Cut down a CTL 312-160-2r Mold to make a ~116 grain SS bullet?

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GunFunZS
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Re: Cut down a CTL 312-160-2r Mold to make a ~116 grain SS bullet?

Post by GunFunZS »

We were able to make and test starter loads with CFE BLK yesterday. I only had access to the pistol with the 1-7 twist. All cycled perfectly and made clean round holes in the targets. I couldn't tell you how well they would group yet. We had an akward position with a pistol with a red dot on it, trying to stabilize a cheek welded buffer tube with the 30 round monopod messing with our sandbag. Next time, we'll have taller sand bags and a proper scope on there. Both of us have poor eyes, and it really looks like I need new glasses again, so magnification would help a lot. As is, we only did ~2.75" -~3" groups, but I really think with better posture and magnification we would cut that in half or better. When I get the load to the finished stage, I'll post my results good, bad, or indifferent without excuses. I'm really looking forward to trying this with the carbine.


I was able to stretch COAL a little so that meant none of them were compressed loads. The next round of testing likely will be. Pressure looked very moderate. The brass all plunked out in a neat pile 2' from the ejection port, and primers looked like they were a little less flattened than factory loads. Brass showed no signs of pressure. BHO functioned perfectly. So there is room for more velocity and pressure. That's good, since all the CFE BLK loads projected pressure was lower than is matched to the hardness of the bullets. I expect the accuracy node to be around 22.5 grains, but I'd have to check back at my figures. The optimal bullet hardness for the chamber pressure would have been about 18.5 BHN, so I could simply cast more out of magnum pistol alloy and keep this data as is, for cheaper bullets which group a little better. I've got some more testing to do. I am pretty confident that CFE BLK is the powder I will stick with.

We didn't test any H110 loads this outing. H110 has much higher pressures than CFE for the same velocity range. Other powders were worse. Probably H110 load development will be a 'backward loading' operation: Start at the starting load, and work down. Based on pressure levels to alloy comparison, the accuracy node will be closer to a grain or so under the starting load.

Video on the topic to follow.
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dellet
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Re: Cut down a CTL 312-160-2r Mold to make a ~116 grain SS bullet?

Post by dellet »

GunFunZS wrote:We were able to make and test starter loads with CFE BLK yesterday. I only had access to the pistol with the 1-7 twist. All cycled perfectly and made clean round holes in the targets. I couldn't tell you how well they would group yet. We had an akward position with a pistol with a red dot on it, trying to stabilize a cheek welded buffer tube with the 30 round monopod messing with our sandbag. Next time, we'll have taller sand bags and a proper scope on there. Both of us have poor eyes, and it really looks like I need new glasses again, so magnification would help a lot. As is, we only did ~2.75" -~3" groups, but I really think with better posture and magnification we would cut that in half or better. When I get the load to the finished stage, I'll post my results good, bad, or indifferent without excuses. I'm really looking forward to trying this with the carbine.


I was able to stretch COAL a little so that meant none of them were compressed loads. The next round of testing likely will be. Pressure looked very moderate. The brass all plunked out in a neat pile 2' from the ejection port, and primers looked like they were a little less flattened than factory loads. Brass showed no signs of pressure. BHO functioned perfectly. So there is room for more velocity and pressure. That's good, since all the CFE BLK loads projected pressure was lower than is matched to the hardness of the bullets. I expect the accuracy node to be around 22.5 grains, but I'd have to check back at my figures. The optimal bullet hardness for the chamber pressure would have been about 18.5 BHN, so I could simply cast more out of magnum pistol alloy and keep this data as is, for cheaper bullets which group a little better. I've got some more testing to do. I am pretty confident that CFE BLK is the powder I will stick with.

We didn't test any H110 loads this outing. H110 has much higher pressures than CFE for the same velocity range. Other powders were worse. Probably H110 load development will be a 'backward loading' operation: Start at the starting load, and work down. Based on pressure levels to alloy comparison, the accuracy node will be closer to a grain or so under the starting load.

Video on the topic to follow.
If your looking for low pressure, stick with the CFE. You will lose about 10% velocity compared to H110. The advantage will be that CFE will cycle anything.

You really have a good possible combo going with the CFE. Treat it like Black powder. Find your seating depth, go to 110% case fill and see what happens. CFE will suck until you compress the crap out of it. You will probably take an inch off your groups.

The only issues I have had with that powder is lack of velocity, dirty and gassy as a sub powder and worse with a pistol gas system. It works well for carbine gas lengths both subs and supers.

If you leave any gap between the powder and bullet it throws wide velocity swings. This is also where pressure seem to climb.

The more I work with it the more I think cast bullets is where that powder might shine, as long as you can keep the case full.
300 Blackout, not just for sub-sonics.
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Re: Cut down a CTL 312-160-2r Mold to make a ~116 grain SS bullet?

Post by GunFunZS »

Thanks for the tips. I did notice a lot of powder fouling for approx sixty rounds. I had attributed the muck to the fact that this pistol was run "wet".
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Re: Cut down a CTL 312-160-2r Mold to make a ~116 grain SS bullet?

Post by GunFunZS »

The goal is safe accurate SS ammo, with repeatable consistent performance at least as good as milsurp 7.62x39, or something like remington core loct 300 BO.

That is to say something that shoots fairly flat and groups well enough for 3 gun in the expected ranges. Ultimately I will probably do a full custom bullet mold to get a better B.C. and then crank them out in serious volume.

I'm willing to use whatever powder, or lead alloy combination is necessary to make that affordably repeatable.

If I get it good enough, I probably won't mess with buying any jacketed ammo. Either that, or I will work up a jacketed load for the occasional ~300yd stage, and dial it in to have a comparable impact point.
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Re: Cut down a CTL 312-160-2r Mold to make a ~116 grain SS bullet?

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I was just struck with one of those blinding flashes of the obvious.

I oughta crowdsource the R&D here. I would mail a few projectiles to a few people if they are willing to report back with their findings. I would want charge weight OAL, groupings @ distance, and rifle specs. Chrono data would be nice too, if you have the tools.

Dellet, Xmalder, anyone?

pm me and I'll mail out bullets to a few people. I will make sure you get enough to be worth the trouble.
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dellet
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Re: Cut down a CTL 312-160-2r Mold to make a ~116 grain SS bullet?

Post by dellet »

GunFunZS wrote:I was just struck with one of those blinding flashes of the obvious.

I oughta crowdsource the R&D here. I would mail a few projectiles to a few people if they are willing to report back with their findings. I would want charge weight OAL, groupings @ distance, and rifle specs. Chrono data would be nice too, if you have the tools.

Dellet, Xmalder, anyone?

pm me and I'll mail out bullets to a few people. I will make sure you get enough to be worth the trouble.
I would be more than happy to help if time frame is a little flexible. Only issue might be powder coating if they need to be.

What weight did these end up at?
300 Blackout, not just for sub-sonics.
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Re: Cut down a CTL 312-160-2r Mold to make a ~116 grain SS bullet?

Post by GunFunZS »

dellet wrote:
GunFunZS wrote:I was just struck with one of those blinding flashes of the obvious.

I oughta crowdsource the R&D here. I would mail a few projectiles to a few people if they are willing to report back with their findings. I would want charge weight OAL, groupings @ distance, and rifle specs. Chrono data would be nice too, if you have the tools.

Dellet, Xmalder, anyone?

pm me and I'll mail out bullets to a few people. I will make sure you get enough to be worth the trouble.
I would be more than happy to help if time frame is a little flexible. Only issue might be powder coating if they need to be.

What weight did these end up at?
I have powder coated them. The post above listed the weight, which was under 125grains. After PC they are 123.4 grains, as cast. (Mostly lino, with a little bit of monotype and solder. ~22 BHN normalized and water quenched.) A softer alloy would probably be closer to 125 grains.


PM me your contact info, and I will get some in the mail to you.

The offer is also directly extended to my friend Dolemite (sp?)

I'll add the answer to some pertinent pm'd questions from xmalder too. He wanted to know which powders I wanted, etc.

I'm messing with CFE BLK and H110. You can duplicate those if you want or use something else. This is hive mind at work. You may think of trying something that would never occur to me, or you may verify or debunk the results I get. More data = ,more better.

Keeping the project goals for me in mind: I would like this bullet to be broadly useful to the average user.

i.e. It should shoot comparably to factory supers. 2MOA or better with common powders out of an AR15 (or pistol AR). It should be at a comparable velocity so the trajectory is comparable. It should cycle reliably, and group repeatably.

Whatever you come up with to acheive those, or even to show that one or more of those goals is impractical with a particular method is useful information.

You can test any combination of variables that let's us see what this can be made to do consistently in the wild.
I'm trying to lock down those in Green below, and tinker with those in red. You can probably think of others that I've overlooked. Orange are a couple variables that I am trying to initially "rough in" then lock down for subsequent testing.
Black are impractical for me to control in my own testing, and more so for crowd testing. I'll edit this list with numbers and colors as I go.

Here's my over-thinking feel free to skip to the "bottom line" below.


Variables that occur to me:

Gun:
1) barrel length
2) gas port location
3) gas port diameter
4) (piston?)
5) suppressor?
6) twist rate.
7) feed ramp interference. initially, unmodified M4
8) aiming device and assembly quality.
9) Chamber and Leade dimensions and finish.

I have access to a 8" 1/7 pistol and a 16" 1/8 carbine. Pistol gas and carbine length respectively. Port size unknown. Both using comparable nikon scopes.

I'm also anticipating a budget frankengun along the following lines:
Carbine setup: 16" light barrel, (faxon) 1-8 , self reprofiled feed ramps, adj gas block a basic $30 compensator, 80% lower, with PSA guts. No forward assist upper with brass deflector and ejection port cover (open to suggestions).

Ammo: The main set of variables we can control well.
1) Projectile shape
2) Powder selection -- I'm starting with H110 and CFE blk.
3) charge weight
4) COAL
5) Primers
6) Velocity - I don't have a chronograph.
7) Alloy/ Hardness
8) Diameter I'm sizing to .309"
9) surface finish of powder coat.

I think our first couple of rounds of testing will help us to decide on a standardized COAL that feeds well for a lot of guns. Then we can tweak velocity. I think it might be worthwhile for me to make bullets in two or three strengths to suit the pressure levels of various powder choices. For now, I'm looking at choosing powders which should get good results with bullets at ~18 BHN (CFE black might prefer this load due to its lower pressure/velocity.) and ~22 BHN (The hardest alloy I can make with supplies. Should give good results with lower charges of H110 and similar.). Available data suggests that most of the popular powders would be happier with bullets closer to 26 BHN, but that isn't going to happen until I can place a big order to rotometals.


conditions of use:
1) range Initial rounds will be done at 55 yards to see that they are on paper, then moved to 100 for grouping.
2) temperature
3) wind
4) stability of shooting position -

I'm aware this is a weak point for my setup. My compromise is a chair and a folding work bench with sandbags for the most stable repeatable and portable rig I can manage.

User:

1) Shooter skill

This is inherently the biggest and least controllable factor. The best I can do is break the project into small enough chunks that I am testing carefully and not rushing. My eyes seem to have gone down hill in the last few months and this is becoming a surprisingly big obstacle to shooting as well as I am used to.

2) elimination of subjective noise from the signal. I'm using the same target at measured distances, and recording what I get, even when it doesn't match my expectations. 5 shot groups for each sample, no fliers excluded. I will bring an extra round or two for each set if I am very aware that I pulled a shot.


The bottom line is that I am way short of the resources to do this thing completely scientifically, but what I can do is give bullets to people who are more set up and methodical than I am. Also I can increase my sample sizes by letting people who don't control those things as carefully test and then I can go back and look at what variables seem to cause their successes or problems. An improved design can mitigate or reduce human variability.
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dellet
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Re: Cut down a CTL 312-160-2r Mold to make a ~116 grain SS bullet?

Post by dellet »

GunFunZS wrote:
dellet wrote:
GunFunZS wrote:I was just struck with one of those blinding flashes of the obvious.

I oughta crowdsource the R&D here. I would mail a few projectiles to a few people if they are willing to report back with their findings. I would want charge weight OAL, groupings @ distance, and rifle specs. Chrono data would be nice too, if you have the tools.

Dellet, Xmalder, anyone?

pm me and I'll mail out bullets to a few people. I will make sure you get enough to be worth the trouble.
I would be more than happy to help if time frame is a little flexible. Only issue might be powder coating if they need to be.

What weight did these end up at?
I have powder coated them. The post above listed the weight, which was under 125grains. After PC they are 123.4 grains, as cast. (Mostly lino, with a little bit of monotype and solder. ~22 BHN normalized and water quenched.) A softer alloy would probably be closer to 125 grains.


PM me your contact info, and I will get some in the mail to you.

The offer is also directly extended to my friend Dolemite (sp?)

I'll add the answer to some pertinent pm'd questions from xmalder too. He wanted to know which powders I wanted, etc.

I'm messing with CFE BLK and H110. You can duplicate those if you want or use something else. This is hive mind at work. You may think of trying something that would never occur to me, or you may verify or debunk the results I get. More data = ,more better.

Keeping the project goals for me in mind: I would like this bullet to be broadly useful to the average user.

i.e. It should shoot comparably to factory supers. 2MOA or better with common powders out of an AR15 (or pistol AR). It should be at a comparable velocity so the trajectory is comparable. It should cycle reliably, and group repeatably.

Whatever you come up with to acheive those, or even to show that one or more of those goals is impractical with a particular method is useful information.

You can test any combination of variables that let's us see what this can be made to do consistently in the wild.
I'm trying to lock down those in Green below, and tinker with those in red. You can probably think of others that I've overlooked. Orange are a couple variables that I am trying to initially "rough in" then lock down for subsequent testing.
Black are impractical for me to control in my own testing, and more so for crowd testing. I'll edit this list with numbers and colors as I go.

Here's my over-thinking feel free to skip to the "bottom line" below.


Variables that occur to me:

Gun:
1) barrel length
2) gas port location
3) gas port diameter
4) (piston?)
5) suppressor?
6) twist rate.
7) feed ramp interference. initially, unmodified M4
8) aiming device and assembly quality.
9) Chamber and Leade dimensions and finish.

I have access to a 8" 1/7 pistol and a 16" 1/8 carbine. Pistol gas and carbine length respectively. Port size unknown. Both using comparable nikon scopes.

I'm also anticipating a budget frankengun along the following lines:
Carbine setup: 16" light barrel, (faxon) 1-8 , self reprofiled feed ramps, adj gas block a basic $30 compensator, 80% lower, with PSA guts. No forward assist upper with brass deflector and ejection port cover (open to suggestions).

Ammo: The main set of variables we can control well.
1) Projectile shape
2) Powder selection -- I'm starting with H110 and CFE blk.
3) charge weight
4) COAL
5) Primers
6) Velocity - I don't have a chronograph.
7) Alloy/ Hardness
8) Diameter I'm sizing to .309"
9) surface finish of powder coat.

I think our first couple of rounds of testing will help us to decide on a standardized COAL that feeds well for a lot of guns. Then we can tweak velocity. I think it might be worthwhile for me to make bullets in two or three strengths to suit the pressure levels of various powder choices. For now, I'm looking at choosing powders which should get good results with bullets at ~18 BHN (CFE black might prefer this load due to its lower pressure/velocity.) and ~22 BHN (The hardest alloy I can make with supplies. Should give good results with lower charges of H110 and similar.). Available data suggests that most of the popular powders would be happier with bullets closer to 26 BHN, but that isn't going to happen until I can place a big order to rotometals.


conditions of use:
1) range Initial rounds will be done at 55 yards to see that they are on paper, then moved to 100 for grouping.
2) temperature
3) wind
4) stability of shooting position -

I'm aware this is a weak point for my setup. My compromise is a chair and a folding work bench with sandbags for the most stable repeatable and portable rig I can manage.

User:

1) Shooter skill

This is inherently the biggest and least controllable factor. The best I can do is break the project into small enough chunks that I am testing carefully and not rushing. My eyes seem to have gone down hill in the last few months and this is becoming a surprisingly big obstacle to shooting as well as I am used to.

2) elimination of subjective noise from the signal. I'm using the same target at measured distances, and recording what I get, even when it doesn't match my expectations. 5 shot groups for each sample, no fliers excluded. I will bring an extra round or two for each set if I am very aware that I pulled a shot.


The bottom line is that I am way short of the resources to do this thing completely scientifically, but what I can do is give bullets to people who are more set up and methodical than I am. Also I can increase my sample sizes by letting people who don't control those things as carefully test and then I can go back and look at what variables seem to cause their successes or problems. An improved design can mitigate or reduce human variability.
Not sure how scientific or methodical I am, but can offer to shoot these across a variety barrel lengths, twist rates and powders, then give you honest feedback on results.
300 Blackout, not just for sub-sonics.
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GunFunZS
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Re: Cut down a CTL 312-160-2r Mold to make a ~116 grain SS bullet?

Post by GunFunZS »

Suits me.
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GunFunZS
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Re: Cut down a CTL 312-160-2r Mold to make a ~116 grain SS bullet?

Post by GunFunZS »

Just did a casting session and a coating session, and got paid.

The bullets for the testers are going out tomorrow!
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