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Discussion Starter · #1 ·
I was shooting on a range the other evening and noticed the loads I was testing had a lot of flash that I was seeing through the scope at the rifle report. One load I tested had none.(IMR4198)
Should the powder burn completely before the bullet exits the barrel as the IMR 4198 did or be burning after the bullet exit. It would seem to me the burning powder flash would indicate that the bullet and pressure behind it are inefficient with a 1 foot flash.
Help me folks. please

The barrel is 22inches. 30-30

RV
 

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RV -

A non-trivial topic you bring up...

First: there are (at least) two types of muzzle flash - the one one nominally sees and that is when the powder is really too slow for the application and one is in fact seeing well ignited but still burning powder grains being ejected behind the bullet. In this case, there is really no harm other than lighting up anything left on the shooting bench or any dry grass nearby... and reducing the efficiency of the charge by half or so... but these loads work and have been used for years. The other standard flash is more degenerative and is the case, typically in a high expansion ratio situation and with hard to light powders, where one doesn't fully light the charge and what one is seeing is smoldering grains being ejected. In this case one is getting very little efficiency from the charge (and typically occurs when one is using a light bullet which offers very little resistance, and hence little confinement and hence poor ignition).

The above comments pertain to conductively ignited loads. In the case of convective ignition, where the charge has finished burning before the bullet has traveled move than an inch or so (~50-80 usecs), one can sometimes see what looks like a muzzle flash, but in fact is a precipitate flash, ie, the muzzle pressure is so low, and as such the gases have cooled sufficiently that one is seeing precipitates forming out of the gas and being ejected. One can see this with dirty but fast burning powders (eg, RedDot).

Quite often one will see a burning flash when one is trying to load down a cartridge by going to slower powders than nominally would be used. If this is the goal, then all things being equal, the flash is simply telling one that they have achieved what they were looking for, ie, bleeding off a significant pressure so as not to accelerate the bullet and give one the intented reduced load. Unfortunately this tends to also lead to unburned grains in the action, and a well grunged barrel. [We went down this path in the mid-90's when we were trying to produce reliable light 4570 loads... and is also what led us to develop/explore the notion of convective ignition (where one uses light charges of fast powders, which burn very cleanly, use all the available energy in the generated gases, but still gives the desired reduced mv).]

Back to your case: 4198 unless used with very light bullets, tends to be a "fast" powder for a 3030 and as such will have time to completely burn before the bullet exits and hence one will not see a flash; conversely if one were to use something like 4350, which is really too slow for the 3030, one would almost always see a burning flash. Reloading for a particular application is really a delicate balance btwn using a faster powder which will have time to completely burn, but may generate too much gas too quickly and force one for pressure reasons to reduce the load and hence reduce the mv... and using a slower powder which will generate the gases more slowly, hence keep Pmax down, but may not have time to finish burning before the bullet has exited the barrel.

hope that helps, and do shoot straight,
greg
www.gmdr.com
 

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GM has pretty well covered it, but I'd like to add, even some medium fast burning powders can give a large muzzle flash. One example; I used to load H-335 in my Remington 660 in .308 Win. This rifle has a 20" barrel. With the max load for the rifle, you could get a ball of fire about four feet across that looked like a photographer's flash going off. This ball was visible an high noon on a mid summers day. Said ball of fire was witnessed by several people. Without hearing protection, the muzzle blast was exremely viscious. When I move to Arizona, I shot up a few of the left over rounds at the range. The ball of fire was even more noticable there, probably because the range has covered benches. No, it wasn't an overload according to all the books I've seen for the time period. When we made the move to Arizona, all my loading data was lost along with some equipment.
My point is, some powders will create a bright flash, regardless of the burning rate.
Paul B.
 

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GM has pretty well covered it, but I'd like to add, even some medium fast burning powders can give a large muzzle flash. One example; I used to load H-335 in my Remington 660 in .308 Win. This rifle has a 20" barrel. With the max load for the rifle, you could get a ball of fire about four feet across that looked like a photographer's flash going off. This ball was visible an high noon on a mid summers day. Said ball of fire was witnessed by several people. Without hearing protection, the muzzle blast was exremely viscious. When I move to Arizona, I shot up a few of the left over rounds at the range. The ball of fire was even more noticable there, probably because the range has covered benches. No, it wasn't an overload according to all the books I've seen for the time period. When we made the move to Arizona, all my loading data was lost along with some equipment.
My point is, some powders will create a bright flash, regardless of the burning rate.
Paul B.
 
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