Please humor me

[Rangeball]

This post is semi- smokeless related. I'm asking here because I'm confident you guys will know if anyone does

I don't shoot a smokeless or any ML, yet . I came here to learn about bullets, ballistics, etc. Mission accomplished Was so impressed that when my brother in law went MZ shopping, I steered him towards a savage, which he bought and is very happy with (250 grain SST, MMP and 42 grains of N-110) right out of the box.

Anyway, I participate in a shotgun slug forum, and shoot an H&R ultra 12g with sabots for deer. I'm working with a couple fellas who are into slug design, and they are currently working on developing a sabot load that will push the same bullets you guys shoot up to smokeless velocities, from a shotgun. May not be doable, but it's sure fun trying Just for the record, these guys are following all reloading protocal and all loads will be pressure tested in a pressure barrel.

Anyway, I've been wondering quite a bit recently about pressure. Smokeless and all rifles develop quite a bit more pressure than shotguns, but isn't that partly due to their smaller bore size and less space for the powder to burn in? Say you take a high velocity shotgun load like the one I shoot, it's a saboted barnes .50 325 grain MZ with 52 grains of Alliant Steel powder. This load has a velocity of 1980 fps and developes safe shotgun pressure. If you shot this same load from a smokeless MZ, wouldn't it develope higher pressure? Any guess how much higher?

Looking at burn rate charts, Steel is a faster burning powder than VV N120. Seeing the success and velocities some of you are getting with 300 grain bullets and VV N120, I am wondering if this might be a good powder to try, but of course am wondering about what pressure it might create. Is there any way to extrapolate pressure date from a MZ rifle load to a shotgun load?

Any input is greatly appreciated

 

[VENISONEATR]

Is that a CCS load or is it your own load?

 

[Rangeball]

It's the CCS High Speed.

 

[RBinAR]

Anyway, I've been wondering quite a bit recently about pressure. Smokeless and all rifles develop quite a bit more pressure than shotguns, but isn't that partly due to their smaller bore size and less space for the powder to burn in? Say you take a high velocity shotgun load like the one I shoot, it's a saboted barnes .50 325 grain MZ with 52 grains of Alliant Steel powder. This load has a velocity of 1980 fps and developes safe shotgun pressure. If you shot this same load from a smokeless MZ, wouldn't it develope higher pressure? Any guess how much higher?

Looking at burn rate charts, Steel is a faster burning powder than VV N120. Seeing the success and velocities some of you are getting with 300 grain bullets and VV N120, I am wondering if this might be a good powder to try, but of course am wondering about what pressure it might create. Is there any way to extrapolate pressure date from a MZ rifle load to a shotgun load?

Any input is greatly appreciated

The first of your questions ask if such a load is shot from a muzzleloader wouldn't the pressure be higher? The answer is YOU BET IT WOULD BE. What you are discribing is called "expansion area" which means that if a certain amount of gas has less room to expand into the pressure will be higher.

I don't know how to compare the load to N110 but I can compare it to another powder shot in the 10ML Alliant 2400. 2400 is slower burning than Steel by about 4%. In the past loads of 2400 have to be restricted to 35 grains or less or sabot disruption occured. With 53 grains of an even faster powder than 2400 the pressure would be higher, much higher, in fact dangerously high so don't ever try it.

I've shot shot shell powders in the 10ML before and they can be used but this powder would have to be restricted to the high 20s load level and maximum 250 grain bullet speed would be about 1850fps. The only reason for such a load is it makes a very low recoil child's or woman's load. And doing that they work very well.

Be careful with your shotshell experiments. Not only do shotshells have the lowest maximum pressures of smokeless arms they are the least tollerant of mistakes.

 

[Rangeball]

Thanks for the insight.

None of any load would be shot by me or others until safe pressure is verified by a pressure test barrel, which is the plan. The beefed up sabot is still in the design stage, hoping some will be machined to test in the near future.

I'm trying to identify powders that might have the best chance at pushing a 325ish grain slug as fast as possible within safe shotgun pressure levels, and am open to all suggestions.

What makes a powder a ML or shotgun powder, if their burn rates are so close? I assume pressure isn't where velocity comes from, as some slower loads create higher pressures when tested.

 

[Mountain Man]

RB or others may chime in here and contribute more to this aspect of your question, but here is one problem, at least as I see it:

You are limited to pressures in the (I believe) 11,500 psi range, and maybe a bit higher with the longer 3"/3.5" shotshells. In contrast, most slower powders really require some minimum pressures to operate consistently over a variety of temperatures. Many of the handgun powders, and (as far as I know) all the rifle powders really need to see pressures in the 30,000 to 40,000 range before they become pretty stable across temperatures. So, using a small enough amount of a slower powder to keep your pressure down low where it must be, you'll likely see some big swings in velocity as temperature climbs or falls.

Going way out on a limb into the theoretical here, the only way I can think of to substantially improve upon the current loads would be use a compound powder charge, consisting of both an uncoated shotshell type powder (fast powder, consistent at low pressure and immediate burn) and a coated shotshell type powder (delayed ignition/burn of those granules, but once the coating is burned off, a fast and consistent burn at low pressure). I don't know if there are any coated shotshell powders produced, or whether any of the coatings used today would burn off consistently at shotgun pressures. Furthermore, I don't know if there is really enough barrel length to make use of a duplexed powder charge.

Have any of you run any calculations to see what the maximum potential velocity is from a 24" or 26" barrel if pressure was at exactly maximum for all barrel/burn time? I have no idea, but it might not be that much more than current velocities. 11.5K, or a little higher if within specs, is a really low pressure to try and get velocity out of.

 

[Rangeball]

Thanks... Great info

Have any of you run any calculations to see what the maximum potential velocity is from a 24" or 26" barrel if pressure was at exactly maximum for all barrel/burn time? I have no idea, but it might not be that much more than current velocities. 11.5K, or a little higher if within specs, is a really low pressure to try and get velocity out of.

No. How would one go about that?

I plead ignorance which I'm trying to solve. The main guy working on this has developed a lot of loads in the past, I'm just doing some thinking and learning

 

[RBinAR]

Thanks for the insight.


I'm trying to identify powders that might have the best chance at pushing a 325ish grain slug as fast as possible within safe shotgun pressure levels, and am open to all suggestions.

What makes a powder a ML or shotgun powder, if their burn rates are so close? I assume pressure isn't where velocity comes from, as some slower loads create higher pressures when tested.

The key to any higher speed level is the load capacity versus the pressure limit. That means that both pressure and powder level contribute to final speed. That's the same in the 10ML or any smokeless arm. It just so happens the 10ML has no case and so can hold a lot of powder.

Loads can be majorly dependent on either pressure or time (this is the same as load level because the more powder the longer the burn). Slow burning loads with a lot of powder still make speed. Lesser amounts can also if the maximum pressure is high enough.

With a shotgun the absolute maximum amount of powder that will fit into the wad is one limit. The maximum standard pressure is the other. The most powder you can get in a 12 gauge wad is less than 60 grains and since the bore has a LARGE volume that much powder would have to be fairly fast to make the maximum pressure at this same level.

So the final word in any cased round is how much powder can the case hold without going over the maximum safe pressure.

What makes a 10ML or other smokeless muzzleloader powder is quite a different animal. The maximum amount of powder you can load is almost unlimited because there is no case. So you can load for very low pressure if the bullet weight is right and still get tremendous power. An example would be the 425 grain bullet I shoot from my 10ML and 50-140. Taking the 50-140 first Hodgdon load data shows if I load 103 grains of Varget I would get 2300fps with a paltry 28,100psi pressure. The same load works great in the 10ML.

Still there are few who want to shoot a 400 grain bullet so load and pressure levels tend to other directions when shooting a smokeless load in a muzzleloader. Lighter weight bullet are common and lower powder charges that make more pressure and less recoil are the norm.

 

[Mountain Man]

... How would one go about that?...

Well, I'm just a lawyer, not a mathematician or rocket scientist. But for somebody with a physics background, I would think that there are equations that take into account the factors of graving resistance, barrel friction, weight, and pressure applied to a piston face (the bullet base) with an area of x square inches.

 

[Rangeball]

Thanks RB.

I think with more than 52 grains of steel CCS was able to get higher velocities but the sabot couldn't take it. That is the first order of business, beefing up the sabot.

I don't know what 8 more grains would do for it, and you could also load in a 3" shell and pick up a bit more space, but I assume pressure will be the limiting factor more so than capacity.

Are there any programs on-line that you can plug in load variables such as powder type, amout and bullet caliber and weight and the output tells you what you can expect such a load to do?

 

[RBinAR]

Thanks RB.

I think with more than 52 grains of steel CCS was able to get higher velocities but the sabot couldn't take it. That is the first order of business, beefing up the sabot.

I don't know what 8 more grains would do for it, and you could also load in a 3" shell and pick up a bit more space, but I assume pressure will be the limiting factor more so than capacity.

Are there any programs on-line that you can plug in load variables such as powder type, amout and bullet caliber and weight and the output tells you what you can expect such a load to do?

Oh lord I hate to hear those words. I remember when 10ML shooters wanted reinforced sabots to shoot higher speeds and the results. You don't want to start imagining that the system limits can be lifted for some artificial reason.

Staying within pressure limits in a shot shell means staying within the limit of the weakest component just as a safe pressure in the 10ML means staying within the safe pressure limits of a bare sabot.

Load developing can't be a guess. Stay with your friend, learn everything he knows and some more then understand everything front and back. It's more important to know where not to go.

You can't get it right in a day. Spend your time, get it right, and then just to be sure set the first few shots off from a safety rest. Load developing is one of those things that might best be dissclaimed by saying "don't attempt this on your own".

 

[Rangeball]

I appreciate your comments. I assure you anything I'm involved in pulling the trigger inches away from my face will have a proven safety record

Didn't the savage shooters get stronger sabots? I was under the impression they did.

 

[Mountain Man]

Stronger sabots? Maybe a little. But the failure point of the sabots is still not significantly higher than the pressure limits of the 10ML itself. (To any others who might be reading, I am NOT saying that you can rely on sabots to tell you the pressure is high enough/too high.)

I find it hard to believe that the hard plastic (much harder than ML sabots) shotgun sabots, some with a sintered metal reinforcement disc in the base, further protected by numerous felt and maybe plastic wads, is that much weaker than ML sabots. Surely they can handle the 11.5K, or a little higher, pressure limit that you have to work with.

 

[RBinAR]

Well, I'm just a lawyer, not a mathematician or rocket scientist. But for somebody with a physics background, I would think that there are equations that take into account the factors of graving resistance, barrel friction, weight, and pressure applied to a piston face (the bullet base) with an area of x square inches.

There sure is a way to predict the pressure from a charge. Back in the old days when I was young and dirt was new we had a small piece of plastic called a slide rule (or pocket computer) that was specifically for understanding load pressure.

That slide rule (which is a collector's item now) was the Powley computer. It based pressue estimates on a number of different items depending what the shooter could supply.

The Powley equations live on with a number of web sites offering variations on the theme. Some are better than others but the all depend on accurate measurement of the varibles to work correctly. Thus me and my pet dinosaur coined the phrase, "garbage in - grabage out".

 

[Rangeball]

Stronger sabots? Maybe a little. But the failure point of the sabots is still not significantly higher than the pressure limits of the 10ML itself. (To any others who might be reading, I am NOT saying that you can rely on sabots to tell you the pressure is high enough/too high.)

I find it hard to believe that the hard plastic (much harder than ML sabots) shotgun sabots, some with a sintered metal reinforcement disc in the base, further protected by numerous felt and maybe plastic wads, is that much weaker than ML sabots. Surely they can handle the 11.5K, or a little higher, pressure limit that you have to work with.

Mountain Man, the big problem is there is only ONE sabot maker for shotgun reloaders, Chris and Emma Young at CCS. They offer a .50 and .45 12 g version, and a .45 20 g. To my understanding, this sabot was designed several years ago, possibly before current plastics were available. I don't believe the design has been updated. I have one of them and it feels different than the Federal (which was designed by Del), SPW used by Hastings and the Winchester partition gold production sabot. I don't know what the upper limits are of this sabot, but Emma Young mentioned they suffered sabot failure when they tried to push it faster than the current 1980 fps.

As I understand it ML sabots have been reformulated and made stronger over the years as velocity potential has increased. I don't think the same can be said about non-commercial shotgun sabots.

 

[Mountain Man]

Well, I'm just a lawyer, not a mathematician or rocket scientist. But for somebody with a physics background, I would think that there are equations that take into account the factors of graving resistance, barrel friction, weight, and pressure applied to a piston face (the bullet base) with an area of x square inches.

There sure is a way to predict the pressure from a charge. Back in the old days when I was young and dirt was new we had a small piece of plastic called a slide rule (or pocket computer) that was specifically for understanding load pressure.

That slide rule (which is a collector's item now) was the Powley computer. It based pressue estimates on a number of different items depending what the shooter could supply.

The Powley equations live on with a number of web sites offering variations on the theme. Some are better than others but the all depend on accurate measurement of the varibles to work correctly. Thus me and my pet dinosaur coined the phrase, "garbage in - grabage out".

RB, I was saying that, just as you can extimate pressure, it should be possible to estimate velocity based on the variables of projectile weight, barrel pressure, barrel length, barrel friction, etc.

 

[wells]

Hi all I'm new here, can someone please give me the contact info for Chris & Emma Young at CCS.
I don't want to take over this post. thanks WELLS

 

[Rangeball]

wells, here ya go-

http://members.fortunecity.com/emmyoung/id10.htm#

 

[wells]

range ball thank you wells