Heavy Cast Subsonic Bullets (500 grain) Range Report

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Re: Heavy Cast Subsonic Bullets (500 grain) Range Report

Postby Bmt85 » Sat Mar 09, 2019 9:47 pm

Kind of like Hoot’s idea, except you can pick up a 16” carbine length gas fairly easily. Something with a higher twist shouldn’t hurt. I looked at Brownells and they have a barrel made for them by who knows, it is a 16”, carbine gas, 1:14 twist that comes with a bolt and brake for $310. Even if the quality isn’t that great, might be worth a try. BCA’s quality isn’t that great, but the 450B cartridge seems to be pretty forgiving because they shoot just fine. If not that, Brownells also sells a Faxon 16”, carbine gas, 1:16 twist barrel for $257, no bolt or brake, though. Faxon has a good track record. Then you have X-caliber, which you could get a basic one made for $280, but there is a wait.

I’d say run one of those with an adjustable gas block. If it works out, sell the GLFA. If not, sell off the new one. You shouldn’t be out much money anyway. Or do what I did, and just keep all of the different builds. Lol
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Re: Heavy Cast Subsonic Bullets (500 grain) Range Report

Postby Rklenke » Sun Mar 10, 2019 8:01 pm

I got out to 100 yards today. I'm giving up the ghost on the 500 grain subs based on performance, but the supers can definitely be worked with. I wish I could post a video on here of the supers hitting some steel, because it was seriously impressive. I will post the video on my parallel Facebook post on the Ruger 450 American Rifle Facebook group though, so if you are a part of that you'll be able to see it. Anyway, here are some photos of the groups:

Subsonic.jpg (114.56 KiB) Viewed 3574 times

No adjustment from 300 grain bullet point of aim

Super sonic.jpg
Super sonic.jpg (83.86 KiB) Viewed 3574 times

6.5" adjustment made
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Re: Heavy Cast Subsonic Bullets (500 grain) Range Report

Postby kbstenberg » Mon Mar 11, 2019 3:52 pm

I will be following your progress with much interest. I am just putting together an Axis (bolt) with a 1/ 14 twist. Which would probably eat the heavies better than your 1/24.
Just today i finished the barrel install and stock adjustment for barrel measurements. It looks more like an Axis with a 12 gauge barrel on it.
My gun will be used primaraly for hunting deer.
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Re: Heavy Cast Subsonic Bullets (500 grain) Range Report

Postby Rklenke » Wed Mar 13, 2019 8:43 pm

Here's to the last step of testing for me. I finally received my .452 sizer die so I've finished up some more bullets to shoot. I'm not going back to subsonic testing, and maybe in the future, I'll try H110 instead of 1680. For now I'll stick with my baseline. I'll get some 100 yard groups this weekend and comment on how they cycled.

As an added bonus, I'll show a bit of my bullet prep and explain why I'm not going to be buying an expensive .458/.459 mold and sizing down to .452 in the future. I'll either wait until a .452 heavy mold is made, or get in on one of those NOE group buy deals.

All of the bullets have some sort or base ring following sizing, a product of going from .459 to .452. The picture is of the worst one I could find.
Fouled base.jpg
Fouled base.jpg (68.09 KiB) Viewed 3541 times

The process to make these bullets is very labor intensive. After casting is sizing, which takes a decent bit of force, and sizing lube. The sizing lube has to come off before they go into powder coat, also the base ring needs to be sanded down and the base cleaned up. Finally is powder coating, or your preferred style of lube. After one coat of powder, the bullets measure .454.
Clean base.jpg
Clean base.jpg (79.43 KiB) Viewed 3541 times

The sanding of the bases is very time consuming which is why I'll stick with .452 molds in the future.
Blue bullets.jpg
Blue bullets.jpg (109.91 KiB) Viewed 3541 times
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Re: Heavy Cast Subsonic Bullets (500 grain) Range Report

Postby Rklenke » Thu Mar 14, 2019 8:40 pm

Not having 24/7 access to a 100 yard range, I decided to run an H110 ladder in my freetime this morning. I don't have the experience with H110 as I do with 1680, so a little bit tougher to read the signs. Simple one shot groups except I shot 3 at 25 grains to explore anomalies. These were run with a 1oz buffer, except for the last round at 25 grains, which was an H2.

20 - 1204 FPS weak extraction
21 - 1280 FPS weak extraction
22 - 1291 FPS full extraction, no lock back
23 - 1364 FPS full extraction, no lock back
24 - 1423 FPS full extraction, no lock back
25 - 1450 FPS stuck case in chamber
25 - 1454 FPS case stuck 1/2 extracted
25 - 1469 FPS stuck case

I don't know how I went from not getting lock back to over-pressure and stuck cases without getting good cycling in the middle. I'm 99% sure 25 grains of H110 is overpressure, although I don't have QL to verify. My assumption is extraction started while pressure was too high. I may go back to the 23 grain sweet spot with more rounds to double check later on this weekend. I'll take any words of wisdom when it comes to H110.

Picture is of a 1450fps round after going through 10-12" of wood.
H110.jpg (117.51 KiB) Viewed 3530 times
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Re: Heavy Cast Subsonic Bullets (500 grain) Range Report

Postby Hoot » Thu Mar 14, 2019 9:27 pm

25gr of H110 should yield the same velocity as 28.3gr of 1680. Predicted velocity for both is 1315 fps out of an 18" barrel. The H110 is predicted to yield 27748 psi and the 1680 28249 psi. The H110 is predicted to burn 99.6% of the powder and the 1680 90.55%.

Both of these loads are so "outside the 9 dots" as to cast even more doubt on QuickLoad's prediction accuracy, so its a dice toss at this point.

Reliable cycling and lock-back are impacted by how much pressure is developed, at what time and for how long. Shooting big, slow, hovering around subsonic, loads takes the normal challenges of reliable cycling and compounds them beyond reliable prediction. Its a matter of "cut and try" at the range, more than mathematically predicable internal ballistics. Translation: You're in the weeds on this one.

Though I don't pursue cast boolit loads in this or any other caliber, I seem to recall reading the efforts of other members here who do and they were using tiny amounts of fast pistol powder, like you'd use for fore forming cases. Then again I might not be recalling that correctly due to not being interested in that persuasion. I had expected more of them to wade in on this as I have other irons in the fire to attend to.

In Theory, there is no difference between theory and practice. In Practice, there is.
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Re: Heavy Cast Subsonic Bullets (500 grain) Range Report

Postby shadowwalker » Fri Mar 15, 2019 1:04 pm

That chunk of lead is way too large for the mid length gas system. The powder burn rate is just way too slow a well.
You might try something along this grain weight.


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Re: Heavy Cast Subsonic Bullets (500 grain) Range Report

Postby Bmt85 » Sat Mar 16, 2019 8:28 am

H110/Win 296 appears to be too fast for running those supersonic. Max pressure is too high, and not getting enough gas to cycle the action. Chances are you were jamming the rifle because the case length grew too much. Could be case head growth, but I’m really thinking case length. What were your numbers for case head and length?

You could try opening the gas port to get more gas into the system, but I would switch powders first, either back to 1680 or maybe something a little slower. If you still don’t get it cycling, then think about opening the gas port.
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Re: Heavy Cast Subsonic Bullets (500 grain) Range Report

Postby plant_one » Sat Mar 16, 2019 3:29 pm

quick question on your sizing process

are you sizing from .459 to .452 in one step?

if so, thats probably why you're seeing the ugly ring at the base of each bullet.

and by having to hand sand them to remove that i suspect you're probably causing a bunch of weight variance in the finished product. which is going to play hell on your accuracy, especailly at subsonic speeds.

you may be much better served to get an intermediate sizing die - lets say .454, and open it up to around .455 with a roll of emery paper or sandpaper so that you're moving the metal less - even if it means two sizing passes to get to your desired diameter.
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Re: Heavy Cast Subsonic Bullets (500 grain) Range Report

Postby Vince » Sun Mar 17, 2019 11:16 am

I'm sure you fellows know that you lose a good bit of velocity in an AR's gas system. I just got a Ruger Ranch in 450BM so I can't comment on the velocity there, but I have many 308's that I shoot cast in that have the same barrel length. One is an AR10 with 20 inch barrel. With the load I'm using I'm getting around 2000 fps velocity with it. If I take the same load and put it in my Browning 308 Varminter bolt action with same barrel length I get much much much velocity and am afraid to post it here as maybe you won't believe it. Another gas rifle, the M1A, has a slightly longer barrel then 20 inches and it doesn't lose nearly as much as the AR10 in fact on par with the Browning bolt action. Think about it, on the AR you have to fill the gas port, the gas block, the gas tube, the carrier key and the carrier cylinder with gas. That's an awful amount of gas which could be pushing the bullet. On the M1A it's a short stroke piston without much gas draw off. To answer a possible question does my AR10 have any excessive gas leaks....NO.
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