Suppressors and subsonic Boolits

[MakeMineA10mm]

Who here shoots through suppressors?

I ask because I have a friend who has several and he has the deepest disdain for cast boolits, because they lead the can's baffles/interior and the lube gums up the insides...

I was thinking with this group of casters here, we should be able to put our heads together and come up with something that is not so objectionable...

My first thought was that if lube is the problem, would a dry lube like LLA on a tumble-lube design work better? (Of course, I've always read and seen that putting liquids that stick - such as boolit lube, lithium grease, etc. - inside a can makes it quieter, so I'm not sure what the objection is...)

Also, I'm wondering what the deal is with the leading inside the can? I'm assuming that the larger bore diameter of the baffles allows gas blow-by which causes erosive melting of the sides of the boolit, which is then deposited on the baffles - much like shooting an undersized boolit.

Any thoughts, ideas, or suggestions?

[yondering]

I only have a can for my .22's, nothing for centerfire... yet. I've read quite a bit from people who say cast boolits will lead up a can, but not too many posts from people who have actually done it. The thing is, 22 rimfire ammo is basically the same thing, but even softer lead than what we usually cast with. I can say that my rimfire can has quite a bit of lead and carbon inside it, but I've put about 4,000 rounds through it so far.
Regarding the boolit lube mucking up the inside of the can, I think that's just something for people to complain about. Boolit lube is easy to dissolve by soaking in solvent, so I don't see the problem there.
Seems like a hard cast boolit, especially at subsonic velocity, shouldn't foul up a can too fast, especially if it was rinsed with solvent regularly.

I've been wanting to get a 45 Colt or 454 lever gun, shorten the barrel and mag tube to 16", and thread it for a can. It would be a lot of fun to hunt with (where it's legal of course). This would be used for heavy cast boolits; a 350gr WFN at 1,000 fps should do pretty well on a lot of game. Wouldn't be enough rounds through it in a lifetime to lead up the can either.

[leadeye]

I remember shooting and helping clean a supressor for a 45 ACP M-10 that belonged to a friend. We had put a lot of rounds through it and took the supressor apart to clean it as it was filthy. It did clean up with some scrubbing and I don't remember seeing anything like leading, mostly just lube and fouling.

[shooter93]

I shoot through several supressors. They will all build up lube and powder residue, most of which can be soaked out. Some will also shave lead and that usually doesn't soak out. Both of the ones I use, a 30 and a 45 caliber can be disassembled easily which is probably the best type to use with cast bullets.

[MakeMineA10mm]

Have any of you tried the tumble-lube route?

[shooter93]

No reason tumble lube wouldn't work, at these speeds you don't need much lube and it does take quite a few rounds to gunk up a suppressor but I do like being able to take them apart....we shoot them a lot.

[shotman]

if you are looking to have something that is quiet then the load needs to be below the 700 fps tumble lube real light--- i have found that if you put the lube in a pan of hot water[160 degree]and get on fast and spread on wax paper they tend to dry harder rick

[yondering]

Actually, it's closer to 1,050 fps that your projectiles must stay below to be subsonic. About 100 fps slower than that is a little quieter, but no reason to stay down around 700 fps.

I'm not sure it would matter if you used tumble lube or regular lube; either one dissolves in solvent, and having a bunch of regular lube mixed in with all the carbon and lead may be helpful when trying to clean out the can. When the lube is dissolved, you might find that the carbon and lead comes out easily. 22 LR ammo uses hard dry wax lube, and not very much of it, and I can tell you that there is no evidence of lube in the can whatsoever. The lead and carbon buildup inside my 22 can is very hard, and won't come out with any normal solvents I know of. I kind of wish the ammo had more soft lube like our cast boolits, in the hopes that it would keep all the lead and carbon from bonding together so solidly.

[redneckdan]

if you get leading, soak the baffles in a mix of 1/1 by volume white vinegar and 3% hydrogen peroxide. This will oxidize the lead and it will wipe away like powder fouling. I know it won't touch copper, carbon steel or stainless steel...not sure about aluminium. I would use it on stainless baffles with out hesitation...better find out your aluminium alloy and test a similar piece of raw metal.

[Echo]

'Way back when I started shooting competitively I used an AF issue High-Standard with a muzzle brake. Not a supressior, of course, but similar in operation. And that booger filled up with lead in a season! Match ammo, too. .22 LR's have little tails on them when they exit the bore, and the muzzle blast knocks them off. With a brake, or supressor, the tails will end up in the equipment. I guess the same might happen with larger caliber boolits.

[JeffinNZ]

Hi
I shoot cast in my suppressed .32-20 Martini. It wears a cut down Lee Enfield barrel so I can spin up to 250gr bullets out of it.
Lube I have found to be the big factor in the amount of gunge that accumulates. Alox based lubes gum up really bad along with powder residue and takes a bit of cleaning off. My own "Beaver Grease" lube designed for BPCR (but great in smokeless) cleans off WAAAYYY easier and I believe this is the non petroleum content. Residue from my lube wipes off with a cloth where as the Alox based lubes require some encouragement from "Ed's Red" to clean up.
I strip down my suppressors periodically and clean them out. The manufacturer here in NZ states that you can clean or not clean but it you choose not to clean the suppressor will eventually become a one piece item (threads will bind) and you will NEVER strip it down. I personally like to strip them down and know they are clean and in good working order.
Here is the rifle and 'can' stripped down.
http://img.photobucket.com/albums/v505/JeffinNZ/Shooting%20stuff/100-0023_IMG.jpg
http://img.photobucket.com/albums/v505/JeffinNZ/Shooting%20stuff/100-0022_IMG.jpg

[MakeMineA10mm]

Very nice information and thanks to all. I really like Jeff's insight from "the bottom of the world." I was wondering about that myself...

Sounds like SPG or our home-made version of it would work a LOT better than any of the commercial or other petroleum based lubes. That leads me to the idear of using normal or slightly larger than normal lube grooves for a boolit design that is specifically designed for suppressors.

[JeffinNZ]

Yeap, I would give SPG a whirl or Lyman BP Gold. Either is more than up to the job.

[kycrawler]

the green stick lube bullshop sels works great in my 308 can i use the lee 200 grain boolits and his lube and the fouling comes off the baffles with mineral spirits

my 22 can gets a trip through the bead blaster to clean the lead and junk off of the baffles in it

[yondering]

Jeff, how quiet is that 32.20, say, compared to a .22 pistol suppressed, or a pellet gun?
That thing is cool! Do you hunt with it?

[JeffinNZ]

Jeff, how quiet is that 32.20, say, compared to a .22 pistol suppressed, or a pellet gun?
That thing is cool! Do you hunt with it?

Yes, I hunt small game with it. Got tired of hares not dropping with subsonic rimfire. I call 'her' Whispering Death.
It is a little louder than a suppressed rimfire due to the bullet displacing more air but is very quiet. In cover (plantation/woods) where the noise is absorbed it is REAL quiet.
Great gun to shoot steel with especially if the targets are 50-100 yards. "Futttt CLANG".

[shotman]

the speed needs to near the speed of sound the smaller bullet can run some what faster but a 45 will be noticeably louder going over the 750fps threshhold On the 22 would spraying the baffles with --say Pam of Kroil help? shotman

[Larry Gibson]

I have used cast in a Sionics since the mid '70s and several military suppressors. As previously mentioned if the bullet does not contact the baffles then leading is not an issue. With Sonic loads using cast bullets (generally in the 1800-2000 fps range) the powder and lube residue (from alox and hard wax lubes) makes cleaning the difficult. If the suppressor is not disassembled frequently it will become impossible to disassemble as they many times do with full powered jacketed loads. Then cleaning the lube residue out is a real problem. With subsonic loads the lube seem to stay softer. I quit shooting cast bullets at sonic velocities because of this.

Also the faster the velocity the higher the RPM and the more the lube wil spin off inside the suppressor. I use LLA with my subsonic loads and have little problem with a heavy accumulation of lube inside the suppressor. Granted the one I use these days is the .30 cal Sionics and I don't shoot that many rounds through it at any one time. The suppressors on subguns or handguns are another story as they get a lot of useage.

A good suppressor makes very little noise with subsonic loads and many times is not recogniseable for what it is. However the bullets going through the air and striking the target can and do make much more noise. At subsonic speeds the the larger the caliber or the blunter the nose the more noise the bullet makes going through the air. Standing to the side you can many times "follow" the bullet through the air by the noise it makes. Of course the larger the caliber and blunter the nose of the bullet the more noise it makes when it strikes the target, esoecially meaty targets.

As alluded to by shotman, the larger the caliber or the blunter the bullet the slower the velocity will have to be for it not to break the speed of sound , i. e. break the sonic barrier. It is not the speed of the bullet that breaks the sonic barier and "cracks". It is the speed of the air traveling around the ogive. For a given velocity of bullet the air traveling around the ogive of the bllet will be traveling faster on the larger and/or more blunt bullet simply because the air has farther to travel. It is when this air breaks the sonic barrier than we get the "crack". If we take a .45 caliber bullet and a .22 caliber bullet of the same profile and ogive the .22 caliber bullet can be pushed faster before it "cracks" than the .45 bullet.

Larry Gibson

[MakeMineA10mm]

Great post, Larry. Thank you.


If you were going to design a cast boolit for suppressed use in say a 9mm, and taking into consideration all you said and know about that, would you design it to use a harder, dried-on lube, like LLA, or would you go the route of a medium-big lube groove boolit to use an ultra-soft, non-wax boolit lube, like SPG?

[Larry Gibson]

I'd definately try a Lee tumble lube bullet first. Since we're talking sub-sonic I'd go with the heavier choices like TL358-158-SWC or TL358-158-2R. The fall back choice would be TL356-124-TC. Howver most Lee bullets for regular lube have fairly small lube grooves. The 358-140-SWC might not be a bad choice either. Since we're not talking a lot of money for these moulds one could try most of them and sellect the one that worked the best. You could then sell the ones that didn't work well on this forum thus recouping much of your money back.

A friend in Oregon with a .45 suppressed MAC-10 has been experimenting with molly coating and Midways spray on mould release. He says he has had excellent results with the spray on mould release. He uses the TL452-230-TC.

Larry Gibson

[r6487]

I have several suppressors, most of which I do not use cast bullets in. One, a suppressed 44 Ruger bolt gun gets jacketed and cast projectiles. Got cast loads for it from the manufacturer. I have one can, where the manufacturer told me any signs of shooting cast stuff and his warranty goes out the window, as it is for a F/A 9mm, cast stuff would make a pretty fair cloud from 30 or 40rd mag dumps anyway. I have another can which does not disassemble, so I stay with jacketed stuff on it. The cans I have that disassemble will always get all internals coated well with (NAPA) anti-seize, which also happens to aid greatly in removal of carbonized gunk from baffles and spacers when cleaning times comes around.

[MakeMineA10mm]

r6487,
Welcome to Cast Boolits! Glad you joined to give me your input.

You reminded me of another issue my buddy has with cast in suppressors - the smoke production. Come to think of it, it would probably be worse with a soft lube like SPG... I think some testing is in my not-too-distant future...

Larry - I appreciate the advice about the TL. I'm thinking the 358-158-2R would be of great interest... Probably is fairly close to what I was thinking about anyway... I might have to add that to the test.

Thanks all!

[Old Ironsights]

Nice Pics Jeff. I'd love to build a fully suppressed barrel for my 96/22... Just can't afforde the BATFE Rectal Exam & Tax Stamp right now...

Larry: Good points - My .357 Subsonics run at about 700fps and are still noisy enough. Not .22 quality, but a bit louder than a .177 Pellet gun.

Using a keith is quieter than a WFN - even at the same velocity.

[Willbird]

I have used cast in a Sionics since the mid '70s and several military suppressors. As previously mentioned if the bullet does not contact the baffles then leading is not an issue. With Sonic loads using cast bullets (generally in the 1800-2000 fps range) the powder and lube residue (from alox and hard wax lubes) makes cleaning the difficult. If the suppressor is not disassembled frequently it will become impossible to disassemble as they many times do with full powered jacketed loads. Then cleaning the lube residue out is a real problem. With subsonic loads the lube seem to stay softer. I quit shooting cast bullets at sonic velocities because of this.

Also the faster the velocity the higher the RPM and the more the lube wil spin off inside the suppressor. I use LLA with my subsonic loads and have little problem with a heavy accumulation of lube inside the suppressor. Granted the one I use these days is the .30 cal Sionics and I don't shoot that many rounds through it at any one time. The suppressors on subguns or handguns are another story as they get a lot of useage.

A good suppressor makes very little noise with subsonic loads and many times is not recogniseable for what it is. However the bullets going through the air and striking the target can and do make much more noise. At subsonic speeds the the larger the caliber or the blunter the nose the more noise the bullet makes going through the air. Standing to the side you can many times "follow" the bullet through the air by the noise it makes. Of course the larger the caliber and blunter the nose of the bullet the more noise it makes when it strikes the target, esoecially meaty targets.

As alluded to by shotman, the larger the caliber or the blunter the bullet the slower the velocity will have to be for it not to break the speed of sound , i. e. break the sonic barrier. It is not the speed of the bullet that breaks the sonic barier and "cracks". It is the speed of the air traveling around the ogive. For a given velocity of bullet the air traveling around the ogive of the bllet will be traveling faster on the larger and/or more blunt bullet simply because the air has farther to travel. It is when this air breaks the sonic barrier than we get the "crack". If we take a .45 caliber bullet and a .22 caliber bullet of the same profile and ogive the .22 caliber bullet can be pushed faster before it "cracks" than the .45 bullet.

Larry Gibson

I cannot disagree more. If the bullet is subsonic the air around it cannot somehow exceed the speed of sound. Larger bullets DO indeed make more flight noise and a larger supersonic crack...but that has NOTHING to do with the air around the bullet somehow magically exceeding the speed of sound with a subsonic projectile.

Bill

[Larry Gibson]

Old Ironsights

Yup, with a WFN the velocity of the air as it is getting pushed across and around that WFN is much higher than the velocity of the bullet itself. It is when the speed of the air breaches the sonic barrier that we here the 'crack". The speed of the bullet itself will be considerably below the actual "speed of sound".

Onetime with a friend we were able to test a .22, a .32, a .35 and a .45 suppressors with different profiles of bullets. My Oehler M35P was used to record the velocity of each shot. The test was done in a large workshop to minimise any collateral noise. Bullets were trapped by a large oak end cut in the bottom of a 30 gallon drum with clay kitty litter over the top of that and a thin rubber (cut from a large truck inner tube) cover stretched over the top. This was then laid down and used to quietly trap the bullets. With the suppressor there was no concern of muzzle blast so the start screen was about 1' in front of the muzzle. The readings were pretty close to true muzzle velocity as the screen spacing was 2'. The was about 15' from the muzzle.

The suppressors were attached to TC Contender barrels of appropriate length for the pistol/revolver cartridges used. As I recall we ran tests on the .22LR, .32 ACP, .32 H&R, .38 Special, and .45 ACP. CF cartridges were loaded with different profiles of bullets on the spot. Powder charges were increased with the velocities ranging from 700 fps range up through 1200 fps depending on the cartridge. A bunch of different types of .22LR were tested.

I must also say that the suppressors were very effective as all that was heard was the hammer drop, a slight shwoosh with the larger or blunter bullets as it went from muzzle to the rubber cover and a slight slap as the bullets hit the rubber. When the sonic barrier was breached there was a distinctive crack or snap depending on the size of the bullet and it's profile. It was most interesting to note how the blunter bullets cracked at much lower velocities. As I was assisting a Class III manufacturer who made the suppressors, he kept the data as it was proprietory information. Perhaps someday he will write an article on our findings but he has since retired and went out of business so that is unknown. It was an interesting and fun experiment anyways.

Larry Gibson

[felix]

So much fun, eh, Larry? Chrysler developed (in Italy) the 10 cylinder sports car in 9 months, including the engine. The final design of the frame and exhaust was done here in USA. Guess what? I took 18 months to get the exhaust right, which included sound and vibration once the suspension was finalized. ... felix

[Larry Gibson]

Willbird

Disagree all you want, but if you think about it it has nothing to do with magic. It has to do with the air having farther to travel around a larger or blunter bullet at a specific bullet velocity. This why a .45 caliber bullet may crack and create a sonic boom while only traveling 950-1000 fps. A .35 cal bullet of identical bullet profile may go over 1000 fps before it cracks. The air traveling over the larger ogive of the larger bullet must travel faster. That is a fact whether we agree or not.

BTW; the "speed of sound" or sonic barrier is generally conceded to be between 1078 and 1150 fps depending on elevation, baromentric pressure, humidity, temperature and numerous other things.

Larry Gibson

[Willbird]

Willbird

Disagree all you want, but if you think about it it has nothing to do with magic. It has to do with the air having farther to travel around a larger or blunter bullet at a specific bullet velocity. This why a .45 caliber bullet may crack and create a sonic boom while only traveling 950-1000 fps. A .35 cal bullet of identical bullet profile may go over 1000 fps before it cracks. The air traveling over the larger ogive of the larger bullet must travel faster. That is a fact whether we agree or not.

Larry Gibson




Please describe to me how the air going around a wadcutter bullet nose has a longer path to travel than if it were passing around a secant Ogive ?? Plain and simple it does not, it has a shorter distance to travel.

[wills]

Wouldn’t Bernoulli’s principle apply somehow?

[Willbird]

There is an effect where an object traveling near the speed of sound can have some air around it traveling at super sonic speeds, the key word is CLOSE to the speed of sound.

I know lots of people firing lots of 45 acp projectiles at velocities a lot higher than 700 fps without experiencing a supersonic crack.

In fact most folks shoot for 1000 to 1050 fps.

Bill

[Larry Gibson]

Willbird

Actually the air has the same distance to travel given equal diameter bullets. Since the air is not moving except to get "around" the bullet it only moves at a right angle to the bullets path. Remember also, to get the speed of the air as it moves around (is pushed out of the way may be a better analogy) the bullet we have to factor in the forward velocity of the bullet. The longer the bullet takes to move the air out of the way the slower the air is going.

Let's say the bullet diameter is .358". With a wadcutter (with a flat nose) the air has to move .179" (to get from the center of the bullet to the edge of the bullet) in the time the bullet moves .001", probably less than that but that's close enough for this explanation. At 1000 fps the air then has to move the .179" in 12 millionths of a second.

Now with a 200 gr .358 Hornady SP the best I can measure the length from the ogive to the tip of the bullet is .54". So, for the air to get from the same center of the bullet to the same outer edge of the bullet the bullet has to travel that .54" forward. At the same 1000 fps the air has to move the .179" in 638 millionths of a second.

Takes longer for the air to move the .179" distance with the pointier bullet. That simply means the air is not moving as fast. If the speed of sound is 1100 fps (example) then the air will be going sonic (cracking) when the WC's velocity 909 fps. Now with the 200 gr Hornady SP the air will be going sonic (cracking) when the SPs velocity is about 1,060 fps. So as we see neither bullet is going 1100 fps (our speed of sound) yet the bullets are cracking and thus "breaking the speed of sound".

Now before you math whiz's go off correcting my figures (they probably are not exact as I did some rounding up and down) it is the concept of how it happens I am explaining here.

BTW; for most 45 ACP bullets they usually start cracking above 1160 fps so what "most folks shoot for" is about right. You also mis interpreted the "700 fps" That was only the range of velocities tested (700 fps for the 32 CP and the .38 with WCs). It was not the range of the bullets going sonic.

Larry Gibson

[FISH4BUGS]

I shoot 9mm and 380 submachineguns (STen, 9mm m16, S&W 76, MAC11 9mm and M11A1 380 - my favorite) and there is now a simple rule: NO LEAD THROUGH THE CAN! PERIOD.
You can shoot lead through it but the gunk will build up and the lead will build up. I returned my can to Bowers for cleaning, but he didn't bother. He replaced all the baffles and cleaned out the tube. He said he had never seen so much lead in a can in his life. All the bullets were 5lbs ww and 1lb linotype, Star sized .at 356 and lubed with Magma blue.
Bowers originally said go ahead. After about 5000 rounds the can was so loud I really wasn't getting any db reduction. I called him and he said return it.
These were cast 147gr lrn for 9mm and standard 100gr RN 380's. The 380's are subsonic anyway.
DO NOT SHOOT LEAD THROUGH YOUR CANS. If you want to get more information, go to the submachinegun forum: www.subguns.com.
Do a search on lead and suppressor. There is a TON of information on that.

[Old Ironsights]

I'm not an expert in fluid dynamics, but a flat-face with a sharp angle will produce more venturi effect than will a sharper-nosed profile.

The more blunt/square an object, the more front-loaded turbulance created, which may account for a sonic effect not directly related to super-sonics.

But then, I'm a word geek, not a math geek.

[yondering]

I knew that a larger bullet creates more flight noise, but I thought that the supersonic crack occurred at the same speed regardless of design. Gonna have to try that out myself. I do know that nose shape doesn't seem to make any difference in this regard with my .22 LR ammo. I have some with a large flat nose and hollow point that is right on the edge of supersonic crack from my Buckmark; I'll try forming the nose to a spitzer shape to see if the crack goes away.

Just to add to the confusion, here's a chart showing that supersonic crack doesn't occur at one specific speed, but rather over a range. It's from some Finnish suppressor website, I can't remember where or I'd post the link.
http://i24.photobucket.com/albums/c26/zthang43/Misc/bulnoise.gif

[MakeMineA10mm]

yondering,
I think I know where you found that... Same place that invented the "Z-baffle". I can't remember the site either, but I've got in my favorites on one of my computers...

As far as boolit shape effecting the noise level, I believe the effect is there, but I'm not convinced it becomes a MAJOR issue at velocities significantly below subsonic. I agree with Larry that something like a H&G#68 with it's relatively flat area will make more noise and probably have a lower required velocity to remain subsonic, but I'd bet it's nearer to 1000fps, rather than 750fps. The extra noise is probably cause by air movement around the boolit that is still subsonic, but is very turbulent as yondering points out.

I don't think the chart from Finland will speak clearly enough about this effect, because the .308 bullets indicated are too close in shape. We really need to compare something with wildly different frontal areas and shape, say a 45 WC (or very flat SWC) and a 308, such as out of the 300 Whisper. (Because both rounds would use a very similar boolit weight and powder change, say 200grs.)

Small Arms Review has done some significant suppressor testing under very scientific conditions, but I don't recall them covering this aspect. It was more about checking the differences between the suppressors, rather than looking for this difference in boolit shape.

I'm back to being seriously confused if lead is OK or not through cans. The only issue I see universal agreement on is the smoke issue. Some say lead is bad for cans and some say it's fine...

[Larry Gibson]

Let me correct an apparent misunderstanding; what I said was; "Powder charges were increased with the velocities ranging from 700 fps range up through 1200 fps depending on the cartridge"

I did not say that the bullets went transonic at those velocities. I particularly did not say that any bullets went transonic or cracked in the 700 fps range. The fact is, as I recall during the test, the bullets went transonic in the low 900 fps range up through almost 1100 fps. Where in that velocity range all depended on the shape of the bullet.

Larry Gibson

[yondering]

You're right Larry. It was shotman that said 700fps. I still don't know why?

[MakeMineA10mm]

Thanks Larry... In reading a thread like this, I sometimes attribute thoughts/concepts to the wrong person. Glad you cleared it up and I hope I didn't put too wrong a words in your mouth. :drinks:

[Artful]

I'm back to being seriously confused if lead is OK or not through cans. The only issue I see universal agreement on is the smoke issue. Some say lead is bad for cans and some say it's fine...

If you can clean your can (and I don't mean dip), you can use cast thru it. I won't own a 22LR can that can't be disassembled and cleaned, one thing to consider is f toxicity. These suppressors (especially in .22LR) are fantastic at condensing the lead vaporized from the friction of the bullet in the bore. If you want the continuous lead exposure from disassembling and cleaning the .22 can, wear protection and be aware of lead contamination.

- my subgun can can be disassembled and cleaned
- my 308 rifle can is sealed so I only use jacket sub and super sonic loadings.
- I have one 9mm pistol can that is sealed and one cleanable
- only cleanable cans get used with cast lead bullets.

here's an intereting read for anyone thinking about a sealed can
http://www.silencerresearch.com/Premiumreviews/dirty_9mm_silencers.htm

[Frozone]

Since this is now a Zombie, I'll add -

Welders use a spray on 'non stick' stuff, ( I don't remember the name and I'm not going to go get it to find out) to make removing the splatter easier.

It works great in keeping the carbon removable. Spray in on inside the can and next cleaning the crud just falls off.

[hunter2]

I shoot cast and jacketed in a 30 cal. can with no ill effects. BUT - I very rarely ever shoot more that 10 shot at a time without cleaning and lubing it down for the next session. The cast I have recovered from the wood blocks look like all the lube is intact. They are bought bullets with lube unknown. There is a project in the works for a trial of equal parts of wax and lard melted and the suppressor dipped, cooled and wiped down. Starting with a new can, heavy .375's cast. With short sessions, this seems to hold some promise. Have read that gc's bullets work better. Will start with them first.....I am going to have to break down and start casting my own. All photographs I have seen of subsonic bullets show the air turbulance at the rear, requardless of nose shape. speed ??? hmmmmm