Light weight subsonics. What available powders are viable?

[Augenblick]

So I bought a Ruger American rifle and was curious about light weight subs. Without the constraints of getting an action to cycle I'm hoping for some really quiet, fun loads. Less mass then less force to propel the bullet.

So I started reading in these forums and looking for data. Lots of data for Trail boss, Red Dot, Bullseye, Tin Star, Unique, Clays etc. There are others not as popularly mentioned but it seems to me to be a majority shotgun/pistol powders.

I found some Hogden data for Trail Boss for 110 -150 gr projectiles. Sierra has loads for 110 - 160 gr for 4198, RL 7 and of course Trail Boss but not really much else

Did the loads in the forums come from something like "these powders are similar in burn rate to Trail Boss so I tried x gr of yz powder?". Maybe I haven't looked into this enough. The other question I have is that the 4198's and RL 7 are much closer to the more "mainstream" 300blk powders in the 1680 neighborhood. So why do these slower powders work in lightweight subs along with the faster shotgun powders? It can't be just burn rate. Something to do with powder volume or amount of gas produced? Maybe quick loads could help? Trail Boss is particularly interesting being the most used load data I found but apparently the fluffiest powder out there too, so greater case fill less SD?

Regardless Trail Boss and most of the powders listed above just aren't available. I was able to find Unique, Bullseye and Alliant Clay Dot(Clays copy.). So given that powder selection what would be your powder of choice for light weight subsonics in a bolt gun?

[BJK]

Decades ago when I was developing a load for 5.56 and an 80 grain Sierra I stayed away from a double base powder. I just thought it was a good idea. Back then there was a theory about detonation with Bullseye. Had some green dot and used that. It worked fine. But you have the choice of so many powders (should they become available). I wanted a powder that was fast and easily ignited due to the large case and not much powder, and again, I wanted to stay away from nitroglycerine in the powder, maybe that was wrong but it's what I did. It worked fine. Without looking into it in depth I think of the choice of Bullseye and Unique I would choose the Unique. I know nothing about the Alliant powder you list.

If you're looking for quiet you want a fast powder. Why? Boyles law. I'm going to make some assumptions to make things easy... One of them is that the 300BLK isn't a bottleneck cartridge. Assuming the powder fully burns in 3" of barrel and the barrel is 16", Boyles Law says that if the volume of a gas is doubled the pressure is halved. So double the gas assuming 40k psi, and I have no idea if that's close to reality, but just follow along. So at 6" the pressure is 20k. At 12" the pressure is 10k. At 16" even less. That would be a pretty quiet load, with a can it would be hellyweird quiet.

I have a .223 load I use in a 16" Contender that uses fast powder and a 33gr blemished bullet that I got in bulk cheap, and is extremely quiet with a can. A butterfly fart is louder and an air rifle MUCH louder. The heavier the bullet the more powder required, the higher the pressure. But Boyles Law is still in charge. So for quiet loads, light bullet and fast powder. OK, that quiet load in the Contender, w/o the can yes, it makes a loud noise, but nothing like the cartridge loaded to maximize velocity. It certainly has no blast.

Good luck with your load.

[bangbangping]

IMO you're not missing anything by not having Trail Boss. I've had horrible ES with it when trying sub loads with light bullets. Of the three powders you list, I've used Bullseye the most and have no issues with it. You'll likely find it to be a bit position sensitive, but that's not unique (pun intended) to that powder.

[Roadrunner1969]

I haven't tried any lightweight subs. The lightest I have used are 190 grain bullets.
My best loads for the Subxs are with Unique, but I did try some HP38 (showed promise), and will likely do some more since I have learned a bit about MV and seating depth. I also got some Titegroup, but haven't tried it yet. Haven't tried Trail boss because I can't get it.
I would try Unique.

[Augenblick]

Thanks for the input it is always appreciated. There are a few threads here dedicated for single shot and bolt gun light weight subsonic loads.

One load that I saw that I thought was really interesting was a Hornady xtp 90gr that some people were reportedly getting to expand at subsonic velocities. I don't think that has and particular practical values other than a sheet range small critter round. They mostly used trail boss which to me makes sense from a power fill perspective. Some reported decent ES and some really bad so it's a have to see for myself kind of thing. Either way trail boss is not to be found. I do see that powder fill/position issues would be a factor with the lighter shorter bullets.

If anyone has any insight about why do many people who developed those light weight subsonic loads used the shotgun/pistol powders I'm interested. As I mentioned before I know there is load data for trail boss but I really didn't find much from other manufacturers for the the other shotgun powders used. Is it just faster = quieter or is it that they are less sensitive to powder position? Just curious thanks.

[popper]

I've done 4.5gr Red Dot but not chronyd, 145gr PB cast, very quiet. 3 almost touching @ 50 about 3: low from CVA SS. Should be about 1100 fps. Playing with WSF now.

[dellet]

Thanks for the input it is always appreciated. There are a few threads here dedicated for single shot and bolt gun light weight subsonic loads.

One load that I saw that I thought was really interesting was a Hornady xtp 90gr that some people were reportedly getting to expand at subsonic velocities. I don't think that has and particular practical values other than a sheet range small critter round. They mostly used trail boss which to me makes sense from a power fill perspective. Some reported decent ES and some really bad so it's a have to see for myself kind of thing. Either way trail boss is not to be found. I do see that powder fill/position issues would be a factor with the lighter shorter bullets.

If anyone has any insight about why do many people who developed those light weight subsonic loads used the shotgun/pistol powders I'm interested. As I mentioned before I know there is load data for trail boss but I really didn't find much from other manufacturers for the the other shotgun powders used. Is it just faster = quieter or is it that they are less sensitive to powder position? Just curious thanks.

Most people develop these loads just because they can. You need the faster powders, with lower charge weights for the quietest loads. Then there is the economics behind it, before the scamdemc you could load these rounds for less than a dime. So if all you want to do is shoot a spinner off the back deck, all the neighbors will hear is the clang on the steel. Possum or raccoon problem solved, maybe as much as a coyote.

3-4 grains per load of powder gives you around 2000 shots per pound.

You end up with a reloadable 22 lr for the most part. Basically just fun to shoot.

Then there are the specialty bullets. Maker bullets has a 110 grain sub bullet that has 3X expansion at around 800 fps. If you have the need.

Just another part of the cartridges versatility to work with.

[Augenblick]

So I got some unique and loaded some 30 cal 90gr xtp and some 150gr Hornady FMJBT and I think I found my first powder position problem.

First the 30 cal 90gr xtp are .309 do a little tight seating but not too bad. I didn't need to neck expand.

Second they are short, really too short to run in a bolt gun or at least a RAR. I was able to get them to feed if I moved the bolt at just the right speed.

Third. I loaded 5 of each charge weight in the pmag. The first round of every group was significantly slower then the next 4. Like 100 - 200 fps slower. Is it possible that the first round recoil redistributed or packed the powder in some way. Is the only thing I can think of.

I also experienced the same thing with the 150gr FMJBT round. First round slow then the follow up rounds were all in the same ball park. Some other had reported this in another thread. Maybe this one?

https://www.300blktalk.com/forum/viewto ... 6&start=60

But I can't remember them coming up with the cause. I'll have to reread.

Is it plausible that because the charge was so low 4.4 gr unique and the bullet so small that the powder shifting in the case caused the first round velocity problem? I've read that but this is my first experience with it. If not any idea of what else it could be?

4.4 gr unique loaded to 1.67" OAL was quiet, MV 1032 fps, grouped to 3"ish at 50 yards. Not alot of room to play with seating depth. Fun to play with but not really a load for a bolt gun. More of a single shot round.

[Augenblick]

The 90gr xtp with 4.4 grains of unique is still one of my favorite loads. I've shortened the oal to 1.649" and wore my glasses and it has tightened up to under a half inch horizontally at 50 yards. Still get vertical stringing which is due to large ES IIRC. I've gotten better at cycling these super short rounds in the RARR.

People come up to me at the range to see what I'm shooting and it never fails to put a grin on their face. It is as quiet as any 22 suppressed I've ever heard. Maybe quieter. Even my wife who is pretty gun phobic giggles when she shoots it.

I'm still searching for a better powder with less position sensitivity and reduced ES so let me know if you know of one AND it is available. The other cool thing with this bullet is it will expand down to 800 fps.

Try it you'll love it.

[30plinker]

My 300bo bolt gun broke before I could get into light subs with it, but I've done some work with TiteGroup in 762x39 using the .312" 85gr XTP bullet

TiteGroup is great for this because it is known to not be position sensitive. Which is good, 'cause 4gr of it is like .34cc in volume, so it really doesn't use a lot of case space in anythign but maybe a 25acp

Found some reference to someone else going down this same path but they were having too much velocity issues and no accuracy to speak of at 6gr.

I dropped down to 3.5gr instead and velocity averaged 850ish but had really big swings over a 5 round string. 4.0gr brought me to 1005fps average for 5 shots, and a high of 1035 and low of 970ish. About 1/2" groups at 25 yards, and zeroing at 40 yards seemed to give the most reasonable trajectory to 75 yards. If I were going to continue down this path, I'd start up in .1gr increments from 4.0 until just at the speed of sound - it seems the higher pressure (and it ain't that high... relatively speaking) helps with shrinking the std dev. on velocity. Might also want to platy wiht crimping....