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Loading for 9MM with 3 inch barrel
5mmgunguy
Member Posts: 3,092 ✭✭
I am loading for a 9MM with a three inch barrel. What would be a good powder for such a short barrel? Currently using Unique and 231. They both work fine and I can match factory ballistics.
I am using 124 gr gold dot and golden saber
I am using 124 gr gold dot and golden saber
Comments
Whatever is the optimum powder for a cartridge will be the optimum powder regardless of barrel length. Choosing any other powder will result in lower than possible performance.
Personally I'd shoot whatever is most accurate unless going for a self defense loading, in which case i'd use factory. An extra few fps wouldn't matter to me.
Other than something like that, if you test five or ten powders in a long barrel, the one that gives the highest velocity will continue to give the highest velocity as you cut the barrel back. The velocity will be progressively lower in shorter barrels, simply because the gas has less time (distance) to work on the bullet. But the "best" powder will always give the highest velocity possible in that barrel length.
We have not addressed accuracy, muzzle blast, bullet choice or any other factor, please note. Those things CAN change, and therefore affect powder choice.
Barrel length is totally immaterial for powder choice. The entire charge in a 9mm round is consumed before the bullet leaves the cartridge mouth. (Any powder not consumed by then won't burn anyway, again making the issue moot.)
Whatever is the optimum powder for a cartridge will be the optimum powder regardless of barrel length. Choosing any other powder will result in lower than possible performance.
IT IS TOTALLY UNTRUE TO SAY THAT ALL OF THE POWDER IN A 9MM,(OR ANY OTHER CARTRIDGE) IS CONSUMED BEFORE THE BULLET LEAVES THE CARTRIDGE MOUTH. AND WHY WON'T THE REMAINING POWDER BURN AFTER THE BULLET STARTS MOVING OUT OF THE CASE? What puts the fire out? Am I imagining that fire ball at the end of my Firestar when shot at night? Eddie
Fire outside the muzzle is not "powder still burning". Unburned but flammable gases produced during the burning of the powder cannot burn within the barrel because gunpowder burns in an oxygen-deficient manner. There isn't enough oxygen to burn all the fuel created. When that fuel mixes with atmospheric air, it can re-ignite. If it does, you have muzzle flash. I can provide a link to a scientific study of this if you are interested.
In a 9mm, the fire goes out because all the propellant is consumed by the time the bullet clears the case. It's that simple. We know that because we can take a pressure trace that records the pressure inside the case over time. In the 9mm, the pressure peak (which signals the end of effective deflagration) occurs while the bullet is still partly in the case.
Rocky
Could you elaborate on the concept that the pressure peak signals the end of effective deflagration. Do you mean this exclusively for small capacity cartridges like 9mm or more generally? Did you do any 9mm testing with slower powders like Blue Dot, Power Pistol, Lil Gun or HS-7? I have found a published 38 Super load for 11.4 grains of Lil Gun with a 147 gr bullet moving at 1180 fps with only 30K CUP. Could they really get that kind of performance with all the powder burning before the bullet leaves the case?
Tim
faster/slower is a relitive term, esp when the entire event from primer hit to muzzle exit is on the order of .002-.003 seconds. However, as a rule of thumb, the distance traveled is fairly short before the powder is burned. As we're discussing the 9x19 cartridge, a fast powder could be completly burned before the bullet moves at all, vs a slower powder that dosn't finish burning unto the bullet base is at the case mouth.
What happens with the slower powders is that they tke longer (and we're talking micro seconds of difference here)) to reach peak, and maintain a higher average pressure (more gas volume released) down the barrel.
There is a difference between powder burning as when lit in open air, and the way that it deflagrates inside the gun.
Deflagration requires a great deal of heat and pressure, and in turn creates more of both. It builds on itself, which is why all the powder in a cartridge can be consumed in a couple thousandths of a second. In ideal circumstances, once the powder begins to deflagrate inside the case, it would continue until it was fully converted to gas.
Circumstances are not ideal, however. The moving bullet not only causes the sealed volume to rapidly increase, but also exposes the hot gasses to increasing amounts of cold metal. That sucks away both heat and pressure, tending to counteract the deflagration. After a certain point, heat and pressure no longer rise, but begin to drop. During the drop, deflagration ceases, by definition.
(That's what I meant when I said that "burning" stops at the pressure peak.)
It is possible for powder that lay in contact with the cartridge case or bullet may never ignite, due to heat loss to the metal. In cartridges with large powder charges (especially bottleneck cartridges) a "plug" of powder can be compressed so tightly behind the bullet that no hot gas can penetrate the plug, and again prevent ignition. It is those un-ignited powder kernels that we sometimes see in the bore or scattered outside the gun. A few of those kernels - the rearmost ones in the "bullet plug" for example - may even ignite or continue to burn outside the bore. But in open air they are burning, not deflagrating.
The ball of flame sometimes seen is as described in the links below, and comes from unconsumed fuel gasses still present AFTER the powder deflagrates. Those gasses are akin to woodsmoke, which can be re-ignited after leaving the flames. Powder kernels burning on the ground are akin to the sparks in a smoke column.
Links to read more on this topic:
http://en.wikipedia.org/wiki/Muzzle_flash
http://www.navweaps.com/index_tech/tech-090.htm
http://findarticles.com/p/articles/mi_m0BTT/is_190_31/ai_n27 380935/pg_2/?tag=content;col1
dtk
faster/slower is a relitive term, ......
What happens with the slower powders is that they tke longer (and we're talking micro seconds of difference here)) to reach peak, and maintain a higher average pressure (more gas volume released) down the barrel.
No kidding[:)], like Lil Gun load I was talking about, very slow pistol powder but fast rifle powder. I use it in 9 x 23, .357 Mag. and .22 Hornet. For certain bullet weights nothing else can come close to its performance.
I think you hit on a key point with the higher average pressure reference and it is relevant to the powder choice for short barreled handgun vs. long barrel handguns. I think is makes since to stick to faster burning powders in short barreled handguns. It may be true (for the most part) that the powder that produces the highest muzzle velocity in a longer barrel will also produce a higher velocity in the shorter barrel the difference will be smaller in the shorter barreled gun. That stated higher average pressure does not have very long to act in the shorter barreled gun. The small velocity benefit from a slower powder in short barreled gun might be offset by other benefits of faster burning powder. Things like cleaner burning, lower muzzle flash, decreased report, lower powder cost per round, decreased leading, increased accuracy. You may not realize all these benefits with the faster burning powder but you will certainly have some.
Tim
But the muzzle flash thing is (as mentioned) only indirectly related to burn rate.
In a 9mm, the fire goes out because all the propellant is consumed by the time the bullet clears the case. It's that simple. We know that because we can take a pressure trace that records the pressure inside the case over time. In the 9mm, the pressure peak (which signals the end of effective deflagration) occurs while the bullet is still partly in the case.
Fire outside the muzzle is not "powder still burning". Unburned but flammable gases produced during the burning of the powder cannot burn within the barrel because gunpowder burns in an oxygen-deficient manner. There isn't enough oxygen to burn all the fuel created. When that fuel mixes with atmospheric air, it can re-ignite. If it does, you have muzzle flash. I can provide a link to a scientific study of this if you are interested. Hey Rock, [:p][:p] I am intrigued, send me the link, better yet post it so all can see. I am thinking of loading a casefull of 4831 short cut behind a LEAD bullet, magnum small rifle primer (get a lotta fire!) in a Dan Wesson .357 magnum with a 2 1/2" barrel to test your theory. The barrel is worn out, so no loss. If all the powder burns within the case, the bullet should exit the barrel. I bet you a Chrispy Chreme jelly filled donut that the bullet either sticks in the barrel or plops to the ground in a few yards. Warning, don't try this with a case full of Bullseye[xx(][:0]. Almost forgot, if all the powder is consumed inside the case, what causes all those little holes in a paper target if you hold the gun close to the paper? How come there are fewer POWDER BURNS the longer the barrel[?][?][?] Enlighten us, Eddie