This is because they use about 0.43 g (6.64 gr) of Vectan Ba10 (read more on how I found this out on this page), which fills the case at only 38%. Even if you do plinking and don’t shoot for precision, this will make you completely miss your target as it translates into a bullet drop of several centimeters. 30-30 Win ammo in France), I measured differences of up to 100 m/s (328 fps) between bullets. 30-30 Win cartridges (from the french brand Sologne which, by the way, is the only one making subsonic. I tried my best to avoid this in my load development, but in this case it can’t be completely avoided and the rather low powder charge (56%) will be the factor limiting accuracy. Accuracy will greatly suffer from this, with the bullet sometimes dropping of several centimeters (up to 10-20 cm/4-8 in) even on short distances (50 m/55 yards). Inconsistent ignitions and erratic pressuresīecause the case fill is low, the powder will never be at the same place in the cartridge and will never burn the same: this will cause pressures and velocities to be very inconsistent from one bullet to another. This could lead to a bullet stuck in the barrel, which is not great. The powder could ignite so bad that the pressure is too low. Let’s imagine now the powder is stacked towards the bullet, far away from the primer and the flash hole. This one is the opposite of the first one. high volume, because p = m/V) and high burning rate. The good combination would be a powder with low density (i.e. However, with faster burning powders, we can go lower, down to 40-30% of case fill. Generally, we do not want to go below 60% of case fill. Thus, we have to be careful when decreasing the volume (volume is different from mass) of powder in a cartridge. If you do this test with 70%+ case fills, you will likely find that there is a big over-pressure, but since in this situation there is no chance of the powder burning all at once (because the case fill is high enough), it’s non-sense. Of course, this test is only useful when the case fill is low and there is an actual risk of the powder burning all at once. This way, the program will make all the powder burn before the bullet moves at all, simulating that all the powder burnt at once. This “full ignition” can be simulated in QuickLOAD by increasing the bullet weight to a very high mass (e.g. If the pressure spike is high enough, it could damage the gun or even cause severe injuries to the user. This is a problem because the primer will ignite much more powder at once than it should (or even all the powder at once), leading to a pressure spike. If we decrease enough the volume of powder into the cartridge, then when we chamber the cartridge (so the cartridge is horizontal) and the powder lays at the bottom of the cartridge, the level of the powder might be below the flash hole and the surface of powder exposed to ignition might be much bigger than normal. There are three main concerns why this is not desirable. However, we can’t simply decrease the amount of powder we put into the cartridge. There will always be some fluctuation between bullets, but we’d like to be in the range of 300 m/s (985 fps) to 320 m/s (1050 fps). Like explained above, our goal is to have a bullet which doesn’t exceed 320 m/s (1050 fps). It is more than twice the velocity of subsonic cartridges (usually around 320 m/s, or 1050 fps). 30-30 Win cartridges you will be able to find and buy will be supersonic, between 650 m/s (2133 fps) and 850 m/s (2789 fps). I’ll explain here how I developed my subsonic. A barrel obstructed with a stuck bullet or anything else can cause severe damage to the firearm and injuries to the user and people around. ALWAYS CHECK YOUR BARREL IS CLEAR OF ANY BULLET/OBSTRUCTION BEFORE FIRING. Subsonic bullets and light loads can cause the bullet to get stuck in the barrel. I do not assume any liability for any damage or injury resulting from the use of this information. DISCLAIMER: The following content includes loading data not covered by currently published sources of tested data for the.