick your brain without insulting you, demanding answers, or looking like and bully for no good reason, should be doable.................

[JMJ]

20 hours ago, BrianK said:

No not really. The difference is the size of the piston that the pressure pushes on and the lightweight bullet as payload. It's totally different than 5.56. Load data gets thrown out the window*. I might need to use scary fast powder and as I get older I get less adventurous. FWIW, I never blew up anything because I always made small moves and I will this time too.

Maybe .220Swift or .22/250 would be more like what I was getting from the .308 handgun, but That would require another rifle. I'm also not going to look and see what the load data is for those cartridges. Maybe they use similar powder charges, but I doubt it. They don't need it because they don't use an oversize piston.

It's probably not going to give me what I want though due to the low volume of the 300BLK case. It's certainly not going to be as dramatic as what I got with .308 Win. I would expect it to give me higher velocity than I would get from the same short barrel if it was chambered for 5.56. But there's only one way to find out.

As for as the can... Not all cans are built the same. Should the sabot get caught in my can it's just a matter of unscrewing the can from the barrel (or just use long rod through the upper) and push it out. Think of the innards as a sort of smoothbore barrel extension. It's less about quiet and more about being short and containing the blast which it does very well (Amtac CQB).

*I'm not going to check my actual load data, so no one should think that what follows is something to be copied. With .308 I remember a full charge (40+ grains) of 1680. The load data that came with the sabots used powder that would have been used with, for example, a 150 grain .30 bullet. I tried their load but knew before busting a primer that it was all wrong; safe, but wrong. If I hadn't run out of room for powder in the case I could have gotten even higher velocity. Or I could have gone to an even faster powder, but my next fastest powder was IMO too big a jump so I stopped where I was. Maybe today I could make that jump, but that experiment was shelved. I didn't expect better accuracy if I got higher velocity. 

But I want to see what a 10" barrel in 300BLK will give me. That's the reason for doing it. Not to duplicate what a 5.56 will do. Right now my fast load is a Maker 85 @2300 fps. I know I can do better than that with a bigger piston, lighter bullet, and MUCH faster powder. If it feeds, and that's a big if, will it even cycle the action? Will there be enough gas at the pistol length gas port for function? I suspect yes, but I don't know that due to the greatly reduced powder volume.

Thanks for this post, your explanation about the “piston” size in relation to the bullet weight makes complete sense to me as to what you’re thinking. Should be interesting to see the results. A close friend and I messed around with some of the Remington Accelerators in his dad’s M742 back in college and couldn’t get them to groups work a sheeit. The faster twist from a 300blk barrel may solve that issue. At the very least you should be mirroring a 5.7x28, which could be fun for varmints and targets. 

[BrianK]

It's not a new to me idea. The military has been using it in tanks for quite some time. I think they call them discarding sabots. The Thunderbolt ground support aircraft may also use them. I used it, as do many others, with shooting black powder.

The twist rate of the 300BLK was lost on me with all the other factors I was considering, but yes, it might mean a cleaner separation. I'm pretty sure my barrel has a 1:8 twist. In the end it'll either work or it won't. If I had a ballistics lab I'd be able to spend the $ and figure out what works best, but what I have is what I have and it'll either work or it won't. There's very little I can do to help it to work.

[BrianK]

It's not a new to me idea. The military has been using it in tanks for quite some time. I think they call them discarding sabots. The Thunderbolt ground support aircraft may also use them. I used it, as do many others, with shooting black powder.

The twist rate of the 300BLK was lost on me with all the other factors I was considering, but yes, it might mean a cleaner separation. I'm pretty sure my barrel has a 1:8 twist. In the end it'll either work or it won't. If I had a ballistics lab I'd be able to spend the $ and figure out what works best, but what I have is what I have and it'll either work or it won't. There's very little I can do to help it to work.

I nearly forgot. That's the story I get from everyone re: the Rem' accelerators. So I guess my 3" groups weren't all that bad. It just wasn't what I was looking for. After that experiment I bought a .17 Remington and throttled the velocity down to 4060fps from 4200+. The bullets were coming apart in the air.