Sub Sonic 38 Special

[Lurch37]

I recently acquired a lever gun in 38/357 which has a 16.5 inch barrel and is threaded for a suppressor. My wish is to start gathering some factory loads as well as material for handloading 38 special, mostly in a sub sonic loading.

In looking thru my reloading books, it seems easy enough to stay under super sonic speeds with several different bullet weights. I have 3 of the powders listed with those being Power Pistol, Win AutoComp, and Win 231. I will be loading jacketed bullets and using either once fired or new brass.

My questions is do any of you have a favorite sub-sonic 38 special load? Do you have any suggestions that might be helpful. I'm not against buying a different powder if I need to. Is there any advantage/disadvantage to using 357 brass in a sub-sonic 38 special loading or should a guy buy both calibers of brass as I would suspect I might load some 357 mag loads too.

 

[Shadow9mm]

Try unique or power pistol.

Few years back i loaded 44spl for a 20in henry. Its a long story but the basics are that pistol powders burn fast and dont produce a lot of gas volume. So velocity out of my lever gun were often slower than a 6in revolver cause the powder burnt up and created a vaccume behind the bullet slowing it down. Tried cfepistol, hp-38, aa#7, power pistol, h110, and unique. Power pistol and unique were the only ones that played nice.

Shoot some 38s before you get going too fast. Some 357 guns are fickle and dont like 38s.

Personally i stick with 357 brass. Trying to shoot 357s after 38s, well even with jacketed bullets it fouls things up and can cause feelings issues. Id expect it to be worse than normal with a suppressor.

 

[44 AMP]

There was no "vacuum". What you get when all the powder turns to gas and there is still considerable barrel length left is a reduction in the "pushing force" but it does NOT go to zero and cannot go to less than zero creating a vacuum.

Friction from the bore combined with a reduction in the gas pressure can slow down the bullet, but there is no vacuum, the bullet exits the bore and there is a muzzle blast, though not as much as a shorter barrel releases.

The speed of sound in air varies with air density, (altitude, humidity, etc) the standard reference number is 1125fps (sea level, moderate temp, etc)

Doesn't matter what powder you're pushing with, if you keep velocity below 1100fps, you won't get the "Crack" of breaking the sound barrier.

Carbine length barrels can increase standard .38SPL speed up to super sonic, but its not a given with every powder used.

The standard 158gr @ 850 from a pistol might go supersonic in a carbine. Faster loads almost always will. IF you want subsonic from a carbine, you will need to reduce most SD pistol loads a bit.

 

[Recycled bullet]

I have used Winchester Auto comp in 38 special brass to shoot 125 grain powder coated hollow points bullets from revolvers and a bolt action rifle. 6 g is when I stopped getting soot on the exterior of the brass and the groups got tightened.

 

[rc]

Like 45 ACP, virtually all 38 special factory loads will be subsonic. Most will be between about 750 to 950 fps unless you get some fancy self defense specialty loads. Even the Winchester USA 130 FMJ military hardball load is a very humble subsonic loading. 38 special is right at home with hard cast bullets and you may want to try some of the new polymer coated ones on the market for cost. While I would buy a lot of 125gr JHPs for plinking 20 years ago, prices have gotten so out of control I'll be buying more cast for 38 and 357 when I run out of what I got. Make sure to get bullets with a crimp groove. Smooth profile bullets don't like to be crimped into. You will want roll crimp dies for your lever gun and SWCs will feed in most lever guns.

https://tbbullets.com/38-357-158gr-swc-polymer-coated/
https://www.grafs.com/retail/catalog/category/categoryId/555?page=4

I can also recommend looking for the standard 158 grain JFP bullets by Armscore in bulk when you can find them.

https://brassmanbrass.com/product/3...etal-jackettmj-armscor-pistol-bullets-500-ct/

I bought some over a year ago but haven't tried them yet. 158 grain LSWC bullets ahead of a full charge of W231 works well in 38 special but you may want RNFP for a silencer. W231 is ideal in 38 special and is the same powder as HP38. Your other two powders are more well suited for higher pressure auto pistol rounds like 9mm, 38 super, 40 and 10mm. If you want to down load 357 magnum for smoother feeding in your lever gun, then you might want to bump up your powder charge of 231 in the bigger cases for consistency. Let us know how this turns out.

 

[Shadow9mm]

There was no "vacuum". What you get when all the powder turns to gas and there is still considerable barrel length left is a reduction in the "pushing force" but it does NOT go to zero and cannot go to less than zero creating a vacuum.

Friction from the bore combined with a reduction in the gas pressure can slow down the bullet, but there is no vacuum, the bullet exits the bore and there is a muzzle blast, though not as much as a shorter barrel releases.

The speed of sound in air varies with air density, (altitude, humidity, etc) the standard reference number is 1125fps (sea level, moderate temp, etc)

Doesn't matter what powder you're pushing with, if you keep velocity below 1100fps, you won't get the "Crack" of breaking the sound barrier.

Carbine length barrels can increase standard .38SPL speed up to super sonic, but its not a given with every powder used.

The standard 158gr @ 850 from a pistol might go supersonic in a carbine. Faster loads almost always will. IF you want subsonic from a carbine, you will need to reduce most SD pistol loads a bit.

Then please explain to me why the rounds were coming out at very inconsistent 200-400fps, had a pop as the bullet left the muzzle like opening a canning jar, and it sounded like a suppressed subsonic firearm? but it came out at around 700fps out of a 4 and 6in in revolver? perhaps not a true vacuum but it is entirely possible that all the powder burned and did not create enough gas volume to maintain pressure to the end of the barrel and it passed the point where it was creating pressure at all and the bullet was essentially creating suction as it traveled.

 

[rc]

Friction is different than Vacuum but both would slow your bullets down in the barrel. Longer barrels have more friction that's why Aguila 22 Colibri don't exit rifle barrels but do exit revolver barrels. You never want to load under powered ammo that is so slow it's that inconsistent. That risks creating an obstructed bore and blammo, you blow out a case and ring your barrel with the next shot. I once read about a guy shooting a ruger 40 carbine that stacked several bullets in the barrel before he realized they weren't coming out Stick with standard or +P 38 special data under heavy bullets and you won't have any problems. Try to back down your loads to below 750fps and you may have a problem out of your rifle.

 

[Shadow9mm]

Friction is different than Vacuum but both would slow your bullets down in the barrel. Longer barrels have more friction that's why Aguila 22 Colibri don't exit rifle barrels but do exit revolver barrels. You never want to load under powered ammo that is so slow it's that inconsistent. That risks creating an obstructed bore and blammo, you blow out a case and ring your barrel with the next shot. I once read about a guy shooting a ruger 40 carbine that stacked several bullets in the barrel before he realized they weren't coming out Stick with standard or +P 38 special data under heavy bullets and you won't have any problems. Try to back down your loads to below 750fps and you may have a problem out of your rifle.

I agree completely, it is not something I am recommending. at the time I was doing some testing with different powders to see what would be optimal, it was a very unexpected result and gave me a pretty good scare. I initially thought it was a squib. However it had rung the steel plate hanging behind he chrono so I knew the bullet had come out. It was a very interesting experience to say the least.

 

[Unclenick]

22 Rimfire, at least with the usual 40-grain bullets, and depending on the load, burns powder out between 14 and 19 inches or so down a rifle barrel. Yet, match loads remain very consistent out of 26" barrels with them. The very light 20-grain Aquilla Colibri probably takes so little pressure to prevent it from going supersonic that powder burnout is much earlier, letting the brass start to spring back from the chamber seal and bleed pressure backward out of the chamber before the bullet clears the muzzle. That could certainly stall a bullet in a rifle barrel.

My suspicion would be that the problem with the 38 lay in inconsistent chamber sealing or brass spring-back timing, too, that started leaking pressure out backward more for some powders than for others. Only powders that sealed the breech consistently were working for you. In the case of 22 RF loads, the brass is new and consistent in its hardness, plus it is very thin. This would assist in consistent sealing in longer barrels unless the pressure gets super low (Colibri, again).

If you have some new brass, you can see if that cuts down on velocity variation with some of the other powders. Though tricker with pistol brass, you could elect to sacrifice a few well-used cases and anneal the last quarter inch of the case to see if that creates a more reliable seal for these low-pressure loads. That would confirm or dismiss my theory without me having to lift a finger.

 

[rc]

I've learned if I'm getting soot on my cases, my loads are TOO WEAK! Usually bumping up the charge will even out pressures, consistently seal the chamber and lower the standard deviation. I believe 22 Colibri are primer only loads. CCI 22 CB shorts are more consistent than 22 CB Longs since they have the same powder charge but very different case volumes. Both can show soot on the cases. A CCI 22 Target short at about 850fps is much more consistent than either of their CB offerings yet the hotter rimfire target load remains subsonic. The same principles apply to reloading 38 special loads in 38 and 357 cases Given the same charge, you generally have more consistent loads with smaller case volume. If you want to make mouse fart loads for a 38 special, a full wadcutter might help with consistency since it's deep seated into the case but probably won't feed through a lever gun.

 

[Recycled bullet]

This is super cool the 38 blackout. I have also used three grains of Tight group with 170 grain powder coated semi-wad cutter and 100% of the time the bullet exits the barrel of my 77/357 bolt action carbine.
I would shoot a bunch of whatever bullet you are intending to use at a Target staple to a cardboard backer and make sure that there is no yawing and bullet holes before mounting the suppressor to avoid the chance of a baffle strike.

When fired it sounds kind of like a 22LR but it hits the plate significantly harder.

I am not comfortable using light loads with jacketed bullets through rifle barrels I believe the friction would consume too much of the kinetic energy generated by the expanding propellant gases and lead to inconsistencies or possibly bullets stuck in the bore and like has been mentioned can provide a severe fear and safety problems.


Reduced loads with fast energetic powders are much safer than reduced loads with slow powders in low pressure small pistol cartridges like 38 special for this reason.

Have you considered casting and powder coating your own bullets?

With practice this is how you can get the highest quality cast bullets for the lowest cost price, tune your loads for exactly what it is that you want to do. Also you can get things that cannot be bought.

The picture is of 357 Magnums that I have cast powder coated and assembled and they work just fine in 38 special brass as well.

In the 357 I shoot the blue hollow points with Hodgdon h110 and in 38 special I like to use Winchester Auto comp.

 

[44 AMP]

Then please explain to me why the rounds were coming out at very inconsistent 200-400fps, had a pop as the bullet left the muzzle like opening a canning jar, and it sounded like a suppressed subsonic firearm? but it came out at around 700fps out of a 4 and 6in in revolver? perhaps not a true vacuum but it is entirely possible that all the powder burned and did not create enough gas volume to maintain pressure to the end of the barrel and it passed the point where it was creating pressure at all and the bullet was essentially creating suction as it traveled.

The reason you heard a "pop" sound is that there was enough pressure differential to make it. Sounded like opening a vacuum sealed jar to your ear. The ear heard a sound, but I doubt the ear can tell if the sound was made by pressure going in or pressure coming out. At low levels they can sound the same to our uncalibrated ears.

Break a light bulb and hear it go "pop". Pop a balloon (with the same approximate pressure differential as the light bulb, and it goes "pop" the same sound to your ear. The direction of gas (air) movement is exactly opposite (air in vs. air out) but the same (approx) amount of movement creates the same sound to our ears.

Now, consider your rifle chamber & barrel as a closed system. The revolver is not, and we'll deal with that separately.

It takes "X" amount of pressure to move the bullet. This amount of pressure must be enough to overcome the bullet inertia, case neck tension /crimp and then bore friction. This is a minimum, and if you don't get it and maintain it, the bullet doesn't come out the end of the barrel.

The pressure generated by the powder gas is many times that minimum. Expansion ratio is the rate of increase in the area the gas has to fill.

Using simple numbers for illustration, say the powder charge creates gas to 10X pressure in the cartridge (gets the bullet moving fast) and by the time the bullet gets to the muzzle the expanded volume of the gas in now only producing 5X pressure, as the bullet exits.

That's only half as much as it started with, but its still several times the minimum needed and many, many times atmospheric pressure.

As long as the pressure in the system is at least 1X the bullet will be moving.

Another point to consider, you got higher speed from 4 & 6" revolvers, right?

How much of the powder charge had not yet burned when the bullet left the barrel?? I think the pressure curve was still increasing at that point, and the barrel length vs. pressure "push" was the opposite of what you saw in the rifle.

 

[Shadow9mm]

The reason you heard a "pop" sound is that there was enough pressure differential to make it. Sounded like opening a vacuum sealed jar to your ear. The ear heard a sound, but I doubt the ear can tell if the sound was made by pressure going in or pressure coming out. At low levels they can sound the same to our uncalibrated ears.

Break a light bulb and hear it go "pop". Pop a balloon (with the same approximate pressure differential as the light bulb, and it goes "pop" the same sound to your ear. The direction of gas (air) movement is exactly opposite (air in vs. air out) but the same (approx) amount of movement creates the same sound to our ears.

Now, consider your rifle chamber & barrel as a closed system. The revolver is not, and we'll deal with that separately.

It takes "X" amount of pressure to move the bullet. This amount of pressure must be enough to overcome the bullet inertia, case neck tension /crimp and then bore friction. This is a minimum, and if you don't get it and maintain it, the bullet doesn't come out the end of the barrel.

The pressure generated by the powder gas is many times that minimum. Expansion ratio is the rate of increase in the area the gas has to fill.

Using simple numbers for illustration, say the powder charge creates gas to 10X pressure in the cartridge (gets the bullet moving fast) and by the time the bullet gets to the muzzle the expanded volume of the gas in now only producing 5X pressure, as the bullet exits.

That's only half as much as it started with, but its still several times the minimum needed and many, many times atmospheric pressure.

As long as the pressure in the system is at least 1X the bullet will be moving.

Another point to consider, you got higher speed from 4 & 6" revolvers, right?

How much of the powder charge had not yet burned when the bullet left the barrel?? I think the pressure curve was still increasing at that point, and the barrel length vs. pressure "push" was the opposite of what you saw in the rifle.

Yes there is enough pressure generated to move the bullet. And that pressure is created by the gasses generated from the burning of the powder. as the bullet moves down the barrel a larger and larger sealed area is created between the bullet and the case in which the gas expands. Depending on the gas volume generated I would think it entirely possible that the gas volume could be insufficient to fill the volume of the barrel. Especially like in my case with a small volume of pistol powder in a larger diameter cartridge with a 20in barrel.

 

[Lurch37]

Thank you all for your input.

I have read online somewhere that a bullet can slow down in certain instances when loaded for pistol velocities.

At this time it is not feasible for me to cast my own bullets. I would however entertain using a cast bullet if it doesn't lead the barrel. I hate scrubbing barrels. I'm thinking I will use 357 brass for all loads too.

Out of my 4 different brands of factory 38 special, 3 have a bullet profile that I think would be safe in a tube magazine, 1 is a JHP, and the other 2 are a truncated cone style. The truncated cone style gives pause as when placed upon the primer of another round, it is almost the same diameter as the primer. I am hoping that this is OK to shoot in a tube magazine?

The 2 FMJ Truncated loads are 125gr @ 865fps and 130gr @ 800fps according to the factory website specs. My Hornady book has 6.1gr of Power Pistol giving 900fps for both a 125gr and 140gr XTP bullet. It also has 5.7gr of Power Pistol giving 850fps for a 158gr XTP. I would think that any of these loads would be a good place to start without fear of too light of a charge and still well below the super-sonic threshold?

 

[Shadow9mm]

Id load a few at 38spl max, seeing as its a 357mag gun. Should be below 357max start and your using 357 brass. See what kind of speed that gets you and work up or down from there. Personally i reserves 110-125g bullets for snub nose 38s. 158s for 3.5in or longer 38s and 357s. And 180s are 357 only. But thats me.

 

[44 AMP]

Depending on the gas volume generated I would think it entirely possible that the gas volume could be insufficient to fill the volume of the barrel.

No, this is not possible. Gas will always fill 100% of the available space.

What happens isn't a lack of gas filling the space, its just when you increase the space the pressure of the gas in the space decreases.

It will not go to zero (relative to atmospheric pressure) but it will be reduced, UNLESS the powder charge is sufficient, and formulated to compensate for that.

This is the point to progressive burning powders. Remember that until the powder is all burned, there is pressure on the unburnt/burning powder, and that pressure changes as the powder burns.

I cannot begin to explain how it is done, but it seems, from what I've read, that the powder burn rate changes with the pressure and that this effect is used to maintain the pressure as the bullet moves down the barrel.

It is certainly possible to have insufficient pressure for various reasons. Generally speaking, when this happens, we call it a "squib".

 

[Recycled bullet]

By manipulating the 1) particle size and shape and then 2) graphite or other flame deterrent coatings can be applied on the outside of the powder ( flakes, logs or granules) as ways to make adjustments to quicken or slow down the relative burning rate of the powder.

Look at a pistol powder or shotgun powder is usually flakes or flattened balls.

Look at rifle powders many are little logs with minuscule perforations. In the example of rifle powder they burn from the outside in and from the inside out and this is how they generate a progressive increase of gas volume generation. As powder burns the pressure and heat increases and the more that it increases the faster the powder Burns. So by changing the size and orientation of the perforations the burning rate can be adjusted for the rifle powders.

 

[Recycled bullet]

It's exactly for these reasons that that fast pistol powders and shotgun powders can be used for normal pistol and shotgun loads and in special circumstances for reduced rifle loads, but as a general rule rifle type gun powders are completely inappropriate for pistol and shotgun shell reloading.

 

[rc]

Why don't you try these 158gr RNFP bullets.
1000 bullets for $100. They should feed a little smoother than SWC bullets and will be safe in a tube magazine. You will be lucky to get 400 158 gr jacketed bullets for the same price.

https://tbbullets.com/38-357-158gr-rnfp-polymer-coated/


https://www.hodgdonreloading.com/reloading-data-center?rdc=true&type=53

 

[Lurch37]

Thanks rc... I will check those out.